13 ECOLOGICAL IMPACT ASSESSMENT
13.1.1 Background
This chapter evaluates the ecological conditions present within the assessment area. This assessment is based upon a review of available literature and on surveys conducted in the area to fill information gaps. From this evaluation of ecological conditions, potential ecological impacts arising from the development of the NENT NDAs are identified, the significance of these impacts is assessed and mitigation measures are proposed, where appropriate, to avoid, minimise and/or compensate for the significant ecological impacts identified.
The ecological assessment has been conducted in accordance with the requirements of Annexes 8 and 16 of the TM-EIAO as well as the requirements set out in Section 3.1.14 of the EIA Study Brief (SB).
13.1.2 Local Legislation, Standards and Guidelines
The relevant legislation and associated guidelines applicable to the present study for the assessment of ecological impact include:
Forests and Countryside Ordinance (Cap. 96) and its subsidiary legislation, the Forestry Regulations;
Wild Animals Protection Ordinance (Cap. 170);
Environmental Impact Assessment Ordinance (Cap. 499) and relevant annexes 8, 11, 16, 20 and 21 of the associated Technical Memorandum;
EIA Study Brief No. ESB-176/2008;
Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) and its subsidiary legislation;Hong Kong Planning Standards and Guidelines (HKPSG) Chapter 10, "Conservation";
Planning, Environment and Lands Bureau Technical Circular 1/97 / Works Branch Technical Circular 4/97,"Guidelines for Implementing the Policy on Off-site Ecological Mitigation Measures";
EIAO Guidance Note No. 6/2002 - Some Observations on Ecological Assessment from the Environmental Impact Assessment Ordinance Perspective;
EIAO Guidance Note No. 7/2002 – Ecological Baseline Survey for Ecological Assessment;
EIAO Guidance Note No. 10/2004 – Methodologies for Terrestrial and Freshwater Ecological Baseline Survey
Revised versions of EIAO Guidance Notes 6/2010, 7/2010 and 10/2010 (issued December 2010)
13.1.3 Study Area and Assessment Area
Two NDAs have been identified: at Kwu Tung North (KTN NDA) and Fanling North (FLN NDA) (see Figure 1.1). These NDAs will proceed concurrently as one integrated project; accordingly they have been considered together for the purposes of this assessment. For consistency, where geographical location is of relevance, findings from KTN have been presented first. The ‘Study Area’ for this Ecological Impact Assessment (EcolIA) covers the two NDAs together with all areas within 500m of the boundaries of the NDAs, and all areas within 500m of infrastructure projects (connecting roads and other services) to be implemented as part of development (Figure 13.1). The ‘Assessment Area’ comprises the Study Area and any areas beyond which may be impacted by the project in accordance with Section 3.4.14.2 of the Study Brief.
13.1.4 Previous Stages of the EIA Process
Potential ecological impacts of the project have previously been assessed in the Stage 1 and Stage 2 Ecological Impact Assessments, prepared during 2009 and 2010, the Stage 3 Ecological Impact Assessment prepared during 2012 (see Section 1.1). The preparation of and findings from these assessments and feedback from public engagement (see Section 2.3.2) have been used to identify and refine potential ecological impacts and mitigation requirements. In particular, during the land use planning and design process assessed in these previous stages of the study alternatives were considered to address potential significant ecological impacts. These included the following:
13.1.4.1 Alternatives to safeguard the conservation value of Long Valley and river channels including Sheung Yue River and tidal section of Ng Tung River
The recognised site of conservation importance at Long Valley (part of the Long Valley and Ho Sheung Heung Priority Site for Enhanced Conservation) is within KTN. Alternatives that would ensure that the ecological value of this site would not be adversely impacted by the NDA project and would be safeguarded in the long term were considered. Alternatives included retaining the existing zoning as Agriculture, rezoning as Conservation Area, rezoning as Other Uses (Nature Park) and excluding some or all of the area from the NDAs. The selected alternative, rezoning the part of Long Valley to the east of the Sheung Yue River as Other Uses (Nature Park) and retaining the agricultural zoning of the section to the west was selected as this would (with further in situ mitigation measures) reduce potential ecological impacts to Long Valley from the Project to an acceptable level and secure the long term conservation value of the area whilst taking into account the interests of stakeholders of land in the surrounding area.
Only low-density and low-rise developments are proposed to avoid direct encroachment upon the flight-line between Ho Sheung Heung Egretry and Sheung Yue River. Further, different height bands are designated within the “OU(C,R&D)” zone along Sheung Yue River to establish a stepped building height profile increasing from the riverside of Sheung Yue River towards Fanling Highway and the NDA Town Centre. In particular, developments fronting the riverside are subject to a maximum building height of 7 storeys while those at the rear are subject to a maximum building height of 10 storeys.
A footbridge crossing the Sheung Yue River is proposed in order to connect the railway station and the existing resident near Yin Kong Village via the open space network in KTN. The location is governed by a number of factors (e.g. the open space arrangement, the existing access ramp to the river, most direct route), including reducing disturbance and fragmentation impacts on waterbirds foraging in the Sheung Yue River.
A second footbridge crossing the Sheung Yue River adjacent to the tidal section of the Ng Tung River is proposed to connect the footpath, cycle track and utilities network between KTN and FLN. The location has been selected based on the location of the existing Sheung Shui Slaughter House and the need to reduce disturbance and fragmentation impacts on fauna in Long Valley and waterbirds foraging in the Sheung Yue River.
See Section 2.3.2, Section 2.3.6.2,Section 2.3.6.3, Section 2.4.1.9 and Section 2.4.1.10).
13.1.4.2 Proposed Kwu Tung Interchange
A new grade-separated interchange, the Kwu Tung Interchange, is proposed as the major access from Fanling Highway to the KTN NDA. Along the Fanling Highway section to the south of the NDA there are many constraints to a new interchange or highway improvement works; both from existing residential buildings at Europa Garden and the need for the new interchange to be located at a minimum distance of 1km from other major interchanges at Pak Shek Au and San in the west. However, placing the interchange to the east of the Sheung Yue River, would have significant ecological impacts on Long Valley.
Having considered the constraints, it is proposed to locate the major interchange at about 400m east of the Sheung Yue River, thus avoiding Long Valley (see Section 2.4.1.2).
13.1.4.3 Alternatives to avoid potential impacts of the Fanling Bypass on sites of ecological significance
It was originally proposed that the Fanling Bypass would be an aboveground link commencing in the west of KTN NDA, running parallel to the west side of the Sheung Yue River, crossing the Ng Tung River then continuing through the north of FLN NDA, connecting in an interchange with Sha Tau Kok Road and joining the Fanling Highway near Wo Hop Shek. Potential significant ecological impacts from this alignment to habitats and species of conservation significance in Long Valley were identified; in particular to wetland habitats of conservation value, waterbirds, flight-lines between Ho Sheung Heung Egretry and foraging areas in Long Valley, and linkages for waterbirds to the Deep Bay area. Potential significant ecological impacts from the bypass being constructed at grade were identified throughout its length.
The alignment route was highly constrained by topography, river channels, existing urban development and infrastructure. Options for placing the bypass on viaduct and constructing submerged or tunnelled sections (the latter by using either, cut and cover, or bored methods) were considered. For the section of the bypass to the west of Man Kam To Road, none of these options was both technically feasible and able to reduce predicted ecological impacts to an acceptable level, so the alternative of adopting an alternative road network for KTN and FLN such that the section of the bypass to the west of Man Kam To Road was no longer required was chosen. Meanwhile, the alternative of placing the eastern section of the bypass on viaduct was adopted as this is predicted to reduce (along with additional in situ mitigation measures in certain locations) the potential ecological impacts along this section to an acceptable level (see Section 2.4.1.4 and Section 2.4.1.5).
13.1.4.4 Alternatives to avoid, minimise or compensate for potential impacts to Man Kam To Egretry
During the course of ecological surveys conducted under this study a previously unknown egretry was discovered close to the Man Kam To Road and within the footprint of the roundabout interchange proposed to form the western terminus of the Fanling Bypass (as described above); Figure 13.1 illustrates the location of the egretry. Alternatives to avoid or minimise impacts to the egretry by adjusting the location of the roundabout were considered but all these were constrained by existing infrastructure and the Ng Tung River to the south (Section 2.4.1.4). Accordingly compensation by provision of an alternative egretry location was adopted as the only feasible mitigation measure. Alternatives for the alternative location were considered, and a suitable site was identified to the west of the existing egretry, with a similar location close to the Ng Tung River and closer to major egret foraging areas in Long Valley than the existing egretry site (see Section 13.8.2.7).
13.1.4.5 Alternatives to avoid and minimise impacts to stream and marsh habitats at Ma Tso Lung
The Ma Tso Lung Stream and its riparian habitats were identified as being an ecologically significant area during the course of this and the Lok Ma Chau Loop studies. An essential road link from KTN to the Loop is proposed under both studies and planning and land use constraints limit alignment options for this road (Section 2.4.1.8). Alternatives to avoid all significant impacts to ecologically significant stream and its riparian habitats were considered and evaluated.
The option of constructing the LMC Loop Eastern Connection Road on viaduct for a length of 130m where the alignment would be within 30m of Ma Tso Lung Stream was considered from an ecological perspective. This option has the benefit that direct impacts on the stream would be avoided. However, engineering constraints would require the height of the viaduct to be less than 2m above ground for the section within 30m of the stream. The shading effect of the viaduct, only 2m above the ground, would have the consequence that it would be impossible for vegetation to grow for much of the width of the viaduct. This would result in direct loss of the existing riparian habitat. Whilst this direct habitat loss could be mitigated, the indirect ecological impacts would have to be considered, as the unvegetated area of such a length would form a significant barrier for fauna using the riparian corridor along the banks of the river. In addition, the unvegetated area would be liable to surface run-off and sediment would be washed into the stream causing adverse impacts to stream fauna. Surface run-off could be avoided by surfacing the area but this would increase the barrier effect of the unvegetated area.
Accordingly, options for diverting the stream were considered and it was resolved to divert the stream for 130m, which would allow for a minimum 15m buffer area to the west of the stream and a 15m to 30m buffer to the east of the stream following diversion. The diverted stream will be restored with natural bed, the riparian corridor will be restored with floodplain flora and riparian tree and shrub species and a permanent barrier will be installed on the east side of the road to prevent terrestrial fauna from straying onto the road and being killed. It is considered that this option will have lower ecological impacts than a narrower buffer and a shorter diverted section, or a wider buffer and a longer diverted section. Figure 13.6b illustrates the alignment chosen.
All feasible alignment options for the road require that it cross the stream at some point; in order to minimise impacts on the stream at the crossing point, a location was chosen where the road will be perpendicular to the watercourse. In addition, the design option as using a viaduct to cross the stream was adopted as this will avoid impacts on the stream and minimise impacts on the corridor (Figure 13.6b).
The location of a new sewage pumping station (a DP-2 project) was changed from the east to the west side of the LMC Loop Eastern Connection Road; thus avoiding direct and indirect impacts on the stream.
13.1.4.6 Alternatives to avoid and minimise loss of, or disturbance to, ecologically significant habitats and species through successive RODP drafts
Throughout the NDAs Study process, and in particular during the course of successive RODP drafts, alternatives to avoid and minimise potential ecological impacts were considered. At an early stage in the process, ‘no-go’ areas for development which might result in significant adverse ecological impacts were identified including, in addition to previously recognised sites of ecological importance which were confirmed as such in this study (notably Long Valley and the Ho Sheung Heung fung shui wood), the Ng Tung River corridor north of the confluence with the Sheung Yue River and most hill areas). Alternatives were then considered, wherever feasible, during the RODP refinement process that would avoid or minimise any other habitats of ecological significance or sites used by species of ecological significance where feasible to the maximum practicable extent. Habitats where alternatives to avoid and/or minimise significant habitat loss were considered and adopted where feasible included most secondary woodland, most plantation of higher ecological value, especially larger blocks, and all wetland habitats except small, previously channelised streams in urban areas.
13.1.4.7 Alternatives for compensatory habitat provision
Despite making efforts to avoid or minimise predicted impacts to habitats of conservation significance, loss of some such habitats (wetland and woodland) proved unavoidable, either as a consequence of direct habitat loss, increased predicted disturbance impacts or habitat fragmentation. Alternatives for compensating for such unavoidable loss that were considered included compensation as close to the original site as was feasible, compensation elsewhere in the NDAs and compensation outside the NDAs, both in and beyond the NDA Study Area. For all but the first of these alternatives, consideration was also given as to whether areas chosen for compensation should be aggregated or constructed and maintained as separate areas. It was decided that in-situ compensation was appropriate and feasible. Consolidating compensation areas at a location elsewhere in the NDAs was chosen as the most practical alternative for implementation and the alternative most likely to meet the mitigation requirements. A wetland compensation area was identified in Long Valley and sites for woodland compensation were identified in grassland habitat of low ecological value in KTN.
Under the EIAO, it is recommended that mitigation measures should seek to avoid, minimise and compensate impacts (in that order of preference). Based on the findings of the draft ecological impact assessments, therefore, the RODP for the NDAs has been revised in order to avoid or minimise identified impacts. The environmental acceptability of the proposed NDA development would, therefore, be assessed under the subject submission based on the latest RODP.
This section provides an overview of the ecological resources in the Study and Assessment Areas in accordance with the requirements of Sections 3.4.14.2 and 3.4.14.3 of the Study Brief. It also details the recognised sites of conservation importance in the Project Area and its vicinity in accordance with Section 13.4.4(vi) of the Study Brief and identifies concurrent and approved projects under consideration that may be of relevance to the assessment process for the current Project.
13.2.1 Location of the NDAs
The NDAs are located in the northern New Territories and are situated to the west (KTN) and the north (FLN) of the existing towns of Sheung Shui and Fanling. The southern boundary of KTN is defined by the Fanling Highway while the northern and western boundary of KTN and the northern boundary of FLN are delineated by hills. These hills separate the NDAs from the lowlands on the south side of Inner Deep Bay and the Shenzhen River catchment. The hills to the north of the NDAs are bisected by the Ng Tung River, which connects the NDAs hydrologically to the Shenzhen River catchment and also provides a corridor linking the NDAs ecologically with Inner Deep Bay, this linkage being most significant for more vagile fauna, especially waterbirds.
13.2.2 Recognised Sites of Conservation Importance in the NDAs and in their vicinity
Recognised sites of conservation importance in Long Valley and in its vicinity are described below and are shown in Figure 13.1.
13.2.2.1 Long Valley and Ho Sheung Heung Priority Site
An area at Long Valley and Ho Sheung Heung was identified by the Environment, Transport and Works Bureau (ETWB) and AFCD as one of the twelve Priority Sites for enhanced conservation under the New Nature Conservation Policy (NNCP). The principal intention of the Priority Sites is to enhance the ecological value of land under private ownership. Measures are proposed in the NNCP to encourage this, including Management Agreements (MAs) and Private-Public Partnership. In the Long Valley and Ho Sheung Heung Priority Site, the Hong Kong Bird Watching Society (HKBWS) and Conservancy Association (CA) in association with local farmers and landowners, are currently involved in a joint MA to manage parts of Long Valley using agricultural practices which enhance the habitat value for wildlife, in particular wetland birds. The application for the 4th phase of the MA at Long Valley was endorsed by the Environment & Conservation Fund Committee (ECFC) on 19th January 2012 and commenced in March 2012 and will be completed in February 2015. Similar MA schemes were completed in 2007, 2010 and 2012. Findings of these studies are referred to in this Report where appropriate.
All of the Priority Site is within the KTN NDA, and hence potentially affected by the Project, either directly or indirectly. As the Priority Site includes both areas of high ecological value and developed areas of much lower ecological value, it is not considered appropriate to treat the Priority Site as a whole as a sensitive receiver in the evaluation of ecological impacts. Accordingly, impacts on areas within the Priority Site, in particular Long Valley, Ho Sheung Heung fung shui and secondary woodland, and the main river channels, are addressed separately in this report.
13.2.2.2 Inner Deep Bay and Shenzhen River Catchment Important Bird Area (including Deep Bay Wetland outside Ramsar Site Priority Site)
Long Valley is contained within the Inner Deep Bay and Shenzhen River Catchment Important Bird Area (IBA), recognised by BirdLife International. The IBA listing is based largely on the international importance of Deep Bay for birds, including globally threatened species, but Long Valley is included as part of the Shenzhen River catchment on the basis of the large diversity of birds present, including globally threatened species (BirdLife International 2013). This designation of the area as an IBA does not confer legal protection on Long Valley.
The part of the IBA within KTN NDA will potentially be affected by the Project, either directly or indirectly; the remainder of the IBA and the Deep Bay Wetland outside Ramsar Site Priority Site may be indirectly affected as a consequence of its ecological and hydrological linkages with the Project Area. Effects are, however, likely to be small or negligible on much of the IBA due to its remoteness from the Project Area.
13.2.2.3 Deep Bay Wetland Area (including Mai Po Nature Reserve, Mai Po Inner Deep Bay Ramsar Site, Mai Po Marshes SSSI and Inner Deep Bay SSSI)
Although Deep Bay itself is located outside the boundary of the NDA Study Area, rivers passing through the NDAs drain into the Shenzhen River, which feeds into Deep Bay. Deep Bay is recognised as an internationally important wetland area, supporting a large abundance and diversity of wetland species including a number of threatened species. The core part of the Deep Bay wetland ecosystem is recognised internationally under the Ramsar Convention as the Mai Po Inner Deep Bay Ramsar Site. Mai Po Nature Reserve is located within the Deep Bay system, alongside Shenzhen River.
The Deep Bay Wetland Area may be indirectly affected as a consequence of its ecological and hydrological linkages with the Project Area. Effects are, however, likely to be small or negligible on much of the area due to its remoteness from the Project Area.
13.2.2.4 Wetland Conservation and Wetland Buffer Areas
The high ecological value of fish ponds in the Deep Bay area was highlighted in the Study on the Ecological Value of Fish Ponds in the Deep Bay area (Aspinwall 1997), one of the recommendations of which was that an area of fishponds and other wetlands in the northwest New Territories be designated as a buffer area. As a consequence, the Wetland Conservation Area (WCA) and a Wetland Buffer Area (WBA) of approximately 500m width were established around the areas described in Section 13.2.2.3 above. These recommendations were incorporated into Town Planning Board Guidelines (TPB PG-No. 12B). The purposes of these two zones are summarised as follows:
Wetland Conservation Area: Aside from the permitted essential infrastructure works or development required to support the conservation of ecological value of the area, no development detrimental to wetland habitats should be permitted within the WCA. Any essential works carried out in the WCA must comply with the ‘no net loss of wetland’ policy and should impose no disturbance impact. Any loss of wetland area or function will require compensatory habitat creation/enhancement.
Wetland Buffer Area: Although certain development is allowed in the WBA, ecological impact assessments should be conducted for any proposal to demonstrate that the development will not result in loss of ecological function of the WCA, i.e. the development would not disturb avifauna and other wildlife utilising fish ponds in the WCA. Certain uses are exempted from the requirement for an ecological impact assessment.
No part of the NDAs fall within the WCA, but a small area of the NDA Study Area is within the WBA (Figure 13.1). There are not expected to be any affects on this area as a consequence of the Project.
13.2.2.5 Ho Sheung Heung and Man Kam To Road Egretries
Ho Sheung Heung Egretry is located a short distance to the north of KTN NDA (within the FCA). The egretry and some of the nearby wetland habitat (used by foraging egrets) is zoned as a Conservation Area (CA) under the Ma Tso Lung and Hoo Hok Wai DPA Plan which was adopted in March 2012 (Plan No. DPA/NE-MTL/2). Ho Sheung Heung Egretry is utilised by Chinese Pond Herons, Eastern Cattle Egrets and Little Egrets. In 2007, this was the largest egretry present in Hong Kong, with a total of 119 nests, however it has declined in importance since then, primarily because of a decline in the number of nesting Chinese Pond Herons. In 2012 it only held 49 nests and was seventh in size of the 21 occupied egretries in Hong Kong in that year.
Another egretry was identified in 2009 in the Study Area during the course of fieldwork for this EIA. This is located at Man Kam To Road (within the FLN NDA). This site supports a lower abundance of ardeids than are present at Ho Sheung Heung with a total of 27 nests of Chinese Pond Herons and Little Egrets found in 2012. It is possible these comprise birds that previously bred at the Ho Sheung Heung Egretry.
Birds breeding in egretries move to nearby wetlands in order to forage for food for both themselves and their chicks. This often leads to well-defined flight-lines between the egretry and important foraging locations. Impacts on these flight-lines could occur through the presence of built structures or construction equipment. Such obstacles may include buildings, roads or railways along the route taken by birds, especially if these are similar in height to the birds’ flight path. The presence of obstacles along the flight-line potentially impacts breeding success at the egretry, either by preventing foraging at favoured locations, or by increasing the energy demands on the birds as they fly for a longer distance in order to avoid an obstacle along the favoured flight path. In an extreme case this could lead to abandonment of the egretry, but it may also mean that insufficient food is brought to chicks in the nest, resulting in decreased chick survival and thus decreased productivity at the egretry. It is important therefore to know about not only the location of the egretry but also flight-lines between the egretry and foraging locations.
Ho Sheung Heung Egretry will not be directly affected by the Project, but there may be indirect affects as some flight-lines from the egretry and some foraging areas of egrets breeding at the egretry are within areas which will be affected. Man Kam To Road Egretry will be unavoidably and directly affected by the Fanling Bypass (see Section 13.1.4.3).
13.2.2.6 Fung shui
wood
Ho Sheung Heung fung shui wood is located to the west of Ho Sheung Heung village. It covers an area of 4.57ha. The woodland was damaged by fire in 2006, which divided it into two halves, but planting of the damaged area and natural regeneration, has partially restored linkages between the two parts of the wood. The wood is entirely within the KTN NDA. While it will not be directly impacted by the Project, it is located close to development areas, hence is potentially affected.
Two other, smaller, fung shui woods are present in the Study Area. That at Tsung Pak Long (0.66ha) in KTN NDA is in an area proposed to be zoned as Green Belt and will not be affected by the Project; that at Kam Tsin is outside the Project Area and will also not be affected.
13.2.2.7 Compensatory Planting Areas and Retained Meanders established under
the ‘Main Drainage
Channels for Sheung Shui, Fanling and Hinterland’ Project
Compensatory planting areas (referred to as Mitigation Plantation in this report) and retained meanders (referred to as Mitigation Wetland) were established as mitigation for the ecological impacts of the above Project along the Ng Tung, Sheung Yue and (mitigation plantation only) Shek Sheung Rivers. All but one of these areas is located within the Project Area and will unavoidably be affected by the Project, either directly or indirectly.
13.2.2.8 Ecologically Important Streams
An Ecologically Important Stream (EIS) system identified by AFCD is located in the Study Area at Kau Lung Hang. The sections of stream identified as ecologically important include Kau Lung Hang Lo Wai, Kau Lung Hang Sang Wai and the Tai Wo Streams to the east and upstream of the MTR East Rail Line and the local access roads, together with a section of the Ma Wat River south of Nam Wa Po. Thus, all ecologically important stream sections are outside, and upstream of, the Project Area boundary and hence will not be affected by the Project. The EIS supports a large population of a rare freshwater fish species Acrossocheilus parallens.
13.2.2.9 Sites of Special Scientific Interest, Special Areas and Country Parks
There are no gazetted sites of conservation importance (Sites of Special Scientific Interest, Special Areas or Country Parks) within or close to the Study Area and hence none of these will be affected.
Mai Po Marshes SSSI and Inner Deep Bay SSSI are wetland sites located downstream from the NDAs and are potentially impacted by development within the NDAs (see Section 13.2.2.3).
13.2.2.10 Frontier Closed Area
The NDAs are located close to the part of Hong Kong which was designated as the Frontier Closed Area (FCA) in 1962. Part of this area is within the NDA Study Area and may be affected by the Project, and a small area, at Ma Tso Lung, is within the Project Area and will be directly affected.
Though not formally recognised as a site of conservation importance, in the past the FCA has had very little disturbance as a result of limitations on human access into the area and, as a consequence, is considered to be potentially important for wildlife. The restrictions on access by people are in the process of being lifted, commencing in February 2012 and scheduled to extend to all but 400ha by 2015; as yet the lifting of restrictions has had only limited effects. The locations of the NDAs mean that these are subject to rather more disturbance than the FCA, although less developed areas at the north of KTN NDA may provide suitable conditions for some of the scarcer species occurring in the FCA.
The following areas in or close to the Study Area were also identified as supporting fauna of ecological significance:
· Hoo Hok Wai (not directly affected by the Project, but potentially affected due to ecological and hydrological linkages, albeit it is rather remote from the Project Area);
· hilly area between Chau Tau and Ma Tso Lung villages (not directly affected but the southeastern fringes may be indirectly affected);
· re-instated fish ponds between Ng Tung River and Ho Sheung Heung Egretry (potentially indirectly affected);
· Ng Tung, Sheung Yue and Shek Sheung Rivers (within the Project Area and potentially affected significantly);
· an area of active and inactive agricultural land, and inactive fish ponds to the southwest of Sandy Ridge, bounded to the west by the Ng Tung River and to the south by Man Kam To Road, where an Eurasian Otter has been recorded (outside the Project Area and not predicted to be affected significantly); and
· hilly areas in the southeast of FLN NDA, south of Wo Hop Shek and above Kau Lung Hang (no affects predicted as they are rather remote from and upstream/uphill of the Project Area).
13.2.3 Development Projects in the Area
Other large-scale projects, which are concurrent, are proposed or are under investigation in the Assessment Area could have a bearing on the ecological impacts arising from development of the NDAs. In particular, these developments, combined with the development of the NDAs, could lead to significant cumulative impacts. The following proposed developments are relevant to the NDAs. Further details relating to these developments, and the implications of these on the NDAs, are provided throughout the text as appropriate.
13.2.3.1 Proposed Boundary Crossing Point at Liantang/Heung Yuen Wai
It is proposed that a new Boundary Crossing Point (BCP) should be constructed at Heung Yuen Wai to connect with Liantang on the Shenzhen side of the border. Part of the development of this BCP would involve the construction of a highway connecting to the existing road network. The connection would be made close to the interchange between the Fanling Bypass proposed under the NDA study and the existing Fanling Highway. An EIA for the BCP (Mott MacDonald 2010) and connecting road was approved with conditions in March 2011 (Register No.: AEIAR-161/2011).
13.2.3.2 Changes to the Boundary of the Frontier Closed Area (FCA)
The existing FCA boundary is located to the north of the proposed NDAs. Restrictions on human access into the FCA limit the levels of disturbance to habitats in within the FCA as well as limiting development pressure on these habitats. The lack of disturbance and development is considered to provide conditions suitable for wildlife which are less common in the rest of the New Territories. As noted in Section 13.2.2.8, commencing in February 2012, the FCA is largely to be opened up to human access and development, with all but 400ha of the FCA to be freed from access restrictions by approximately 2015. The potential impacts of opening up the FCA were considered and evaluated in the Land Use Planning for the Closed Area Feasibility Study (Arup 2010). Of particular relevance in relation to the current Project is the future of the Hoo Hok Wai area, as this is probably a foraging area for ardeids breeding at Ho Sheung Heung Egretry.
13.2.3.3 Proposed Development of Lok Ma Chau Loop (LMC Loop)
The LMC Loop comprises an undeveloped area of land on the boundary of Hong Kong and Shenzhen which was isolated during channels of Shenzhen River. It is proposed to develop this area for educational uses. An EIA is currently underway for this proposed development (EIAO Study Brief Application Nos.: ESB-201/2008 and ESB-238-2011). It is proposed that one access route to the LMC Loop development would pass through KTN NDA, and that the NDA could also provide facilities to support the LMC Loop development.
13.2.3.4 Construction of Cycle Tracks and the Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River and at Nam Sang Wai, Yuen Long
Construction of a cycle track from Sha Po Tseun to the Shek Sheung River is proposed. Within the NDA study area it will run through KTN, passing along the northern side of the Fanling Highway, the western (Ho Sheung Heung) side of the Sheung Yue River and the western (Long Valley) side of the Shek Sheung River. An EIA (Atkins China. 2008) for this project was approved without conditions on 12 Mar 2009 (Register No.: AEIAR-133/2009).
In addition, a Study Brief (ESB-179/2008) has been issued for a cycle track proposed to be constructed at Nam Sang Wai, Yuen Long. This location is a distance from the current project’s Study Area but may be of relevance in the assessment of potential cumulative impacts on the Deep Bay Wetland ecosystem.
13.2.3.5 Provision of Cremators at Wo Hop Shek Crematorium
An EIA (Hyder 2008) has been approved for this project (AEIAR-119/2008), which is located in the southeast of the Study Area to the south of Fanling, outside the Project Area boundary. Construction of this project is currently in progress and it is scheduled to be completed by around 2014 (Allied Environmental Consultants Ltd. 2012). Construction is not, therefore, expected to be concurrent with the NDAs Project.
13.2.3.6 Site Formation and Associated Infrastructural Works for Development of Columbarium, Crematorium and Related Facilities at Sandy Ridge Cemetery
An application for a Study Brief (ESB 257-2013) for this project was issued in March 2013. The proposed project area is located to the east of the Lo Wu Boundary Crossing Point and hence is over 1km from the closest point within the NDAs and is separated from the NDA Study Area by Sandy Ridge and Lo Wu MTR Station. Road works associated with the project are proposed in a small part of the existing developed area of Sheung Shui.
13.2.3.7 Development of Organic Waste Treatment Facilities, Phase 2
A Study Brief (ESB 226/2011) has been issued under the EIAO for an organic waste treatment facility at Sha Ling, to the east of Kong Nga Po. This facility is planned to recover reusable materials which are currently disposed of in landfill sites. It would be constructed on the site of an existing livestock waste composting plant which it would replace. The site straddles the 500m line from the nearest point in the NDAs (Cheung Po Tau in FLN). Given that the site is an existing livestock waste control centre, habitat loss impacts are likely to be minimal, if any.
13.2.3.8
Proposed Residential Development
East of Ping Kong, Sheung Shui
A Study Brief (ESB No: 230/2011) has been issued under the EIAO for a proposed residential development to the east of Ping Kong. The proposed scheme would involve construction of about 184 three-storey houses on an area of 20.9ha. At the closest point, this development is approximately 1,300m from KTN NDA and 1,600m from FLN NDA and is separated from the NDAs by the existing towns of Fanling and Sheung Shui.
13.2.3.9 Proposed Residential Developments in and around the Deep Bay Wetland Area
A number of residential developments are under construction or proposed in and around the Deep Bay Wetland Area. While these are remote from the Study Area for the current Project, they are potentially of relevance in the assessment of cumulative impacts to the Deep Bay Wetland ecosystem.
An EIA Report has been approved for a Comprehensive Residential Development at Wo Shang Wai, Yuen Long (AEIAR-120/2008) and this project is under construction. An EIA Report has been approved for a Development at Fung Lok Wai, Yuen Long at Lot 1457 R.P. in D.D. 123, but construction has not yet commenced.
In addition, EIA Study Briefs have been issued for the following projects: Proposed Comprehensive Development and Wetland Protection near Yau Mei San Tsuen (ESB-182/2008); Proposed Residential Development within ‘Residential (Group D)’ Zone at Various Lots in D.D. 104, Yuen Long (ESB-2004/2009), Proposed Residential Development within ‘Recreation’ (‘REC’) Zone at Various Lots in D.D. 104, Yuen Long (ESB-207/2009) and Proposed Low-rise and Low-density Residential Development at Various Lots and their Adjoining Government Land in D.D. 104, East of Kam Pok Road, Mai Po, Yuen Long (ESB-210/2009); Proposed Comprehensive Development with Wetland Enhancement (CDWE) at Nam Sang Wai and Lut Chau (ESB-234/2011 and ESB-244/2011): Proposed Comprehensive Development at Lin Barn Tsuen, Yuen Long (ESB-239/2011) and Proposed Alternative Comprehensive Development at Lin Barn Tsuen, Yuen Long (ESB-254/2012); and Proposed Comprehensive Development at Wing Kei Tsuen, Yuen Long (ESB-240/2011).
This Section details studies/surveys that have been reviewed and from which relevant findings have been utilised in accordance with the requirements of Section 3.4.14.4(i) of the Study Brief (in order to determine areas that required further survey). In this Section the most significant observations from these previous studies are summarised. How the significance of observations has been assessed in the current study is described in Section 13.4.3.8. Where appropriate, findings are also included and discussed in Section 13.5 (Ecological Profile of the Study Area) and Section 13.6 (Description and Ecological Evaluation of Habitats and Species). Details are also included in the relevant Appendices.
13.3.1 Previous Environmental Impact Assessment for the NDAs
Both NDAs were previously surveyed for an Environmental Impact Assessment (Maunsell 2003). Fieldwork for the ecological impact assessment was conducted during 1999 and included surveys of vegetation, avifauna, invertebrates (butterflies and dragonflies), freshwater fish, mammals and herpetofauna.
The report identified the importance of Long Valley as a site of High Ecological Value with a relatively large area of freshwater wetland with limited fragmentation, low levels of human disturbance and proximity to the Deep Bay wetlands. During the surveys Long Valley was found to have high ecological value for fauna but the floral diversity was limited by vegetation control as part of the normal agricultural practices.
This report also identified the Mitigation Meanders as being of High Ecological Value. This evaluation was a prediction as it is stated in Maunsell (2003) that channelisation works were in progress at that time. Fish ponds to the north of the Ng Tung River were also shown as being of High Ecological Value in Figure 8.4q of Maunsell (2003), but this appears to be contradicted in the habitat evaluation in Maunsell (2003) where the ecological value of fish ponds in Fanling North was stated to be Moderate to High.
13.3.2 Management Agreements (MAs) at Long Valley
As noted in Section 13.2.2.1, commencing in 2005 and continuing to the present, MAs under the NNCP have been implemented whereby the conservation value of the Priority Site has been enhanced by non-governmental organisations (the CA and HKBWS). Surveys conducted as an element of these MAs have included surveys of birds, amphibians, reptiles and mammals using the Long Valley and Ho Sheung Heung areas (HWBWS 2012, HKBWS in litt., Hung & Pang 2008, Wan 2010) .
Bird surveys as an element of these MAs have been conducted regularly at Long Valley since December 2005 by the HKBWS[1]. Many of the species recorded during the HKBWS surveys (spanning more than six years of weekly surveys, with the addition of observations from other birdwatchers) are irregular in occurrence at Long Valley, but the high number of species recorded reflects the importance of this site for birds.
Camera trapping of mammals was carried out in Long Valley and at Ho Sheung Heung fung shui wood between February 2009 and February 2010. This study completed a total of 2,852 hours of camera trapping at these sites. During this period, single pictures were obtained of a Eurasian Wild Pig Sus scrofa and a Small Indian Civet Viverricula indica, both at Ho Sheung Heung fung shui woodland. Domestic cats and dogs were more frequently photographed, but these may be associated with the nearby village houses. This represents a very low observation rate for mammals; the occurrence index (photographs per 100 camera trapping days) for these two species in areas of Hong Kong surveyed by Shek (2006) is 9.8 for Small Indian Civet and 9.2 for Eurasian Wild Pig.
13.3.3 AFCD Biodiversity Survey
AFCD maintains a Biodiversity Database for the long-term monitoring of biodiversity in Hong Kong. Data collected by AFCD between 2002 and June 2012 reports the presence of five species of mammal, 112 species of bird, 15 species of reptile, 11 species of amphibian, seven species of fish, 34 odonate species and 57 species of butterfly in the KTN NDA. In the FLN NDA, AFCD surveys reported the presence of one mammal species, 57 species of bird, ten species of reptile, ten species of amphibian, 16 species of fish, 35 odonate species and 42 species of butterfly. It should be noted, however, that the AFCD’s territory-wide biodiversity survey does not necessarily cover or represent the existing ecological conditions of the NDA Study Area.
Camera trapping to survey for mammals has previously been conducted by AFCD in the Fanling area, close to the interchange for the proposed Fanling Bypass. Species recorded include East Asian Porcupine, Small-toothed Ferret Badger, Red Muntjac, Masked Palm Civet, Leopard Cat, Eurasian Wild Pig and Small Indian Civet (AFCD in litt, Shek et al. (2007).
13.3.4 Hong Kong Biodiversity Survey
The University of Hong Kong published the results of a biodiversity study of Hong Kong in 2001 (Dudgeon & Corlett 2001). Although the sites and species recorded do not provide complete coverage of the area, data are included from within the Study Area for KTN NDA. No species were identified in surveys conducted under this study in the NDA Study Area which were not also reported in other studies or surveys in the same areas. However a bat which was suspected to be a Pomona Leaf-nosed Bat was observed, this species has not been reported in the Study Area by other studies.
13.3.5 EIA for Liantang/Heung Yuen Wai Boundary Control Point
The EIA report for Liantang/Heung Yuen Wai BCP was approved in March 2011. This report covers not only the site of the BCP but also the proposed connecting road. The interchange of this connecting road with the Fanling Highway is located close to the proposed interchange of the Fanling Bypass (Figures 13.1 to 13.3). The most significant observations made in this study in the current Study Area were those of Indian Forest Skink and Copperhead Racer, and Eastern Lilysquatter, The first two of these species were observed in the area to the east of Tong Hang Tung Chuen and Indian Forest Skink was also found east of Wo Hop Shek. Eastern Lilysquatter was reported from near Kau Lung Hang. These three species are not otherwise known in the Study Area. Other species of conservation significance reported by this study, all in these two areas, were also reported under other studies.
13.3.6 Feasibility Study for FCA
Following the announcement by the Security Bureau in 2006 that the FCA would be reduced to 400ha by 2015, the Planning Department commissioned the Land Use Planning Feasibility Study to formulate a planning framework to guide the conservation and development of the Study Area (the FCA at that time), based on the principle of sustainable development. The study included a Strategic Environmental Assessment, the findings and recommendations from which served as inputs to various stages of the Study. This study was completed in 2010; fieldwork for the study was undertaken in 2008.
As is shown in Figures 13.1 to 13.3, the Study Area for the FCA Study included the northern part of KTN NDA. Surveys conducted under this study found relatively few species of conservation significance in the NDA Study Area. However, the only observation of Eurasian Otter in the Study Area (to the east of the Ng Tung River to the north of Fu Tei Au) came from this Study.
13.3.7 EIA for LMC Loop Development
The Planning and Engineering Study on the Development of the Lok Ma Chau Loop (LMC) includes as its Study Area the LMC Loop, the LMC Meander, Hoo Hok Wai (HHW) and two areas designated for infrastructural connections, one of which runs through the Ma Tso Lung area to link up with the KTN NDA. Ecological surveys for the Study were conducted from June 2009 to May 2010. During these surveys the high ecological value of the fish ponds and associated wetlands at HHW for large waterbirds was confirmed, as was the importance of the flight-line corridor connecting this area with wetlands elsewhere in the Deep Bay area. The Study also confirmed the importance of HHW, the LMC Meander and the LMC Loop for Eurasian Otter, while the crab Somanniathelpusa zanklon were recorded in Ping Hang Stream, and Rose Bitterling was recorded in a stream near LMC Road.
In respect to the NDA Study Area, the stream network in the Ma Tso Lung area was considered to be of moderate to high ecological value due to the presence of Three-banded Box Terrapin (listed as Critically Endangered by IUCN (2013) and found during surveys conducted under the current study) and diverse stream fauna. The marsh at Ma Tso Lung was considered to be of low to moderate ecological value due to its potential for enhancement and connectivity with nearby wetland. The ecological value of the seasonally wet grassland adjacent to the marsh was considered to be low to moderate; numbers and diversity of fauna were low, though small numbers of Chinese Bullfrog were noted. Of other habitats in the Ma Tso Lung Area, secondary woodland, plantation and shrubland were all considered to be of low to moderate ecological value, as was upland grassland between Lok Ma Chau Tsuen and Ma Tso Lung Tsuen. In addition to the fauna species discussed above, other species meeting the conservation concern criteria of Fellowes et al. (2002) included Small Snakehead, Somanniathelpusa zanklon and Ruby Darter, recorded in lower-lying areas, and Chinese Cobra, Common Rat Snake, Small Three-ring, Spotted Angle, Danaid Egg-fly and Red Muntjac recorded on the slopes of the valley. Spotted Angle is not otherwise known from the Study Area, while the observation of Red Muntjac is the only confirmation that this species still occurs in the Study Area. This species was considered to be formerly present in the Long Valley area by Hung and Pang (2008).
13.3.8 EIA for Lok Ma Chau Spur Line
The Sheung Shui to Lok Ma Chau Spur Line passes through the KTN NDA. The original proposal was for this railway to be situated on a viaduct through the Long Valley area, but the final alignment was revised so that the railway is actually located in a bored tunnel underneath KTN and Long Valley. As part of the EIA (BBV 2002), baseline surveys were conducted along the alignment corridor during 2000-2001; surveys conducted at Long Valley are relevant to the NDA study.
This study noted the importance of wetland habitats in Long Valley, especially for bird species of conservation importance, 29 species of which were recorded in Long Valley in surveys reported under this study. The occurrence of Eurasian Eagle Owl, not otherwise known from the study area was reported, however it is not clear if the observations relate to areas within the NDA Study Area. The most significant findings of other fauna reported under this study were of Reeve’s Terrapin from Long Valley; and the relatively high abundance and diversity of the herpetofauna in Long Valley. The importance of Long Valley for butterflies was also noted, but data were largely derived from surveys undertaken by Bascombe, as reported in Maunsell (2003)
13.3.9 EIA for Cycle Tracks between Sha Po Tsuen and Shek Sheung River
An EIA for the construction of cycle tracks and associated supporting facilities for the section between Sha Po Tsuen and Shek Sheung River was approved in 2009. This includes a section at Long Valley in the KTN NDA. Surveys conducted for the EIA included surveys of the drainage channels around Long Valley (Sheung Yue and Shek Sheung Rivers). These surveys recorded the presence of waterbirds in the Sheung Yue River channel; 14 species were noted, of which ten were considered to be of conservation significance. Of these species, Grey Heron and Little Egret were reported in the largest numbers on a regular basis, though a single flock of 44 Pied Avocets was noted on one occasion.
Also of considerable relevance to the current study are: the habitat evaluations of the river channels and adjacent habitats, especially Long Valley and plantation, including mitigation plantation; predicted ecological impacts on these habitats and species utilising them; and the mitigation measures proposed. Long Valley wetland habitats were evaluated as of high ecological importance under this study, the river channels were considered to be of moderate ecological importance, but the plantation along the river channels (including mitigation plantation) was considered to be of low ecological importance. Impacts of the cycle track project on all of these habitats were predicted to be of low significance and, with mitigation it was considered that there would be no significant overall loss of valuable ecological habitat. With mitigation, residual impacts of the project on surrounding habitats and species were considered to be minor. This mitigation included the proposal to carry out works near Long Valley during the dry season (between October and March) to avoid the breeding season of Greater Painted-snipe and to prevent any potential disturbance to breeding and nesting birds.
13.3.10 Egretry Counts in Hong Kong
The number of active nests in each of the Hong Kong egretries is counted annually by the HKBWS as part of the Mai Po Inner Deep Bay Waterbird Monitoring Programme under AFCD’s contract. This includes counts at the two egretries present in the Study Area (Ho Sheung Heung and Man Kam To Road). Results of the monitoring from recent years are included in Tables 13.1 and 13.2.
Table 13.1 - Number of egret nests
recorded at Ho Sheung Heung Egretry
2007 – 2012 (from Anon 2007,
2008a, 2009, 2011, 2012a, 2012b)
|
Species |
2007 |
2008 |
2009 |
2010 |
2011 |
2012 |
Mean |
|
Great Egret |
- |
1 |
- |
- |
- |
- |
0.2 |
|
Little Egret |
31 |
25 |
34 |
42 |
36 |
33 |
33.5 |
|
Eastern Cattle Egret |
17 |
18 |
14 |
25 |
12 |
12 |
16.3 |
|
Chinese Pond Heron |
71 |
29 |
23 |
19 |
2 |
4 |
24.7 |
|
Total |
119 |
73 |
71 |
86 |
50 |
49 |
74.7 |
Table 13.2 - Number of egret nests recorded at Man Kam To Road Egretry 2009 - 2012 (from Anon
2009, 2011, 2012a, 2012b)
|
Species |
2009 |
2010 |
2011 |
2012 |
Mean |
|
Little Egret |
- |
2 |
3 |
6 |
2.8 |
|
Chinese Pond Heron |
15 |
22 |
20 |
21 |
19.5 |
|
Total |
15 |
24 |
23 |
27* |
22.3 |
*Peak number of nests
reported; only five nests remained in July following clearance of bamboos
containing part of the colony (HKBWS 2012b).
13.3.11 Drainage Improvement Works
Ecological impacts of the channelisation of the Ng Tung, Shek Sheung and Sheung Yue Rivers were assessed under the EIA Study for the Main Drainage Channels for Fanling, Sheung Shui, Fanling and Hinterland. The importance of Long Valley for wetland birds was acknowledged, resulting in the retention of meanders as mitigation for ecological impacts (Maunsell 1997). The implementation of this project resulted in significant changes to the Study Area, both as a consequence of the channels of the major rivers, and the implementation of mitigation measures to compensate for impacts to wetland and woodland habitats. Partly due to the time that has elapsed and partly due to the changes instigated by these works, some data collected in the Study are of limited relevance to the context of the current study.
However, Maunsell (1997) detailed findings of an unpublished study of the butterfly fauna of the Ho Sheung Heung area undertaken by Bascombe. These findings have been quoted by several subsequent studies, notably BBV (2002) and Maunsell (2003).
13.3.12 Drainage Improvement in the Northern New Territories – Package B, KTN 01 at Tsung Yuen, Kwu Tung North, Sheung Shui
This report (submitted in 2012) assesses a proposed underground reception drain along Ho Sheung Heung Road and the upgrading of an artificial irrigation channel adjacent to Tsung Yuen Village. Long Valley fell within the 500m Study Area for the study. Wet and dry season field surveys were undertaken between November 2011 and May 2012. Species recorded were typical of the habitats in the area, though the largely dry season survey period meant that data were not representative of species more abundant in the wet season, including amphibians, dragonflies and butterflies. No species additional to those recorded in the current or other studies were observed. Residual impacts of the project with mitigation were considered to be mitigated to an acceptable level.
13.3.13 Provision of Cremators at Wo Hop Shek Crematorium
Four months of ecological surveys were conducted across the wet season in order to assess the impacts of the provision of additional cremators at the existing Wo Hop Shek Crematorium. Habitats, flora and major faunal groups were surveyed between March and June 2006 in the Study Area for the Project. Low numbers of species were recorded during the faunal surveys, all typical of the habitats present. The most significant finding was Short-legged Toad Xenophrys brachykolos recorded in semi-natural woodland. The exact location of this sighting is not certain but was either just inside or just outside the Study Area for the current project, to the southeast of the crematorium. Woodlands on the slopes of hills within the Study Area were classified as being of Moderate or Moderate to High ecological value. Other remaining habitats were generally Low or Low to Moderate ecological value (Hyder 2008). This project is currently still underway but is scheduled to be completed prior to the commencent of the current project.
13.4.1 Background
Ecological surveys of the Study Area were conducted in accordance with the requirements of the EIAO-TM and the Study Brief, with particular regard paid to the requirements of Section 3.4.14.4 of the latter. Section 3.4.14.4(i) notes that the assessment should review the findings of relevant studies and surveys, including the NENT Study, completed in 2003, for which 12 months of ecological surveys had been undertaken in 1998/99 covering a full year’s seasonal variation. All available information from the NENT Study and other relevant studies and surveys regarding the ecological character of the Study Area was collated and reviewed. This review took into account that the survey work for the NENT Study was carried out before the establishment of the EIAO Study Brief mechanism.
In Section 3.4.14.4(ii) it is stated that the assessment should evaluate the information collected from Section 3.4.14.4(i) and identify any information gap relating to the assessment of potential ecological impacts and determine whether ecological surveys are required to bridge any identified information gap for the purpose of establishing a comprehensive and updated ecological profile. This process was carried out via both field survey (to determine whether there had been any significant change in habitats) and desktop review.
Thus, in Section 3.4.14.4(iii) it is stated that field surveys necessary to bridge any identified information gap, the duration of which should be at least nine months covering both wet and dry seasons, should be undertaken.
In order to meet these requirements, the following survey methodology was followed.
Firstly, aerial photographs were utilised to identify the continuous and contiguous urban area of Sheung Shui and Fanling. Subsequently, an initial field survey of all habitats except for the continuous and contiguous urban area of Sheung Shui and Fanling, the delineation of which did not need to be ground-truthed, was carried out to identify and delineate the following:
· Dryland terrestrial habitats, including forest, shrubland and grassland, that had previously been identified as ecologically important habitats and/or as supporting species of conservation significance;
· All areas identified as wetland habitats in the NENT Study and/or which appeared to be wetland from examination of aerial photographs, such habitats are particularly likely to experience change in a relatively short period and are known to be particularly important in Hong Kong for fauna of conservation significance;
· All areas where previous or current ecological mitigation or conservation measures were in place;
· Long Valley, including the area north of the Sheung Yue River and south and east of Ho Sheung Heung;
· Areas not falling into at least one of the above categories; i.e. dryland habitats that had not previously been identified as being of ecological importance.
Routes for systematic surveys were then determined. Potential ecological impacts on golf course habitat, located to the south of the Fanling Highway, were not envisaged to be significances, even if evaluated on a precautionary basis; and it was considered that habitat mapping of the golf course area could be undertaken in a satisfactory manner using aerial photographs. Accordingly, this habitat was excluded from survey routes.
Survey routes, covering all other habitats in the Study Area, were then devised to ensure that the requirements of the EIAO-TM and the Study Brief (in particular Section 3.4.14.4(ii)) were met. Particular attention was paid to wetland habitats (e.g. Long Valley, marsh, watercourses, mitigation wetlands, pond), which generally support a relatively high number of species of conservation significance. Sampling points for surveys of aquatic stream fauna were selected based on an initial field survey of all watercourses to determine those that might potentially be of conservation significance.
Non-wetland habitats likely to be of conservation significance were also surveyed, including Ho Sheung Heung fung shui woodland and other areas of secondary woodland and mitigation plantation, as well as shrubland, grassland/shrubland and grassland at Crest Hill. Dryland habitats west of Sheung Yue River and south of Ng Tung River, as well as in river valleys were also surveyed. Riparian corridors, an important habitat for wetland-dependent and wetland-associated fauna were surveyed where accessible.
In addition, all development areas and their environs were included in surveys and methodologies for flora and fauna. The latter included, in particular, grassland and dry agriculture between Fanling and the Ng Tung River, which were included in floral surveys and faunal survey routes.
The main survey period for the assessment covered the 12 months between July 2008 and June 2009; survey periods for some fauna groups were shorter than this, in accordance with the recommended survey seasons detailed in EIAO Guidance Note No. 7/2010.
Given the long duration of the NDA study and the evolving process of RODP preparation, further surveys to cover any residual information gaps were conducted, as required, until the end of April 2013. These additional surveys have been used to verify and update the ecological baseline information and confirm that this information remains valid, as well as to collect additional ecological baseline information of the Study Area.
In addition, data collected as part of other studies and published during the course of this Study were also incorporated. These included the following:
· The final report of the Land Use Planning for the Closed Area – Feasibility Study (Arup 2010) which contained the results of surveys in adjacent areas, including an area of abandoned ponds and wet agriculture north of Fu Tei Au near Sha Ling, to the east of Ho Sheung Heung Egretry;
· The EIA Report for Construction of Cycle Tracks and the Associated Supporting Facilities Sha Po Tsuen to Shek Sheung River (Atkins China. 2008) which contained data from surveys of waterbirds in Sheung Yue River;
· The Final Report for Provision of Cremators at Wo Hop Shek Crematorium (Hyder 2008) which contained data from surveys of areas near the cemetery, in the southeast of the Study Area;
· The Environmental Impact Assesment Report for Liantang/Heung Yuen Wai Boundary Control Point (Mott MacDonald 2010) which also provided data from the southeast part of the Study Area.
· The Final Report for Review, Design and Tender Documentation for Drainage Improvement Works at Tsung Yuen, Kwu Tung North. Environmental Review for KTN01 Document No. 296472/005/C (Mott MacDonald 2012) which included data from the northern part of Long Valley;
· Monitoring data in relation to birds, herpetofauna and mammals which had been collected since 2005 under the Management Agreements at Long Valley (see Section 13.3.2), Publications such as Hung & Pang (2008) and Wan (2010) summarised and analysed some of the data collected, while data are also made available at intervals on the website of the Hong Kong Bird Watching Society[2];
Finally, the Ma Tso Lung area was surveyed for the ongoing LMC Loop Study during the period between June 2009 and May 2000, and findings in relation to the wetland and grassland habitats (in particular) of that area were used to inform assessments in relation to that northern part of the KTN NDA. Survey methods utilised in that study followed those documented in the EIAO Guidance Note No. 10/ 2004. Of relevance to the current Study Area were surveys conducted for mammals, birds, herpetofauna, butterflies, dragonflies and stream fauna. Surveys for birds were conducted monthly for twelve months; except for aquatic fauna which was surveyed once in the wet season and once in the dry season, surveys for other fauna were conducted monthly during the active periods for these groups (as detailed in the EIAO Guidance Note No. 10/ 2004). Details of survey methodologies and periods for habitat, botanical and faunal surveys carried out for the current study are provided in Section 13.4.2 below.
13.4.2 Habitat and Botanical Survey Methodologies
Initial maps of habitats within the Study Area were prepared from HKSAR Government aerial photographs taken in 2007 and 2008. The maps were then ground-truthed in order to ensure these reflected current conditions and to distinguish between habitats (in particular wet and dry agriculture, dry lowland grassland and seasonally wet grassland, and secondary woodland, plantation and orchard) which could not always be reliably distinguished on aerial photographs. Ground-truthing in the field was undertaken during September 2008 and May 2009 (the latter period primarily in order to identify seasonally wet habitats).
Additional surveys were conducted during April to July 2012 and in April 2013 in order to confirm the habitats present and to update the habitat maps (where required) in areas of lowland agricultural land, grassland and wetland which are subject to relatively rapid habitat change due to human influences and natural processes.
Botanical surveys of habitats identified during the mapping process were carried out during September to October 2008 and May 2009; with further surveys in July 2012 and April 2013. These characterised the vegetation conditions present in each habitat, including the typical species of plant present.
13.4.3 General Approach to Faunal Survey Periods and Methodologies
The EIA
Study Brief specified that duration of field surveys should be at least nine
months; it was decided to extend this to 12 months from July 2008 to June 2009
in order to fully cover seasonal differences in species and numbers of the most
vagile group (birds), to maximise chances of encountering low density and
cryptic species and to cover the active periods of all seasonally active groups
within the same continuous period. Survey periods for faunal groups are
detailed in Table 13.3.
Given the long duration of the NDA study and the evolving process of RODP preparation, further surveys to verify validity of information collected in 2008-2009, to collect additional information and cover any residual information gaps for all faunal groups were conducted, as required, until the end of April 2013. These additional surveys have been used to update the ecological baseline information and confirm that this information remains valid.
Table 13.3 – Survey period for floral and faunal surveys; July 2008 to June 2009 (except where indicated)
|
Month |
J |
A |
S |
O |
N |
D |
J |
F |
M |
A |
M |
J |
|
Habitat mapping |
|
|
x |
|
|
x |
||||||
|
Botanical survey |
x |
x |
|
x |
||||||||
|
Mammals |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
|
Birds (day-time) |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
x |
|
Birds (night-time) |
x |
x |
x |
x |
x |
x |
||||||
|
Egretry flight-line surveys* |
x |
|
|
x |
x |
|||||||
|
Herpetofauna |
x |
x |
x |
x |
x |
x |
||||||
|
Fish and other stream fauna |
x |
x |
x |
x |
||||||||
|
Dragonflies |
x |
x |
x |
x |
x |
x |
||||||
|
Butterflies |
x |
x |
x |
x |
x |
x |
* Surveys at Ho Sheung Heung Egretry were conducted in May to July 2009;
surveys at Man Kam To Road Egretry were conducted
during June to July 2009 and May to July 2011.
13.4.3.1
Mammals
Since mammals in Hong Kong, including many those of conservation significance, are secretive and often nocturnal, surveys were conducted in parallel with bird and herpetofauna surveys (including some qualitative night-time surveys) in an effort to increase the body of baseline data on mammal diversity and numbers in the Study Area. In addition to direct observation, any observations of signs of mammal activity (such as tracks, scats or burrows) were actively sought. As a corollary, survey frequencies for terrestrial mammals followed those detailed below in respect of birds and herpetofauna.
Review of previous studies or surveys suggested that a number of bat species were present in the Study Area, as is typical of agricultural areas in Hong Kong, though no species of conservation concern were known to occur with certainty. Bat roosts were sought during day-time surveys of birds and herpetofauna.
Bat detector survey was undertaken during the night-time survey. The survey started shortly after sunset and covered habitats of potential importance to bats, especially wetlands and woodlands. During the survey, echolocation calls of foraging bats were recorded (using frequency division). The structure of the echolocation calls from these recordings was later analysed to identify species as far as possible (the lack of literature on echolocation call structure makes the field identification of some bat species in Hong Kong impossible, and some species remain unidentified from the recordings). The relative abundance of each species in the habitat was estimated from the field and from recordings using a scale from 1 (single individual recorded) to 5 (very abundant).
Those areas of the Study Area covered by mammal surveys and survey routes are shown in Figure 13.2.
13.4.3.2
Birds
Systematic bird surveys followed a line transect and started within one hour of dawn, to coincide with the period of maximum bird activity. All bird species found during the surveys were recorded, and numbers of any species of conservation importance (according to criteria listed in Section 13.4.3.8) and wetland-dependent species were counted. Species lists for each NDA were also supplemented by observations of birds during other faunal surveys.
Baseline bird surveys were conducted once per month during July 2008 to June 2009 and twice per month in Long Valley south and east of the Sheung Yue River during September 2008 to April 2009.Night-time bird surveys were conducted every two months during July 2008 to June 2009. These followed a similar methodology and transect to the daytime surveys, and started shortly after dusk.
The channelised Sheung Yue River to the west of Long Valley was also known to be important to foraging birds, especially egrets breeding at the Ho Sheung Heung Egretry and probably also the Man Kam To Road Egretry. In order to better understand the use of the channels by waterbirds in relation to tidal changes, surveys were conducted along the Sheung Yue River channel on twice per month during August 2008 to June 2009. During the surveys, a line transect was followed alongside the channel recording all wetland-dependent birds present within the channel. Due to the tidal nature of the channel, which influences the activity and abundance of birds present, surveys were conducted in the morning and afternoon on each survey date to cover varying stages of the tidal cycle. The Ng Tung and Shek Sheung Rivers were surveyed in the course of standard bird transects as field surveys showed that the numbers of most species using these rivers were much smaller and, in the case of the Ng Tung River, less influenced by the tidal cycle (as shown Figure 13.4).
Those parts of the Study Area covered by bird surveys and transect routes are shown in Figure 13.3, and bird survey areas and routes followed for survey transects along the Sheung Yue, Ng Tung and Shek Sheung Rivers are shown in Figure 13.4.
13.4.3.3 Egretry Flight-lines
Two egretries are known within the Study Area: Ho Sheung Heung Egretry and Man Kam To Road Egretry, the latter having been found during the course of bird surveys undertaken for this study. Surveys of flight-lines were conducted at both egretries. These surveys lasted for a period of two hours, starting in the early morning (between 06:00 and 06:30) to cover the peak period of activity for foraging egrets. During the surveys, any birds seen leaving the egretry were watched to record the direction of flight and, as far as possible, the distance flown. The flight height of birds leaving the egretry towards the KTN Project Area was also recorded to permit assessment of the potential impacts of building height on flight-lines.
Five flight-line surveys were conducted at the Ho Sheung Heung Egretry between May and July 2009. Birds were observed from two vantage points (Figure 13.3), permitting the observation of birds flying north towards Hoo Hok Wai and south towards Long Valley and east over the Ng Tung River towards FLN. At the Man Kam To Road Egretry two flight-line surveys were conducted during late June and early July 2009 and another three were conducted between May and July 2011. Surveys were conducted from the bridge where the Man Kam To Road crosses Ng Tung River (Figure 13.3).
13.4.3.4 Reptiles
The review of previous surveys and studies, in particular the NENT Study, suggested that the Study Area supported a relatively small number of reptile species, all of which were typical of lowland areas in Hong Kong and none of which were of conservation significance. Reviewed in this context, updating of the survey data in accordance with the Study Brief followed the standard survey protocol described in Section 13.4.1 above.
Reptile surveys were conducted once per month during July to September 2008 and March to June 2009. On each survey date, a transect survey was conducted on which all reptiles observed foraging or basking in the open were identified and counted. Many reptiles are cryptic or secretive, and active searching was carried out in appropriate microhabitats, such as underneath stones, logs or other objects lying on the ground. Any observations of reptiles during other faunal surveys were also included in order to provide a more thorough assessment of the reptile communities present in the area. Reptiles were also searched for during stream surveys (see Section 13.4.3.7)
Survey
routes and areas covered by reptile surveys are shown on Figure 13.2.
13.4.3.5 Amphibians
All amphibians are wetland-dependent during at least a part of their life cycle; unsurprisingly, the review of previous surveys and studies showed that the main areas of importance to amphibians in the Study Area were lowland wetland habitats or those close to wetlands. Reviewed in this context, updating of the survey data in accordance with the Study Brief following the standard survey protocol described in Section 13.4.1 above was considered appropriate, as this focused on such habitats.
Amphibian surveys were conducted once per month during July to September 2008 and March to June 2009. In addition, night-time surveys were conducted once per month during March to June 2009. These surveys of amphibians concentrated on recording the distinctive vocalisations of advertising males, for which the peak activity occurs in the early wet season, especially after dusk and during or after rain. During surveys transect routes were followed, but surveys deviated from these routes to ensure that habitats suitable for amphibians were visited and all amphibians seen or heard were identified and counted. In addition, amphibians were also searched for during stream surveys (see Section 13.4.3.7).
Survey
routes and areas covered by amphibian surveys are shown on Figure 13.2.
13.4.3.6 Butterflies/Dragonflies
The review of previous surveys and studies found that areas along the Sheung Yue River at Ho Sheung Heung and Tsung Pak Long had been identified as of importance for butterflies by Bascombe (1993). Many of these species were not found in surveys undertaken for the NENT Study, which took place after extensive habitat alterations arising from channelisation of the river. Accordingly, surveys in this area to confirm the findings of the NENT Study were considered appropriate in the present study.
With this exception, previous studies, including surveys for the NENT Study, had not found a high diversity or abundance of butterflies or dragonflies, nor had localities supporting species of conservation importance been found. Reviewed in this context, updating of the survey data in accordance with the Study Brief following the standard survey protocol described in Section 13.4.1 above was considered appropriate. This included a focus on habitats along the Sheung Yue River that (at least formerly) were of importance to butterflies, and wetlands (including streams) which are the habitats of primary importance to dragonflies; as well as the Ho Sheung Heung and Crest Hill area which had been identified as of importance to butterflies in the past, as noted above.
These two groups were surveyed simultaneously by means of a transect survey of the NDA and adjacent habitat. Particular attention was given to favoured habitats for the groups, including woodland/shrubland for butterflies and wetland habitats and streams for dragonflies. All adult butterflies and dragonflies seen during the surveys were recorded and counted. Surveys were conducted monthly during July to September 2008 and April to June 2009.
Survey routes and areas covered by butterfly and dragonfly surveys are shown on Figure 13.2.
13.4.3.7 Stream Fish and Invertebrates
Review of previous studies and surveys revealed limited information on fish and other stream fauna in the Study Area. Accordingly, fish and aquatic invertebrates were surveyed in all river channels and in both channelised and natural streams. As far as possible, streams were surveyed along their full length within the Study Area, though this proved impractical in some locations due to topographical and access constraints.
Fish and aquatic invertebrates were surveyed by direct observation and trapping using a hand net; whenever possible, these captured individuals were identified in situ and released immediately, although some invertebrates were preserved in 70% ethanol solution for later identification.
Survey locations where stream fish and invertebrate surveys were surveyed quantitatively are shown in Figure 13.2. Combined, quantitative surveys for these groups were conducted at least once during the survey period at these locations.
13.4.3.8 Species of Conservation Significance and Protected Species
Section
3.4.14.4(iv)(e) of the Study Brief requires that species that are rare,
endangered and/or listed under local legislation, international conventions for
conservation of wildlife/habitats or Red Data Books are given due consideration
in establishing an ecological profile of the assessment area.
In
this report, the following legislation, conventions and criteria in respect to
rare, endangered and protected species are considered to be of relevance and
hence have been given due consideration.
Species are considered to be of conservation significance based on criteria and lists provided by BirdLife International (2013), the IUCN Species Survival Commission (IUCN 2013), the China Red Data Book (CRDB) (Wang 1998) and Fellowes et al. (2002). Categorisations of relevance to this study are listed below:
International criteria
· Critically Endangered (CR);
· Endangered (EN);
· Vulnerable (VU);
· Near Threatened (NT);
· Data Deficient (DD);
· Least Concern (LC).
Listing under the first four of these categories is considered to be of relevance when assessing whether an observation of a species is of significance, subject to the other criteria discussed below. Listing as DD is noted in the report but is not considered of relevance to the assessment process for this study.
National (China) Criteria
· Endangered (EN);
· Vulnerable (V);
· Near Threatened (NT);
· Rare (R);
· Indeterminate (I).
Listing under the first four of these categories is considered to be of relevance in assessing whether an observation of a species is of significance, subject to the other criteria discussed below. However, for some species, the conservation status in China may differ from Hong Kong and thus not all species of conservation significance in China are of conservation significance in Hong Kong. Such species are discussed in Section 13.5. Listing as I is noted in the report but is not considered of relevance to the assessment process for this study.
Local (Hong Kong) Criteria
· Global Concern (GC);
· Regional Concern (RC);
· Local Concern (LC).
Listing by Fellowes et al. (2002) under any of these categories is considered to be of relevance in assessing whether an observation is of significance, subject to the other criteria discussed below. While Fellowes et al. (2002) was used as the baseline criterion for determination of species of local conservation significance, more recent sources, including Hong Kong Bird Reports, Chan et al. (2011) (for butterflies), Tam et al. (2011) for dragonflies and the AFCD Biodiversity Database were utilized in the evaluation of the significance of observations of species listed by Fellowes et al. (2001) in the light of current knowledge as to their status.
The conservation status of flora was not evaluated by Fellowes et al. (2002). In the absence of such evaluation, flora records are considered to be of relevance in assessing whether an observation of a species is of significance if they are included in international or national lists of species of conservation concern (as described above); and are protected under Hong Kong legislation; and were not considered by Xing et al. (2000), Wu and Lee (2000) and Baretto et al. (2011) to be common or very common; and were found in a wild state.
Reference to the conservation status under the criteria described above (except LC under international criteria) is made for all species in Appendices 13.1 to 13.9 of this report. However, an observation of a species is not necessarily of relevance to the ecological evaluation process and hence is not necessarily referred to in the habitat and impact evaluation process. Such observations include the following:
· Observations of species in habitats atypical of the habitats typically utilised by the species in the Study Area, for example wetland-dependent species in woodland habitats or dryland species in wetland habitats, as such habitats are not of significance to such species;
· Observations of species on an irregular or occasional basis in small numbers, especially if a species is vagile and/or opportunisti and utilises a number of common habitats;
· With respect to species listed as of conservation concern by Fellowes et al. (2002), due regard has been paid to as to whether an observation meets the restrictedness criteria as defined by these authors. Thus, species which are listed by Fellowes et al. as being of conservation concern on the basis of breeding or roosting sites have not been evaluated as of conservation significance in this report unless these observations refer to breeding or communal roosting sites;
· With respect to impact evaluation, observations of a species in a habitat or area where impacts on that species would be of minimal severity, and/or where the habitat is widespread in the Study Area, hence the effect on carrying capacity of the Study Area for that species would be low;
· Species for which the Hong Kong population is not considered to be of natural origin.
In respect to the foregoing, and elsewhere in this ecological assessment, species have been evaluated as typically utilising a habitat by combining findings from the literature review, findings from surveys conducted under the current study, and the professional experience of the study team.
Protection status of fauna and flora under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) and the Forestry Regulations (under Cap. 96) in Hong Kong and protection status in China are listed in Appendices 13.1 to 13.9 of this report; except in respect to birds and bats in Hong Kong as all species in these groups are protected. Protection status of species in China has not been used as an evaluation criterion in this report, for two reasons. Firstly, the Hong Kong SAR has a different legal system to China; hence Chinese law does not affect the protection status of fauna and flora in Hong Kong. Secondly, whilst the protection status of a species in Hong Kong is generally aligned with its local conservation status, the protection status of a species in China is intended to reflect the threats to that species and its status in China; this may often not correspond to the conservation status of a species in Hong Kong.
Protection status of species in Hong Kong is noted in Section 13.5 of this report. However, it is not considered relevant to the evaluation of habitats and impacts on habitats or species with two exceptions:
· In the absence of local conservation criteria for flora in Fellowes et al. (2002), protected plant species which were not considered to be common or very common by Xing et al. (2000), Wu and Lee (2000) and Baretto et al. (2011) are considered to be of significance in the evaluation of impacts on habitats, as described above;
· Death or damage to individuals of protected species is considered in the evaluation of potential mortality impacts on fauna and flora.
13.5.1 Introduction
The following section of the assessment provides an ecological profile of the Study Area based on results of field surveys undertaken under the current study and data from relevant previous and concurrent studies and surveys, together with a description of the ecological characteristics of all of the habitats present. Data and analysis follow the requirements of the EIAO-TM and Section 3.4.14.4(iv) of the Study Brief.
13.5.2 Description of the Physical Environment
The Study Area comprises slightly over 2000ha in the northern New Territories. Except for small areas in the extreme west and north, the entire area is within the catchment of the Ng Tung River and its tributaries. The Ng Tung River itself is a tributary of the Shenzhen River which drains westwards into Deep Bay. Much of the Study Area is a flat lowland floodplain at an elevation of less than 20m. This plain is bounded to the northwest by low hills rising to 183m at Tai Shek Mo near the northern edge of the Study Area and to the northeast by another range of hills which reach 164m at High Hill.
There are no topographical features defining the western and southern boundaries of the Study Area, but to the southeast and east it is defined by a range of higher and more rugged hills which reach 440m at Cloudy Hill (Kau Lung Hang Shan).
13.5.3 Overview of Habitats Present
Most habitats in the Study Area are typical of the northern New Territories. These lowlands support a complex mixture of habitats, including a variety of active agricultural uses, abandoned agricultural land, woodlands (including plantation and secondary woodland), village land and urban development (Figure 13.5). Being located on flat land in river valleys, some areas are seasonally or permanently wet. The area also contains a number of low hills, which support a less complex mix of grassland, shrubland, plantation and woodland habitats.
Wetland areas, especially those near Long Valley at the western end of the Study Area, are of particular ecological importance. These show ecological connection to the more extensive Deep Bay wetlands and attract many of the same species, especially birds. Long Valley itself contains one of the largest remaining areas of wet agriculture in Hong Kong and contains a mixture of wetland habitats supporting various species with a limited distribution in the territory.
Table 13.4 - Habitats within the NDA Study
Area and NDA Boundaries1,2
|
Habitat |
KTN NDA |
KTN Study Area |
FLN NDA |
FLN Study Area |
|
Dry Agriculture |
14.12 |
14.91 |
9.24 |
15.87 |
|
Wet Agriculture |
19.53 |
23.27 |
0.58 |
3.53 |
|
Fung
Shui Wood |
5.28 |
5.94 |
- |
- |
|
Golf Course |
- |
30.72 |
- |
- |
|
Grassland |
95.75 |
250.38 |
32.49 |
199.88 |
|
Grassland/ Shrubland |
2.88 |
6.50 |
0.45 |
41.50 |
|
Major Watercourse |
8.79 |
22.95 |
27.10 |
36.49 |
|
Marsh |
5.60 |
11.17 |
- |
- |
|
Minor Channelised Watercourse |
0.24 |
4.29 |
2.11 |
12.67 |
|
Minor Natural Watercourse |
0.29 |
0.29 |
- |
- |
|
Mitigation Wetland |
1.45 |
1.57 |
2.66 |
2.75 |
|
Mitigation Plantation |
7.95 |
10.58 |
8.92 |
13.19 |
|
Orchard |
2.65 |
8.23 |
6.83 |
11.36 |
|
Plantation |
91.12 |
169.21 |
26.09 |
235.15 |
|
Pond |
10.97 |
15.49 |
2.79 |
7.64 |
|
Seasonally Wet Grassland |
4.22 |
13.06 |
1.21 |
1.76 |
|
Secondary Woodland |
6.76 |
38.56 |
0.09 |
70.93 |
|
Shrubland |
11.95 |
57.83 |
- |
5.05 |
|
Urban/ Residential Area |
125.56 |
260.50 |
40.71 |
450.89 |
|
Village Area |
37.12 |
67.35 |
10.51 |
100.60 |
|
Waste Ground |
6.58 |
7.43 |
0.65 |
2.64 |
|
Total |
458.83 |
1020.23 |
172.43 |
1211.90 |
1Note that
Study Areas for KTN and FLN overlap; Ng Tung and Shek Sheung Rivers are treated
as the boundary between the KTN and FLN areas to avoid double-counting of
areas.
2 Note that in Table 13.4 habitats
which were evaluated collectively as ‘Long Valley’ are listed separately. The
area of each habitat within Long Valley is listed in Table
13.16.
13.5.4 Ecological Characteristics of the Study Area
Ecological characteristics of the study area are described below based on data from relevant previous studies and surveys and survey findings from the current study. In view of the large size of the Study Area, ecological characteristics of KTN and FLN are generally described separately. This is considered appropriate as, while there are important ecological linkages between the two NDAs, there are also significant physical and ecological differences, especially in lowland habitats. In particular, the undeveloped floodplain area in KTN is much broader than FLN, where it forms a relatively narrow corridor between the developed area of Sheung Shui and Fanling and the hills to the north. In addition, while linkages are provided by the Ng Tung River corridor for birds, the developed area of Sheung Shui largely severs linkages between the area north of Fanling and lowland habitats in KTN for terrestrial fauna.
Accordingly, in the following section, floral and faunal species (found during this and in previous relevant studies) and habitats are described and evaluated, first for KTN and then for FLN. The locations of records of flora and non-avian fauna of conservation significance (where known) are illustrated in Figure 13.6.
13.5.4.1 Flora
Botanical surveys were conducted, in order to verify, update and supplement findings of previous surveys and studies. During these surveys most habitats within the Study Area were found to be dominated by plant species that are common throughout Hong Kong. Full details of the vegetation present in each habitat are given in the habitat assessments (Section 13.6); the following is a summary of overall conditions.
A number of mature hillside plantations are present with canopies containing exotic tree species. These support a moderately diverse native understorey, but the herbaceous and woody plant species present are generally common or very common in Hong Kong. Plantation stands dominated by old, mature trees (such as Dimocarpus longan, Cinnamomum camphora, Celtis sinensis, Ficus virens var. sublanceolata and Ficus microcarpa) are common in villages and urban/residential areas. Secondary woodland, especially that at Ho Sheung Heung, and fung shui wood at Ho Sheung Heung supports a more diverse understorey and overstorey, with the mature overstorey dominated by Celtis sinensis, Cinnamomum camphora and Microcos paniculata.
Wet and dry agricultural land in Long Valley and adjoining villages is actively managed and planted with commercial crops (such as Brassica chinensis, Ipomoea aquatica, Lactuca sativa and Nasturtium officinale). Wet agricultural land also supports common wetland plant species along the vegetated bunds, but plant species diversity in the habitat is generally low.
The Study Area of the FLN NDA is bisected by the channelised Ng Tung River, with lowland grassland and mostly abandoned agricultural land along each side. Habitats within the Study Area are mostly anthropogenic, supporting common to very common plant species with limited conservation value. However, mature plantations and secondary woodland adjacent to villages north of the Ng Tung River and in the southeast of the Study Area support a richer diversity of understorey species, and these plantations and woodlands often show strong ecological linkages with the surrounding hillside grassland and shrubland habitats. A number of mature, old-growth trees (including Ficus microcarpa, Celtis sinensis and Cinnamomum camphora) were recorded within villages and a few mature tree individuals within the Study Area are registered Old and Valuable Trees (including Cinnamomum camphora, Eucalyptus citriodora, Ficus microcarpa and Melaleuca quinquenervia).
Flora species of conservation significance and/or protected flora species found in a wild state during the course of surveys conducted for this study included Aquilaria sinensis in four areas. All specimens were saplings, with two in the fung shui woodland and one in the secondary woodland at Ho Sheung Heung, one in secondary woodland at Ma Tso Lung, three in secondary woodland south of Pak Shek Au and two in plantation east of Wo Hop Shek. This species is listed as globally Near Threatened and Vulnerable in China, but is common in Hong Kong. In view of the status of this species in Hong Kong and the fact that all specimens found were saplings, a significant impact on this species from the project is not predicted.
The fern Cibotium barometz was found alongside the Ngam Pin watercourse. This species is also listed as Vulnerable in China but is very common in Hong Kong. Gnetum luofuense was recorded in fung shui woodland at Ho Sheung Heung and secondary woodland near Siu Hang Tsuen. Despite being considered globally Near Threatened it is very common in Hong Kong. Two orchid species, Pecteilis susannae and Spathoglottis pubescens were found in plantation near Cheung Po Tau Stream, Sha Ling. Both these species are protected in Hong Kong, Spathoglottis pubescens is abundant and widespread in Hong Kong and was evaluated as of Least Concern in Hong Kong by Baretto et al. (2011). However, Pecteilis susannae is infrequent and restricted and was evaluated as Endangered by Baretto et al (2011).
In addition, Ailanthus fordii, Aquilaria sinensis and Pavetta hongkongensis were recorded in fung shui woodland/secondary woodland at Ho Sheung Heung by Maunsell (2003) and Aquilaria sinensis was found east of Tong Hang Tung Chuen by Mott MacDonald (2010).
Specimens of Rhododendron simsii found in plantation areas are considered to be planted specimens, and are excluded from further assessment.
A list of all floral species recorded in both the KTN and FLN areas is provided in Appendix 13.1.2 and 13.1.3, as is a list of all protected species or those of conservation significance recorded in the Study Area during this and previous studies is provided in Appendix 13.1.1. The latter is summarised in Table 13.5, together with the areas and habitats in which they were found. Locations of flora of conservation significance and protected flora found during the course of the current and previous surveys and studies are shown in Figure 13.6.
Table
13.5 - Flora species of Conservation Significance, and Protected Species, recorded in an apparently wild
state in the Study Area during the Current and/or Previous Studies.
|
Species |
Conservation and Protection
Status |
Areas/ Habitats |
|
Ailanthus fordii |
Cap. 96A, Near Threatened2 |
Secondary woodland at Ho Sheung Heung |
|
Aquilaria sinensis |
Vulnerable1; Near Threatened2, Category II2; |
Secondary woodland and fung shui woodland at Ho Sheung Heung, Ma Tso Lung, south of Pak Shek Au, east of Tong Hang Tung Chuen and plantation east of Wo Hop Shek |
|
Cibotium barometz |
Vulnerable2, Category II2 |
Natural
watercourse at Ngam Pin |
|
Gnetum luofuense |
IUCN Near Threatened1 |
Fung Shui woodland at Ho
Sheung Heung, secondary woodland near Siu Hang Tsuen |
|
Pavetta hongkongensis |
Cap. 96A |
Fung Shui / Secondary
woodland at Ho Sheung Heung |
|
Pecteilis susannae |
Cap. 96A |
Plantation near Cheung Po Tau Stream, Sha Ling |
|
Spathoglottis pubescens |
Cap. 96A |
Plantation near
Cheung Po Tau Stream, Sha Ling |
Notes
1. IUCN. 2013
2. South China
Institute of Botany & Agriculture, Fisheries and Conservation Department
2003. Rare and Precious
Plants of Hong Kong. AFCD, Hong Kong.
13.5.4.2 Mammals
Terrestrial Mammals
Historic records suggest that mammal diversity in the KTN area may have been higher in the past, or perhaps simply reflect the incremental accumulation of reports of low density and/or cryptic species over time. Terrestrial mammal species reported by the NENT Study in KTN (Maunsell 2003) comprised Greater Bandicoot Rat, Leopard Cat, East Asian Porcupine and Small Asian Mongoose. The population of Small Asian Mongoose in Hong Kong is not considered to be of natural origin; hence observations of this species do not meet the criteria of conservation significance followed in this study.
Camera trapping surveys carried out at Long Valley and Ho Sheung Heung in 2009/10 (Wan 2010) recorded only single individuals of both Small Indian Civet and Eurasian Wild Pig and domestic dogs and cats during camera-trapping, as well as a sighting of Greater Bandicoot Rat. Further camera-trapping surveys undertaken since 2008 in Ho Sheung Heung fung shui woodland and listed in the AFCD Biodiversity database also recorded Small Indian Civet and Eurasian Wild Pig and, in addition, Masked Palm Civet and Leopard Cat.
Based on interviews with local farmers at Long Valley, Hung & Pang (2008) reported the past and continued presence of East Asian Porcupine, Small-toothed Ferret Badger, Leopard Cat and Masked Palm Civet, but only the historic presence of Red Muntjac. They also stated that Greater Bandicoot Rat, East Asian Porcupine and Masked Palm Civet are rare. Red Muntjac was, however, found in the Ma Tso Lung area in surveys conducted for the LMC Loop Study. Four species of small mammals (Musk Shrew, Roof Rat, Brown Rat and Ryukyu Mouse) were recorded from the Long Valley area in the Hong Kong biodiversity survey (Dudgeon & Corlett 2001). Of these, Ryukyu Mouse has a restricted distribution in Hong Kong, but all the other species are common and widespread (Shek 2006).
Very few terrestrial mammals were recorded during mammal surveys conducted under the present study in KTN: a single Small Asian Mongoose was observed at Long Valley and evidence of Eurasian Wild Pig activity was noted in shrubland at Crest Hill and at the edge of Ma Tso Lung marsh.
Maunsell (2003) recorded Leopard Cat in Fanling North, while Mott MacDonald (2010) recorded Leopard Cat and Eurasian Wild Pig in the Wo Hop Shek area. No terrestrial mammals are listed in the AFCD Biodiversity database for FLN. However, camera trapping surveys conducted by AFCD to the east of Kau Lung Hang recorded East Asian Porcupine, Small-toothed Ferret Badger, Red Muntjac, Masked Palm Civet, Leopard Cat, Eurasian Wild Pig and Small Indian Civet. Though these surveys appear to have been undertaken in the wooded hills beyond the Study Area limit, it seems likely that some of these species occur in the Study Area on occasion.
However, perhaps the most significant mammal observation in the FLN area is a sighting of Eurasian Otter in ponds to the east of the Ng Tung River, north of Fu Tei Au and south of Sha Ling, during surveys conducted under the FCA Study.
Evidence of two terrestrial mammal species was found during surveys in the FLN NDA Study Area: a Small Indian Civet scat was found in grassland/shrubland at Tong Hang. Small Indian Civet is a protected species in Hong Kong, but does not meet the criteria of a species of conservation significance followed in this study. In addition, a Grey Shrew, which is considered an uncommon species in Hong Kong (AFCD Biodiversity Database) was seen in a village area. No evidence (tracks, droppings etc.) was found in FLN to indicate the presence of larger mammal species.
Most terrestrial mammals in Hong Kong, especially larger species, require moderate to large areas of natural or semi-natural woodland habitats with limited human activity and an absence of physical barriers (notably major roads, river channels and settlements) to movements and dispersal. In general, more disturbed habitats can be tolerated only temporarily by mammals (e.g. at times of food shortage during the cool, dry season). Overall, therefore, given the limited cover of woodland habitats, their high degree of fragmentation, the high levels of human disturbance, and the presence of significant barriers to movement (notably highways and river channels) in the area, it is most unlikely that significant populations of larger terrestrial mammal species are present in either NDA.
Eurasian Otter is a possible exception to the habitat constraints amongst large mammal species recorded or suspected to occur in the area, in that it is a lowland wetland open country species with a Hong Kong distribution limited to the Deep Bay area for which waterways are the primary movement and dispersal corridors. However, with only a single record of this species in the Study Area, it is apparent that its occurrence is constrained by other factors, most likely high levels of human activity.
Eurasian Otter has regularly been reported from Hoo Hok Wai (e.g. Shek (2006)). These and other records from field and questionnaire surveys were summarised for the LMC Loop Study. In view of this, it is not surprising that this wide-ranging and low density species occurs in the Study Area on occasion, (e.g. the Sha Ling record). Eurasian Otter is globally listed as Vulnerable by IUCN and as of Regional Concern by Fellowes et al. (2002).
Bats
Maunsell (2003), Mott MacDonald (2012) and the AFCD Biodiversity database reported the presence of Short-nosed Fruit Bat in KTN. In addition, Dudgeon & Corlett (2001) reported the suspected occurrence of Pomona Leaf-nosed Bat, in Long Valley.
At least five bat species were recorded during surveys conducted under the present study. These included Short-nosed Fruit Bat, Brown Noctule, Japanese Pipistrelle and two insectivorous bat species that could not be certainly identified based on echolocation call structure in KTN (see Appendix 13.2). Japanese Pipistrelle was abundant in Long Valley and other nearby wetland habitats, and one of the unidentified species was also reasonably common in these habitats.
The AFCD Biodiversity database lists Short-nosed Fruit Bat in plantation in FLN, and fieldwork for this Study also recorded that species, as well as Japanese Pipistrelle and one unidentified species.
The LMC Loop Study recorded predominantly Japanese Pipistrelle in the Loop/Hoo Hok Wai area, with very small numbers of both Brown Noctule and a further unidentified species.
The only positively identified bat species listed Maunsell (2003) which can definitely be ascribed the current Study is Short-nosed Fruit Bat. Though considered to be of conservation importance by Maunsell (2003); Short-nosed Fruit Bat is listed as Indeterminate in the CRDB, hence does not meet the criteria of conservation significance followed in the current study. This species is widely distributed, even in urban habitats, in Hong Kong, hence is of little relevance to the evaluation of habitats or potential impacts on species. Impacts on roosts, may, however, be of significance in respect to potential mortality impacts.
Other bat species listed by Maunsell (2003) were speculative; in view of the difficulty of identifying insectivorous bats in the field, these speculations are not considered further in the current study.
Maunsell (1997) stated that Japanese Pipistrelle and Lesser Yellow Bat had been recorded ‘in abundance in the upper reaches of the Indus (Ng Tung) River’. It is not clear from this reference if this observation was from within the Study Area for the current project; hence it is not mapped in Figure 13.6a.
Accordingly, Pomona Leaf-nosed Bat and Brown Noctule are the only bat species of conservation importance known (or suspected to occur) within the KTN Study Area, but these data should be viewed on a precautionary basis in view of the difficulty of observing and identifying bats.
Appendix 13.2 lists all species recorded in or near the Study Area in this and previous studies.
Table
13.6 - Mammal Species of Conservation Significance Recorded in the Study Area
during the Current and/or Previous Studies.
|
Species |
Conservation and
Protection Status |
Areas/Habitats |
|
Pomona Leaf-nosed Bat Hipposideros pomona |
(Local Concern)1 |
Possibly present in Long
valley (Dudgeon and Corlett 2001) |
|
Brown Noctule Nyctalus noctula |
Potential Regional
Concern/(Regional Concern)1 |
Village area in KTN (Ho
Sheung Heung). |
|
Greater Bandicoot Rat Bandicota indica |
Local Concern1 |
Long Valley |
|
East Asian Porcupine Hystrix brachyura |
Potential Global Concern1 |
Long Valley |
|
Eurasian Otter Lutra lutra |
Regional Concern1, Near Threatened2,
Vulnerable3 |
Single record in
abandoned pond on east side of Ng Tung River near Sha Ling |
|
Masked Palm Civet Paguma larvata |
Potential Regional
Concern1 |
Ho Sheung Heung fung shui wood, Long Valley |
|
Leopard Cat Prionailurus bengalensis |
Vulnerable3 |
Ho Sheung Heung fung shui wood , Long Valley, Wo Hop
Shek and Tong Hang Tung Chuen in plantation/secondary woodland |
|
Red Muntjac Muntiacus muntjak |
Potential Regional
Concern1 |
Ma Tso Lung, Long Valley,
but considered absent now |
Note:
1.
Fellowes et al. (2002). Letters in brackets
represents the assessment is on the basis of restrictedness in breeding and/or
roosting sites rather than in general occurrence.
2.
IUCN (2013)
3.
China Red Data Book (Wang 1998)
13.5.4.3 Birds
Appendix 13.3 lists all 263 bird species, including 121 species of conservation significance, recorded in the Study Area in this and previous studies.
Maunsell (2003) recorded 39 species of birds at KTN, 61 at FLN and 112 at Long Valley. The high figure for the latter area reflects the diverse mosaic of habitats present, which are attractive to a broad range of species. Most of the 21 species of conservation importance identified in that study occurred in agricultural and marsh habitats at Long Valley.
Regular monitoring and other observations made in Long Valley have reported a total of 278 bird species in this area, including 93 species of conservation significance since December 2005, (HKBWS 2012 and HKBWS in litt.).
Surveys for the LMC Loop, the FCA, and other recent studies within or adjacent to the current Study Area did not add any relevant observations of species of conservation significance to those recorded in this study. This is perhaps largely because where the study areas for these other studies overlap with that of the current Study Area, the habitats largely comprise upland grassland, plantation, young secondary woodland and developed areas, none of which support either high densities or numbers of bird species of conservation significance (see Figures 13.3 and 13.5). In total, 57 wetland-dependent bird species or species of conservation significance were recorded at KTN on surveys conducted for the current study. This is a high total that reflects the ecological importance of this area, not only at Long Valley, and the diversity of habitats which are present in the NDA as a whole; of terrestrial habitats widespread in Hong Kong only large areas of mature forest are absent. Of these species, 57 species, 43 are considered to be of conservation concern in Hong Kong (Fellowes et al. 2002, BirdLife International 2013).
Daytime surveys at Long Valley recorded the presence of 91 bird species, including 37 species considered by Fellowes et al. (2002) to be of conservation concern in Hong Kong. During night-time surveys, 14 bird species were recorded, including two species not recorded on daytime surveys and nine of conservation concern. Many of the species recorded at Long Valley are considered to be wetland-dependent.
Species (and their peak counts) for which significant counts were made in Long Valley during the surveys include Little Egret (130), Eastern Cattle Egret (27), Chinese Pond Heron (43), Greater Painted-snipe (43), Black-winged Stilt (49), Little Ringed Plover (65), Wood Sandpiper (119), Common Snipe (101), Pintail/Swinhoe’s Snipe (24), Bluethroat (4), Stejneger’s Stonechat (14), Black-browed Reed Warbler (13), Zitting Cisticola (12), Red-throated Pipit (26), Yellow-breasted Bunting (12) and White-rumped Munia (260).
Part of the reason for the high abundance and diversity of birds at Long Valley is the diversity of the mosaic of habitats, especially wetland habitats, which are present. Further, it is considered that the relatively large area of continuous and contiguous wetland habitats at Long Valley is of relevance in this regard. This allows birds to utilise Long Valley habitats to fulfill many or all of their requirements (such as food and shelter) within the area. For example, Greater Painted-snipe forages in shallow ponds and lightly-vegetated wet agricultural land, but is largely dependent upon heavily-vegetated wetland habitats for roosting. This benefit from the inter-relationships between habitats also extends to non-wetland habitats in the habitat mosaic. Examples of such inter-relationships include the utilisation of dry agricultural land for foraging, but marsh for roosting, by a number of passerine bird species and use of wet agricultural land for foraging, but plantation as a refugium from disturbance, by starlings. In addition, Long Valley has benefited since 2005 from habitat management for nature conservation. Much of this management has been actively directed towards improving the diversity and numbers of birds present, including by addressing the requirements discussed above.
Generally, habitats and areas in KTN NDA away from Long Valley were found to support a lower abundance and diversity of birds, especially species of conservation significance. Nevertheless, 32 wetland-dependent bird species or species of conservation significance were recorded on surveys conducted under the current study. Of these species, 25 are considered to be of conservation significance. The smaller numbers and lower diversity of wetland bird species of other wetland areas, when compared with Long Valley, is considered to be a consequence of the small size, fragmentation, lack of diversity and limited connectivity with other wetland habitats of these areas.
A partial exception to the limitations on the ecological value of wetland habitats in KTN and in FLN (with the exception of Long Valley) are the main channelised rivers. These rivers comprise large areas of wetland habitat and are physically and hydrologically linked to Long Valley. However, they are very simple and homogenous habitats and use by birds is highly constrained by these limitations and their hydrological regimes. As a consequence, they are only utilised by a limited number of bird species and only as feeding areas. Essentially, they are only used for foraging by bird species which can forage in open wetland habitats and, at least for a part of the time, by bird species which are not highly sensitive to disturbance. In addition, foraging opportunities are constrained by water depths in tidal sections and in sections where water levels are permanently high.
Thus, the tidal section of Sheung Yue River is regularly used by many of the wetland bird species present in Long Valley that are not deterred or excluded by the constraints discussed in the previous paragraph. As shown in Appendix 13.3.13, surveys in this channel recorded the presence of 27 wetland-dependent and wetland-associated bird species over the course of the year. The river is under tidal influence, and this impacted the number of individuals recorded; the number of individuals was generally higher during periods of low tide. Surveys were conducted during both high and low tide on each survey date to compensate for this variation in abundance. Some species were recorded in this channel in significant numbers in a Hong Kong context, notably Little Egret (peak count 92), Little Ringed Plover (peak count 23) and Green Sandpiper (peak count 12), whereas numbers of other species were either not significant in a Hong Kong context (e.g. Grey Heron) or were not species of conservation significance.
The downstream section of the Ng Tung and Shek Sheung Rivers are also under tidal influence and are used by much the same species, albeit in smaller numbers (Appendix 13.3.15). The one exception was Great Cormorant, for which the downstream section of the Ng Tung River is the only area/habitat regularly used in the Study Area. Even here, however, numbers of this species are insignificant in a Hong Kong context. Eleven wetland-dependent or wetland-associated bird species were recorded on these river sections during systematic surveys conducted under the current study.
Atkins (2008) also surveyed the Shek Sheung and Sheung Yue River channels, recording low numbers of species also recorded in this study, with the exception of Pied Avocet, a flock of 44 of which was seen to fly to Long Valley. Mott MacDonald (2012) evaluated the Sheung Yue River as of moderate to low ecological importance, due to its moderate importance as a foraging wetland birds at low tide. Species noted were all found in the current study.
The Ng Tung River channel is also used as a flight corridor by birds moving between foraging and nesting and roosting locations. The Sheung Yue and Shek Sheung Rivers are largely perpendicular to such locations and are not used as corridors to a significant extent (Figure 13.11a - b).
Non-wetland habitats away from Long Valley are relatively little used by bird species of conservation importance; with the notable exception of Ho Sheung Heung Egretry which is situated in plantation/orchard.
The absence of large areas of mature forest is reflected in the limited numbers of bird species, especially species of conservation significance associated with such habitat in the Study Area, However, some woodland species recorded in the Ho Sheung Heung fung shui wood, including Black-naped Monarch, Mountain Tailorbird and Two-barred Warbler are uncommon in this part of the New Territories.
Crest Hill, which contains a number of natural or semi-natural dryland habitats, including young secondary woodland, shrubland and grassland, supports a representative range of species found in such habitat in Hong Kong, but is not considered to be of conservation significance for such species with the exception of Eurasian Hobby which has bred there in the past (Carey et al. 2001) and was found there in summer during the current study. Golden-headed Cisticola was found in grassland there in the non-breeding season. However, this species is widespread, if thinly distributed, in upland grassland in the New Territories in winter and it is not considered that Crest Hill is of significance for this species.
While it is not certain if it has occurred in the Study Area, Eurasian Eagle Owl has been recorded in upland grassland above Chau Tau in the southeast of the Study Area.
Both the number of species and the number of species of conservation importance observed in the Study Area is very high in a Hong Kong context. While this is considered to be an accurate reflection of the importance for birds of the KTN area and Long Valley in particular, the high mobility of most species results in birds occurring relatively frequently in small numbers or on a transitory basis in habitats and localities that are atypical of the ecological requirements of the species. This, when combined with intensive survey coverage, results in a relatively high proportion (compared with other faunal groups) of bird species’ records relating to observations of species that are of infrequent occurrence and/or in atypical habitats.
Long Valley receives particularly intensive bird survey coverage in a Hong Kong context (for example the HKBWS has undertaken weekly bird surveys in Long Valley since December 2005) and, in this context, the number of bird species of conservation importance recorded in Long Valley on a regular basis and/or in significant numbers is much more important than the total number of species recorded. The same point applies, to a somewhat lesser extent, elsewhere in the Study Area.
A total of 37 wetland-dependent bird species or species of conservation significance were recorded during daytime bird surveys in FLN between July 2008 and June 2009. This includes 26 species considered by Fellowes et al. (2002) to be of conservation significance in Hong Kong.
Among the 26 bird species of conservation significance recorded, most are wetland-dependent species. The most important area for these was the channelised Ng Tung River, although some individuals were also recorded in nearby mitigation wetlands, ponds or sometimes agricultural land. Other species of conservation concern were recorded in plantation, grassland and grassland/shrubland. Most of these species were recorded in low numbers, except Red-billed Starling, which was recorded in flocks in a variety of habitats; this species is common around lowlands in the northern New Territories.
A total of 17 wetland-associated species were recorded in the non-tidal Ng Tung River (Appendix 13.3). Most were in low numbers, apart from Little Egret, of which up 43 were recorded in any one count, and Little Ringed Plover, for which the peak count was 51.
Of the 57 species for which records were collected in the Hong Biodiversity Database during 2002 to June 2012, only five species were additional to those recorded in the present study. Of these, two were of conservation significance, Striated Heron, listed as of Local Concern as a breeding species, and Chinese Penduline Tit, listed as of Regional Concern by Fellowes et al. (2002). The preferred habitats of Striated Heron in Hong Kong are intertidal and marsh areas especially where there is mangrove in the breeding season and wooded streams in the winter. Chinese Penduline Tit is a reed-dependent species in Hong Kong. The habitats used by these species are either absent or of very limited presence in FLN, and neither species is likely to be present in the Study Area in significant numbers and hence are not considered of significance in the habitat evaluation and impact assessment process.
Maunsell (2003) recorded 61 species of birds at FLN. Of these, seven species (Little Egret, Chinese Pond Heron, Greater Painted-snipe, Black-winged Stilt, Pallas’s Grasshopper Warbler, Zitting Cisticola and Red-billed Starling) meet the conservation significance criteria of the current study. Habitats discussed with respect to their utilisation by birds by Maunsell (2003) were: active wet agricultural land (noted as of importance for rare avifauna species including Greater Painted-snipe); inactive wet and dry agricultural land (noted being used by a number of rare avifauna species); active fishpond (noted as of importance for rare avifauna species including Greater Painted-snipe); and inactive wet and dry agricultural land (noted being used by a number of rare avifauna species).
Surveys for the Liantang/Heung Yuen Wai BCP (Mott MacDonald 2010) and other studies within the current Study Area did not add any species of conservation significance to those recorded in this Study. This is perhaps largely because where the study areas for these other studies overlap with that of the current Study Area, the habitats largely comprise upland grassland, plantation, young secondary woodland and developed areas, none of which support either high densities or numbers of bird species of conservation significance (see Figures 13.3 and 13.5).
However, in the Wo Hop Shek/Yuen Leng area Mott MacDonald (2010) recorded a fairly diverse suite of 56 species, including low numbers of eight wetland-dependent species (albeit some were recorded from non-wetland habitats atypical of the species), as well as shrubland birds. Given the high degree of mobility of birds and their propensity to occur in habitats not of ecological significance to the species, it is inappropriate to map the exact locality of all records of species of conservation importance, as this would give a misleading impression of the significance of the locality for the species. A more appropriate alternative is to ascribe bird observations to the habitats in which they occur on a regular basis and/or in significant numbers in the Study Area. This is presented in Appendix 13.3.1.
The regularly occurring bird species of conservation significance occurring in the Study Area, together with their typical habitat preferences and, where appropriate, area of occurrence, are listed in Table 13.7. Given the differences between the two, a distinction is made between marsh areas at Long Valley (LV) and those away from there.
A number of bird species are listed in the China CRDB which are not listed as of conservation concern under international or Hong Kong criteria. Those species falling into this category and found in the Study Area, and the reasons why they are not considered to be of conservation significance in Hong Kong (and hence in this report) are noted below. These species are not considered further in the evaluation of habitats and impacts of the Project except where specifically referred to.
· Crested Goshawk – this species was considered to be uncommon by Carey et al. (2001). However, it is widespread as a breeding species in wooded habitats throughout Hong Kong and is considered to have increased as woodland has matured.
· Common Emerald Dove – this species was considered to be a scarce but widespread resident by Carey et al. (2001). It is found in a variety of wooded habitats including forest, forest edge, fung shui woods, small wooded groves and shrubland and was considered by Carey et al. (2001) to be increasing in numbers.
· Greater Coucal – this species is a common and very widespread resident in Hong Kong and occurs in a diverse range of habitats.
Table 13.7 - Bird
species both of
conservation significance and of regular occurrence in the Study Area and typical habitat
utilisation (LV = Long Valley).
|
Species |
Level of Concern * |
Species regularly recorded in Long Valley† |
Species regularly recorded away from Long
Valley† |
Typical habitats or areas utilised |
|
Little Grebe Tachybaptus ruficollis |
LC |
Y |
Y |
ponds north of Ho Sheung Heung |
|
Great Cormorant Phalacrocorax carbo |
PRC |
- |
Y |
larger watercourses |
|
Grey Heron Ardea cinerea |
PRC |
Y |
Y |
larger watercourses and less disturbed ponds |
|
Great Egret Egretta alba |
PRC (RC) |
Y |
Y |
larger watercourses and less disturbed ponds |
|
Intermediate Egret Egretta intermedia |
RC |
Y |
Y |
less disturbed vegetated ponds and marshes |
|
Little Egret |
PRC (RC) |
Y |
Y |
most wetland habitats not suffering intense disturbance |
|
Eastern Cattle Egret Bubulcus coromandus |
(LC) |
Y |
Y |
less disturbed grassy and marshy areas |
|
Chinese Pond Heron Ardeola bacchus |
PRC (RC) |
Y |
Y |
most wetland habitats |
|
Black-crowned Night Heron Nycticorax
nycticorax |
(LC) |
Y |
Y |
most open water wetland habitats; distribution unclear due to
nocturnal habits |
|
Yellow Bittern Ixobrychus sinensis |
LC |
Y |
Y |
densely vegetated wetland areas |
|
Von Schrenck’s Bittern Ixobrychus
eurhythmus |
RC |
Y |
- |
densely vegetated wetland areas, probably rare |
|
Cinnamon Bittern Ixobrychus
cinnamomeus |
LC |
Y |
- |
densely vegetated wetland areas |
|
Eurasian Teal Anas crecca |
RC |
Y |
Y |
less disturbed pond and watercourses |
|
Black Kite Milvus migrans |
(RC) |
Y |
Y |
common and widespread in all habitats |
|
Crested Serpent Eagle Spilornis cheela |
(LC) |
|
Y |
wooded areas, including Crest Hill |
|
Peregrine Falcon Falco peregrinus |
(LC) |
|
Y |
open country |
|
Eurasian Hobby Falco subbuteo |
(LC) |
Y |
Y |
open country, nests at woodland edge |
|
Japanese Quail Coturnix japonicus |
LC NT |
Y |
Y |
open country and grassland |
|
Ruddy-breasted Crake Porzana fusca |
LC |
Y |
Y |
marsh, wet agriculture |
|
Pheasant-tailed Jacana Hydrophasianus chirurgus |
LC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Greater Painted-snipe Rostratula benghalensis |
LC |
Y |
Y |
marsh, wet agriculture |
|
Black-winged Stilt Himantopus himantopus |
RC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Pied Avocet Recurvirostra avosetta |
RC |
Y |
- |
pond, marsh (LV) |
|
Oriental Pratincole Glareola maldivarum |
LC |
Y |
Y |
marsh (LV), wet agriculture |
|
Pacific Golden Plover Pluvialis fulva |
LC |
Y |
- |
marsh, wet agriculture |
|
Little Ringed Plover Charadrius dubius |
(LC) |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Marsh Sandpiper Tringa stagnatilis |
RC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Common Greenshank Tringa nebularia |
RC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Wood Sandpiper Tringa glareola |
LC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Swinhoe’s Snipe Gallinago megala |
LC |
Y |
Y |
pond, marsh, wet agriculture |
|
Temminck’s Stint Calidris temminckii |
LC |
Y |
- |
pond, marsh, wet agriculture |
|
Long-toed Stint Calidris subminuta |
LC |
Y |
- |
pond, marsh, wet agriculture |
|
Pacific Swift Apus pacificus |
(LC) |
|
Y |
forages aerially over diverse habitats |
|
Pied Kingfisher Ceryle rudis |
(LC) |
Y |
Y |
pond |
|
White-throated Kingfisher Halcyon smyrnensis |
(LC) |
Y |
Y |
pond, marsh |
|
Citrine Wagtail Motacilla citreola |
LC |
Y |
Y |
pond, marsh (LV), wet agriculture |
|
Red-throated Pipit Anthus cervinus |
LC |
Y |
Y |
pond, marsh (LV), wet and dry agriculture |
|
Pechora Pipit Anthus gustavi |
LC |
Y |
- |
pond, marsh (LV), wet agriculture |
|
Buff-bellied Pipit Anthus rubescens |
LC |
Y |
- |
pond, marsh (LV), wet and dry agriculture |
|
Bluethroat Luscinia svecica |
LC |
Y |
- |
marsh, wet agriculture (LV) |
|
Brown-headed Thrush Turdus chrysolaus |
LC |
- |
Y |
wooded areas |
|
Pallas’s Grasshopper
Warbler Locustella certhiola |
LC |
Y |
Y |
marsh, wet agriculture |
|
Zitting Cisticola Cisticola juncidis |
LC |
Y |
Y |
marsh (LV), dry agriculture |
|
Golden-headed Cisticola Cisticola exilis |
LC |
Y |
Y |
marsh (LV), dry agriculture, upland grassland |
|
Chestnut-eared Bunting Emberiza fucata |
LC |
Y |
Y |
marsh (LV), dry agriculture |
|
Yellow-breasted Bunting Emberiza aureola |
RC VU |
Y |
Y |
marsh (LV), dry agriculture |
|
Japanese Yellow Bunting Emberiza sulphurata |
GC VU |
Y |
- |
marsh (LV), dry agriculture |
|
Grey-capped Greenfinch Carduelis sinica |
LC |
- |
Y |
open, parkland-type
habitats |
|
Chinese Grosbeak Eophona migratoria |
LC |
-Y |
Y |
diverse wooded
areas |
|
Red-billed Starling* Sturnus sericeus |
GC |
Y |
Y |
pond, marsh, wet agriculture |
|
White-shouldered Starling Sturnus sinensis |
(LC) |
Y |
Y |
diverse
open country areas, wooded areas; apparently restricted to anthropgenic
habitats as a breeding species in Hong Kong where it nests in man-made
structures. |
|
Black-naped Oriole Oriolus chinensis |
LC |
- |
Y |
wooded areas |
|
Collared Crow Corvus torquatus |
LC NT |
Y |
Y |
pond, watercourses
both natural and channelised |
† Species
recorded are noted as regularly recorded at Long Valley or away from Long
Valley (Y indicates recorded, - indicates not recorded) based on field surveys
for this study, Carey et al. (2001),
other observations by the Study Team and other studies (Monitoring of priority
site by AFCD; Surveys of Long Valley by HKBWS; Sheung Shui to Lok Ma Chau Spur
Line EIA).
* Level of Concern generally follows Fellowes et al. (2002): LC – Local Concern, RC –
Regional Concern, PRC Potential Regional Concern, GC – Global Concern, PGC –
Potential Global Concern. Letters in parentheses indicate the assessment is
based on breeding and/or roosting sites rather than general occurrence. Level
of Concern given in bold refers to global population assessment by BirdLife
Interntaional: NT – Near-threatened, VU – Vulnerable, EN – Endangered, CR –
Critically Endangered.
13.5.4.4 Ho Sheung Heung Egretry
As described in Section 13.3, there is an important egretry at Ho Sheung Heung, located in orchard and plantation. Flight-lines linking this egretry were surveyed during the current study and are described in this section.
The major flight-lines observed from the egretry are shown in Figure 13.7, showing the proportion of individuals (of all species) recorded following each route. To the south of the egretry, major flight-lines were observed over the Lo Wu Correctional Institution towards the KTN NDA (Flight-line 1), towards Long Valley (Flight-lines 2 and 3), along the Shek Sheung River (Flight-line 4) and along the Ng Tung River towards the FLN NDA (Flight-line 5). To the north of the egretry, most birds were observed following the line of hills (Flight-line 6) or the Ng Tung River (Flight-line 7) towards Hoo Hok Wai, or crossing the river towards an area of ponds and wet agriculture opposite the egretry (Flight-line 8).
A total of 785 flights were observed during the surveys, including 298 Little Egret, 225 Eastern Cattle Egret and 262 Chinese Pond Heron. Overall, 58.3% of flights were to the south of the egretry (towards Long Valley, the Shek Sheung River or the Ng Tung River), while 28.5% were towards the north (towards Hoo Hok Wai or the Shenzhen River) and 13.2% were over the Ng Tung River towards the east. With regard to flight-lines to the south, 40.4% (of the overall total) were oriented toward Long Valley, while 12.4% were along the Ng Tung River. The Lo Wu Correctional Institution was under construction at the time of surveys, and thus it is possible that the relative importance of the Long Valley-oriented flight-lines might have been impacted. However, in flight-line surveys carried out after construction for PLNQ 73/2011 Ecological Field Survey of Hoo Hok Wai commissioned by the Planning Department, 45% of birds were recorded flying from the egretry toward Long Valley in June 2012, suggesting there was minimal impact. With regard to the latter study, in total, 56.6% of birds were recorded flying in a southerly direction, 7.5% were recorded flying east towards Sha Ling and 35.9% were recorded flying north towards Hoo Hok Wai. Birds flying towards the north and east would not be affected by proposed developments in the NDA.
Behaviour differed between different species. Approximately 58% of Little Egrets were observed flying south, many of which flew close to the Lo Wu Correctional Institution or followed the tidal section of the Ng Tung River. The majority of Eastern Cattle Egrets (74%) also flew towards the south, mostly between the Lo Wu Correctional Institution and the Shek Sheung River. Slightly larger numbers of Chinese Pond Herons were observed to fly north rather than south (45% flying south); of the birds flying south, many followed the Shek Sheung River or flew close to the Lo Wu Correctional Institution.
The height of birds flying towards the south was recorded. As shown in Table 13.8, most birds heading south were less than 20m above the ground (17% below 10m, 62% between 10 and 20m). This was particularly true for flight-lines heading towards Long Valley, the Shek Sheung River or the FLN NDA (Flight-lines 2, 3, 4 and 5). These birds were constrained by the presence of overhead wires, which presented an obstacle to flying birds. Several individuals approaching at a similar height to the wires were seen to make manoeuvres to avoid collisions, either by returning to the egretry or changing flight height. Most of the birds flying along the line of hills to the west of the Lo Wu Correctional Institution (Flight-line 1) were higher than the wires, but this represented a relatively small proportion of individuals. Whilst the wires posed an obstacle, the birds showed no avoidance of the bridge over the Ng Tung River, which was overflown by birds using Flight-line 5, indicating that they were habituated to this relatively low horizontal structure.
Table
13.8 - Heights of
birds (all species) leaving Ho Sheung Heung Egretry along flight-lines towards the south (values
are % of birds on each flight-line within the given height range)
|
Height (m) |
Flight-line* |
Overall |
||||
|
1 |
2 |
3 |
4 |
5 |
||
|
0-10 |
0 |
6 |
10 |
51 |
3 |
17 |
|
10-20 |
5 |
75 |
80 |
44 |
71 |
62 |
|
20-30 |
2 |
6 |
5 |
3 |
5 |
5 |
|
30-40 |
7 |
10 |
5 |
2 |
11 |
7 |
|
40-50 |
14 |
3 |
0 |
0 |
8 |
3 |
|
50-60 |
9 |
0 |
0 |
0 |
0 |
1 |
|
60+ |
64 |
0 |
0 |
0 |
3 |
6 |
*
Flight-line 1: over Lo Wu Correctional Institution (LWCI), Flight-line 2:
between LWCI and pylon, Flight-line 3: between pylon and Ng Tung River,
Flight-line 4: S along Ng Tung River/Shek Sheung River, Flight-line 5: W along
Ng Tung River.
To the south of the Ho Sheung Heung Egretry, flight path routes are significantly impacted by the presence of the Lo Wu Correctional Institution which is 13m in height (at the time of the flight-line surveys when construction work was underway, impact may have been more pronounced) and a nearby pylon approximately 45m in height. Approximately 19% of birds were observed flying between these two obstacles (Flight-line 2). The height of flight-lines was also constrained by obstacles in the area. Electric wires apparently presented an obstacle to birds flying south towards the NDA, and most birds were observed flying underneath these cables (less than 20m). Birds on Flight-line 1 were at a higher altitude over the Lo Wu Correctional Institution.
Transect surveys conducted at KTN NDA between April and July 2009 (the peak breeding period for ardeids in Hong Kong) indicated that Long Valley is an important foraging area for all three of the species breeding at Ho Sheung Heung (Table 13.9). The Sheung Yue River is also important for foraging Little Egrets, especially during low tide periods. Wet agriculture north of Long Valley was also shown to be important for foraging Eastern Cattle Egrets during the breeding season. These findings broadly support the observations during the flight-line counts at the Ho Sheung Heung Egretry.
Table 13.9
- Distribution of ardeid species breeding at Ho Sheung Heung during the 2009
breeding season (April – July)
|
Species |
Peak Count in Long Valley |
Peak Count in Sheung Yue
River |
Peak Count elsewhere in Kwu
Tung North |
|
Little Egret |
39 |
66 |
12 |
|
Eastern Cattle Egret |
13 |
0 |
14 |
|
Chinese Pond Heron |
12 |
5 |
5 |
13.5.4.5 Man Kam To Road Egretry
The Man Kam To Road Egretry was discovered on 19th June 2009. Nests are located in a patch of bamboo to the east of Man Kam To Road, north of the Ng Tung River (within the boundary of the FLN NDA). Due to the proximity of the two sites, and the similarity of foraging areas, it is thought that this egretry may be derived from birds which formerly bred at Ho Sheung Heung, where the population of Chinese Pond Herons has declined in recent years (Anon 2009). Surveys in 2009 recorded up to 15 nests of Chinese Pond Heron (Anon 2009), representing approximately 5% of the population of this species in Hong Kong, Numbers have increased slightly subsequently, with 21 nests of Chinese Pond Heron and six nests of Little Egret recorded in 2012 (Anon 2012b)
Two flight-line surveys were conducted at the egretry in late June and early July 2009 and three flight-line surveys were conducted from May to July 2011 to help investigate the potential indirect impacts to the egretry. In total, 238 observations of Chinese Pond Herons and 20 of Little Egrets leaving the egretry were made during these five surveys. As shown in Figure 13.8, most birds flew towards the south-west, either following the Ng Tung River (46.4% of birds) or directly over the developed land (sewage treatment works and slaughterhouse) to the south-west (21.0% of birds). These birds were most likely heading towards foraging sites in Long Valley or nearby channels. A moderate proportion of birds (13.5%) flew east along the Ng Tung River, presumably to foraging sites in the river, mitigation meanders or nearby agricultural land. Few birds flew to sites north of the river or south-east from the egretry.
In contrast to flight-lines from the Ho Sheung Heung Egretry, there was no difference in the height of most flight-lines, with birds flying from the egretry at nest or bamboo height (i.e. 5 – 7m); this was presumably due to the absence of any obstructions at or near the egretry which necessitated birds gaining or losing height and the level topography of the egretry site. Neither vehicles on the Man Kam To Road and on the bridge over the Ng Tung River, nor the bridge itself, appeared to pose any obstruction or cause birds to deviate from a direct line from the egretry, at least as far as the flight-lines were visible from the observation point. There was, however, some indication that birds using Flight-line 3 were gaining altitude gently as they flew further away from the egretry, perhaps in order to clear the Shek Wu Hui Sewage Treatment Works. This was not quantified due to the difficulty in estimating the height above the ground of birds seen at a relatively low height relative to their horizontal distance from the observer.
An exception to similar height above the ground of flight-lines was Flight-line 5 (along the Ng Tung River to the east): birds following this flight-line lost height once they were over the river then continued along the river at a low level, either at or below the level of the channel sides. Clearance of nesting substrate and a decline in occupancy from 23 nests in June 2012 to five in July 2012 was noted. Despite these changes to the site, nine nests of Chinese Pond Herons were present in April 2013. Ho Sheung Heung was also re-occupied in April 2013.
It is not unusual for the location of egretries to change in Hong Kong. For instance, during the period from 2007 to 2013, twelve egretries were abandoned and seven new egretries were found. Up to four egretries were abandoned (in 2013) and up to three egretries were found (in 2011) in any one year during this period. In addition to egretries being founded and abandoned, it is also not unusual for egretry sites to move a short distance, either entirely or partially (Anon 2007, 2008a, 2009, 2011, 2012a, 2012b). The distinction between an egretry being abandoned and one moving a short distance followed by Anon (2007, 2008a, 2009, 2011, 2012a, 2012b) is 500m, representing the usual minimum foraging range of a colony.
Accordingly, the possibility that either or both of the Ho Sheung Heung and Man Kam To Egretries might be abandoned, or their locations might change, or that entirely new egretries might be established in the Study Area within the project period of the NDA development must be considered in the evaluation of potential impacts of the project. Consideration should also be given to the need to check for the presence of egretries prior to the commencement of construction activities in areas which are suitable as egretry locations. Suitable locations are lowland areas within 500m of wetlands with trees and bamboos available as nesting habitat. Such areas may include developed and village areas as well as more natural habitats. Consideration must also be given to the requirement to implement additional mitigation measures to address impacts on any new egretries, egretry flight-lines and foraging areas.
In this regard, it should be noted that whereas it is
relatively rare for an egretry site to be abandoned for an entire breeding
season and then re-occupied in subsequent years (Young and Cha 1995, Carey et al. 2001) this has happened on at
least three occasions in the last ten years. Accordingly, abandonment for a
single season should not be seen as confirmation that a site has been abandoned
temporarily; a site may be re-occupied if, for example, a source of disturbance
which caused abandonment is no longer present in a subsequent breeding season.
13.5.4.6 Reptiles
Appendix 13.4 provides a summary of records from this and previous studies, and details of data collected during field surveys for this study.
Only four species of reptile were recorded in KTN by Maunsell (2003), three by Mott MacDonald (2012), while 15 are listed in the AFCD Biodiversity database and 23 species were reported for Long Valley by Hung and Pang (2008) and Wan (2010).
A total of 14 reptile species were recorded in the KTN NDA during surveys conducted under the current study of which four are considered to be of conservation significance (see Appendix 13.4). These comprised a dead Indo-Chinese Rat Snake found in the channelised Ho Sheung Heung Watercourse, a Banded Krait found near a pond to the east of Ho Sheung Heung village, a Chinese Soft-shelled Turtle recorded along the edge of the Ng Tung River and, of greatest significance, a Three-banded Box Terrapin in a stream at Ma Tso Lung, in the north-west of the KTN NDA (note that this is not mapped in Figure 13.6 for reasons of wildlife protection).
Hong Kong may be one of the last sites globally to support wild populations of Three-banded Box Terrapin (KFBG 2009), which favour clean streams but also wander into adjacent habitats, especially riparian woodland, and can be found several hundred metres from streams (Karsen et al. 1998, Paul Crow pers. comm.). Parts of the Ma Tso Lung Stream are of low water quality, but the section in which the terrapin was recorded is relatively clean and is bordered by riparian woodland and plantation. All reptiles of conservation significance recorded in this and previous studies are listed in Table 13.10, together with the various conservation status listings and areas/habitats where these species were found. In this regard, Indo-chinese Rat Snake is not listed from Ho Sheung Heung Watercourse in this table, as listing of a dead specimen from an unsuitable habitat is considered unrepresentative and potentially misleading.
Two areas in KTN are of significance for reptiles of conservation importance: the Long Valley and Ma Tso Lung areas. Whilst the number of observations in Long Valley is no doubt partly a consequence of the relatively intense survey effort there, it is also likely that the combination of open wetland and dryland habitats leads to food (amphibians, rodents and small birds) for snakes being relatively abundant.
The significance of Ma Tso Lung is likely to be a consequence of the mix of habitats and limited human activity. Habitat linkages between wetland habitats, especially the relatively unpolluted Ma Tso Lung Stream with woodland cover and Ma Tso Lung marsh, are likely to be important in maintaining reptile populations in KT.
In FLN, two species were recorded by Maunsell (2003), including Chinese Cobra in active agricultural land in FLN, while ten were reported by the AFCD Biodiversity database. During fieldwork for this study, eleven reptile species were recorded during surveys (Appendix 13.4). All species recorded are common and widespread in Hong Kong (Karsen et al. 1998).
A total of 16 species have been recorded in FLN by this and previous studies (Appendix 13.4), of which Burmese Python and Indo-chinese Ptyas korros and Common Rat Snakes are of conservation significance; the latter two were recorded in FLN during this study. The location of the first of these observations is unknown, but Common Rat Snake was found in mitigation woodland on the north side of the Ng Tung River and in the riparian zone of the Kau Lung Hang Streams.The locations of all records of species of conservation significance are mapped (where known) in Figure 13.6.
Of the species of reptile that have been recorded in or near the Study Area during this and previous studies (see Appendix 13.4), those that are assessed as of conservation significance by one or more authorities are listed in Table 13.10 together with the habitats or areas in which they are present in the Study Area.
Table 13.10
- Reptile Species of Conservation Significance Recorded in the Study Area
during the Current and Previous Studies.
|
Species |
Conservation and Protection Status |
Areas/Habitats |
|
Reeve’s Terrapin Scincella
reevesii |
Global
Concern1, Endangered2, Conservation Dependant3. |
Long
Valley. |
|
Three-banded Box Terrapin Cuora
trifasciata |
Global
Concern1, Critically Endangered2,3. |
Stream
and wooded riparian zone at Ma Tso Lung (single record). |
|
Chinese Soft-shelled Turtle Mauremys
mutica |
Global
Concern1, Vulnerable2,3. |
Ng Tung
River and adjacent wetland areas including Long Valley. |
|
Tokay Gecko Gekko
gecko |
Regional
Concern3, Endangered5. |
Long
Valley, but doubt over origins. |
|
Common Water Monitor Varanus
salvator |
Regional
Concern1, Critically
Endangered3. |
Occasionally
in Long Valley, though wild population now presumed extinct. |
|
Five-striped Blue-tailed Skink Plestiodon
elegans |
Local
Concern1 |
Ma Shi
Po area, FLN (habitat uncertain, an anecdotal report by local naturalists). |
|
Indian Forest Skink Sphenomorphus
indicus |
Local
Concern1. |
Tong
Hang Tung Chuen, FLN, wooded habitats. |
|
Burmese Python Python
bivittatus |
Potential
Regional Concern1, Vulnerable2, Critically Endangered3. |
Long
Valley and Fanling North area; occurs in variety of open country habitats. |
|
Buff-striped Keelback Amphiesma
stolatum |
Local
Concern1. |
Long
Valley, Ma Shi Po area, FLN (anecdotal report by local naturalists). |
|
Copperhead Racer Elaphe
radiata |
Potential Regional Concern1, Endangered 3. |
Secondary
woodland near Tong Hang Tung Cheun in
FLN, |
|
Indo-Chinese Rat Snake Ptyas
korros |
Potential
Regional Concern1, Endangered3. |
Mitigation
plantation on the north side of the Ng Tung River and near Kau Lung Hang
Stream in FLN, found in diverse open country habitats, widespread in HK. |
|
Common Rat Snake Ptyas
mucosus |
Potential
Regional Concern3, Endangered5. |
Diverse
open country habitats, widespread in HK, including Ma Tso Lung, |
|
Banded Krait Bungarus
fasciatus |
Regional
Concern1 Endangered3. |
Lowland
wetland habitats, fairly widespread in HK. |
|
Many-banded Krait Bungarus
multicinctus |
Potential
Regional Concern1, Vulnerable3. |
Long
Valley. |
|
Chinese Cobra Naja
atra |
Potential
Regional Concern1, Vulnerable3. |
Long
Valley, Ma Tso Lung, agricultural land in FLN (Maunsell 2003). |
|
King Cobra Ophiophagus
hannah |
Appendix
II CITES2, Potential Regional Concern1, Vulnerable2,
Critically Endangered3. |
Long
Valley. |
Notes
1. Fellowes et
al. (2002)
2. IUCN (2013)
3. China Red Data Book (Zhao 1998)
13.5.4.7 Amphibians
Maunsell (2003) recorded nine species of amphibians, of which Chinese Bullfrog is of conservation significance; no amphibian species of conservation significance were recorded in KTN by Mott MacDonald (2012). The AFCD database for KTN and FLN recorded the same range of species plus Butler’s Pigmy Frog and, at KTN, Greenhouse Frog; the latter is an invasive, exotic species. Surveys as part of the MAs for Long Valley and Ho Sheung Heung have recorded 12 species (Hung and Pang 2008), including two not recorded elsewhere in the Study Area: Three-striped Grass Frog and Two-striped Grass Frog, the latter of which is of conservation significance. There is, therefore, broad consistency in historical data regarding the amphibian community in lowland wetlands in the Study Area (see Appendix 13.5).
Ten amphibian species were recorded in KTN during surveys conducted under the current study. The abundance and diversity of amphibians was highest in wet agriculture, and ponds, especially around Long Valley (see Appendix 13.5). The only species of conservation importance recorded, Chinese Bullfrog, was recorded in a variety of habitats in KTN NDA, in small numbers, including in village habitat; however, individuals in such habitat may relate to ex-captive individuals. Although of conservation significance, this species is regarded as common in Hong Kong.
Maunsell (2003) recorded four species in FLN, including Chinese Bullfrog, which is also reported for the area in the AFCD Biodiversity database for 2002-12, as well as another nine common and widespread species.
Ten amphibian species were recorded during initial surveys for this study in FLN, matching exactly the species reported in the AFCD Biodiversity database. The highest diversity of species was recorded in wet and dry agricultural land, with rather few in natural and channelised stream courses. The moderate numbers of vocalizing amphibians in wet agricultural land suggest that this habitat may be of some importance as a breeding and nursery ground for amphibian species. The species present included Chinese Bullfrog, which was found to be relatively abundant in riparian plantation and grassland at Kan Lung Tsuen (northeast of Leung Yeuk Tau) and in agricultural land at Siu Hang San Tsuen. Spotted Narrow-mouthed Frog was particularly abundant in seasonally wet grassland. The latter species is not regarded as a species of conservation significance, however.
Two further species of conservation significance were recorded in the Study Area in wet season 2013, both in plantation habitat near Wo Hop Shek Cemetery, in the southeast of FLN. These were Lesser Spiny Frog and Brown Wood Frog.
Very similar patterns of occurrence were recorded by previous studies, (Appendix 13.5) though Hyder (2008) recorded Short-legged Toad in the Wo Hop Shek area in plantation or secondary woodland, either within or just outside the Study area for the current project; this species is listed as Endangered by IUCN and of Potential Global Concern by Fellowes et al. (2002). Thus, three anuran species of conservation significance, two of which (Brown Wood Frog and Short-legged Toad) are woodland-dependant, have been found in woodland near Wo Hop Shek Crematorium, suggesting that this area may be of some significance for anuran species.
Table 13.11 lists amphibians of conservation significance that have been recorded in the Study Area.
Table 13.11
- Amphibian Species of Conservation Significance Recorded in the Study Area
during the Current and Previous Studies.
|
Species |
Conservation
and Protection Status |
Areas/
Habitats |
|
Short-legged Toad Xenophrys brachykolos |
Potential Global Concern1, Endangered2. |
Plantation/secondary woodland near Wo Hop Shek Crematorium, possibly in
Study Area. |
|
Chinese Bullfrog Hoplobatrachus chinensis |
Potential Regional Concern1. |
Variety of agricultural and marsh habitats in Study Area, including
irrigation ponds in dry agriculture, and at Ma Tso Lung. |
|
Lesser Spiny Frog Paa exilispinosa |
Potential Global Concern1, Vulnerable2 |
Plantation habitat near Wo Hop Shek Crematorium. |
|
Brown Wood Frog Rana latouchii |
Local Concern1 |
Plantation habitat near Wo Hop Shek Crematorium. |
|
Two-striped Grass Frog Rana taipehensis |
Local Concern1 |
Long Valley though scarce. |
Notes
1. Fellowes et al. (2002)
2. IUCN (2013)
13.5.4.8 Fish
All species recorded in or near the Study Area are listed in Appendix 13.6, while those of conservation significance recorded in this or previous studies are listed in Table 13.12.
The current study recorded nine species in KTN, of which those native to Hong Kong are Goldfish, Chinese Barb and Swampy Eel. The only species of potential conservation importance was Climbing Perch, up to five individuals of which were recorded in natural and channelised stream habitats. Climbing Perch appears to have colonised Hong Kong recently; the species is native to South China but it is unclear whether the colonisation of Hong Kong has occurred naturally or by human introduction. In view of uncertainty regarding the conservation status of this species in China and the fact it is regarded as ‘Data Deficient’ by IUCN, it is not treated here as a species of conservation significance.
The native species were recorded from natural streams; this suggests these streams are relatively clean, but these fish communities have been influenced by the introduction of exotic species.
Common aquaculture species were observed in fish ponds in the KTN NDA, including Grass Carp and Nile Tilapia; these are not considered to be of ecological importance. Previous studies have recorded Common Carp in KTN (AFCD HK Biodiversity database). These are not considered to refer to naturally-occurring individuals, and thus the species is not regarded as of conservation importance. In addition, Small Snakehead was recorded in the Ma Tso Lung San Tsuen Stream during field surveys for the LMC Loop Study.
Fish surveys in FLN for the current study recorded twelve species, several of which are not native to Hong Kong. The native species recorded were Acrossocheilus parallens, Predaceous Chub, Freshwater Minnow, Oriental Weatherfish, White-spotted Walking Catfish, Freshwater Goby and Barcheek Goby. The first of these, Acrossocheilus parallens, listed as of Global Concern by Fellowes et al. (2002), was recorded in the Kau Lung Hang Stream; while Predaceous Chub, listed as Vulnerable in the CRDB, was found in an upstream section of the Siu Hang San Tsuen Stream.
Most streams in the area are heavily impacted by human activity and are unlikely to support significant populations of stream-dependent fauna (including fish), especially species of conservation importance. Fish diversity observed in the stream at Siu Hang San Tsuen was relatively high, however and also included one species of conservation significance, as is noted above.
Common Carp and Small Snakehead were reported in the Ma Wat River by Mott MacDonald (2010); however, the first of these had most probably been introduced by human activity to the watercourse concerned; both of these records are believed to refer to the AFCD Biodiversity Database records discussed below. Biodiversity Database records collected by AFCD during 2002 to June 2012 recorded an additional seven species of fish (Appendix 13.6.1), none of which meet the criteria of conservation significance followed in this study; Broken-band Hillstream Loach, listed as Data Deficient by IUCN (2013) is widespread in Hong Kong and is considered to be common (AFCD Biodiversity Database.
Both of the species of conservation significance listed in the Biodiversity Database, Acrossocheilus parallens and Small Snakehead, were reported by this or other studies. However, the Biodiversity Database records provide a fuller picture of the distribution of these species in the Study Area: Acrossocheilus parallens has been found in many locations in the Kau Lung Hang Lo Wai Watercourse, the Kau Lung Hang San Wai Watercourse, the Ma Wat River south of Nam Wa Po and at the confluence of the Ma Wat River and the Tai Wo Watercourse; while Small Snakehead has been recorded from the Kau Lung Hang Lo Wai Watercourse, at the confluence of the Ma Wat River and the Tai Wo Watercourse and in an upstream location in the Tai Wo Watercourse.
Table 13.12
- Fish Species of Conservation Significance Recorded in the Study Area during
the Current and Previous Studies.
|
Species |
Conservation
Status |
Areas/
Habitats |
|
Acrossocheilus
parallens |
Global Concern1 |
Channelised and
natural streams in the Kau Lung Hang Streams EIS (including a section of the
Ma Wat River). |
|
Predaceous Chub Parazacco spilurus |
Data Deficient2,
Vulnerable3 |
Channelised stream
with banks and bed of natural materials and of good water quality at Siu Hang
San Tsuen. |
|
Small Snakehead Channa asiatica |
Local Concern1. |
Channelised and natural streams in the Kau
Lung Hang Streams EIS (including a section of the Ma Wat River) and in Ma Tso
Lung San Tsuen Stream. |
Notes
1. Fellowes et al. (2002).
2. IUCN (2009).
3. China
Red Data Book (Wang 1998).
13.5.4.9 Butterflies
Surveys carried out in the early 1990s in the KTN area by M. Bascombe recorded a total of 110 butterfly species within the Study Area (Maunsell 1997, Dudgeon & Corlett 2001, Maunsell 2003) (see Appendix 13.7.1). Species recorded by Bascombe that have not been recorded in field surveys for the current study or in surveys conducted under other subsequent studies are listed in Appendix 13.7.13. Further, only 36 butterfly species were recorded by the NENT Study in KTN (Maunsell 2003), and it was suggested in that study that habitat had been lost for many of the species recorded previously by Bascombe. However, it should be noted that Maunsell (2003) appears to have wrongly attributed a number of Bascombe’s records to the NENT Study Area including two species of conservation significance, Vagrant and Common Birdwing, not otherwise known from the current Study Area. The lack of recent records suggests that some of these species may, indeed, have been lost from the area. Based on Appendix 13.7.13, the habitats potentially affected are bamboo groves and woodland or woodland edge areas.
A relatively high total of 86 butterfly species was recorded for KTN in surveys for this study, including seven species (including one identified as Potanthus sp. of Local Concern (Fellowes et al. 2002) (Table 13.13). Shrubland and fung shui woodland around Crest Hill and Ho Sheung Heung were found to be of particularly diverse (Appendix 13.7.2), though Potanthus sp. and Danaid Egg-fly were the only species of conservation significance found in these habitats in this study.
Field work for the LMC Loop study recorded 52 species in the lowland mix of marsh, seasonally wet grassland, village edge, woodland, shrubland and grassland at Ma Tso Lung in the north of the Study Area or in adjacent areas. Findings from this and other surveys in this area included four species of conservation significance: Pale Palm Dart, Spotted Angle (from two locations), Danaid Egg-fly and Small Three-ring (also from two locations). All of these species were recorded in open country habitats, either in hillside grassland or in wet grassland in and around Ma Tso Lung marsh. The presence of these four species of conservation importance, together with the diversity of species present, suggests that the mix of habitats in this area combine to make it relatively significant for butterflies.
Although there may have been some long-term loss in butterfly habitat, the butterfly community in the KTN NDA area remains diverse. This is supported by findings from AFCD surveys, which have recorded 57 species in KTN, 11 of which are additional to those recorded in the present study, albeit none of these are of conservation significance. This diversity is associated largely with the woodland and shrubland habitats around Ho Sheung Heung and Crest Hill, which support species that are uncommon in the northwest New Territories. These habitats may be important for the recolonisation and spread of butterfly species as woodland matures.
In FLN a total of 52 butterfly species (including one unidentified swift) were recorded within the Study Area during faunal surveys for this study (Appendix 13.7.3). This is a relatively low total, and suggests that habitats around the FLN NDA are of relatively lower quality for butterflies, probably due to a relatively low diversity of larval food plant species. Two butterfly species recorded are of Local Concern in Hong Kong (Pale Palm Dart and Commander).
Of 15 additional species listed in the AFCD Biodiversity Database from the FLN during the period from 2002 to June 2012, none are of conservation significance. None of the 26 species recorded in this area by Maunsell (2003) were of conservation significance.
Butterfly species of conservation
significance recorded in the Study Area during the current and previous studies
are listed in Table 13.13. Potanthus sp. is not included in this
table, as a certainly identified Potanthus,
Common Dart P. pseudomaesa, is
listed. Species status
in Hong Kong as defined by Chan et al.
(2011) is listed in Table
13.13 and Appendix 13.7.2 to 13.7.13, has been given due
consideration, but has not been used
as a primary criterion for determining conservation significance in Table 13.13 and
hence has not been utilised in the evaluation of habitats or assessment of
impacts, except where stated.
Table 13.13
- Butterfly Species of Conservation Significance Recorded in the Study Area
during the Current and Previous Studies.
|
Species |
Conservation
Status / Rarity |
Areas/
Habitats |
|
Dark Brown Ace Halpe porus |
Local Concern1, Very Rare2 |
Ho Sheung Heung and
Tsung Pak Long (Bascombe)/ Bamboo groves. |
|
Common Dart Potanthus
pseudomaesa |
Local Concern1, Rare2. |
Ho Sheung Heung
(Bascombe)/ Abandoned agricultural lands, grassland. |
|
Hainan
Palm Dart Telicota
besta |
Local Concern1,
Very Rare2. |
Lo Wu area
(Bascombe)/ Abandoned exposed grassland, shrubland. |
|
Pale
Palm Dart Telicota colon |
Local Concern1,
Rare2. |
Edge of marsh at Ma
Tso Lung, waste ground near Ma Wat Tsuen, in FLN/ abandoned agricultural
land, grassland. |
|
Spotted Angle Caprona alida |
Local Concern1,
Very Rare2 |
Ma Tso Lung/
Grassland. |
|
Lesser Forest Blue Taraka hamada |
Local Concern1,
Rare2 |
Tsung Pak Long
(Bascombe)/ Bamboo groves. |
|
Pale
Hedge Blue Udara dilecta |
Local Concern1,
Very Rare2 |
Dry agriculture at
Long Valley. |
|
Brown Onyx Horaga albimacula |
Local Concern1, Very Rare2 |
Tsung Pak Long and
Ho Sheung Heung (Bascombe)/ Forest. |
|
Peacock Royal Tajuria cippus |
Local Concern1,
Rare2 |
Plantation near Fung
Kong Shan in KTN and secondary woodland near Tong Hang Tung Chuen, FLN. |
|
Common Pierrot Castalius rosimon |
Local Concern1, No verified sightings in recent years2 |
Ho Sheung Heung,
Tsung Pak Long and near Lo Wu (Bascombe)/ Coastal shrubland, wasteland. |
|
Danaid
Egg-fly Hypolimnas
misippus |
Local Concern1,
Uncommon2 |
Wet agriculture in
Long Valley, hillside grassland at Ma Tso Lung, shrubland at Crest Hill in
KTN. |
|
Commander Moduza procris |
Local Concern1,
Very Rare2 |
Channelised
watercourse in Long Valley, dry agriculture near Ma Shi Po in FLN. |
|
Painted
Lady Vanessa cardui |
Local Concern1,
Rare2, non-breeding migrant in Hong Kong. |
Wet agriculture in
Long Valley. |
|
Small
Three-ring Ypthima norma |
Local Concern1,
Very Rare2 |
Crest Hill and Ma
Tso Lung areas/ upland grassland on hillsides and seasonally wet grassland. |
|
Small
Grass Yellow Eurema
brigitta |
Local Concern1, Rare2 |
Ho Sheung Heung
(Bascombe)/ Shrubland, abandoned agricultural lands. |
Notes
1. Fellowes et
al. (2002).
2. Chan et al. (2011).
13.5.4.10 Dragonflies
A total of 30 odonate species were recorded on surveys in KTN for this study. Only two species of conservation interest were recorded, both of which are listed by Fellowes et al. (2002) as of Local Concern. The first was Scarlet Basker (also recorded in the area by Mott MacDonald (2012)), which has, however, increased in recent years and is now relatively common in lowland areas in Hong Kong, especially around fish ponds (Wilson 2004). The second was Ruby Darter, which is also now considered to be common in Hong Kong.
The AFCD Biodiversity Database lists 34 dragonfly species in as having been recorded in KTN during 2002 to 2012, of which six were not recorded in the present study. Of these six, Orange-backed Threadtail and Blue Chaser are considered to be of Local Concern by Fellowes et al. (2002).
Fieldwork for the LMC Loop study recorded one species of conservation significance at Ma Tso Lung: Ruby Darter; this species is now are considered to be common in Hong Kong.
A
total of 32 species was recorded in FLN during field work for this study. Most are common and widespread in Hong
Kong, but Fellowes et al. (2002) consider
Ruby Darter, Blue Sprite and Dingy Dusk-hawker to be of Local Concern, and
Emerald Cascader to be of Potential Global Concern. However, like Common Evening Hawker, Dingy Dusk-hawker is active at dusk
(as its common name suggests), and thus tends to be under-recorded in general
dragonfly surveys, which are usually undertaken at other times of day (as was
the case in surveys for the present study). Recent surveys have confirmed that
this species is common and widespread in Hong Kong and this is reflected in its
current categorisation as ‘Common’ on the AFCD Biodiversity Database.
Accordingly, whilst included in Table 13.14 for consistency, the current status has been taken into account in
evaluation of habitats and assessment of the ecological impacts of the Project.
Seven additional species are listed in the AFCD Biodiversity Database as having been recorded in FLN b during 2002 to June 2012, with only Scarlet Basker of conservation significance; as noted above, this is now relatively common in lowland areas.
Although Maunsell (2003) did not record any species of conservation significance, Mott Macdonald (2010) reported three such species in the Study Area: Eastern Lilysquatter was recorded in the Kau Lung Hang area, Ruby Darter was seen near the Ma Wat River to the north of Kiu Tau, while Emerald Cascader was reported from near Tong Hang Tung Chuen, apparently in secondary woodland (Appendix 13.8 and Figure 13.6c). All dragonfly species of conservation significance recorded in the present and previous studies, together with conservation status assessment and occurrence in the Study Area, are listed in Table 13.14.
Table 13.14 - Dragonfly Species of
Conservation Significance Recorded in the Study Area during the Current and
Previous Studies.
|
Species |
Conservation
Status |
Areas/
Habitats |
|
Eastern Lilysquatter Paracercion melanotum |
Local Concern1, Uncommon2 |
Kau Lung Hang Streams near Ma Wat River. |
|
Blue Sprite Pseudagrion microcephalum |
Local Concern1, Common2 |
Natural watercourse in FLN. |
|
Orange-backed Threadtail Prodasineura croconota |
Local Concern1, Common2 |
Wooded stream in Kwu Tung North. |
|
Dingy Dusk-hawker Gynacantha
subinterrupta |
Local Concern1, Widespread and common3 |
Mitigation wetland
in FLN. |
|
Blue Chaser Potamarcha
congener |
Local Concern1, Common2 |
Small ponds and
marshes, Kwu Tung North. |
|
Ruby Darter Rhodothemis rufa |
Local Concern1, Common2 |
Ma Tso Lung, near
Ma Wat River in the Kiu Hang area,, Kau
Lung Hang Streams. |
|
Scarlet Basker Urothemis signata |
Local Concern1, Common2 |
Pond and
mitigation wetland in KTN, also in FLN. |
|
Emerald Cascader Zygonyx iris |
Potential Global
Concern1, Abundant2 |
Natural
watercourse in FLN near Tong Hang Tung Chuen, apparently in secondary
woodland Kau Lung Hang Streams. |
Notes
1. Fellowes et
al. (2002).
2. Tam et al. (2011).
3. AFCD Biodiversity Database
(2012).
13.5.4.11 Aquatic Invertebrates
Surveys of aquatic invertebrates in streams in KTN identified the presence of 21 taxa. Most (19 taxa) were found in semi-natural streams, especially those within the catchment of Ma Tso Lung Stream, suggesting that water quality in these streams is relatively good. In lowland habitats, such as mitigation wetlands and lowland streams, macroinvertebrate communities were dominated by freshwater snails, which are usually very abundant in suitable habitats and can tolerate disturbed and moderately polluted environments.
The freshwater crab Somanniathelphusa zanklon, considered to be of Global Concern and listed as endangered by IUCN (2013), was the only species of conservation significance recorded. This species is listed by IUCN (2013) as endemic to Hong Kong. This species was recorded in the Ma Tso Lung San Tsuen Stream. The species was also recorded from the Tung Fong Watercourse, a moderately polluted artificial channel, which is not considered to be suitable habitat. The individual present in this habitat may have been transported downstream by water currents.
According to IUCN (2013), Somanniathelphusa zanklon occurs in a variety of lotic and lentic lowland habitats, and is fairly tolerant of organic pollution, although it prefers unpolluted riverine habitats and slow-flowing low-gradient streams where the substratum might be muddy. It also inhabits irrigation ditches and flooded furrows, and has been found among the roots of floating plants such as the exotic Eichhornia crassipes or the trailing roots and stems of riparian grasses and other plants.
Surveys for the LMC Loop Study in
the Ma Tso Lung San
Tsuen Stream also found Somanniathelphusa zanklon. It was also found in
a polluted watercourse near Chau Tau village in surveys conducted under the LMC
Loop Study.
Surveys of aquatic invertebrates in FLN recorded 24 taxa in the Study Area. Diversity was reasonably high in both the channelised and natural streams (14 and 18 taxa, respectively), compared with only three species recorded in the mitigation wetlands. As in KTN, one species of Global Concern was recorded, the freshwater crab Somanniathelphusa zanklon. The stream at Siu Hang San Tsuen was found to be a good habitat for aquatic macroinvetebrates, including the uncommon freshwater bivalve Corbicula fluminea, atyid shrimp, aquatic moth larvae and fishfly larvae. These indicate that this stream may not be highly disturbed. A lowland stream located within the agricultural land to the north of Tin Ping Shan Tsuen was also found to support a diversity of aquatic invertebrates, including C. fluminea and various odonate larvae, but this stream seems to be dependent upon irrigation from a pumping station constructed by AFCD to provide irrigation water for adjacent agricultural land.
Somanniathelphusa
zanklon was recorded in channelised watercourses at Sheung Shui Wa Shan, Tin Ping Shan Tsuen and Ma Wat Wai. The first of these is a concrete channel, those at Tin Ping Shan Tsuen and
Ma Wat Wai have been informally channelised where they flow through village
areas but include sections with semi-natural stream beds.
Details of
aquatic invertebrates recorded in surveys for the current study are included in
Appendix 13.9.
Table 13.15
- Aquatic Invertebrate Species of Conservation Significance Recorded in the
Study Area during the Current and Previous Studies.
|
Species |
Conservation Status |
Areas/ Habitats |
|
Somanniathelphusa zanklon |
Global Concern1, Endangered2 |
Natural and channelised watercourses at Ma Tso Lung, Chau Tau, Tung Fong, Tin Ping Shan Tsuen, Sheung Shui Wa Shan and Ma Wat Wai |
Notes
1. Fellowes et
al. (2002).
2. IUCN (2013).
In this Section, ecological
characteristics of each habitat type present in the Study Area are described in
accordance with the requirements of Section 13.4.14.4(iv)(c) of the Study
Brief. Maps for the NDAs showing the types and locations of habitats are provided
in Figures 13.6a-v; representative photographs of the
habitat types and important ecological features are presented in Appendix 13.11. In interpreting the habitat maps, it
should be noted that differences in the assessment criteria required under
Section 3.14.4 (Ecological Impact) and Section 3.4.13 (Landscape and Visual
Impact) of the Study Brief result in not all habitat areas being mapped
identically in these two sections of this report. Significant differences, and
reasons for them, are noted below:
·
Grassland,
grassland/shrubland and shrubland have been mapped (and evaluated) as different
habitats in the ecological impact assessment as their ecological
characteristics differ, however they have been treated as a single habitat
(shrubland/grassland mosaic) in the landscape and visual assessment, where they
are considered to have similar landscape and visual characteristics;
·
Different
types of wooded habitat (fung shui wood, secondary woodland, plantation,
mitigation plantation and orchard) have been mapped (and evaluated) as
different habitats in the ecological impact assessment as their ecological
characteristics differ, however they have been treated as a single habitat
(hillside/lowland woodland) in the landscape and visual assessment, where they
are considered to have similar landscape and visual characteristics;
·
Wet
and dry agricultural land have been mapped (and evaluated) as different
habitats in the ecological impact assessment as their ecological
characteristics differ, however they have been treated as a single habitat
(agricultural land) in the landscape and visual assessment, where they are
considered to have similar landscape and visual characteristics. In addition,
small areas which have been mapped as other habitats in the ecological impact
assessment (such as orchard, grassland and plantation) have not always been
regarded as significant in the landscape and visual assessment and have been subsumed
within the area mapped as agricultural land;
·
In
a number of parts of the Study Area habitats which have been mapped as a mosaic
of developed areas, farmland and natural and semi-natural habitats in the
ecological impact assessment have been regarded as a single habitat type (rural
development area) for the purposes of the landscape and visual assessment and
mapped accordingly.
In accordance with the approach throughout
this study, where there are significant differences in the ecological
characteristics of habitats in KTN and FLN, habitats in KTN are described
first.
The complex habitat mosaic of Long Valley, where there are important linkages between habitats, and where many fauna species may be dependent on, or associated with, more than one of these habitats is described and evaluated in this Section as one habitat unit.
13.6.1 Habitats
13.6.1.1 Long Valley
Long Valley, comprising areas both north and south of Sheung Yue River, contains a highly complex mosaic of microhabitats. The principal habitats present are wet and dry agricultural land, ponds and grassland, some of which is seasonally wet. In addition, mitigation woodland plantation is present along the Ng Tung, Sheung Yue and Shek Sheung Rivers, and there are also smaller areas of mitigation wetland (former Sheung Yue River meanders), plantation (largely of fruit trees)and small developed areas.
The area included in the Long Valley
habitat evaluation includes all the areas described in the previous paragraph. However, there is no universally
agreed definition of the boundaries of Long Valley. Whilst the boundaries are
clear in the east (where the Ng Tung and Shek Sheung Rivers form an obvious
boundary), and are relatively clear in the southeast (where there is a
topographical change, as is discussed below), they are more diffuse in the
southwest and, especially, in the northwest in the area to the east of Ho
Sheung Heung River. The approach followed in this report has been to include
all areas of more or less continuous and contiguous wetland in Long Valley, as
is described here, but to exclude more fragmented wetland areas on the
periphery, especially where inclusion of such areas would lead to inclusion of
significant areas of non-wetland habitats and developed areas. Except for the plantations, these areas either currently contain
wetland habitats or are topographically similar (hence could easily be flooded
by gravitational flow) but are currently occupied by dryland habitats.
As noted
above, the dry agricultural fields to the south of Long
Valley (near Yin Kong village) are raised approximately 1.5 - 2 m above the
level of the land closer to the Sheung Yue River; thus, they cannot be easily
flooded in this way. In addition, these fields are highly fragmented by
developed areas, grassland and wooded habitats. These agricultural areas are
described and evaluated in Section
13.6.1.2 below.
In
addition, the Sheung Yue River, whilst contained within the area shown as Long
Valley in Figure 13.6 for the purposes of
ascribing faunal observations to location (as observations from this river are
often attributed to observers as from Long Valley), has been described and
evaluated as a different habitat in Section
13.6.1.6 below.
The wetland conditions in Long Valley are maintained by water from a number of sources, including rainfall (both directly and by retaining wet season rainfall in ponds for subsequent dry season use) and wells. In addition, Long Valley south of the Sheung Yue River receives water which is abstracted from the Sheung Yue River above a fabridam on the river located to the west of the Fanling Highway and delivered by gravity via the Long Valley Watercourse. The area north of the Sheung Yue River also receives some water from the Tsung Yuen Watercourse and one mitigation meander receives water via the Ho Sheung Heung Watercourse.
The mix of habitats in Long Valley is similar on the north and south sides of the Sheung Yue River, but whereas the ponds on the south side of the river are managed, either for production and/or with conservation objectives, many of the ponds on the north side of the river were abandoned for many years and became partially or wholly overgrown, often with invasive or ruderal facultative wetland herbs. This process of habitat degradation has been partially reversed in recent years, through the MA mechanism, but several ponds near to Ho Sheung Heung village remain in a poor condition. Similarly, many grassland areas on the north side of the river have developed by vegetational succession from abandoned farmland, or have been colonised by ruderal herbs and grass species after ponds have been filled. On the south side of the river most such areas have been deliberately left fallow for short periods for agricultural and/or conservation management reasons, as is discussed below.
As was noted in Section 13.3.2, Long Valley MAs managed by the CA and HKBWS, with the participation of farmers in adusting their farming practices to meet conservation objectives, have been in place since 2005. MAs currently cover approximately 12ha in Long Valley. This is subject to change, both in the total and individual areas involved, as participation in the MA scheme is voluntary. Partly as a consequence of MA objectives, but also in accordance with the individual preferences of farmers, and the growth stage of the crops involved, conditions in Long Valley vary both seasonally and within seasons. Such changes apply, especially, in the areas of wet and dry agricultural land and in the ponds to the south of the Sheung Yue River.
The wet agricultural fields comprise a complex mosaic of active and inactive fields. Common wet agricultural crops include Water Spinach Ipomoea aquatica and Water Cress Nasturtium officinale, while some fields (mostly those under the MAs) are cultivated with Water Chestnut Eleocharis dulcis, Rice Oryza sativa, Chinese Arrow-head Sagittaria sagittifolia subsp. leucopetala and Water Caltrop Trapa natans. Water levels in individual fields are variable. Most inactive fields in the area are seasonally wet, retaining water through the wet season, while active fields may be managed for wet or dry crops. Water levels are therefore dependent upon the actions of the farmers and the MA objectives.
Inactive fields are quickly colonised by common and widespread pioneer herb species such as grasses Brachiaria mutica, Panicum maximum and herbs Ipomoea aquatica, Mikania micrantha, Bidens alba, Commelina diffusa, Cyclosorus interruptus and Ludwigia perennis. Other common herbaceous plants are present in lower abundance, including Kyllinga monocephala, Kyllinga aromatica, Polygonum glabrum, Polygonum lapathifolium and sedge Cyperus spp.
Some fields are used for cultivation of dry crops (including Chinese Aloe Aloe vera var. chinensis, Chinese Chives Allium tuberosum, Chinese White Cabbage Brassica chinensis, Lettuce Lactuca sativa, Matrimony Vine Lycium chinense and Egg-plant Solanum melongena) in certain seasons. The use of fields for dry agricultural crops is often temporary and these fields may be flooded in other seasons according to the preferences of the farmer and the MA objectives. Vegetation around cultivated fields is relatively poorly developed due to regular management by farmers to control non-crop species. Plant species present along field bunds include grasses Eleusine indica and Panicum paludosum, sedges Cyperus iria and Kyllinga monocephala, and fruit trees Musa x paradisiaca, Dimocarpus longan, Litchi chinensis and Mangifera indica.
As noted above, many ponds in Long Valley to the north of the Sheung Yue River are former fish ponds that are now abandoned and overgrown. These ponds are close to Ho Sheung Heung Village and are somewhat disturbed by human activities. Ponds to the south of the river include a group of ponds surrounded by high bunds in the centre of this area which have long been managed for the cultivation of invertebrate food to be supplied to aquarists. Other shallow ponds, which may be temporary, are also used for this purpose, the cultivation of lily and lotus or left fallow: management of such ponds is largely driven by MA objectives.
Small areas of marsh habitat are also present in Long Valley. These largely comprise areas where wet agricultural land has been left fallow (either passively or as an MA objective) and have been colonised by wetland herbs of agricultural land as well as crop species. A slightly larger area of marsh is present in the extreme north of Long Valley near the Lo Wu Correctional Institution. This has formed from a former pond that was temporarily filled as a works area and then restored topographically but not returned to fishery use. Plant species diversity is moderate and dominated by exotic wetland species such as Brachiaria mutica and Sesbania cannabina and the invasive exotic tree species Leucaena leucocephala, but also includes some native wetland herb species including Polygonum japonicum, Commelina diffusa and Ludwigia octovalvis.
Mitigation wetlands, created to compensate for ecological impacts of the channelisation of the Ng Tung, Sheung Yue and Shek Sheung Rivers, and now maintained by AFCD, are located along the Sheung Yue River. Habitats in the meanders are ponds (including lotus ponds) and marsh with wetland plant species, such as Commelina diffusa, Cyperus flabelliformis, Cyperus malaccensis, Hedychium coronarium and Ludwigia perennis and Nelumbo nucifera.
Small areas of grassland, plantation and developed area are also present in the habitat mosaic, and though individually these are of lower ecological value than the wetland areas, they add to the species diversity of the site and the habitats are utilised opportunistically by species that generally use the open country habitats.
The mitigation plantations, managed by AFCD as mitigation for the ecological impacts arising from channelisation of the rivers, largely comprise exotic tree species, though some native tree species such as Ficus microcarpa, Ficus virens and bamboo clumps are present, and relatively young (the trees are approximately 15 years old). Both factors result in their being assessed as of relatively low ecological value. However, though of limited intrinsic value in themselves, the plantations are of significant value in screening wildlife in Long Valley from disturbance arising from human activities on the tracks alongside the rivers. In addition, as with the other non-wetland habitats present, these plantations add to the habitat diversity, and hence the associated faunal diversity, of the area.
The complex mix of microhabitats (especially that of permanently and seasonally wet agricultural land, mitigation wetlands, marsh and ponds) provides conditions suitable for a wide diversity of wetland fauna species. There are strong ecological links not only between habitats present within Long Valley but also further afield to the Deep Bay wetland areas. The mixture of habitats present, with strong ecological linkage between them, is responsible for the high ecological value of the site and it is for this reason that ecological evaluation and impact assessments consider the site as a whole rather than breaking it into its consituent habitats. Furthermore, many individual animals and species may be dependent upon the presence of more than one microhabitat for different needs at different times.
In this regard, it should be noted that in the NENT Study, which pre-dated the implementation of MAs in Long Valley, Maunsell (2003) evaluated the active wet agricultural land in Long Valley as of High Ecological Value with potential for enhancement; active dry agricultural land was considered be of Moderate Ecological Value, again with potential for enhancement; and inactive wet and dry agricultural land were considered to be of High Ecological Value with potential for enhancement. Maunsell (2003) also considered ponds in Long Valley to be of High Ecological Value with enhancement potential, and both marsh and mitigation meanders in Long Valley were considered to be of High Ecological Value.
Long Valley is well known as an important site for wetland fauna, especially birds (Appendix 13.4). The site is recognised internationally as part of the Inner Deep Bay and Shenzhen River Catchment Important Bird Area (IBA), although this does not confer any legal protection on the site. The bird community includes a variety of species associated with freshwater wetland habitats, many of which have a relatively restricted distribution in Hong Kong. A total of 278 bird species have been recorded at Long Valley since December 2005, including surveys as part of the regular monitoring conducted by Hong Kong Bird Watching Society (HKBWS 2012 and HKBWS in litt.). Overall, from all sources, a total of 93 species listed by Fellowes et al. (2002) as species of conservation concern in Hong Kong or listed by BirdLife International as globally threatened have been recorded in Long Valley. While many of the species recorded during the HKBWS surveys (spanning more than seven years of weekly surveys, with the addition of observations from other bird watchers) are irregular in occurrence at Long Valley, the high number of species recorded reflects the importance of this site for birds.
Many of the wetland bird species are
present in numbers that are significant from a Hong Kong perspective,
especially those species associated primarily with wet agricultural land. As
elsewhere, active dry fields generally support fewer species than wet fields,
but this is affected by location and ecological linkages. Many
seasonally or permanently dry agricultural fields close to wetland areas are
used regularly by species generally considered to be at least
wetland-associated, especially Little Ringed Plover, Yellow Wagtail and
Red-throated Pipit.
Much of the
ecological significance of Long Valley for bird species is a function of the
high numbers and diversity of species present, and both of these criteria are
higher outside the breeding season. However, Long Valley also provides a
breeding/nursery ground for some bird species. Greater Painted-snipe has been
proven to breed (e.g. Maunsell (2003)) and probably does so regularly as this
species is present in Long Valley throughout the year (e.g. Binnie, Black &
Veatch (2002)). It is likely that Long Valley supports a significant proportion
of the breeding population of this species in Hong Kong. Other species of
conservation significance which may breed (or for which habitat conditions are
suitable for breeding) include Little Grebe, Yellow Bittern, Cinnamon Bittern,
Slaty-breasted Rail, Little Ringed Plover, Zitting Cisticola and
White-shouldered Starling (the last of these in man-made structures).
Observations during 2009 flight-line surveys suggest that Long Valley is also used as a foraging site by ardeids breeding in the egretries at Ho Sheung Heung and Man Kam To Road. Approximately 34% of birds observed leaving Ho Sheung Heung were seen to fly directly towards Long Valley, both north and south of Sheung Yue River. Little Egrets and Eastern Cattle Egrets seemed to be particularly dependent upon this area (58% and 74% of individuals, respectively), whereas only 45% of Chinese Pond Herons from this egretry flew in this direction. Approximately 68% of Chinese Pond Herons leaving Man Kam To Road egretry were heading in the general direction of Long Valley. During the breeding season (April – July), bird surveys at Long Valley recorded up to 39 Little Egrets,13 Eastern Cattle Egrets and 12 Chinese Pond Herons, indicating that many birds from the egretries were indeed foraging at this site.
As shown in Sections 13.5.5.6 and 13.5.5.9 and Appendices 13.2, 13.4 to 13.6 and 13.8, in addition to birds, other wetland or wetland-associated fauna, especially amphibians and dragonflies, are also diverse and some species occur in high numbers in Long Valley.
Most species recorded are widespread in Hong Kong, but mammal species recorded include Greater Bandicoot Rat, East Asian Porcupine, Masked Palm Civet and Leopard Cat, all of which are of conservation significance. Herpetofauna species of conservation significance include Reeve’s Terrapin, Burmese Python, Buff-striped Keelback, Many-banded Krait, Chinese Cobra, King Cobra, Chinese Bullfrog and Two-striped Grass Frog. In addition, Red Muntjac, Tokay Gecko and Water Monitor would be of conservation significance if these species were found to be still present and/or of natural origin.
Four butterfly species of conservation
significance were recorded during surveys conducted under the current study:
Pale Hedge Blue, Painted Lady, Danaid Egg-fly and Commander. In addition to
these species, the following additional butterfly species of conservation
significance have been recorded in other surveys and studies: Dark Brown Ace,
Small Grass Yellow, Lesser Forest Blue, Brown Onyx and Common Pierrot have been seen in the Ho Sheung
Heung area and hence may occur in Long Valley. Of these species, Dark Brown Ace and
Lesser Forest Blue are associated with bamboo groves. Bamboo groves form an
element of areas of mitigation plantation in Long Valley, accordingly Long
Valley habitats may be of significance for these species. Similarly, Danaid
Egg-fly is associated with agricultural land and wetland as well as shrubland,
so Long Valley may be of significance for this species. The other species are
more typically associated with habitats not present in Long Valley (uplands for
Pale Hedge Blue and the migrant Painted Lady; shrubland and/or woodland for
Commander and Brown Onyx), whilst Common Pierrot has not been seen in Hong Kong
for many years (Lo and Hui 2010) so Long Valley is not likely to be of
significance for these species.
One dragonfly
species of listed as being of conservation significance by Fellowes et al. (2002), Scarlet Basker, has been
recorded, though this species is common in fishpond areas in Hong Kong (AFCD
Biodiversity Database (2012).
Table
13.16 - Ecological evaluation of Long
Valley
|
Criteria |
Assessment |
|
Naturalness |
All habitats are anthropogenic and most are actively managed. Some
areas, including inactive agricultural land, marsh, ponds, grassland and
plantation show some natural succession through colonisation and habitat
maturation, but succession is maintained at an early stage by management. |
|
Size |
The overall area (57.61ha) is large and is one of the largest
freshwater wetland areas in Hong Kong. The area of wet agricultural land
(19.11ha, but this fluctuates) is also large in a Hong Kong context. The area
of ponds (7.92ha) is small in a Hong Kong context but large in the Study
Area. The areas of marsh (5.58ha), mitigation wetland (1.02ha), dry
agricultural land (8.80ha), grassland (3.80ha), seasonally wet grassland
(1.26ha), plantation (2.68ha), mitigation plantation (3.81ha), watercourse
(0.16ha) and developed area (3.47ha) are small in the context of the Study
Area except for the area of marsh which is of a moderate size. |
|
Diversity |
A diverse mixture of microhabitats supporting moderate floral
diversity but a highly diverse community of wetland fauna species, especially
birds. |
|
Rarity |
The shallow freshwater wetland habitats (wet agricultural land,
shallow ponds and freshwater marsh) forming a sizeable and varied mosaic of
linked microhabitats that are rare and declining in Hong Kong. Dry
agricultural land is fairly common in Hong Kong, but rarely shows such
ecological connection to wetland habitats. Other dryland habitats are common.
The habitats support a high number of rare bird species and also rare species
of other fauna including mammals, reptiles, amphibians, dragonflies and
butterflies, some of which are wholly or largely restricted to Long Valley
habitats in the Study Area. |
|
Re-creatability |
Could be re-created in areas with suitable soil conditions and
hydrology. |
|
Fragmentation |
A single mosaic of ecologically linked microhabitats. Fragmented by
the Sheung Yue River for most terrestrial fauna, but not for wetland bird
species. |
|
Ecological linkage |
Strong ecological linkage between the constituent habitats. Ecological
linkage also to main river channels, especially the Sheung Yue River, for
wetland birds, to Ho Sheung Heung Egretry for ardeids and to Deep Bay wetland
ecosystem for some wetland bird species. |
|
Potential value |
Currently of high value but with potential for further enhancement
with appropriate management. |
|
Nursery/ breeding ground |
Known to be a breeding ground for Greater Painted-snipe and various
amphibian and dragonfly species, some of which are of conservation
significance. Suitable conditions exist for a number of other bird species of
conservation significance and some of these may breed. Used for foraging by
birds breeding in Ho Sheung Heung Egretry. |
|
Age |
Agricultural use of the area presumably dates back a long time but
habitats maintained at an early successional stage. Plantation habitats are
young (age approximately 15 years). |
|
Abundance/ Richness of wildlife |
Known to support an abundant and diverse community of wetland species,
especially birds. Considered to be of significance for a number of wildlife
species including mammal, bird, reptile, amphibian, dragonfly, and butterfly
species. |
|
Ecological value |
Area to the south of the Sheung Yue River of High to Very High
Ecological Value. Area to the north of the Sheung Yue River of High Ecological Value due to smaller
size, lower habitat diversity and relatively low value of pond areas. |
13.6.1.2 Agricultural land (excluding Long Valley)
Away from Long Valley, most agricultural land in the Study Area is found to the north and east of Sheung Shui/Fanling, primarily around Ma Shi Po, with smaller areas scattered through other lowland areas. Individual farmed areas are small and most are highly fragmented by developed areas, though there are some larger areas around Ma Shi Po.
Most of this agricultural land is utilised for dryland crops, but some areas; (notably around Chau Tau Tsuen in the west of KTN and near the Ng Tung River in FLN); are, at least, seasonally wet and and are utilised for wet agricultural crops.
Floral species diversity in agricultural land in the Study Area away from Long Valley is low and a few common and widespread species are dominant. Species cultivated include Aloe vera var. chinensis, Allium tuberosum, Brassica chinensis, Lactuca sativa, Lycium chinense, Solanum melongena, Ipomoea aquatica, Ipomoea batatas and Nasturtium officinale. Common species found on field bunds include grasses Eleusine indica and Panicum paludosum and sedges Cyperus iria and Kyllinga monocephala. Fruit trees such as Dimocarpus longan, Litchi chinensis and Mangifera indica are also often present along field edges and around village areas.
Faunal diversity in agricultural land in KTN away from Long Valley is constrained by the small areas present, their fragmentation and, in most areas, limited linkages with adjacent habitats; although at Chau Tau an area of wet agricultural land does have linkages with adjacent marsh and seasonally wet grassland.
Surveys conducted under the present study found wet agricultural land in KTN away from Long Valley to be utilised by small numbers of wetland bird species of conservation significance, with Red-billed Starling present in moderate numbers in some areas. High numbers and moderate diversity of amphibians were also found, including one species of conservation significance, Chinese Bullfrog. Dry agricultural land in KTN is of limited significance for fauna of conservation significance with occasional records of species that occur in larger numbers in other habitats, primarily wetlands. Other than incidental records of wetland-dependent or associated birds, only one bird species of conservation significance, Zitting Cisticola, was found in dry agricultural land during the present study. This species is not dependent on this habitat and occurs in larger numbers in grassland and wetland habitats. Similarly, a record of Chinese Bullfrog is of limited significance as this species is dependent on wetland habitats. Wet agricultural land in FLN supports moderate diversity but low numbers of wetland bird species of conservation significance. However, both wet and dry agricultural land areas in FLN support high numbers and moderate diversity of amphibian species. Most species are not of conservation significance, but Chinese Bullfrog is present in small numbers and anecdotal evidence suggests that Two-striped Grass Frog may have occurred, at least in the past.
Two reptile species of conservation
significance have been reported from the Ma Shi Po area by naturalists,
Five-striped Blue-tailed Skink and Buff-striped Keelback, and it is reasonable
to anticipate that these and some other snake species of conservation
significance reported from the Study Area may occur in agricultural land in FLN
in small numbers, given their habitat requirements. In addition, Maunsell (2003) reported a
sighting of Chinese Cobra in active agricultural land in FLN, but the location
was not stated.
Amongst invertebrates, one butterfly species, Commander, was found in surveys for the current study, but as this is primarily a woodland and shrubland species its occurrence in agricultural land is of low significance.
The status of agricultural land in the Study Area changes frequently between active and inactive; both within seasons and between years due to the preferences of individual farmers and the decision of landowners as to whether to make land available to farming tenants. Some areas are farmed more or less continuously, while other areas may be utilised more sporadically. In addition, the area of active agricultural land in the Study Area has declined, since the time of the NENT Study (Maunsell 2003) and during the course of the current Study, especially in FLN.
The change in status of agricultural land is of relevance to the ecological assessment process: active agricultural land may provide conditions suitable for different fauna species than inactive areas; further, the conditions in inactive areas change over time as vegetational succession proceeds.
Thus, Maunsell (2003) considered active wet agricultural land to be of Moderate Ecological Value in both KTN away from Long Valley and in FLN; active dry agricultural land was considered to be of Low to Moderate Ecological Value in both areas; while inactive agricultural land (both wet and dry) was considered to be of Low Ecological Value in KTN and of Moderate Ecological Value in FLN. The reasons for the higher evaluation in FLN included the larger areas present, significantly greater functional linkages with adjacent habitats, and significantly greater numbers and diversity of fauna (especially dragonflies, amphibians and birds), and the presence of rare species. The higher evaluation of inactive dry agricultural land relative to active dry agricultural land in FLN reflected the observation that the inactive dry agricultural land provided suitable nursery and breeding conditions for ‘a wide array of wildlife including rare residents’ and the higher abundance of dragonflies and amphibians.
The consequences of this change over time - with wet agricultural land tending to decline in value if it is left inactive but the value of dry agricultural land tending to increase - need not affect the overall ecological assessment process, so long as there is no overall trend in the relative proportions of agricultural land which is active and inactive.
However, in the present study), the decline in the area of active agricultural land, (especially in FLN, during the course of the study period, may affect the assessment if this only takes into account current conditions. Accordingly, in the current study, while wet and dry agricultural land areas have been evaluated separately, active and inactive areas have been combined for the purposes of assessment and evaluation. The higher value of active wet agricultural land and the higher value of inactive dry agricultural land has been utilised in the evaluation process, where relevant, on a precautionary basis.
Table
13.17 - Ecological evaluation of
Agricultural Land (excluding Long Valley)
|
Criteria |
Wet Agricultural Land – KTN
(excluding Long Valley) |
Wet Agricultural Land - FLN |
Dry Agricultural Land - KTN |
Dry Agricultural Land FLN |
|
Natural-ness |
An artificial habitat created and managed for the cultivation of
various crop species and subject to regular human activity. |
|||
|
Size |
Small patches are present and total area is small (4.16ha). |
Small patches are present and total area is small (3.53ha). |
Small patches are present and total area is small (6.11ha). |
Small patches; but the overall area is moderate (15.87ha). |
|
Diversity |
A low diversity of plant species due to typical crop cultivation
practices. Low to moderate diversity of fauna. |
Low diversity of flora and fauna. |
Flora diversity is low but fauna diversity is low to moderate. Most species are generalists
that occur in several habitats common in the Study Area and/or are species
common in the Study Area. In addition, many of the species, notably birds,
are associated with wetland habitats and use this habitat on an incidental
basis. |
Low floral diversity but fauna diversity is low to moderate. Most
species are generalists that occur in several habitats common in the Study
Area and/or are species common in the Study Area. In addition, many of the
species, notably birds, are associated with wetland habitats and use this habitat
on an incidental basis. |
|
Rarity |
Such small and fragmented areas of wet agricultural habitat are common in Hong Kong, but area is declining. Wetland bird species of conservation significance present in small numbers. Of these, seven species (Watercock, Pintail Snipe, Swinhoe’s Snipe, Citrine Wagtail, Pallas’s Grasshopper Warbler and Oriental Reed Warbler) are largely restricted to wet agricultural land and Long Valley habitats in the Study Area, while one species (Bull-headed Shrike) is largely restricted to these habitats and dry agricultural land in the Study Area. One butterfly species, Danaid Egg-fly, may be largely restricted to wet agricultural land and Long Valley habitats in the Study Area. Other rare species are not restricted to wet agricultural land or a small number or area of habitats. |
A common habitat type in Hong Kong, but area is declining. Supports a
small number but few individuals of rare fauna species. One bird species,
Bull-headed Shrike, is largely restricted to dry agricultural land, wet
agricultural land and Long Valley habitats in the Study Area. Other rare
fauna species are not restricted to dry agricultural land or a small number
or area of habitats. |
||
|
Re-creatability |
Easily re-creatable if suitable hydrological conditions are present. |
Easily re-creatable. |
||
|
Fragmen-tation |
Highly fragmented. |
|||
|
Ecological linkage |
That at Chau Tau has some linkages with nearby seasonally wet
grassland and marsh. Otherwise, only very limited linkages. |
Some linkages for wetland birds with the Ng Tung River and Long
Valley. |
Area to the east of Yin Kong has some linkages to Long Valley. Other
areas have few linkages. |
That in the Ma Shi Po area has some linkages with nearby lowland
grassland, much of which is former agricultural land. Other areas have few
linkages. |
|
Potential value |
Limited potential for enhancement due to small size and, especially,
fragmentation. |
Some potential for enhancement but constrained by fragmentation. |
||
|
Nursery/ breeding ground |
Number of vocalising amphibians suggests that moderate numbers breed
in the area. |
None known. |
||
|
Age |
Unknown but maintained at an early successional stage by regular
management. |
|||
|
Abundance/ Richness of wildlife |
Low to moderate abundance and diversity of amphibians. Low abundance
and diversity of other fauna. |
Low to moderate abundance and diversity of amphibians. Low abundance
and diversity of other fauna |
Low abundance but low to moderate diversity of wildlife; however, many of the species recorded
(notably wetland birds) are more associated with other habitats and utilise
dry agricultural land only occasionally and/or opportunistically. This
habitat is largely occupied by generalist species for which it is not of
significance at a population level. |
|
|
Ecological value |
Low to Moderate Ecological
Value, primarily due to importance for a number of bird species largely
restricted to this and Long Valley habitats in the Study Area. |
Low Ecological Value. |
||
13.6.1.3 Ponds (excluding Long Valley)
Away from Long Valley, there are two main areas of ponds in the Study Area; both these areas are adjacent to the Ng Tung River. Ponds on each side of the tidal Ng Tung River are inactive or are abandoned and are largely overgrown. Floral diversity is low, with those ponds on the west side of the river largely covered by Water Hyancinth Eichhornia crassipes. Faunal diversity is low to moderate, but small numbers of wetland birds, including breeding ardeids, amphibians and dragonflies use these ponds. The most significant observation was a sighting of Eurasian Otter in the pond areas on the east side of the river during surveys conducted for the FCA Study. This is the only confirmed sighting of this Globally Near-threatened species in the Study Area.
Also of significance, however, is the role of these ponds in maintaining the linkage between Long Valley and the Deep Bay wetland ecosystem. Ardeids, including ardeids breeding at Ho Sheung Heung Egretry, use this corridor in significant numbers.
Ponds on the north side of the Ng Tung River in the west of FLN are also inactive or abandoned and largely overgrown with invasive floating vegetation. The ponds are largely surrounded by woodland habitat (orchard and plantation). Again, however, these ponds are of significance for their role in maintaining a flight-line corridor, in this case that between Long Valley and the tidal Ng Tung River and between the Ng Tung River in FLN and Man Kam To Road Egretry.
A single inactive pond straddling the Study Area boundary and located at Tse Koo Hang lies at the edge of the Hoo Hok Wai wetland area. This pond is a part of the much larger fishpond area present in the Deep Bay wetland ecosystem. As such, it is evaluated separately in Table 13.18 below.
An active pond (utilised for rearing fish fry) of 0.95ha is present at Fung Kong. Bunds of this pond are kept clear of herbaceous vegetation, though it is largely surrounded by fruit trees. Measures to minimise loss of fish are in place; nevertheless, small numbers of ardeids are regularly present around this pond. A single inactive pond of moderate size is present south of Ho Sheung Heung. This pond has some linkages with Long Valley and regularly supports small numbers of waterbirds. Neither of these ponds is conveniently evaluated as a part of a larger area of pond or wetland habitats; accordingly these are also evaluated separately below.
Finally, a few isolated, inactive or abandoned ponds are scattered through the Study Area. These ponds are too small in size, too isolated from other wetland habitats and/or too disturbed to support wetland fauna in significant numbers or to be of significance for species of conservation importance (Table 13.18).
Maunsell (2003) categorised ponds as active fish ponds, inactive fish ponds and other ponds, with the latter category covering the aquaculture production ponds in Long Valley, water storage ponds and other unmanaged ponds. A total of 12.7ha of ponds were found, of which approximately 3ha were in Long Valley, and of which 3.4ha were active fish ponds. Allowing for the different Study Areas, the area of ponds has not, therefore, changed significantly in recent years. In Maunsell (2003) ponds away from Long Valley were considered to have a Moderate Ecolological Value.
Table
13.18 - Ecological evaluation of Ponds
(excluding Long Valley)
|
Criteria |
Ponds along the Ng Tung
River |
Pond at Tse Koo Hang |
Larger Ponds in KTN away
from Long Valley |
Small Ponds scattered
through the Study Area |
|
Naturalness |
Man-made. |
|||
|
Size |
Small area in total (8.69ha). |
Small within the Study Area (0.43ha) but forms a part of the Deep Bay
wetland ecosystem (total area between LMC and Ng Tung River approx. 184ha). |
Small (the active pond at Fung Kong is 0.95ha, while the area of
inactive ponds south of Ho Sheung Heung is 1.18ha). |
Small individually and in total (2.96ha). |
|
Diversity |
Low floral diversity and low to moderate faunal diversity. |
Low floral and faunal diversity due to small size, but the larger area
has moderate to high faunal diversity. |
Low floral and faunal diversity. |
|
|
Rarity |
A moderately common habitat, especially in the north-west
NewTerritories. Some fauna of conservation significance, including wetland
dependent species, utilise this habitat but numbers are small and/or use is
irregular. |
|||
|
Re-creatability |
Can be re-created in suitable low-lying locations with appropriate
hydrological conditions. |
|||
|
Fragmentation |
Moderately fragmented by developed areas and non-wetland habitats. |
Not fragmented. |
Highly fragmented. |
|
|
Ecological linkage |
Linked to other wetland habitats by the Ng Tung River. Ponds along the
tidal Ng Tung River form part of the flight-line corridor between Long Valley
and Ho Sheung Heung Egretry and the Deep Bay wetland ecosystem; ponds along
the Ng Tung River in FLN form part of the corridor linking wetlands along the
River with Long Valley |
An integral part of the Deep Bay wetland ecosystem and has significant
linkages with adjacent wetland habitats. |
Some linkages with Long Valley for areids. |
No significant linkages. |
|
Potential value |
Value could be improved with dedicated management for wildlife. |
Value could be improved with dedicated management for wildlife but
constrained by size. |
||
|
Nursery/ breeding ground |
Not known to be a significant breeding ground, but ponds are utilised
as foraging areas by breeding ardeids from Ho Sheung Heung Man Kam To
Egretries. |
Not known to be a significant nursery/ breeding ground. |
||
|
Age |
Unknown. |
|||
|
Abundance/ Richness of wildlife |
Low to moderate abundance and diversity of wetland birds, herpetofauna
and dragonflies. |
Probably low due to small size, but moderate abundance and diversity
of wetland birds, herpetofauna and dragonflies in the wider area. |
Low. |
|
|
Ecological value |
Moderate to High for ponds along the tidal Ng
Tung River due to their role in maintaining linkages. Moderate for ponds to the north of the Ng Tung River in FLN for
the same reason but linkages are less important. |
High as an element of
the wider area. |
Low to Moderate, primarily due to providing
foraging areas for ardeids. |
Low. |
13.6.1.4 Marsh
Away from Long Valley, marsh habitat in
the Study Area is limited to an area in the extreme north-west, near Ma Tso
Lung village (outside the boundaries of the proposed NDA) and an area to the
west of Chau Tau village in the extreme south-west of the Study Area. Both of
these marshes were surveyed and evaluated under the LMC Loop Study. There is no marsh habitat in FLN.
Faunal diversity of both of these marsh areas is limited by lack of microhabitat diversity. However, the marsh at Ma Tso Lung has linkages with adjacent seasonally wet grassland and the Ma Tso Lung Stream system, while that at Chau Tau has linkages with nearby wet agricultural land and seasonally wet grassland.
Despite this, a number of fauna species of conservation significance have been found in the Ma Tso Lung marsh and linked wetland habitats in surveys conducted under the present study, the FCA Study and the LMC Loop Study. While some of these fauna species are not wetland-dependent or wetland-associated, the following observations are of significance in the assessment and evaluation of the marsh habitat.
Common Rat Snake appears to be reasonably
common in the Ma Tso Lung area based on field surveys carried out for the
LMC Loop and FCA Studies. Many-banded Krait was recorded in the LMC Loop study
in village area habitat at Ma Tso Lung, while Chinese Cobra was recorded in
shrubland near Tse Koo Hang (at the edge of the Ma Tso Lung area). While none of these species are
wetland-dependent, it is probable that the combination of streams, marsh,
seasonally wet grasslands and adjacent non-wetland habitats, together with
limited human presence are of some importance for these species.
Chinese
Bullfrog was recorded in the Ma Tso Lung Stream and in marsh in several nearby locations in surveys conducted for
the current study and the LMC Loop Study.
Two butterfly species of conservation significance, Pale Palm Dart and Small Three-ring, have been found in Ma Tso Lung marsh. The larval food plants of both
of these species are common grasses: larvae of Pale Palm Dart feed on Miscanthus sinensis and Pennisetum purpureum, while those of
Small Three-ring feed on Ischaemum barbatum (AFCD Biodiversity Database, Lo & Hui 2010, Xing et al. 2000, Young and Yiu 2002, Young and Yiu. 2011).
None of these grasses
are obligate wetland species, but both Pennisetum
purpureum and Ischaemum barbatum
are often present in wetlands. The edges of the marsh may, therefore, be used by these
butterfly species but
it is unlikely to be of high importance as grassland is abundant in the area. Indeed,
as well as being recorded in marsh, Small Three-ring has also been found in
seasonally-wet grassland and hillside grassland in the area.
One dragonfly species of conservation significance, Ruby Darter, was found in the Ma Tso Lung marsh in surveys for the current study. This is a marsh and pond-dependent species.
One dragonfly species of conservation significance, Scarlet Basker, which is also a marsh and pond-dependent species, was found in Chau Tau marsh in surveys condicted for the Loop Study and Chinese Bullfrog was found in wetland habitat nearby, also in surveys conducted for the Loop Study.
In terms of avifauna, the lack of structural diversity of these marsh areas restricts opportunities severely for the type of bird species that occur more numerously at Long Valley. However, species able to utilise closed-marsh such as Ruddy-breasted Crake, Gallinago snipe and Greater Painted-snipe, or the edges of such areas (e.g. White-throated Kingfisher) do occur.
Table 13.19 - Ecological evaluation of Marsh
|
Criteria |
Ma Tso Lung Marsh |
Chau Tau Marsh |
|
Naturalness |
Semi-natural. |
|
|
Size |
Moderate in size in a HK context (3.93ha). |
Moderate in size in a HK context (1.65ha inside Study Area boundary,
total area 3.50ha). |
|
Diversity |
Low floral diversity but low to moderate faunal diversity. |
Low floral and faunal diversity. |
|
Rarity |
Lowland freshwater marsh is a relatively scarce and declining habitat
in HK; three reptile; one amphibian; two butterfly and one dragonfly of
conservation significance recorded in or near the marsh (though reptiles not
wetland-dependent). |
Lowland freshwater marsh is a relatively scarce and declining habitat
in HK; one amphibian and one dragonfly species of conservation significance
recorded in or near the marsh. Very small numbers of wetland-dependent bird
species. |
|
Re-creatability |
Could be re-created where land has suitable hydrological conditions. |
|
|
Fragmentation |
Fragmented by roads and non-wetland habitats. |
Largely fragmented by developed areas. |
|
Ecological linkage |
Ecological and hydrological linkages to ponds, streams, grassland and
shrubland nearby. |
Some linkages to nearby wet agricultural and seasonally-wet grassland
habitats. |
|
Potential value |
Potential for increase under appropriate management regime. |
Potential for increase under appropriate management regime; but
constrained by developed area nearby and fragmentation. |
|
Nursery/ breeding ground |
Suitable breeding area for amphibians and dragonflies. May be utilised
by Chinese Bullfrog, Small Three-ring and Ruby Darter as a nursery/breeding
area. |
Suitable breeding area for amphibians and dragonflies. May be utilised
by Chinese Bullfrog, and Scarlet Basker as a nursery/breeding area. |
|
Age |
Unknown. |
|
|
Abundance/ Richness of wildlife |
Low to moderate. |
Low. |
|
Ecological value |
Low to Moderate taking into
account linkages with other wetland and semi-natural habitats. |
Low. |
13.6.1.5 Mitigation wetland
In addition to the mitigation wetlands along the Sheung Yue River, which form an element of the Long Valley habitat complex described in Section 13.6.1.1, three further meanders to the southwest of Long Valley, along the Sheung Yue River, and eight meanders of the Ng Tung River (all in FLN) have also been retained as wetland habitat to provide mitigation for the ecological impacts of channelisation. These have been managed by AFCD as ponds or marshes, in which habitat management has included the planting of wetland plants and riparian vegetation (Chik & Lam 2007). These mitigation meanders are described and evaluated below.
The wetlands are planted with common wetland plants such as Cyperus flabelliformis, Cyperus malaccensis and Hedychium coronarium. Herbaceous vegetation, including grasses Brachiaria mutica, Panicum maximum and Imperata koenigii and herbs Bidens alba, Mimosa pudica, Ludwigia octovalvis, Polygonum barbatum and Polygonum lapathifolium, is common on the bunds, which are also planted with a few trees including Acacia confusa, Cinnamomum camphora, Ficus virens var. sublanceolata and Sapium sebiferum.
Faunal species diversity in the mitigation wetlands was generally low to moderate, probably because of their small size and regular disturbance by people, including, in some cases, regular utilisation by anglers. However, the 17 species of dragonfly recorded in surveys conducted for the current study included a single Dingy Dusk-hawker, which is of Local Concern, in one of the Ng Tung River meanders. This species is, however, now considered to be widespread and common in Hong Kong, hence observation of a single individual is not of significance. Wetland birds were mostly common species, but also included Eastern Water Rail, which is an uncommon winter visitor to Hong Kong. The wetlands may also provide foraging areas for ardeids breeding at Ho Sheung Heung and Man Kam To Road Egretries.
These mitigation wetlands were under construction/to be constructed at the time of the NENT Study, but were predicted to be of High Ecological Value by Maunsell (2003) when established. However, it is uncertain if the high level of disturbance which they now experience, following the opening of the maintenance access roads along the river channels for public enjoyment, was anticipated or taken into account in reaching this conclusion.
Table
13.20 - Ecological evaluation of
mitigation wetlands along the Ng Tung and Sheung Yue Rivers
|
Criteria |
Ng Tung River Meanders |
Sheung Yue River Meanders |
|
Naturalness |
Former
semi-natural meanders of the adjacent river, but modified and artificially
isolated by channelisation of the river. |
|
|
Size |
Eight small, isolated patches of wetland. Total 1.57ha. |
Two small,
isolated wetland areas constituting 2.66ha. |
|
Diversity |
Low to Moderate
floral and faunal diversity. |
|
|
Rarity |
Semi-natural wetland habitats are not uncommon in Hong Kong, but are
rarely managed for ecological mitigation. Some wetland bird species of
conservation significance. |
Semi-natural
wetland habitats are not uncommon in Hong Kong, but are rarely managed for
ecological mitigation. Some wetland bird species of conservation
significance. |
|
Re-creatability |
Could be readily
re-created if suitable hydrological conditions present. |
|
|
Fragmentation |
Wetlands are somewhat fragmented but show some connectivity via the
Ng Tung River. |
Wetlands are
somewhat fragmented but show some connectivity via the Sheung Yue River |
|
Ecological linkage |
Some ecological linkages to the Ng Tung River and probable linkages
for ardeids with egretries at Ho Sheung Heung and Man Kam To Road. |
Some ecological
linkages to the Sheung Yue River and probable linkages for ardeids with
egretries at Ho Sheung Heung and, probably to a lesser extent, Man Kam To
Road. |
|
Potential value |
Currently
subject to human disturbance following the opening of the maintenance access
roads along the river channels for public enjoyment. Value could be
increased by reducing disturbance and additional management measures, but
constrained by the small size of the habitat patches. |
|
|
Nursery/ breeding ground |
No significant
breeding grounds known. |
|
|
Age |
Mitigation
wetlands are comparatively new but based on old river meanders. |
|
|
Abundance/ Richness of wildlife |
Low to moderate
diversity and abundance of wildlife but moderate diversity of dragonflies. |
|
|
Ecological value |
Low to Moderate |
Low to Moderate |
13.6.1.6 Major Channelised Watercourses
Three large channelised watercourses, the Ng Tung River, the Shek Sheung River and the Sheung Yue River in which the banks and/or stream bed have been modified to enhance water flow and limit flooding risk are present in the Study Area. Locations of these channelised watercourses are shown in Figure 13.9 and are assessed and evaluated below.
The watercourses are similar in physical
characteristics: all were channelised during the 1990s (Maunsell 1997) and have
grasscrete sides; the Shek Sheung and Sheung Yue Rivers have a concrete
substrate. The Ng Tung and Sheung Yue Rivers and the section of the Shek Sheung
River on the east side of Long Valley are subject to tidal influences. The Ng Tung River in FLN upstream as
far as its confluence with the Ma Wat River is maintained at a permanently high
level by dams, as is the Sheung Yue River above a point just to the south of
where it is crossed by the Fanling Highway. All the rivers are spanned by a
number of bridges (vehicular and pedestrian) of a similar conventional concrete
design with piers in the channels (Figure 3.4 and Plates 61, 63 and 64 in Appendix
13.11).
All bridges
are low structures with no significant elements projecting above the
carriageway level. There is no evidence that the bridges have any fragmentation
impact on flight-lines; most ardeids appear to fly over them at approximately
5m to 10m above the carriageway level of the bridges without making significant
horizontal or vertical adjustments to their flight paths. A possible exception
is the Fanling Highway Bridge over the Sheung Yue River. Relatively few
waterbirds appear to fly over this bridge; however this may because there are
few foraging areas present along the section of river south of the highway,
rather than the bridge acting as a barrier to movement. However, those that do fly over the bridge do
so at typical heights, suggesting that the birds are habituated to the bridges, as was found during flight-line
surveys at the Ho Sheung Heung egretry conducted under this study (see Section 13.5.4.4), and avoidance of the structure and
traffic is not a major constraint to their flight paths.
Due to the artificial substrate and
regular management by DSD, plant species diversity on the banks of these
watercourses is low. Common herbaceous herbs and grasses are dominant,
including Bidens alba, Brachiaria mutica, Mimosa pudica, Panicum
maximum, Sesbania cannabina and Wedelia trilobata.
Thus, as a
consequence of their design and operational requirements, the rivers are highly
uniform and lack structural and microhabitat diversity. Their use by fauna is highly constrained by these limitations and their hydrological
regimes. As a consequence, they are only utilised by a limited number of bird
species and only as feeding areas. Essentially, they are only used for foraging
by bird species which can forage in open wetland habitats and, at least for a
part of the time, by bird species which are not highly sensitive to
disturbance. In addition, foraging opportunities are constrained by water
depths in tidal sections and in sections where water levels are permanently
high.
The bird species using the Sheung Yue
River in the most significant numbers are Little Egret, Little Ringed Plover
and Green Sandpiper (see Appendix 13.3). Flight-line surveys at Ho Sheung
Heung Egretry showed that this river was a potential destination for birds
flying south from the egretry and this is supported by the numbers of species
(especially Little Egret) foraging in the river during the breeding season. A
peak count of 66 Little Egrets foraging in the river during the breeding season
was made during surveys conducted for the current study. The Ng Tung River is also regularly used by wetland-dependent
birds, especially in the intertidal downstream area and the exposed concrete
channel near Ma Shi Po. Of the eleven wetland bird species recorded from the
river, most were present in relatively low abundance, but counts included up to
43 Little Egrets and up to 51 Little Ringed Plover. Flight-line surveys also showed that the Ng
Tung River north of Ho Sheung Heung Egretry is an important movement corridor
for breeding egrets; some of these may forage in the river while others may use
the river as a movement corridor to other foraging areas along the Shenzhen
River.
Other than
Great Cormorant, for which the tidal section of the Ng Tung River is the only
regular site in the Study Area (albeit it occurs in very small numbers relative
to the Hong Kong population), all bird species of conservation significance
regularly utilising the rivers also occur regularly in other wetland habitats
in the Study Area, and only two (Black-winged Stilt and Pied Avocet) are
restricted to the rivers and a limited number of other habitats. Neither
Black-winged Stilt nor Pied Avocet was recorded on the rivers during systematic
surveys undertaken in 2008-09; however both species now occur there regularly,
especially the former (M.R. Leven pers. obs.). The status of both species in
Hong Kong and in Long Valley has changed in recent years: Black-winged Stilt,
which was formerly a non-breeding migrant to Hong Kong now breeds regularly,
while Pied Avocet, which was formerly largely restricted to inter-tidal
mudlflats, now regularly forages in fishponds and is regularly present in
moderate numbers in Long Valley (Hong Kong Bird Reports, HKBWS 2012). These two
species regularly occur only on the rivers and in Long Valley, but numbers in
the river are not high and are insignificant in a Hong Kong context, and both
species, especially Pied Avocet, use Long Valley on a more regular basis (Study
Team pers. obs).
Flight-line
surveys conducted at the Man Kam To Road Egretry showed
that the western section of Ng Tung River is an important movement corridor for
Chinese Pond Herons breeding at this egretry. Most birds were observed to fly
west (downstream). This suggests that their destination was the Ng Tung River
itself, Long Valley or the Sheung Yue River. All of these areas are within two
kilometres of the egretry so are well within the foraging range of breeding
Chinese Pond Herons.
A Chinese Softshell Turtle Pelodiscus sinensis (listed as of global conservation concern by Fellowes et al. (2002)) was recorded in an amenity planting strip between the tidal channel of the Ng Tung River and the service road during surveys conducted under the current study. On being disturbed by the observer it retreated into the Ng Tung River. The river would provide suitable habitat for this species, though the grasscrete channel banks are unlikely to be suitable for nesting.
Table 13.21 - Ecological evaluation of Major Channelised Watercourses
|
Criteria |
Ng Tung River |
Sheung Yue River |
Shek Sheung River |
|
Naturalness |
Artificial habitat created by modification of streams courses. |
||
|
Size |
Large (approx. 4700m in length). |
Large (approx. 3300m in length). |
Moderately large (approx. 2300m in length). |
|
Diversity |
Highly uniform habitat, with very limited structural diversity. Floral
diversity low; faunal diversity also low but includes several bird species of
conservation significance. |
Highly uniform habitat, with very limited structural diversity. Floral
diversity low; faunal diversity low for most groups but moderate for wetland
birds, including species of conservation significance. However, all but two
of these species use a variety of wetland habitats in the Study Area; the two
species restricted to the rivers and Long Valley habitats occur more
regularly and in larger numbers in Long Valley. |
Highly uniform habitat, with very limited structural diversity. Floral
and faunal diversity low but including some bird species of conservation
significance. However, all but two of these species use a variety of wetland
habitats in the Study Area; the two species restricted to the rivers and Long
Valley habitats occur more regularly and in larger numbers in Long Valley. |
|
Rarity |
Channelised watercourses are very common in Hong Kong; but rivers of
this size are few. The tidal downstream section is particularly rare in a
Hong Kong context. Several wetland bird species and Chinese Soft-shelled
Turtle are of conservation significance. However, bird species of
conservation significance using this habitat are relatively common in the
Study Area. Further, all but two of these species use a variety of wetland
habitats in the Study Area; the two species restricted to the rivers and Long
Valley habitats occur more regularly and in larger numbers in Long Valley. |
Channelised watercourses are very common in Hong Kong; but rivers of
this size are few. Several wetland bird species are of conservation
significance. However, bird species of conservation significance using this
habitat are relatively common in the Study Area. Further, all but two of
these species use a variety of wetland habitats in the Study Area; the two
species restricted to the rivers and Long Valley habitats occur more
regularly and in larger numbers in Long Valley. |
|
|
Re-creatability |
Could be re-created where suitable hydrological conditions present. |
||
|
Fragmentation |
Habitat is somewhat fragmented by roads/bridges (except tidal section
which is not fragmented). Non-tidal
section is fragmented for aquatic fauna by dams; avoidance of structures and
disturbance from people may deter some disturbance sensitive bird species
from utilising as a movement corridor. |
Habitat is somewhat fragmented by roads/bridges. Significantly
fragmented for aquatic fauna by dam upstream from the Fanling Highway Bridge.
The movement corridor for large waterbirds from Ho Sheung Heung Egretry and
to Long Valley is currently not fragmented. |
Tidal section is slightly fragmented by a bridge. Non-tidal section is
fragmented for aquatic fauna by dams; avoidance of structures and disturbance
from people may deter some disturbance sensitive bird species from utilising
as a movement corridor. |
|
Ecological linkage |
Tidal section has significant linkages to Deep Bay wetland ecosystem,
linkages to Long Valley wetland habitats and Ho Sheung Heung Egretry. Tidal
section also has linkages to linkages to other major channelised
watercourses. Non-tidal section has linkages to Man Kam To Road Egretry and
some linkages to other habitats in FLN. |
Significant linkages to Long Valley wetland habitats and Ho Sheung
Heung Egretry and to Ng Tung River. |
Significant linkages to Long Valley wetland habitats. |
|
Potential value |
Limited potential to increase value of riparian vegetation due to
operational constraints, as vegetation must be managed such that it does not
impede water flow and increase flood risk. No potential to increase value in
other ways due to operational constraints. |
||
|
Nursery/ breeding ground |
Not known to be a breeding ground for species of conservation
significance (and highly unlikely to be so due to physical characteristics),
but provides a foraging site for egrets from Ho Sheung Heung Egretry
(especially Little Egret). |
Not known to be a breeding ground for species of conservation
significance (and highly unlikely to be so due to physical characteristics),
but provides a foraging site for egrets from Ho Sheung Heung Egretry
(especially Little Egret). |
Not known to be a breeding ground present for species of conservation
significance (and highly unlikely to be so due to physical characteristics). |
|
Age |
Watercourses have been fairly recently channelised (about 10-15
years). |
||
|
Abundance/ Richness of wildlife |
Moderate abundance but low diversity of wetland birds including
species of conservation significance. Only able to be utilised by a small
number of species due to uniformity of habitat; low abundance and diversity
for other fauna of conservation significance. |
Moderate abundance and diversity of wetland birds including species of
conservation significance. Only able to be utilised by a small number of
species due to uniformity of habitat; low abundance and diversity of other
fauna of conservation significance. |
Low abundance and diversity of wildlife but used by small numbers of
some bird species of conservation significance. |
|
Ecological value |
Tidal section of Moderate
Ecological Value due to importance in maintaining linkages between Long
Valley and the Deep Bay wetland ecosystem and as a foraging area for
waterbirds of conservation significance. Non-tidal section of Low to Moderate Ecological Value due
to importance in maintaining ecological linkages and use as a foraging area
by small numbers of waterbirds of conservation significance. |
Moderate Ecological Value due to its
importance as a foraging area for moderate to high numbers waterbirds of
conservation significance, albeit the species diversity is relatively low and
all species occur in a variety of wetland habitats and/or larger numbers
elsewhere in the Study Area. |
Low to Moderate Ecological
Value due to some utilisation by waterbirds of conservation significance. |
13.6.1.7 Minor Watercourses/Stream
Minor watercourses/streams are distributed
throughout the Study Area (Figure 13.9). None of these watercourses
are entirely natural throughout their entire length, though some are largely
natural in their upper reaches. In the following section, a broadly
geographical approach has been taken to presentation, beginning in the
northwest of KTN and proceeding eastwards and southwards. In addition to the watercourses
described below, a few small, largely seasonal, watercourses in upland areas
which lack a defined riparian corridor are shown on Figure 13.10 and are
considered, where relevant, in the evaluation of the adjacent habitats.
Ma Tso Lung Stream and tributaries
The upper and middle reaches of the Ma Tso Lung Stream and its tributaries are largely natural, with only limited anthropogenic influences from adjacent and nearby development. Vegetation around the stream in these sections is largely plantation, containing a closed canopy of fruit trees (such as Dimocarpus longan and Litchi chinensis) which has been naturally colonized by native understorey species (such as the herbs Alocasia odora and Lophatherum gracile and the tree Schefflera heptaphylla).
In the lower reaches where it lies in the north of the Project Area, the channel consists of natural materials, but it is maintained and shaped by regular management. Vegetation in this section is grassland, which may be seasonally wet, but is cut periodically. Downstream of this section, to the edge of the Study Area, the stream is partially channelised, but the streambed is largely natural. Adjacent vegetation in this section of the stream is seasonally wet grassland and marsh.
The potential ecological value of some sections of the stream may be limited by upstream pollution sources (largely village areas), but it appears that the water is cleaned naturally to some extent as it progresses, and it is able to support a moderately diverse invertebrate community in the middle reaches.
Fauna species of conservation significance recorded in the middle and upper reaches of the Ma Tso Lung Stream include the globally critically endangered Three-banded Box Terrapin, recorded in surveys conducted as a part of the current study. Surveys conducted under the current study and surveys for the LMC Loop Study also logged the presence of Chinese Bullfrog in several locations along and near to these sections of the stream.
In the lower reaches of Ma Tso Lung Stream and the
adjacent and closely ecologically linked Ma Tso Lung Marsh, three reptiles and
one amphibian of conservation significance have been found in recent surveys: Chinese Cobra and Common Rat
Snake were found in surveys for the Loop Study, and Many-banded Krait was found
in surveys for the FCA Study. While none of these species are
wetland-dependent, it is probable that the combination of streams, marsh,
seasonally wet grasslands and adjacent non-wetland habitats, together with
limited human presence are of some importance for these species. Chinese
Bullfrog was recorded in the marsh area and in several nearby locations in
surveys conducted for the current study and the Loop Study.
Also present in Ma Tso Lung Marsh and
hence potentially dependent upon Ma Tso Lung Stream is one dragonfly species of conservation
significance, Ruby Darter which is associated with marsh and pond habitats (see
Section 13.6.1.4). Pale Palm Dart and Small Three-ring, both
butterfly species of conservation significance, were also found in wetland at
Ma Tso Lung, these species is unlikely to be dependent on the wetland habitats
in the area as their larval food plants are common grasses which are not
obligate wetland species.
Though it is slightly disturbed by domestic pollution and anthropogenic structure, Ma Tso Lung San Tsuen Stream also supports fauna species of conservation significance. Species found in surveys conducted for the current study and the LMC Loop Study included Small Snakehead, Chinese Bullfrog, the crab Somanniathelphusa zanklon (in two locations) and Ruby Darter.
Table 13.22 - Ecological evaluation of Ma Tso Lung Stream
|
Criteria |
North: Ma Tso Lung Stream |
Ma Tso Lung San Tsuen
Stream |
|
Naturalness |
Largely natural in the upstream and midstream sections; partially
channelised but with natural stream bottom and largely natural banks in the
lower reaches. Some pollution but water quality largely good. |
Largely natural, but some disturbance from adjacent structures and
pollution. |
|
Size |
Ma Tso Lung stream is narrow
(<5m) but moderate in length (5600m including upper tributaries). |
Ma Tso Lung San Tsuen Watercourse is narrow and relatively short
(1000m). |
|
Diversity |
Moderate diversity of riparian vegetation; especially in the middle
and upper reaches. Moderate diversity of fauna in stream and riparian
corridor. |
Low diversity of riparian vegetation. Moderate diversity of fauna in
stream and riparian corridor. |
|
Rarity |
Streams with this limited level of human activity are uncommon in Hong
Kong and declining due to channelisation. Three-banded Box Terrapin is
globally critically endangered; several other species of conservation
importance are present in and near the stream and ecologically and
hydrologically linked habitats. |
Streams with this limited level of human activity are uncommon in Hong
Kong and declining due to channelisation. Three species, including two stream
specialists (Small Snakehead and Somanniathelphusa
zanklon) were recorded in and along the stream; several other species of
conservation importance are present in ecologically and hydrologically linked
habitats. |
|
Re-creatability |
Middle and upper sections are not easily re-creatable; partially
channelised lower section could be re-created. |
Not easily re-creatable. |
|
Fragmentation |
Some fragmentation due to roads, structures and pollution but riparian
corridor largely unfragmented. |
Slightly fragmented by structures and pollution. |
|
Ecological linkage |
Significant ecological and hydrological linkages to adjacent and
downstream habitats: plantation in upper and middle sections; marsh,
seasonally wet grassland and shrubland in lower sections. Riparian corridor
of Ma Tso Lung Stream is a significant ecological corridor. |
Significant ecological and hydrological linkages to and downstream habitats:
marsh and seasonally wet grassland. |
|
Potential value |
Some potential for enhancement, especially in Ma Tso Lung Stream, by
preventing pollution or by improvement to riparian vegetation. |
Some potential for enhancement by preventing pollution or by
improvement to riparian vegetation. |
|
Nursery/ breeding ground |
Stream fauna of conservation significance presumably breeds in the
stream or marsh. |
Stream fauna of conservation significance presumably breeds in the
stream or marsh or downstream marsh or stream habitats. |
|
Age |
Not known, but modified by past human activity, especially to riparian
vegetation. |
Not known, but modified by past human activity, especially to riparian
vegetation. |
|
Abundance/ Richness of wildlife |
Moderate abundance and diversity of riparian and stream fauna with
several species of conservation significance present including Three-banded
Box Terrapin. |
Low to moderate abundance and diversity of riparian and stream fauna
with several species of conservation significance present. |
|
Ecological value |
Upper and midstream section of Ma Tso Lung Stream of High Ecological Value because of
presence of Three-banded Box Terrapin; lower section of Moderate to High Ecological Value because of presence of several
species of conservation significance and importance of riparian corridor. |
Ma Tso Lung San Tsuen Stream of Moderate
to High Ecological Value due to presence species of conservation
importance. |
Pak
Shek Au Watercourse and Chau Tau Village Watercourses
Pak Shek Au
Watercourse comprises two concrete-lined ‘v-shaped’
drainage ditches bordering the Castle Peak Road (Chau Tau section) empty into a
roadside culvert. They only flow after rain and do not support any stream
fauna.
The Chau
Tau Village Watercourses comprise two minor and polluted channels in the east
of the village. They were surveyed for the LMC Loop Study and were found to
support a small number of the crab species Somanniathelphusa zanklon which is of conservation significance. These
streams were evaluated as of low ecological value under that study.
Tung
Fong/Shek Tsai Ling Watercourse and Kwu Tung Watercourse
These watercourses are the upper and lower sections of the same river basin respectively. They are largely channelised with vertical concrete sides and bottom and are polluted by grey water run-off from nearby open storage and Ho Sheung Heung Road. However, part of the upstream section of the Tung Fong Watercourse is not channelised and has a rocky, semi-natural streamcourse. This section of the watercourse only flows seasonally and is highly degraded and polluted by human activities. The species complexity and abundance of fauna and flora species on both watercourses is low.
The only fish species recorded in surveys conducted
under the current study was the exotic Mosquito Fish. However, the endangered
crab Somanniathelphusa zanklon was
recorded in the concrete-lined channel of the Tung Fong Watercourse. This
species occurs in a variety of lotic and lentic lowland habitats, including
irrigation ditches, and is fairly tolerant of organic pollution, but generally
favours a muddy substrate, so the individual recorded may have been displaced
from habitat upstream. Surveys conducted under the current and LMC Loop studies
have found this species in a number of streams in the area of varying
ecological value. Thus, while of relevance to the assessment process, in view
of the habitat preferences of this species, the presence of this species is considered
to be of limited relevance to the assessment of the ecological value of the
watercourse habitat as a whole.
No flora or other fauna of conservation significance
has been recorded from this stream.
Table 13.23 - Ecological evaluation of Tung Fong/Shek Tsai Ling Watercourse and Kwu Tung Watercourse
|
Criteria |
Assessment |
|
Naturalness |
Largely channelised with ‘u-shaped’ concrete channel, upper section of
Tung Fong Watercourse is a natural rocky channel, but this section is highly
disturbed by anthropogenic activity and is seasonal. |
|
Size |
Small. |
|
Diversity |
Low faunal and floral diversity. |
|
Rarity |
A common habitat type in urban and village areas in HK; however one
crab species of conservation significance, Somanniathelphusa
zanklon, was found, albeit in atypical and probably unsuitable habitat. |
|
Re-creatability |
Readily re-created. |
|
Fragmentation |
Connected hydrologically, but fragmented ecologically by urban/village
development. |
|
Ecological linkage |
No significant linkages. |
|
Potential value |
Very little potential for enhancement without complete re-engineering
of channels. |
|
Nursery/ breeding ground |
Not known to be an important nursery or breeding ground and most
unlikely due to small size, artificial nature and pollution. However,
presence of Somanniathelphusa zanklon suggests
that this species may breed, perhaps in the upstream section. |
|
Age |
Unknown. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of fauna. |
|
Ecological value |
Low Ecological Value. |
Fung Kong and Ho Sheung Heung Watercourses
These watercourses are the upper and lower sections of the same catchment, respectively, and are situated to the west of Ho Sheung Heung village. Most sections of these watercourses lie in vertical-walled concrete channels; some sections of the Fung Kong Watercourse have been channelised by villagers and are not lined with concrete. However, these sections are highly disturbed by anthropogenic structures and pollution while vegetation is dominated by the aggressive exotic climber Mikania micrantha and common herb species such as Panicum maximum and Bidens alba. Other than a dead Indo-Chinese Rat Snake Ptyas korros found in a vertical-walled section of Ho Sheung Heung Watercourse (which may have fallen in and cannot be considered as an individual utilising the habitat), only very limited pollution-tolerant fish and invertebrate stream fauna species were recorded during surveys conducted under the present study.
This watercourse does, however, supply water to a mitigation meander on the Sheung Yue River; in view of the polluted state of the watercourse it is not clear if this hydrological linkage is beneficial.
Table 13.24 - Ecological evaluation of Fung Kong and Ho Sheung Heung Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Largely channelised with ‘u-shaped’ concrete channel, part of Fung
Kong Watercourse has been ‘informally’ channelised and is not lined with
concrete. Highly disturbed by anthropogenic activity. |
|
Size |
Small. |
|
Diversity |
Low faunal and floral diversity. |
|
Rarity |
A common habitat type in urban and village areas in HK; one reptile of
conservation significance (Indo-chinese Rat Snake) was found in surveys,
however the individual was dead and in unsuitable habitat. |
|
Re-creatability |
Readily re-created. |
|
Fragmentation |
Connected hydrologically, but fragmented ecologically by urban/village
development. |
|
Ecological linkage |
No significant ecological linkages, but linked hydrologically to a
mitigation meander downstream on the Sheung Yue River. |
|
Potential value |
Very little potential for enhancement without complete re-engineering
of channels. |
|
Nursery/ breeding ground |
Not known to be an important nursery or breeding ground and most
unlikely due to small size, artificial nature and pollution. |
|
Age |
Unknown. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of fauna. |
|
Ecological value |
Low Ecological Value. |
Tsung Yuen Watercourse
This small watercourse passes through Ho Sheung Heung San Tsuen and agricultural land in the north of Long Valley. The watercourse is partly channelised, but part of the channel is semi-natural, albeit highly polluted by domestic discharge from the village. Riparian vegetation is dominated by disturbance-tolerant exotic species such as Brachiaria mutica and Kyllingo polyphylla. Only pollution-tolerant fish and stream invertebrate species were found in this channel during surveys conducted under the current study. However, these included one fish species, Climbing Perch, which is listed as Data Deficient by IUCN. This species appears to have colonized Hong Kong in recent years, but it is uncertain if the population has reached Hong Kong naturally.
The unchannelised section of this stream is programmed to be channelised during 2013 - 2016.
Table
13.25 - Ecological evaluation of Tsung
Yuen Watercourse
|
Criteria |
Assessment |
|
Naturalness |
Partly channelised but largely semi-natural sides and stream bottom.
Highly disturbed by anthropogenic activity. |
|
Size |
Small. |
|
Diversity |
Low faunal and floral diversity. |
|
Rarity |
A common habitat type in urban and village areas in HK. One fish
species, Climbing Perch, present but origin uncertain. |
|
Re-creatability |
Readily re-created. |
|
Fragmentation |
Fragmented by urban/village development. |
|
Ecological linkage |
No significant ecological linkages. |
|
Potential value |
Could be enhanced by sensitive channelisation and control of
pollution. |
|
Nursery/ breeding ground |
Not known to be an important nursery or breeding ground and most
unlikely due to small size, artificial nature and pollution. |
|
Age |
Unknown. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of fauna. |
|
Ecological value |
Low Ecological Value. |
Lo Wu Correctional Institution Watercourse
This ‘watercourse’ is a vertical concrete-lined drainage ditch and only flows after rain and is not of ecological significance. No fish were found and the only invertebrates present in a heavily polluted pool were exotic gastropods during surveys conducted under the current study.
Ngam Pin Watercourse
This small watercourse is located in the north of the Study Area, rising on the east side of Crest Hill and flowing into ponds adjacent to the Ng Tung River. The lower portion of the watercourse borders storage yards and other anthropogenic structures but the natural stream bed is retained. As the watercourse is highly disturbed by human activities in the lower section, riparian vegetation here largely comprises ruderal species such as Bidens alba, Alocasia macrorhizos and Praxelis clematidea. However, a clump of the protected riparian fern species Cibotium barometz was found beside the watercourse. This species is listed as a Category II nationally protected species in China (CSIS 2013) and is protected under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586). It is, however, very common in forest and shrubland in Hong Kong (Xing et al. 2000).
The upper section of this stream is largely natural but its ecological value is constrained by its small size and low flow, with the upper reaches being seasonal.
No fish
or stream invertebrates were found in the stream during surverys conducted
under the current study.
Table 13.26 - Ecological evaluation of Ngam Pin Watercourse
|
Criteria |
Assessment |
|
Naturalness |
Largely natural but disturbed by anthropogenic activity in the lower
section which is polluted. |
|
Size |
Small and narrow (700m in length) with limited flow in the dry season. |
|
Diversity |
Low faunal diversity, but riparian vegetation moderately diverse along
its upper reaches. |
|
Rarity |
Small natural streams are moderately common in Hong Kong but
declining. One fern, Cibotium barometz,
of conservation significance found, but this species is common in Hong Kong. |
|
Re-creatability |
Not easily re-creatable. |
|
Fragmentation |
Somewhat fragmented in its lower reaches by developed areas. |
|
Ecological linkage |
Limited ecological linkage to surrounding habitats but hydrological
linkage to ponds west of Ng Tung River. |
|
Potential value |
Some potential for enhancement by preventing pollution or by
improvement to riparian vegetation in lower reaches. |
|
Nursery/ breeding ground |
No breeding grounds known and unlikely due to small size and
pollution. |
|
Age |
A long-established habitat but with past human activity, especially to
riparian vegetation. |
|
Abundance/ Richness of wildlife |
Low diversity and low abundance of wildlife. |
|
Ecological value |
Low to Moderate Ecological
Value due to natural condition of upstream section. |
Long Valley Watercourse
The Long Valley Watercourse is an irrigation channel that delivers water from the Sheung Yue River to Long Valley. Water is abstracted above a fabridam on the river upstream from the Fanling Highway. The upstream section is a concrete-lined channel; water quality is relatively high but the concrete lining severely limits its ecological function.
The middle and downstream sections comprise a network of manually created ditches, largely with earth sides and bottom, which are frequently modified by farmers for irrigation and other agricultural purposes.
Fish and stream invertebrate species found
in stream surveys conducted under the current study found one fish species,
Climbing Perch, in the downstream section of the watercourse within Long
Valley. This species is
not considered to be of conservation significance.
Table 13.27 - Ecological evaluation of the Long Valley Watercourse
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat. |
|
Size |
Small. |
|
Diversity |
Low habitat diversity; low diversity of stream fauna. |
|
Rarity |
A common habitat type in Hong Kong. No rare species of conservation
significance recorded in the stream. |
|
Re-creatability |
Could be re-created where suitable hydrological conditions present. |
|
Fragmentation |
Upper reaches fragmented by roads and developed area but not
hydrologically fragmented. |
|
Ecological linkage |
Ecologically linked to other
wetland habitats in Long Valley. |
|
Potential value |
Significant potential for enhancement within Long Valley. |
|
Nursery/ breeding ground |
Not known to be an important nursery or breeding ground but likely to
be utilised by wetland-dependent fauna in Long Valley. |
|
Age |
Unknown but upstream section modified during river channelisation
works and downstream sections regularly modified by farming activities. |
|
Abundance/ Richness of wildlife |
Moderate abundance but relatively low diversity of stream fauna due to
anthropogenic activity. |
|
Ecological value |
Low to Moderate Ecological
Value largely due to its ecological linkages to other wetland habitats in
Long Valley. |
Cheung Po Tau Stream
This and the Fu Tei Au Watercourse comprise one catchment area which drains into the Ng Tung River in the northwest of FLN, but are fragmented by the village of Hung Kiu San Tsuen. The Cheung Po Tau Stream is a natural watercourse in its upper reaches but the lower section is a concrete-lined channel. The entire watercourse is seasonal. It is somehat disturbed by human activity, including hillfire, in its upper reaches, and highly disturbed close to Hung Kiu San Tsuen.
The upper section of Cheung Po Tau Stream is located under the plantation woodland. The plantation is dominated by the exotic tree Melaleuca quinquenervia but native shrub species such as Rhus chinensis are found below the tree canopy. Two wild orchid species were recorded on the roadside close to the upper section of the stream; two individuals of Spathoglottis pubescens and 57 individuals of Pecteilis susannae were identified. All wild native orchid species are protected under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) and the Forestry Regulations (Cap. 96A) in Hong Kong. The population of Pecteilis susannae has undergone a dramatic decline due to extensive collection and hill fire, hence it is listed as infrequent and restricted by Barretto et al. (2011). The other orchid species Spathoglottis pubescens is regarded as abundant and widespread (Barretto et al. 2011).
Being seasonal, no fish species were found during surveys conducted in the Cheung Po Tau Stream under the current study. However, water quality was found to be fair and a moderate diversity, but low numbers of stream fauna species was found. Though not of conservation significance, an uncommon dragonfly species Elusive Adjutant Aethriamanta brevipennis was found near the lower section of watercourse in surveys conducted under the current study. This species is considered as uncommon by Tam et al. (2011). In addition, Bush Hopper Ampittia dioscorides, a wetland-dependent butterfly species which is considered to be uncommon in Hong Kong (AFCD Biodiversity Database 2012), was also recorded near the stream in surveys conducted under the current study.
Table
13.28 - Ecological evaluation of Cheung Po
Tau Stream
|
Criteria |
Cheung Po Tau Stream |
|
Naturalness |
Semi-natural habitat in its upstream section but with human impacts to
riparian habitats; lower section channelised and highly disturbed. Relatively
unpolluted in its upstream section, but lower section polluted. |
|
Size |
Small. |
|
Diversity |
Habitat, floral and faunal diversity low to moderate. |
|
Rarity |
Natural streams are common but declining in Hong Kong. Two protected
orchid species present in riparian corridor. |
|
Re-creatability |
Not easy to re-create. |
|
Fragmentation |
Fragmented by developed area in its lower reaches. |
|
Ecological linkage |
Some ecological linkages with adjacent woodland and shrubland
habitats. |
|
Potential value |
Potential for improvement if riparian corridor protected from fire and
other anthropogenic impacts. |
|
Nursery/ breeding ground |
Not known to support important breeding grounds. |
|
Age |
A relatively long-established habitat but with some human influence. |
|
Abundance/ Richness of wildlife |
Moderate diversity but low numbers of riparian and stream fauna. |
|
Ecological value |
Low to Moderate due to rarity of
habitat and protected and uncommon species in riparian corridor. |
Fu
Tei Au Watercourse
This seasonal watercourse is channelised with vertical concrete sides and floor. Thus, its ecological value is severely limited and this is exacerbated by pollution from the nearby developed area and storage yard. As the stream is channelised, plant diversity and coverage were found to be very low. Species such as Ipomea carica, Mikania micrantha, Wedelia trilobata and Panicum maximum were recorded. No fish or aquatic invertebrates were found in surveys of Fu Tei Au Watercourse conducted under the current study and no fauna of conservation significance is present.
Table
13.28a - Ecological evaluation of Fu Tei Au Watercourse
|
Criteria |
Fu Tei Au Watercourse |
|
Naturalness |
Man-made habitat. Polluted. |
|
Size |
Small. |
|
Diversity |
Low diversity of fauna and flora. |
|
Rarity |
A common habitat in Hong Kong. |
|
Re-creatability |
Easy to re-create. |
|
Fragmentation |
Fragmented by developed areas. |
|
Ecological linkage |
Little ecological linkage between these and other habitats. |
|
Potential value |
Little potential for improvement of value without significant
engineering works. |
|
Nursery/ breeding ground |
Not known to support important breeding grounds. |
|
Age |
Created relatively recently during the Ng Tung River channelisation. |
|
Abundance/ Richness of wildlife |
Low. |
|
Ecological value |
Low Ecological Value. |
Sheung Shui Wa Shan
Watercourses
These twin watercourses pass through Sheung Shui Wa Shan Village. They are channelised in ‘u-shaped’ concrete channels below the villages, but the upper sections in the villages are ‘informally’ channelised. Though somewhat polluted, water quality was found to be fair in both channels in stream surveys conducted under the present study.
Only exotic fish species were recorded in these surveys, but a single individual of a crab species of conservation significance, Somanniathelphusa zanklon was recorded in the eastern channel. This species occurs in a variety of lotic and lentic lowland habitats, including irrigation ditches, and is fairly tolerant of organic pollution. Surveys conducted under the current and LMC Loop studies have found this species in a number of streams of varying ecological value in the area.
No flora or other fauna of conservation significance
has been recorded from these streams.
Table 13.29 - Ecological evaluation of Sheung Shui Wa Shan Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat. |
|
Size |
Small. |
|
Diversity |
Low habitat diversity; low diversity of stream fauna. |
|
Rarity |
A common habitat type in Hong Kong. The crab species Somanniathelphusa zanklon of
conservation significance was recorded in the eastern channel. However, only
a single individual was found, suggesting that the population of this species
in this stream is small. |
|
Re-creatability |
Easily re-created. |
|
Fragmentation |
Fragmented by developed areas. |
|
Ecological linkage |
No significant ecological linkages. |
|
Potential value |
Very little potential for enhancement without complete re-engineering
of channels. |
|
Nursery/ breeding ground |
Not known to be an important nursery or breeding ground. However,
presence of Somanniathelphusa zanklon suggests
that this species may breed in the eastern watercourse. |
|
Age |
Unknown but modified during river channelisation works. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of wildlife. |
|
Ecological value |
Low to Moderate Ecological Value due to presence of Somanniathelphusa zanklon on a precautionary basis as this
species is listed as of Global Concern, albeit it appears to be quite
widespread in the Study Area and in Hong Kong. |
Siu Hang San Tsuen
This stream
is a tributary of the Ng Tung River; the downstream section passes through a
mitigation wetland maintained by AFCD, while the upstream section flows through
agricultural land. The downstream section is in a concrete-lined channel; the
upstream section is semi-natural but has been excavated to improve flow. Floral
diversity along the riparian corridor is typical of agricultural land in the
upstream section and of mitigation wetland in the downstream section.
However,
the aquatic faunal community is moderately diverse including the native fish
Predaceous Chub Parazacco spilurus,
which is common in Hong Kong but is listed as ‘Vulnerable’ in the Chinese Red
Data Book. The dragonfly community of the stream is also diverse, with 19
species recorded including Blue Sprite (of Local Concern) and Emerald Cascader
(of Potential Global Concern). However, despite these species being listed as
of respectively local and international conservation significance, Blue Sprite
is common in Hong Kong and Emerald Cascader is abundant (AFCD Biodiversity Dateabase
2012).
Table 13.30 - Ecological evaluation of Siu Hang San Tsuen Stream
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat, but upstream section has banks and stream floor of
natural materials; some human impacts to riparian habitats. |
|
Size |
Small in size (<5m in width and 1200m in length). |
|
Diversity |
A moderate diversity of fish and invertebrates. |
|
Rarity |
Upstream section is a relatively common stream type in Hong Kong;
channelised downstream section is common. Stream fauna includes one fish
species and two dragonfly species of conservation significance (Predaceous
Chub, Blue Sprite and Emerald Cascader). However, all of these species are
considered to be common or abundant in Hong Kong. None of these rare species
have been found in the lower section of stream. |
|
Re-creatability |
Could be re-created relatively readily. |
|
Fragmentation |
Rather fragmented in this area. |
|
Ecological linkage |
Upstream section has ecological linkage with adjacent agricultural
habitats; downstream section has linkages with mitigation wetland which it
flows through. |
|
Potential value |
Value could be increased by enhancement of vegetation in riparian
corridor. |
|
Nursery/ breeding ground |
Predacious Chub and other stream fish species must breed in the
stream. |
|
Age |
A relatively long-established habitat but with some human influence. |
|
Abundance/ Richness of wildlife |
Moderate abundance and diversity of stream fauna. |
|
Ecological value |
Upstream section of Moderate
Value due to stream fauna; downstream channelised section of Low to Moderate Ecological Value, largely due to linkages with adjacent
mitigation wetland. |
Man Kok Village, Tin Ping Shan Tsuen, Shek Wu San
Tsuen and Ma Shi Po Watercourses
These four small watercourses are located to the south of the Ng Tung River in FLN. All are channelised: Man Kok Village and Shek Wu San Tsuen Watercourses are concrete drainage channels, Tin Ping Shan Tsuen Watercourse is also a concrete channel in its upstream and downstream sections, but part of the midstream, which passes through agricultural land, has sides and bed of natural materials. Finally, Ma Shi Po Watercourse is a seasonal ditch, partly hand dug and partly concrete-lined where it passes through the village; this stream is heavily polluted by grey water.
Stream surveys undertaken under the current study in the Tin Ping San Tsuen Watercourse found no fish species of conservation significance and one individual of the crab species, Somanniathelphusa zanklon, which is of conservation significance. As discussed elsewhere in this Report, surveys conducted under the current and LMC Loop studies have found this species in a number of streams of varying ecological value in the area. Thus, while of relevance to the assessment process, the presence of this species is considered to be of limited relevance to the assessment of the ecological value of the watercourse habitat as a whole.
Table 13.31 - Ecological evaluation of Man Kok Village, Tin Ping Shan Tsuen, Shek Wu San Tsuen and Ma Shi Po
Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat, largely concrete-lined channel but the midstream
section of Tin Ping San Tsuen Watercourse, and sections of Ma Shi Po
Watercourse, have banks and floor of natural materials. All are highly
disturbed by adjacent developed and village areas and are moderately to
highly polluted. |
|
Size |
All are small in size; Mai Shi Po Watercourse is very small. |
|
Diversity |
Low diversity of fish and invertebrates. |
|
Rarity |
Streams of this type are common in Hong Kong; crab species Somanniathelphusa zanklon found in a
channelised section of the Tin Ping Shan Tsuen Watercourse is of conservation
significance but is present in several streams in the Study Area. |
|
Re-creatability |
Could be re-created relatively readily. |
|
Fragmentation |
Fragmented by developed areas. |
|
Ecological linkage |
Some linkages with adjacent agricultural habitats. |
|
Potential value |
Limited potential for enhancement without significant re-engineering
works; Ma Shi Po Watercourse could be enhanced by eliminating pollution but
potential limited by size, seasonality and adjacent developments. |
|
Nursery/ breeding ground |
Somanniathelphusa zanklon may breed in Tin
Pan Shan Tsuen Watercourse. |
|
Age |
Age unknown but all modified in recent years by river channelisation
works. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of stream fauna. |
|
Ecological value |
Low Ecological Value. |
Ma Wat River
This watercourse, which drains into the Ng Tung River in the east of Fanling, is much the largest of the smaller watercourses in the Study Area, at least in its lower reaches. These lower reaches, north of the point where the MTRC East Rail Line crosses the river, have been channelised by creation of a trapezoidal channel with concrete/masonry-lined sides and a concrete floor with a low flow channel (Figure 13.9b illustrates the different sections of the river).
Upstream from this this point to the crossing point of the Fanling Highway the river has been channelised by creation of a trapezoidal grassed concrete channel with cellular paving on the sides and a rock and gravel floor.
South (and upstream) from this point to the southern limit of the Study Area, the channel has gabion sides and a rocky floor and the channel is sufficiently wide to allow establishment of semi-natural herbaceous riparian vegetation in many places. A short length of the upstream section, to the south of Nam Wa Po, is included in the Kau Lung Hang Streams EIS, which was designated due to the presence of Acrossocheilus parallens, a fish species of conservation significance. Another fish species of conservation significance, Small Snakehead, has also been recorded in this stream section (AFCD Biodiversity Database). Common Carp has also been recorded in the EIS. This species is listed as Vulnerable globally by IUCN (2013), but its presence in this location may not be natural.
Table 13.32
- Ecological
evaluation of Ma Wat River
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat, largely concrete-lined channel in lower reaches,
midstream section with an engineered trapezoidal section and rock/gravel
floor; upstream section an engineered channel with gabion sides, rock/gravel
floor and areas with semi-natural riparian vegetation. |
|
Size |
Moderate width but relatively long (length approx. 5.1km). |
|
Diversity |
Low diversity of fish and invertebrates. |
|
Rarity |
Two fish species of conservation significance, Small Snakehead and Acrosssocheilus parallens, have been
recorded, the latter species is of global conservation concern. |
|
Re-creatability |
Could be re-created. |
|
Fragmentation |
Fragmented by developed areas, roads and railway. |
|
Ecological linkage |
Downstream linkage with Ng Tung River, upstream linkages to
tributaries; limited linkages to adjacent habitats. |
|
Potential value |
Limited potential for enhancement without significant re-engineering
works. |
|
Nursery/ breeding ground |
None known, but the fish species of conservation significance, Acrossocheilus parallens and Small
Snakehead, may breed in the
upstream section where suitable habitat appears to be present. |
|
Age |
Age unknown but midstream and upstream sections significantly modified
in recent years by river channelisation works. |
|
Abundance/ Richness of wildlife |
Moderate abundance and diversity of stream fauna in mid and upstream
sections but fish community dominated by exotic species. |
|
Ecological value |
Downstream and midstream sections of Low Ecological Value; upstream
section of Moderate Ecological Value due
to presence of fauna species of conservation significance. |
San Uk
Tsuen, Ma Wat Wai and Tong Hang Watercourses
These small watercourses all drain into the Ma Wat River. All are concrete-lined channels in their lower reaches within the Study Area and all are located within developed areas. Water quality in the San Uk Tsuen Watercourse was found to be poor in stream surveys conducted under the current study, but the water quality in the other channels was fair. No fish or invertebrate species of conservation significance were found in two of the streams during surveys conducted under the current study, while in Ma Wat Wai Stream the crab Sommaniathelphusa zanklon was recorded. This species is listed as of global conservation concern, but has been found in several watercourses in the Study Area.
Table 13.33
- Ecological
evaluation of San Uk Tsuen, Ma Wat Wai and Tong Hang Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Man-made habitat but with semi-natural sections, especially upstream;
all influenced by human activity. |
|
Size |
All are small in size. |
|
Diversity |
Low diversity of fish and invertebrates. |
|
Rarity |
Streams of this type are common in Hong Kong. Sommaniathelphusa zanklon, recorded in the Ma Wat Wai
Watercourse, is of conservation significance. |
|
Re-creatability |
Could be re-created relatively readily. |
|
Fragmentation |
Fragmented by developed areas. |
|
Ecological linkage |
No significant ecological linkages. |
|
Potential value |
Limited potential for enhancement without significant re-engineering
works; constrained by adjacent developments. |
|
Nursery/ breeding ground |
None known. |
|
Age |
Age unknown but all modified in recent years by river channelisation
works. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity of stream fauna; fish community dominated
by exotic species. |
|
Ecological value |
San Uk Tsuen and Tong Hang Watercourses are of Low Ecological Value. Ma Wat Wai Watercourse Low to Moderate Ecological Value due to presence of Somanniathelphusa zanklon on a
precautionary basis as this species is listed as of Global Concern, albeit it
appears to be quite widespread in the Study Area and in Hong Kong. |
Kau Lung Hang Watercourses
The Kau Lung Hang Lo Wai, Kau Lung San Wai, Yuen Leng and Tai Wo Watercourses are, together with a short section of the Ma Wat River discussed above, designated as an EIS due to the presence of Acrossocheilus parallens. The Kau Lung Hang Watercourses meet just south of Kiu Tau and the combined stream joins the Ma Wat River slightly to the east of the Fanling Highway.
During surveys conducted under the current
study the combined channels at Kiu Hang were found to be channelised and
polluted and no fish or invertebrate species of conservation significance were
found. The lower section of the Kau Lung Hang Watercourses was also channelised
at the time of surveys and somewhat polluted. Despite this, Acrossocheilus parallens
was found to be common. The marsh-associated dragonfly species, Ruby Darter,
was found in this area during surveys conducted under the current study but is
probably not dependent upon the streams. Another dragonfly species of conservation
significance, Eastern Lilysquatter, was reported in this area by Mott MacDonald
(2010). One additional fish species of conservation significance, Small
Snakehead, is listed for the EIS and the dragonfly species, Emerald Cascader,
is listed for the stream system in the AFCD Biodiversity Database.
In
addition, a Common Rat Snake, a species of Potential Regional Concern was found
in the riparian zone of the Kau Lung Hang Stream in surveys conducted for this
study, albeit this species occurs in a variety of habitats and is not
wetland-dependent.
These streams are currently all being channelised under the DSD Project 4148CD/A ‘Drainage Improvement Works in Ping Kong, Kau Lung Hang, Yuen Leng, Nam Wa Po and Tai Hang areas’; the evaluation below assumes completion of these works.
Table 13.34
- Ecological
evaluation of Kau Lung Hang Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Channelisation works are in progress, when these are completed the
lower sections will be man-made habitat but the upstream sections will remain
natural. |
|
Size |
Small. |
|
Diversity |
Moderate diversity of fish and invertebrates. |
|
Rarity |
A common habitat in Hong Kong; Acrosssocheilus
parallens is of global conservation concern; Small Snakehead, found in
the watercourses, and three dragonfly species, Eastern Lilysquatter, Ruby
Darter and Emerald Cascader, found in the riparian area, are also of
conservation significance. Common Rat Snake also found, but this species is
not wetland-dependent. |
|
Re-creatability |
Could be re-created. |
|
Fragmentation |
Slightly fragmented in the lower sections. |
|
Ecological linkage |
Downstream linkage with Ma Wat River; upstream sections may have some
linkages to adjacent habitats. |
|
Potential value |
Limited potential for enhancement. |
|
Nursery/ breeding ground |
Acrosssocheilus parallens must breed in the
streams; the other species of conservation significance present may also
breed. |
|
Age |
Age unknown but recently modified by river channelisation works. |
|
Abundance/ Richness of wildlife |
Assumed to be moderate following channelisation. |
|
Ecological value |
Moderate Ecological Value as habitat will
be highly modified, but several species of conservation significance are
present including Acrosssocheilus
parallens which is of global conservation concern. |
Nam Wa Po
Watercourses
These seasonal tributaries of the Ma Wat River flow from the ridge of Wo Hop Shek. All are heavily shaded by a tree canopy of common plantation species. No fauna species of conservation concern were recorded.
Table 13.35
- Ecological
evaluation of Nam Wa Po Watercourses
|
Criteria |
Assessment |
|
Naturalness |
Semi-natural but modified in lower sections. |
|
Size |
Small and seasonal. |
|
Diversity |
Low due to small size and seasonality and surrounding plantation. |
|
Rarity |
A common habitat in Hong Kong. |
|
Re-creatability |
Could be re-created. |
|
Fragmentation |
Slightly fragmented in the lower sections. |
|
Ecological linkage |
Some linkages to adjacent habitats. |
|
Potential value |
Limited potential for enhancement. |
|
Nursery/ breeding ground |
None known. |
|
Age |
Unknown. |
|
Abundance/ Richness of wildlife |
Low |
|
Ecological value |
Low |
13.6.1.8 Grassland, Grassland/Shrubland and Shrubland
Natural succession of vegetation from grassland to grassland/shrubland and eventually shrubland occurs when land on hillsides, abandoned agricultural land, filled ponds or wasteground is left undisturbed. The condition of microhabitats present and speed of succession to shrubland depends upon relief, the soil and hydrological conditions present at the site. Within the Study Area, most of the hillside area is covered by grassland, which is maintained by periodic fire. Hillside shrubland is present around Mat Tso Lung, on the east side of Crest Hill and at Ki Lun Shan in KTN; with smaller areas in the north of FLN and in other scattered locations through the Study Area.
Grassland, grassland/shrubland and shrubland habitats support similar plant species but the diversity and relative abundance of shrubs and small trees increases as the habitat matures. Common species in these habitats within the NDA Study Area include the grasses Imperata koenigii, Miscanthus sinensis, Neyraudia reynaudiana and Panicum maximum, fern Dicranopteris pedata, herbs Conyza sumatrensis, Crotalaria pallida, Mimosa pudica, Spilanthes paniculata, Tridax procumbens and shrubs Baeckea frutescens, Breynia fruticosa, Eurya chinensis, Litsea rotundifolia var. oblongifolia, Rhaphiolepis indica, Rhus chinensis, Rhus succedanea and Wikstroemia indica. Isolated trees were often recorded in shrubland; common species include Acacia confusa, Aporusa dioica, Celtis sinensis, Ilex rotunda, Litsea glutinosa and Pinus massoniana.
Faunal communities in the grassland and shrubland habitats are fairly species-poor, with the exception of butterflies. The butterfly community of shrubland around Crest Hill was found to be diverse, including a number of woodland-associated species that are uncommon in the north-west New Territories. Species recorded included Danaid Egg-fly of Local Concern. However, this species also occurs around ponds and lowland wetlands, so this habitat is unlikely to be particular significance for this species. Small Three-ring, also of Local Concern, was recorded in hillside grassland on Crest Hill close to Ho Sheung Heung and near Ma Tso Lung. As this species is not dependent on this habitat and also occurs in shrubland, lowland and coastal grassland and wetland fringes, the presence of this species in this location is not considered to be of particular conservation significance.
Few species of conservation significance
are present in, or dependent upon, upland grassland and shrubland habitats in
the Study Area. One bird species of conservation importance, Eurasian Hobby,
was noted over shrubland on Crest Hill. This species is considered to be of
local conservation concern as a breeding species. Eurasian Hobbies typically
utilise abandoned corvid nests for breeding, and a pair is thought to have bred
on Crest Hill on a pylon in such a location in the past (Carey et al. 2001). Golden-headed
Cisticola was also recorded in upland grassland on Crest Hill. This species is considered to be
of Local Concern by Fellowes et al.
(2001); however it is fairly widespread as a passage migrant and winter
visitor in grassland habitat in the northern New
Territories. The
observation at Crest Hill, which was of three birds outside the breeding
season, is not, therefore, considered to be of conservation significance.
Eurasian Eagle Owl has not definitely been recorded from the Study Area but has occurred in the Chau Tau area in the past (Carey et al. 2001). Grey Nightjar was recorded calling over upland grassland at Cheung Po Tau and Wa Shan in FLN in surveys conducted under the current study. Only one breeding record of this species in Hong Kong is listed by Carey et al. (2001), but this species is now considered by members of the study team to breed in upland grassland/shrubland areas in a number of locations in the New Territories. The species is not associated with grassland of higher ecological value, even occurring in recently burnt areas.Shrubland in the Ma Tso Lung area is a part of the habitat complex in this area, which is of significance for a number of fauna species of conservation significance, including butterfly and reptile species. While none of these species may be primarily dependent on the shrubland element of the habitat complex, shrubland probably forms a significant habitat element for some of them.
Much of the lowland habitats close to the Ng Tung River (especially to the south of the river) comprise grassland and grassland/shrubland derived from vegetative succession on long-abandoned agricultural land. Such habitats generally support relatively low plant diversity, dominated by widespread and weedy vegetation including exotic grasses Panicum maximum and Brachiaria mutica.
Smaller areas of lowland grassland with similar ecological characteristics are found elsewhere in the Study Area, notably around Ho Sheung Heung.
Fauna species found in lowland grassland tend to be habitat generalists and this habitat is not qualitatively of significance for any species regularly occurring in the Study Area. However, seasonally wet lowland grassland may be utilised by amphibian and wetland bird species which also use other lowland wetland habitats.
Table 13.36 - Ecological evaluation of upland grassland, grassland/ shrubland and shrubland
|
Criteria |
Upland Grassland |
Grassland/ Shrubland |
Shrubland |
|
Naturalness |
Semi-natural habitat on hill slopes. |
Semi-natural habitat as part of succession from grassland to
shrubland. |
A semi-natural habitat derived from succession on grassland habitats. |
|
Size |
Extensive in the Study Area (311.60ha). |
Moderate areas present in the Study Area (50.21ha). |
A moderately large area in the north of the Study Area on Crest Hill,
small areas elsewhere (62.66ha in total). |
|
Diversity |
Low diverisity of flora and fauna species. |
Low diverisity of flora and fauna species. |
Moderate diversity of flora and butterflies, low to moderate diversity
of birds, low diversity of other fauna. |
|
Rarity |
A common habitat type in Hong Kong. Grey Nightjar recorded at Cheung
Po Tau and Wa Shan and Small Three-ring recorded on hillside adjacent to Ma
Tso Lung and at Crest Hill. |
A common habitat type in Hong Kong. |
A common habitat type in Hong Kong. Eurasian Hobby is of conservation
significance as a breeding species. |
|
Re-creatability |
Could be re-created if suitable land present. |
Easily re-created on suitable land. |
Could be re-created by planting of shrub species but takes several
years to mature. |
|
Fragmentation |
Largely fragmented. |
Fragmented. |
Not fragmented on slopes of Crest Hill. Moderately fragmented
elsewhere. |
|
Ecological linkage |
Some ecological linkage to shrubland. |
Ecological linkages to nearby grassland and shrubland. |
Ecological linkage to grassland and woodland habitats. |
|
Potential value |
May be improved by preventing fire on hills. |
Value will increase if allowed to mature into shrubland. |
Value could be enhanced by natural succession and colonization of more
species (especially fauna). |
|
Nursery/ breeding ground |
Not known to support significant breeding grounds; but Eagle Owl may
breed at Chau Tau and Grey Nightjar at Cheung Po Tau. |
Not known to be a significant nursery ground. |
Pylon in shrubland at Crest Hill has been utilised by breeding
Eurasian Hobby (of local conservation significance as a breeding habitat). |
|
Age |
Maintained at an early successional stage. |
A fairly early successional habitat. |
A mid-succession habitat undergoing succession to woodland. |
|
Abundance/ Richness of wildlife |
Relatively low abundance and diversity of wildlife present. |
Low abundance and diversity of wildlife. |
Generally low abundance and diversity but may be low to moderate for
birds and a diverse community of butterflies present in shrubland on Crest
Hill. |
|
Ecological value |
Upland grassland generally of Low
Ecological Value, but that at Chau Tau, Cheung Po Tau, and Wa Shan of Low to Moderate Ecological Value due to possible presence of
Eurasian Eagle Owl and Grey Nightjar. |
Grassland/shrubland in this area of Low Ecological Value. |
Shrubland on Crest Hill of Moderate
Ecological Value due to presence of breeding Eurasian Hobby and diverse
butterfly community. Shrubland around Ma Tso Lung of Low to Moderate Ecological Value due to its role in a habitat
complex of importance to several species of conservation significance. Small
patches elsewhere of Low Ecological
Value. |
Table
13.37 - Ecological evaluation of lowland
grassland,
|
Criteria |
Assessment |
|
Naturalness |
Semi-natural habitat derived from succession on abandoned agricultural
land. |
|
Size |
A relatively large area is present within the Study Area (132.21ha). |
|
Diversity |
Low diversity of flora and fauna. |
|
Rarity |
A common habitat type in Hong Kong. |
|
Re-creatability |
Could be re-created on suitable land. |
|
Fragmentation |
Somewhat fragmented by developed areas. |
|
Ecological linkage |
Ecological linkage to seasonally wet grassland and some linkages to
agricultural land. |
|
Potential value |
Limited potential. |
|
Nursery/ breeding ground |
None of significance known. |
|
Age |
Maintained at an early successional stage. |
|
Abundance/ Richness of wildlife |
Low abundance and diversity. |
|
Ecological value |
Low Ecological Value. |
13.6.1.9 Seasonally Wet Grassland
Some of the lowland grassland, close to Ma Tso Lung village, is seasonally wet. This habitat is derived from poorly-drained abandoned agricultural land that is flooded during the wet season, permitting the establishment of wetland plant species. A moderately diverse plant community is present, but this is dominated by common herbaceous vegetation such as grass Brachiaria mutica, Panicum maximum and herbs Ipomoea aquatica, Mikania micrantha, Commelina diffusa, Cyclosorus interruptus and Ludwigia perennis. Other common herbaceous plants (such as Kyllinga monocephala, Kyllinga aromatica, Polygonum glabrum, Polygonum lapathifolium and sedge Cyperus spp.) and a few isolated trees (mostly Macaranga tanarius, Ficus hispida and Trema tomentosa) are also present. Chinese Bullfrog was recorded in this habitat at Ma Tso Lung during field work for the LMC Loop study, and it is connected with marsh and riparian areas along Ma Tso Lung Stream. In view of these factors, it is of higher ecological value than other areas of the same habitat in the Study Area.
Small areas of seasonally wet grassland are also present near Chau Tau and along the Ng Tung River in FLN. Vegetation in these areas differs little from the adjacent lowland grassland, and is dominated by ruderal grassand herb species, though the proportion of facultative wetland species may be higher.
Though it may be utilised by wetland bird and amphibian species, all bird and amphibian species found in this habitat occur in several habitat types, and are not restricted to this habitat, or to this habitat and a small number of other habitat types (see Appendix 13.3.1, Appendix 13.5.2 and Appendix13.5.3). Small Three-ring, found in this habitat at Ma Tso Lung was also found in hillside grassland and marsh habitat nearby. The distribution of this butterfly is related to that of its larval foodplant, the very common grass species Ischaemum barbatum which also grows on dry hillslopes so it too is highly unlikely to be dependent upon this habitat.
Table
13.38 - Ecological evaluation of
seasonally wet grassland
|
Criteria |
Ma Tso Lung |
Near Chau Tau |
Along the Ng Tung River |
|
Naturalness |
Semi-natural and has developed through natural succession. |
||
|
Size |
Moderate (8.99ha). |
Small (1.68). |
Small (1.80ha). |
|
Diversity |
Vegetation low in floristic diversity, lacking structural complexity. |
Vegetation largely ruderal herbs and grasses, diversity low. |
|
|
Rarity |
Not uncommon in Hong Kong. Utilised by some wetland bird and
amphibian species of conservation significance and one such butterfly
species at Ma Tso Lung (Small Three-ring) but none of these species are
restricted to this habitat or this and a small number of other habitats or
areas. All bird species of conservation significance recorded in this
habitat occur in larger numbers in other wetland habitats. |
||
|
Re-creatability |
Readily re-created given suitable hydrology. |
||
|
Fragmentation |
Little fragmentation. |
Somewhat fragmented by developed areas. |
|
|
Ecological linkage |
Linkage with adjacent marsh and stream habitats. |
Linkage with marsh and wet agricultural land nearby. |
Linkage with adjacent wetland and grassland habitats. |
|
Potential value |
Enhancement as marsh possible. |
||
|
Nursery/ breeding ground |
None of significance known. |
||
|
Age |
Unknown. |
||
|
Abundance/ Richness of wildlife |
Low. |
Generally low but may be used by moderate numbers of common
amphibians. |
|
|
Ecological value |
Low to Moderate due to moderate size and
utilisation by fauna species of conservation significance. |
Low due to small
size and low numbers of fauna of conservation significance, none of which
are restricted to this habitat. |
Low due to small size and low numbers of fauna of
conservation significance, none of which are restricted to this habitat. |
13.6.1.10 Fung Shui Wood
Fung shui woods were identified at Ho Sheung Heung, Tsung Pak Long and Kam Tsin. The fung shui woods at Ho Sheung Heung and Tsung Pak Long are located within the boundary of the Project Area, while that at Kam Tsin is outside this boundary but within the Study Area. No fung shui woodland was identified in FLN.
The fung shui wood at Ho Sheung Heung formerly contained a closed and continuous woodland canopy, but was damaged by a fire in 2006, which divided the wood into two halves. Seedlings/saplings of native tree species typical of fung shui woodland, including Aquilaria sinensis, Garcinia oblongifolia and Sterculia lanceolata, were planted to help connect and restore the woodland area and these, together with natural regeneration, have now partially restored the linkages between the fung shui woodland areas. The structural integrity of the remaining woodland habitat is moderate. The overstorey of this wood is dominated by Cinnamomum camphora, Machilus pauhoi, Litsea glutinosa, Microcos paniculatus and Schefflera heptaphylla. The understorey and sub-canopy contains a diverse collection of common shrubs and trees, including Acronychia pedunculata, Aporusa dioica, Bridelia tomentosa, Canthium dicoccum, Celtis sinensis, Desmos chinensis, Litsea cubeba, Litsea rotundifolia var. oblongifolia, Maesa perlarius, Psychotria asiatica and Uvaria macrophylla. Climbers such as Gnetum luofuense (listed as near-threatened by IUCN), Embelia laeta and Rourea minor are common. Two saplings of Aquilaria sinensis were found in surveys conducted under the current Study. In surveys for the NENT study, as well as Aquilaria sinensis, two other plant species of conservation significance were recorded, Alianthus fordii and Pavetta hongkongensis, but it is not clear if they were found in the fung shui wood or the adjoining secondary woodland (Maunsell 2003).
The grassland resulting from the hill fire is generally covered by Miscanthus sinensis and the fern Dicranopteris pedata, with a small number of shrubs such as Glochidion eriocarpum, Melastoma dodecandrum, Rhodomyrtus tomentosa and Rhus chinensis.
The Ho Sheung Heung fung shui woodland was found to support a diverse butterfly community (42 species) in surveys conducted under the current study. No species of conservation significance were recorded, but several species are woodland-associated and unusual in this part of Hong Kong. Butterfly species of conservation significance have previously been recorded in the area by Bascombe (Maunsell 2003); a list of such species is provided at Appendix 13.7.4, from which it is possible to determine those not recorded in the current study or in other subsequent studies (see Appendix 13.7.13).
Some woodland bird species recorded in the
Ho Sheung Heung fung shui wood are
uncommon in this part of the New Territories, including Black-naped Monarch,
Mountain Tailorbird and Greenish Warbler. In terms of mammals, two mammal species of conservation
significance, Masked Palm Civet and Leopard
Cat, have been recorded in the woodland.
Kam Tsin fung shui wood is a small remnant highly degraded
woodland patch embraced by the village. It receives frequent human disturbance
and supports a poor plant diversity and simple vegetation structure with no understorey.
The overstorey includes several large Cinnamomum
camphora and Dimocarpus longan. Faunal surveys were not carried out in this area under the current
study; other surveys or studies have not
identified this wood as being of conservation significance for fauna or flora
species.
Tsung Pak Long fung
shui wood is a small woodland patch near the village. The woodland is
mainly dominated by the typical fung shui
woodland species of Cinnamomum
camphora and Sterculia lanceolata.
As the woodland is highly disturbed, some other common ruderal species such as Leucaena leucocephala, Eleusine indica and
Bidens alba were also commonly
recorded at the edge of the woodland. Faunal surveys
were not carried out in this area under
the current study; other surveys or
studies have not identified this wood as being of conservation significance for
fauna or flora species.
Table
13.39 - Ecological evaluation of fung
shui woods
|
Criteria |
Ho Sheung Heung Fung Shui wood |
Kam Tsin Fung Shui wood |
Tsung Pak Long Fung Shui wood |
|
Naturalness |
Semi-natural woodland, initially created by
human action but since allowed to develop naturally. |
Now highly-modified habitat created by human planting and subject to
intense human disturbance. |
Semi-natural habitat created by human planting and subject to human
disturbance. |
|
Size |
Moderately sized, although reduced following fire in 2006; 4.57 ha of
habitat present. |
Small in size (0.66ha). |
Small in size (0.72ha). |
|
Diversity |
Supports a moderate diversity of vegetation. Moderate diversity of
fauna especially birds and butterflies. |
Vegetation species diversity is very low and largely restricted to a
few large trees; most of understorey replaced by concrete car park. Faunal
diversity unknown but likely to be low in view of degradation of habitat. |
Vegetation species diversity is low. Faunal diversity unknown but
likely to be low in view of small size and high levels of human activity. |
|
Rarity |
Fung shui woodlands of this
size are uncommon in Hong Kong. Alianthus
fordii is rare in Hong Kong; other plant species of conservation
significance (Aquilaria sinensis
and Gnetum luofuense) also
recorded, albeit only a few saplings of A.
sinensis recorded; neither species rare in Hong Kong. Two mammal species
of conservation significance (Masked Palm Civet and Leopard Cat) recorded and
some historic records of butterfly species of conservation significance are
likely to relate to this area (Maunsell 2003). |
Similar fung shui woodland
showing human disturbance is common in Hong Kong. |
|
|
Re-creatability |
Could be re-created in the long term, although trees would take a long
time to become mature. |
Re-creation probably impractical due to surrounding village
development. |
Could be re-created although trees would take a long time to become
mature. |
|
Fragmentation |
Somewhat fragmented; fragmentation increased by recent fire. |
Highly fragmented by development. |
Somewhat fragmented by development. |
|
Ecological linkage |
Ecological linkage to adjoining secondary woodland and nearby
plantation and shrubland habitats. |
No significant linkages. |
Some ecological linkages to nearby plantations. |
|
Potential value |
Value will increase as replanted trees mature to replace damaged
woodland. |
Small in size and surrounded by developed land, so potential value is
limited. . |
|
|
Nursery/ breeding ground |
Not known to support any significant nursery or breeding grounds. |
||
|
Age |
Likely to be moderately old. |
||
|
Abundance/ Richness of wildlife |
Good diversity of butterflies, including some species unusual in the
north-west NewTerritories; moderate diversity and abundance of birds. |
Likely to be low due to small size, lack of understorey, disturbance
and fragmentation. |
Likely to be relatively low due
to small size, disturbance and fragmentation. |
|
Ecological value |
Moderate Ecological Value. |
Low Ecological Value. |
Low to Moderate Ecological
Value |
13.6.1.11 Secondary Woodland
Kwu
Tung North
Four small to moderately-sized secondary woodland patches were identified at Tse Koo Hang near Ma Tso Lung, at Pun Uk Tsuen north of Chau Tau, south of Pak Shek Au on the north slope of Ki Lun Shan and at Ho Sheung Heung, either as regenerated woodland on hillsides or as remnants of old woodland patches behind villages or traditional graves. The plant species diversity in these woodlands is relatively rich, with closed and continuous canopy and reasonably complex structure. Native trees, such as Cinnamomum camphora, Microcos paniculata, Celtis sinensis and Ficus variegata var. chlorocarpa, dominate in the overstorey. The subcanopy and understorey support a variety of native climbers, shrubs and trees such as Mallotus paniculata, Psychotria asiatica, Desmos chinensis, Aporusa dioica, Litsea glutinosa, Litsea rotundifolia var. oblongifolia, Phyllanthus emblica, Sarcandra glabra and Sapium sebiferum.
The protected tree species Aquilaria sinensis was recorded in the woodland close to Ma Tso Lung, Ho Sheung Heung and south of Pak Shek Au. It was also recorded in woodland near Pun Uk Tsuen during the LMC Loop Study. Although this species is commonly found in lowland forest and fung shui woods in Hong Kong, it is regarded as Near Threatened in the China Plant Red Data Book. In Hong Kong, it is protected under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586). In surveys for the NENT study, as well as Aquilaria sinensis, two other plant species of conservation significance were recorded in woodland at Ho Sheung Heung, Alianthus fordii and Pavetta hongkongensis, but it is not clear if they were found in the fung shui wood or the adjoining secondary woodland (Maunsell 2003).
Secondary woodlands in KTN were not found to be of importance for fauna species of conservation significance in surveys conducted under the current study. However, while the exact locations of some observations of fauna of conservation significance in the Ho Sheung Heung area are not clear, it seems probable that some relate to the secondary woodland in this area.
Fanling
North
In FLN a relatively large area of woodland was identified behind Siu Hang San Tsuen and Siu Hang Tsuen. This woodland comprises a mixture of areas which are in the process of evolving from plantation, and the overstorey of much of the woodland contains a significant proportion of plantation and orchard species, as well as colonizing native trees, including Cinnamomum camphora, Dimocarpus longan, Microcos paniculata and Sterculia lanceolata. The understorey supports richer floristic diversity, including herbs Alocasia odora and Lophatherum gracile, shrubs (such as Litsea rotundifolia var. oblongifolia, Psychotria asiatica and Uvaria macrophylla) and trees (Archidendron clypearia, Celtis sinensis, Claoxylon indicum, Cratoxylum cochinchinense and Schefflera heptaphylla). The climber Gnetum luofuense was found in this woodland; this species is listed as near-threatened by IUCN, but is common in Hong Kong.
Similar, but smaller patches of of mixed secondary woodland and plantation are present elsewhere in the north of FLN.
A smaller secondary woodland patch is located to the north of Fu Tei Au Road. Dominant trees in this woodland include a mixture of native (Celtis sinensis, Cinnamomum camphorum, Sapium sebiferum, Microcos paniculata, Tetradium glabrifolium and Liquidambar formosana) and exotic (Melia azedarach and Acacia auriculiformis) tree species, forming a semi-closed canopy ranging from 5 to 15 m in height. The understorey is rich in common shrubs of native (such as Psychotria asiatica, Bridelia tomentosa, Ligustrum sinense, Clerodendrum cyrtophyllum) and exotic (such as Lantana camara) species. Native (Tetracera asiatica) and exotic (Mikania micrantha) climbers were also common in the woodland. This woodland patch appears to be derived from natural regeneration and colonisation of trees as a result of seed dispersal by birds and/or bats.
A number of woodland patches are present on hill slopes to the southeast of FLN. Again, these comprise a mixture of areas where plantation and orchard have been colonized by native tree and shub species and areas where shrubland has matured into young secondary forest. Aquilaria sinensis was recorded in such habitat in surveys conducted under the Liantang/Heung Yuen Wai Study (Mott MacDonald 2010).
Secondary
woodland in FLN was not found to be of importance for fauna species of
conservation significance in surveys conducted under the current study.
However, whilst the exact locations of some observations are unclear, it seems
possible that secondary woodland to the east of Kau Lung Hang in the Study Area
may be utilised by some of the mammal species found during AFCD camera trapping
surveys. One woodland-associated mammal species, Leopard Cat, two reptile
species, Copperhead Racer and Indian Forest Skink, and one butterfly species, Peacock Royal of
conservation significance were found in woodland in this area, near Tong Hang Tung
Chuen and near Wo
Hop Shek in surveys conducted under the Liantang/Heung Yuen Wai Study by Mott
MacDonald (2010); however other species noted from this habitat in that study (Black
Kite and Emerald Cascader) are not dependent or associated with woodland.
Table
13.40 - Ecological evaluation of secondary
woodland in KTN
|
Criteria |
Secondary Woodland – Ho
Sheung Heung |
Secondary Woodland – Tse
Koo Hang |
Secondary Woodland – Pun Uk
Tsuen |
Secondary Woodland – south
of Pak Shek Au |
|
Naturalness |
Derived from natural vegetation succession of
suitable undisturbed habitat. |
|||
|
Size |
A
fairly small area present, totalling 2.74ha. |
A
small to medium-sized area present, totalling 5.19ha. |
A
small to medium-sized area present, totalling 5.90ha. |
A
moderate to large area present totalling 17.62ha. |
|
Diversity |
A fairly diverse vegetative community with
diversity of microhabtiats. |
Moderate floral diversity and structural
complexity. |
||
|
Rarity |
Woodland habitat is common in Hong Kong, but
is relatively uncommon in this part of the NewTerritories. Alianthus fordii, a near-threatened
plant species found in woodland at Ho Sheung Heung woodland, is rare in Hong
Kong. |
|||
|
Re-creatability |
Could be re-created in the long term, but
trees would take a long time to mature. |
|||
|
Fragment-ation |
Rather unfragmented. |
Somewhat fragmented by road and marsh
habitats. |
Somewhat fragmented by village areas. |
Somewhat fragmented by roads and developed
areas. |
|
Ecological linkage |
Closely linked to nearby plantation and fung shui Wood. |
Some linkages with nearby grassland and
grassland/ shrubland habitat. |
Linkage with adjacent hillside shrubland and
grassland. |
Linkage with adjacent plantation, hillside
shrubland and grassland. |
|
Potential value |
Potential for increase in value with
maturation of nearby habitats, but limited in scope as woodland near climax
stage. |
Potential for increase with maturation. |
||
|
Nursery/ breeding ground |
Not known to support a significant breeding
ground. |
|||
|
Age |
Unknown, but relatively long-established
habitat. |
Unknown but areas in south are probably
recently formed by maturation of shrubland. |
||
|
Abundance/ Richness of wildlife |
Moderate, especially butterflies. |
Low. |
||
|
Ecological value |
Relatively good quality of habitat but not
particularly large, so considered to be of Moderate Ecological Value. |
Low to Moderate due to small size and isolation. |
Moderate as relatively extensive woodland areas could provide suitable habitat
for birds and mammals. |
Low
to Moderate due to disturbance and age. |
Table 13.41 - Ecological evaluation of secondary woodland in FLN
|
Criteria |
Secondary
Woodland – Siu Hang Tsuen |
Secondary
Woodland - Fu Tei Au |
Secondary
Woodland – Hill slopes in the southeast of FLN (Tong Hang Tung Chuen, Kau
Lung Hang and Wo Hop Shek) |
|
|
Naturalness |
Semi-natural habitat derived from vegetation
succession on shrubland and plantation. |
|||
|
Size |
Moderately extensive area (28.91ha). |
Small area (1.36ha). |
Moderately extensive area (41.78ha). |
|
|
Diversity |
Relatively rich flora present, typical of
secondary woodland habitats. |
Low to moderate diversity of flora. |
||
|
Rarity |
A common habitat type in Hong Kong. No
species of conservation significance are known from these areas. |
A common habitat type in Hong Kong; some
woodland-dependent or associated fauna species of conservation significance
present including Leopard Cat, Indian Forest Skink, Copperhead Racer and
Peacock Royal. In addition, three such amphibian species; Lesser Spiny Frog,
Brown Wood Frog and Short-legged Toad were found in area of plantation and
secondary woodland near Wo Hop Shek. |
||
|
Re-creatability |
Can be re-created but maturation of trees
would take a long time. |
|||
|
Fragmentation |
Somewhat fragmented. |
|||
|
Ecological linkage |
Linked to nearby plantation habitats. |
|||
|
Potential value |
Could be enhanced by plantation of trees in
adjacent habitats to increase woodland size and by natural succession. |
|||
|
Nursery/ breeding ground |
No significant breeding grounds known. |
|||
|
Age |
Fairly mature so probably relatively old. |
Mostly rather early successional stage
woodland |
||
|
Abundance/ Richness of wildlife |
Moderate diversity but numbers relatively
low. |
|||
|
Ecological value |
Woodland at Siu Hang and Wa Shan of Moderate Ecological Value because of
size. |
Small woodland patch by Fu Tei Au Road of Low to Moderate Ecological Value. |
Moderate
Ecological Value because of size and
presence of some fauna of conservation significance. |
|
13.6.1.12 Plantation
Plantation is one of the dominant habitat types within the Study Area, occurring in a variety of locations and with a variety of functions. Plantations within the Study Area include hillside plantation, roadside plantation and urban plantations associated with villages, playgrounds and public facilities.
The canopy of these plantations generally comprises exotic tree species, of which Melia azedarach, Acacia confusa, Acacia mangium, Lophostemon confertus, Melaleuca quinquenervia, Leucaena leucocephala and Delonix regia are particularly common in the Study Area. The overall plant species diversity may be moderately high, however, especially in hillside plantations where colonisation occurs from adjacent shrubland, and the habitat is subjected to lower levels of human disturbance or vegetation management. Vegetation management in other plantation habitats limits the natural colonisation of understorey species.
Tree mixes within the villages often contain the exotic tree Dimocarpus longan or native Cinnomomum camphora, Ficus microcarpa and Celtis sinensis as the overstorey, with an understorey containing a limited diversity of native shrubs and trees.
Upland plantation habitats in KTN are
ecologically linked to shrubland on Crest Hill and the Ho Sheung Heung fung shui woodland as well as the
mixture of semi-natural habitats in the Ma Tso Lung area. The habitats around
Crest Hill and Ho Sheung Heung were found to support a moderate community of
butterflies (30 species), and could be expected to attract more species if left
undisturbed so that more plant species are able to colonise. Similarly, the
plantation in the Ma Tso Lung area is likely to be of significance to some of
the fauna species of conservation importance in this area.
Two
saplings of the protected tree species, Aquilaria
sinensis were found in plantation east of Wo Hop Shek; however this is not
a rare species in Hong Kong, hence does not meet criteria of conservation
significance for this study, particularly as only two saplings were found.
Likewise, the protected orchid species Spathoglottis
pubescens found near Cheung Po Tau Stream, Sha Ling is abundant and
widespread in Hong Kong. However, another orchid species found Pecteilis susannae, which was
considered to be ‘Endangered’ by Baretto et
al. (2011) is of conservation
significance.
Lesser Spiny Frog and Brown Wood Frog were
found in plantation in the Wo Hop Shek area in surveys undertaken under the
current study, and it is also likely that plantation in this area could be
utilised by species found in secondary woodland in the area, including
Indian Forest Skink, recorded by Mott MacDonald (2011). In addition, a third anuran species of
conservation significance, Short-legged Toad, has also been found in the area
(Hyder 2008) and may occur in plantation in the Study Area.
Roadside plantations and those in developed areas generally have lower diversity of plant species and structure, and are subject to moderate or high levels of human disturbance or intrusion. The surrounding urban land uses also typically isolates these plantations from other woodland habitats. Consequently, these plantations are generally of lower ecological value than the more naturalized hillside plantations.
Usage of lowland plantation in the Study Area by fauna of conservation significance is largely limited to occasional opportunistic use by fauna that is not dependent on this habitat such as waterbirds, herpetofauna and butterflies, but it may have some significance for Chinese Grosbeak and Red-billed Starling, albeit neither species is dependent on this habitat.
However, both Ho Sheung Heung and Man Kam
To Road Egretries are located in lowland plantation (the former also partly
in orchard). These plantations are, therefore, of particular significance for
the breeding ardeids. The plantation supporting Man Kam To Road Egretry was
slightly damaged in 2012, but, based on a check in April 2013, was still being
used as an egretry.
Three
butterfly species were found in roadside and urban plantation or mitigation
plantation, which were considered to be rare by Lo (2010). These were Grass
Demon and Small Cabbage White in KTN and Conjoined Swift in FLN. Grass Demon is
stated to be rare but widely distributed in agricultural fields in Hong Kong,
while the other species are stated to be rare but no habitat requirements are
in the AFCD Biodiversity Database (2012). The foodplant of Conjoined Swift is
stated to be Microstegium ciliatum, a
very common herb of wasteland and streamsides by Xing et al. (2000). Small
Cabbage White is generally considered to be an invasive pest species of
agricultural crops. Accordingly,
since none of these species, or their larval host plants are dependent on,
or highly associated with, plantation woodland, and none meet the criteria for
conservation significance used in this assessment, they are not considered
further in the habitat evaluation or ecological impact assessment processes.
Figure 13.11 indicates those areas where plantation largely comprises hillside plantation of higher ecological value, though to some extent there is a continuum between the characteristics and hence the ecological significance of the two plantation types.
Table 13.42 - Ecological evaluation of plantation
|
Criteria |
Hillside Plantation |
Roadside and Urban
Plantation |
|
|
Naturalness |
An artificially-created habitat but some areas with natural
colonisation of vegetation. |
An artificially-created habitat but some areas with limited natural
colonisation of vegetation. |
|
|
Size |
A large area (100.20ha in Study Area boundary). |
A large area (299.48ha in Study Area boundary). |
|
|
Diversity |
Low to moderate floral diversity. |
Low floral diversity with many exotic species. |
|
|
Rarity |
A common habitat type in Hong Kong. One rare orchid species, Pecteilis susannae was found in this
habitat near Cheung Po Tau Stream, Sha Ling; two amphibian species of
conservation significance, Lesser Spiny Frog and Brown Wood Frog near Wo Hop
Shek Crematorium and two further herpetofauna species which have been
recorded in the area (Indian Forest Skink and Short-legged Toad) may also
occur. One butterfly species of conservation significance, Peacock Royal,
found in this habitat near Fung Kong Shan, KTN. |
A common habitat type in Hong Kong. No rare species that is
considered to be of conservation significance or other rare species is
restricted to this habitat, or this habitat and a small number of other
habitats in the Study Area. |
|
|
Re-creatability |
Easily re-creatable although trees would take a long time to mature. |
||
|
Fragmentation |
Moderately fragmented. |
Highly fragmented. |
|
|
Ecological linkage |
Some ecological linkages to similar habitats nearby, especially
shrubland and woodland. |
Some ecological linkages to adjacent semi-natural habitats. |
|
|
Potential value |
Value would increase by natural vegetation succession if habitat left
undisturbed. |
Limited scope for increase in value due to fragmentation and
disturbance. |
|
|
Nursery/ breeding ground |
None known. |
Ho Sheung Heung and Man Kam To Road Egretries are located in
plantation. |
|
|
Age |
Judging by the size of trees present, some areas are moderately old. |
||
|
Abundance/ Richness of wildlife |
Low to moderate abundance and diversity of wildlife; especially birds
and butterflies. |
Low to moderate numbers and low diversity of wildlife. |
|
|
Ecological value |
Low to Moderate Ecological
Value. |
Low Ecological Value except Ho
Sheung Heung Egretry plantation of Moderate
to High Ecological Value due
to presence of a large egretry. The Man Kam To Road Egretry planation is
considered to be of Low to Moderate
ecological value as it is small, disturbed and has been damaged and the
egretry is small in a Hong Kong context. |
|
13.6.1.13 Mitigation Plantations
In addition to the mitigation plantations along the Sheung Yue River which were assessed as an element of the Long Valley habitat complex, other mitigation plantations are present elsewhere on the Ng Tung, Sheung Yue and Shek Sheung Rivers. All are managed by AFCD as mitigation for the ecological impacts arising from channelisation of the rivesr. These largely mostly comprise corridors of plantation located along the channelised rivers, as well as some patches adjacent to agricultural land to the north and south of the rivers. Tree species planted are often exotic species and are consequently of relatively low ecological value, although some native species are also present within the plantation areas.
Though of limited value in themselves due
to fragmentation and the predominance of exotic species, the plantations on the
north and south sides of the Sheung Yue River, alongside wetlands at Ho Sheung
Heung and the west side of the Shek Sheung River are of value in screening
wildlife in Long Valley from disturbance arising from human activities on the tracks
alongside the rivers.
As with other areas of lowland plantation
in the Study Area, utilisation by fauna of conservation significance is largely
limited to occasional opportunistic use by fauna not dependent on this habitat
such as waterbirds, open country birds, herpetofauna and butterflies. An Indo-Chinese Rat Snake was found
in surveys conducted under the current study in mitigation plantation to the
north of the Ng Tung River, this species is listed as
Endangered in the CRDB and of Potential Regional Concern by Fellowes et al. (2002).
Table
13.43 - Ecological evaluation of mitigation plantations
|
Criteria |
Assessment |
|
Naturalness |
An artificially-created habitat but designed to provide some function
similar to natural habitat. |
|
Size |
Total area is relatively small (19.89ha) and individual woodland
patches small. |
|
Diversity |
A fairly low diversity of planted tree species with relatively
limited colonisation by other plant species. |
|
Rarity |
Plantation woodland is a common habitat in Hong Kong. An Indo-Chinese
Rat Snake was found in this habitat on the north side of the Ng Tung River.
Whilst of conservation significance, this species is found in widespread
open country habitats and is not considered to be restricted to one or a few
habitats or small parts of the Study Area by virtue of its habitat
requirements or other factors. |
|
Re-creatability |
Could easily be re-created in suitable locations. |
|
Fragmentation |
Highly fragmented into small patches. |
|
Ecological linkage |
Some ecological linkage with adjacent habitats. |
|
Potential value |
Some potential for an increase in value especially if managed to
increase the proportion of native tree and shrub species. |
|
Nursery/ breeding ground |
None known. |
|
Age |
Planted fairly recently. |
|
Abundance/ Richness of wildlife |
Fairly low abundance and richness of wildlife. |
|
Ecological value |
Although planted for ecological mitigation, the value of these
plantations is limited by the degree of fragmentation resulting in
small-sized patches of habitat and the predominance of exotic species and
hence of Low intrinsic ecological value. However, of Low to Moderate Value functionally, as a screen to reduce
disturbance fauna using the adjacent river channels. |
13.6.1.14 Orchard
A number of orchard areas are scattered through the Study Area; many of these are close to village and agricultural areas. These orchards are small in size and mainly cultivated with fruit crops, largely Litchi chinensis and Dimocarpus longan. This habitat is subject to regular vegetation management and human disturbance, and hence supports low plant and faunal diversity. The Ho Sheung Heung Egretry is located partially in plantation and partially in orchard; this has been taken into account in the evaluation of the specific plantation area at Ho Sheung Heung which is occupied by the egretry, the same criteria, and hence evaluation apply to the orchard area at Ho Sheung Heung occupied by the egretry, however this is not reflected in Table 13.44, in order to avoid unnecessary duplication.
Table
13.44 - Ecological evaluation of orchards
|
Criteria |
Assessment |
|
Naturalness |
An artificial habitat used for cultivation of fruit crops. |
|
Size |
A few small patches present, totalling 17.78ha. |
|
Diversity |
A low diversity of plant species due to ongoing management of
vegetation for benefit of crop species. |
|
Rarity |
A common habitat type around Hong Kong villages. |
|
Re-creatability |
Easily re-creatable. |
|
Fragmentation |
Fragmented. |
|
Ecological linkage |
Some orchards have linkages to nearby farmland, plantation and
shrubland. |
|
Potential value |
Ecological value would be increased by permitting establishment of
understorey vegetation. |
|
Nursery/ breeding ground |
No nursery or breeding grounds known (other than Ho Sheung Heung
Egretry, considered under lowland plantation above. |
|
Age |
Varies, but most are moderately mature. |
|
Abundance/ Richness of wildlife |
Diversity and abundance are low. |
|
Ecological value |
Low Ecological Value. |
13.6.1.15 Golf Course
Part of Fanling Golf Course is located in the south of the Study Area. Golf course is a highly modified landscape with high maintenance short grassland and tree patches, largely of exotic species; these are often managed to reduce or minimise understorey. Other than ground-truthing to check that this habitat was as shown in aerial photographs, field surveys were not undertaken in this habitat and the evaluation was based on a desktop review. This review found no evidence that golf course in the Study Area is significance for any flora or fauna species.
Table 13.45 - Ecological evaluation of golf course
|
Criteria |
Assessment |
|
Naturalness |
An artificial habitat used for active recreation. |
|
Size |
A relatively large area occupying 30.72ha in the south of the Study
Area. |
|
Diversity |
From aerial photographs and ground-truthing it was evident that plant
species diversity was highly influenced by the management regime and hence
likely to be low. Fauna diversity was not assessed. |
|
Rarity |
One of six golf courses in Hong Kong. |
|
Re-creatability |
Easily re-creatable. |
|
Fragmentation |
Not fragmented. |
|
Ecological linkage |
Few ecological linkages to other habitats. |
|
Potential value |
Ecological value would be increased by permitting establishment of
understorey vegetation and by managing water features for wildlife. |
|
Nursery/ breeding ground |
No nursery or breeding grounds known and unlikely due to management
regime and high level of human activity. |
|
Age |
Present for many years but succession arrested by management
activities. |
|
Abundance/ Richness of wildlife |
Low. |
|
Ecological value |
Low Ecological Value. |
13.6.1.16 Waste Ground
Waste ground is semi-natural habitat which has evolved on abandoned developed land following the early stages of vegetation succession. Plant species diversity is very low, supporting only common and widespread ruderal species such as Bidens alba, Mimosa pudica, Brachiaria mutica, Rhynchelytrum repens and Leucaena leucocephala. If left undisturbed, it can be expected that the land will gradually evolve towards more natural habitat as a result of vegetation succession, although the speed and nature of this succession depends upon the local conditions. No species of conservation significance in the Study Area are dependent on or associated with this habitat.
Table
13.46 - Ecological evaluation of waste
ground
|
Criteria |
Waste Ground |
|
Naturalness |
Anthropogenic habitat on unused developed land. |
|
Size |
Small area present within Study Area (9.99ha). |
|
Diversity |
Low. |
|
Rarity |
A common habitat in Hong Kong. |
|
Re-creatability |
Easily re-creatable. |
|
Fragmentation |
Fragmented. |
|
Ecological linkage |
None of significance. |
|
Potential value |
If left undisturbed potential for some improvement as more species
colonise. |
|
Nursery/ breeding ground |
None known. |
|
Age |
An early successional habitat on recently abandoned land. |
|
Abundance/ Richness of wildlife |
Low. |
|
Ecological value |
Low Ecological Value. |
13.6.1.17 Village Area and Urban/Residential Area
In the Study Area, these habitats include villages, urban areas and roads and other infrastructure. Vegetation in these habitats is dominated by a variety of exotic species planted for ornamental or screening purposes, including herbs, climbers and trees. Such areas are generally subject to regular and intensive vegetation management. Plantation trees such as Aleurites moluccana, Bombax ceiba, Eucalyptus citriodora, Ficus microcarpa, Melia azedarach and Melaleuca quinquenervia are commonly present along the roadside. Other plantation species are also often present in the vicinity of these habitats, as described in the previous section of this report.
The village and residential areas support a high diversity of planted species, of which many are exotic, fruit trees Artocarpus macrocarpus, Averrhoa carambola, Clausena lansium, Dimocarpus longan, Litchi chinensis and Manilkara zapota are often present in village areas. A number of Cinnamomum camphora, Eucalyptus citriodora, Ficus microcarpa and Melaleuca quinquenervia in the Study Area are registered as Old and Valuable Trees by Leisure and Cultural Services Department.
Faunal diversity is very low, and
generally restricted to common and widespread commensal and
disturbance-tolerant species. White-shouldered Starling, which appears to be restricted to man-made
structures as breeding sites in Hong Kong, was recorded in the breeding season
in Siu Hang Tsuen in FLN and may breed there. This species was was considered
to be a rare breeding species in Hong Kong by Carey et al. (2001) with a population of less than 50 pairs, and was
evaluated as of local conservation concern as a breeding species by Fellowes et al. (2002). However, it has increased
significantly in Hong Kong in recent years and is now considered to be a
locally common breeding species, with the population increase attributed to use
of nest boxes (Hong Kong Bird Report 2009-10).
Table
13.47 - Ecological evaluation of village
and urban/residential area
|
Criteria |
Assessment |
|
Naturalness |
Man-made artificial habitats. |
|
Size |
An extensive area present in the Study Area (875.18ha). |
|
Diversity |
Floral diversity low with many exotic species. |
|
Rarity |
A very common habitat in Hong Kong. Fauna largely comprises common and
disturbance-tolerant species not restricted to one or a few habitats;
White-shouldered Starling was recorded in the breeding season in Siu Hang
Tsuen; this observation is not considered of significance in respect to the
ecological evaluation of this habitat: this species is listed as of local
conservation concern by Fellowes et al.
(2002) but it is now considered to be a locally common breeding species. |
|
Re-creatability |
Easily re-creatable. |
|
Fragmentation |
Not particularly fragmented. |
|
Ecological linkage |
Limited ecological linkages. |
|
Potential value |
Potential value limited by high levels of human activity but suitable
management of vegetation could lead to some ecological enhancement. |
|
Nursery/ breeding ground |
None known. |
|
Age |
Variable. |
|
Abundance/ Richness of wildlife |
Low diversity, abuandance low in urban areas and low to moderate in
village areas. |
|
Ecological value |
Low Ecological Value. |
13.6.2
Species Evaluations
In the following Section the protection status of species (where this is relevant to the ecological assessment process), status in Hong Kong and conservation status (i.e. whether a species is considered to be of conservation significance in a Hong Kong, China or international context) are summarized, and an ecological value is ascribed to the species in the context of the Study Area, Hong Kong, China and internationally. This is not intended to substitute for the impact assessment process, but to provide an indication of the weight which has been attached to the presence of a species during the course of this process.
It should be noted that protection status in this context only applies to Hong Kong legislation to protect flora and fauna in respect of the ways it has been used in the evaluation and impact assessment processes; other protection status, for example that relating to trade under Cap. 586, is not relevant in this context and has not been considered.
13.6.2.1 Flora
Table 13.48
- Ecological evaluation of flora of conservation significance recorded in the
Study Area
|
Species |
Protection Status |
Status in HK |
Conservation Status |
Ecological Value |
|
Ailanthus fordii |
Cap. 96A |
Rare. Widely cultivated for roadside planting and ornamental purpose |
Near Threatened2 |
Low (because widely cultivated) |
|
Aquilaria sinensis |
- |
Commonly found in lowland forest and fung shui wood |
Vulnerable1 Near Threatened |
Medium |
|
Cibotium barometz |
- |
Very common and
widely distributed |
Vulnerable1 |
Medium |
|
Gnetum luofuense |
- |
Very common |
IUCN Near Threatened1 |
Low |
|
Pavetta hongkongensis |
Cap. 96A |
Common |
Nil |
Low |
|
Pecteilis susannae |
Cap. 96A, |
Infrequent and Restricted3 |
Nil |
Medium |
|
Rhododendron simsii |
Cap. 96A |
Common, but often
planted |
Nil |
Not Applicable as
all specimens considered to have been planted |
|
Spathoglottis pubescens |
Cap. 96A, Cap. 586 |
Abundant and Widespread 3 |
Nil |
Low |
Notes
1. Sun, W. 1998. Aquilaria sinensis. In: IUCN 2010. IUCN Red List of Threatened Species Version 2010.4. <www.iucnredlist.org>. Downloaded on 19 January 2011.
2. South China Institute of Botany & Agriculture, Fisheries and Conservation Department 2003. Rare and Precious Plants of Hong Kong. AFCD, Hong Kong.
3. Barretto, G., Cribb, P. and Gale, S. 2011. The Wild Orchids of Hong Kong. Natural History Publications (Borneo) Kota Kinabalu: Kadoorie Farm & Botanic Garden. Hong Kong.
13.6.2.2 Mammals
One species, Pomona Leaf-nosed Bat, is
only of possible occurrence. All bat species are protected by law in Hong Kong under the Wild
Animals Protection Ordinance (Cap 170), and are not listed individually in Table 13.49.
Table 13.49
- Ecological evaluation of mammals of conservation significance recorded in the
Study Area
|
Species |
Protection Status |
Conservation Status |
Distribution in HK |
Ecological Value |
|
Pomona Leaf-nosed Bat* |
Cap 170. |
(Local Concern)1 |
Widespread |
Medium |
|
Brown Noctule |
Cap 170. |
Potential Regional
Concern/(Regional Concern)1 |
Fairly widespread |
Medium |
|
Greater Bandicoot Rat |
- |
Local Concern1 |
Highly localised. |
Medium |
|
East Asian Porcupine |
Cap 170. |
Potential Global Concern1 |
Widespread |
Medium |
|
Eurasian Otter |
Cap 170. |
Regional Concern1, Near Threatened2,
Vulnerable3 |
Restricted to northwest
NT |
High |
|
Small-toothed Ferret Badger |
Cap 170. |
- |
Widely distributed |
Low |
|
Masked Palm Civet |
Cap 170. |
Potential Regional
Concern1 |
Fairly widely
distributed. |
Medium to High |
|
Small Indian Civet |
Cap 170. |
- |
Widely distributed |
Low |
|
Leopard Cat |
|
Vulnerable3 |
Widely distributed |
Medium |
|
Red Muntjac |
|
Potential Regional
Concern1 |
Widely distributed |
Medium |
Note:
1. Fellowes et al. (2002). Letters in brackets represents the
assessment is on the basis of restrictedness in breeding and/or roosting sites
rather than in general occurrence.
2. IUCN (2013).
3. China Red Data Book (Wang 1998).
*: species not recorded with
certainty in Study Area.
13.6.2.3Birds
A total
of 121 species of conservation significance have been recorded in the Study
Area. A full list is provided in Appendix 13.3.1, which includes their
distribution and abundance in Hong Kong and their conservation status based on
assessments by BirdLife International and Fellowes et al. (2002). This includes many species that are rare within the
Study Area or for which the numbers occurring are not of conservation
importance. A list of species of conservation importance that are considered to
regularly occur in the Study Area is provided in Table
13.7. Rather than repeating the list of species in this section,
however, it is more helpful to break it down into categories, and provide an
assessment of ecological significance for each. The conservation status of
individual species is provided in Table
13.7 and in Appendix 13.3.1.
All bird
species are protected by law in Hong Kong under the Wild Animals protection
Ordinance (Cap 170), and hence are not listed individually as protected species
in Table 13.50.
Table 13.50
- Ecological evaluation of birds of conservation significance recorded in the
Study Area
|
Species |
Conservation Status |
Distribution in HK |
Ecological Value |
|
Ardeids |
Many RC, some LC or (LC)1 |
Most confined to New
Territories, in particular the northwest |
High |
|
Other wetland-dependent non-passerines (seeTable 13.7 and Appendix 13.3.1) |
Most LC or (LC), some RC1 |
Most confined to New
Territories, in particular the northwest |
Medium to High |
|
Raptors |
Black Kite is (RC)1,
while the remainder are (LC)1 |
Black Kite very
widespread, others fairly widespread but localised |
Medium |
|
Eurasian Hobby |
(LV) |
Rare and localised in New
Territories as a breeding species |
High |
|
Eurasian Eagle Owl |
RC |
Localised on open
hillsides |
High (but not of certain
occurrence) |
|
Grey Nightjar |
LC |
Localised on open
hillsides |
Medium |
|
Yellow-breasted and Japanese Yellow Bunting |
Both VU2,
former RC1, Japanese Yellow Bunting is GC1 |
Lowland open-country
areas of northwest NT |
Medium to High |
|
Red-billed Starling |
GC1 |
Widespread in lowland
open-country areas of New Territories |
Low to Medium |
|
Other wetland-dependent or wetland-associated passerines (see Table 13.7
and Appendix 13.31) |
LC1 |
Fairly widespread in New
Territories |
Medium |
|
Non wetland-associated species (see Table 13.7 and Appendix 13.31) |
LC1 |
Fairly widespread in New
Territories |
Low to Medium |
Notes
1:
Fellowes et al. (2002).
2:
IUCN (2013).
13.6.2.4 Reptiles
Table 13.51 - Ecological evaluation of
reptiles of conservation significance recorded in the Study Area
|
Species |
Protection Status |
Distribution in HK |
Conservation Status |
Ecological Value |
|
Reeves' Terrapin |
Cap 170 |
Widespread. Common in the past but rarer in
recent years. |
Global
Concern1, Endangered2, Conservation
Dependent3 |
High. |
|
Three-banded Box Terrapin |
Cap.
170, |
HK has
largest population in world. Widely distributed but rare. |
Global
Concern1, Critically Endangered2 Critically Endangered
in China3. |
Very
High. |
|
Chinese Soft-shelled Turtle |
Cap. 170 |
Highly
restricted, only in northwest NT. |
Global
Concern1, Vulnerable2,3. |
Medium. |
|
Tokay Gecko |
Nil |
Restricted
distribution |
Regional
Concern1, Endangered3. |
Low
(records likely to be of released individuals). |
|
Common Water Monitor |
Cap 170 |
Extinct
in the wild |
Regional
Concern1, Critically
Endangered/Extinct in Wild3 |
Low
(modern records attributed to escapes). |
|
Five-striped Blue-tailed Skink |
- |
Woodlands in the New Territories |
Local
Concern1. |
Medium
(but anecdotal record). |
|
Indian Forest Skink |
Nil |
Present in eastern and central New Territories. |
Local
Concern1. |
Low. |
|
Burmese Python |
Cap. 170
|
Widely
distributed |
Potential
Regional Concern1, Lower Risk/Near Threatened2,
Critically Endangered3. |
Medium
to High. |
|
Buff-striped Keelback |
Nil |
Uncommon but widely distributed
in central New Territories and Lantau Island. |
Local
Concern1. |
Low. |
|
Copperhead Racer |
Nil |
Widely
distributed |
Potential Regional Concern1,
Endangered 3. |
Medium. |
|
Indo-Chinese Rat Snake |
Nil |
Widely
distributed |
Potential
Regional Concern1, Endangered3 |
Medium. |
|
Common Rat Snake |
Nil |
Widely
distributed |
Potential
Regional Concern1, Endangered3. |
Medium. |
|
Banded Krait |
Nil |
Locally
distributed |
Regional
Concern1 Endangered3 |
Medium. |
|
Many-banded Krait |
Nil |
Widely
distributed |
Potential
Regional Concern1, Vulnerable 3, |
Medium. |
|
Chinese Cobra |
Nil |
Widely
distributed |
Potential
Regional Concern1, Vulnerable3. |
Medium. |
|
King Cobra |
Cap 170 |
Widely
distributed |
Potential
Regional Concern1 Vulnerable2, Critically Endangered3 |
High. |
Notes
1. Fellowes et
al. (2002).
2. IUCN (2013).
3. China Red Data Book (Zhao 1998).
13.6.2.5 Amphibians
Table 13.52
- Ecological evaluation of amphibians of conservation significance recorded in
the Study Area
|
Species |
Protection
Status |
Distribution
in HK |
Conservation
Status |
Ecological
Value |
|
Short-legged Toad |
Nil |
Widely distributed in upland forest streams |
Potential Global Concern1, Endangered3 |
High (but not certain in Study Area) |
|
Chinese Bull Frog |
Nil |
Quite widely distributed in HK. |
Potential Regional Concern1 |
Medium. |
|
Lesser Spiny Frog |
Nil |
Widespread |
Potential Global Concern1, Vulnerable3 |
Low to Medium |
|
Brown Wood Frog |
Nil |
New Territories and Lantau |
Local Concern1 |
Low to Medium |
|
Two-striped Grass Frog |
Nil. |
Restricted in HK. |
Local Concern1 |
Medium. |
Notes
1. Fellowes et al. (2002).
2. IUCN (2013).
3. China Red Data Book (Zhao 1998).
13.6.2.6 Fish
Table 13.53
- Ecological evaluation of fish of conservation significance recorded in the
Study Area
|
Species |
Protection
Status |
Distribution
and Status |
Conservation
Status |
Ecological
Value |
|
Acrossocheilus
parallens |
Nil |
Uncommon |
Global Concern1 |
Medium |
|
Predaceous Chub |
Nil |
Common and
widespread in HK. |
Vulnerable2 |
Low. |
|
Small Snakehead |
Nil |
Uncommon in the
wild. |
Local Concern1. |
Medium. |
Notes
1. Fellowes et al. (2002).
2. China
Red Data Book (Yue and Chen 1998).
13.6.2.7 Butterflies
Table 13.54
- Ecological evaluation of butterflies of conservation significance recorded in
the Study Area
|
Species |
Protection
Status |
Distribution
in HK |
Conservation
Status |
Ecological
Value |
|
Dark Brown Ace |
Nil |
Locally distributed |
Local Concern1, Very Rare2. |
Medium |
|
Common Dart |
Nil |
Locally distributed |
Local Concern1, Rare2. |
Medium |
|
Pale
Palm Dart |
Nil |
Locally distributed |
Local Concern1,
Rare2. |
Medium |
|
Hainan
Palm Dart |
Nil |
Locally distributed |
Local Concern1,
Very Rare2. |
Medium |
|
Small
Grass Yellow |
Nil |
Locally distributed |
Local Concern1, Rare2. |
Medium |
|
Lesser Forest Blue |
Nil |
Locally distributed |
Local Concern1,
Rare2. |
Medium. |
|
Brown Onyx |
Nil |
Distribution uncertain. |
Local Concern1, Very Rare2. |
Medium |
|
Peacock Royal |
Nil |
Locally distributed |
Local Concern1,
Rare2. |
Medium |
|
Common Pierrot |
Nil |
Locally distributed |
Local Concern1, No verified sightings in recent years2. |
Low to Medium. |
|
Pale
Hedge Blue |
Nil |
Locally distributed |
Local Concern1,
Very Rare2. |
Medium |
|
Small
Three-ring |
Nil |
Locally distributed |
Local Concern1,
Very Rare2. |
Medium |
|
Painted
Lady |
Nil |
Locally distributed |
Local Concern1,
Rare2. |
Medium |
|
Danaid
Egg-fly |
Nil |
Locally distributed |
Local Concern1,
Uncommon2. |
Low to Medium |
|
Commander |
Nil |
Locally distributed |
Local Concern1,
Very Rare2. |
Medium |
|
Spotted Angle |
Nil |
Locally distributed |
Local Concern1,
Very Rare2. |
Medium |
Notes
1. Fellowes et
al. (2002).
2. Chan et al. (2011).
13.6.2.8 Dragonflies
Table 13.55
- Ecological evaluation of dragonflies of conservation significance recorded in
the Study Area
|
Species |
Protection
Status |
Distribution
in HK |
Conservation
Status |
Ecological
Value |
|
Eastern Lilysquatter |
Nil |
Widely distributed |
Local Concern1,
Common2 |
Low |
|
Blue Sprite |
Nil |
Widely distributed |
Local Concern1,
Common2 |
Low |
|
Orange-backed Threadtail |
Nil |
Largely restricted to
northeast New Territories |
Local Concern1, Common2 |
Low to Medium |
|
Dingy Dusk-hawker |
Nil |
Widely distributed |
Local Concern1,
Common3 |
Low |
|
Blue Chaser |
Nil |
Widely distributed |
Local Concern1,
Common2 |
Low |
|
Ruby Darter |
Nil |
Widely distributed |
Local Concern1,
Common2 |
Low |
|
Sapphire Flutterer |
Nil |
Widely distributed |
Local Concern1,
Common2 |
Low |
|
Scarlet Basker |
Nil |
Largely restricted to
northwest New Territories in HK. |
Local Concern1,
Common2 |
Low to Medium |
|
Emerald Cascader |
Nil |
Widely distributed |
Potential Global Concern1 Abundant2 |
Medium |
Notes
1. Fellowes et
al. (2002).
2. Tam et al. (2011).
3 AFCD Biodiversity Database
(2012).
13.6.2.9 Aquatic Invertebrates
Table 13.56
- Ecological evaluation of aquatic invertebrates of conservation significance
recorded in the Study Area
|
Species |
Protection Status |
Distribution in HK |
Conservation Status |
Ecological Value |
|
Somanniathelphusa zanklon |
Nil. |
HK endemic, but quite widely distributed. |
Global Concern1, Endangered2. |
Medium. |
Notes
1. Fellowes et
al. (2002).
2. IUCN (2013).
This section assesses significance of the potential
direct and indirect, primary and secondary, on-site and off-site, and
cumulative impacts of the Project. The approach adopted is to address impacts
on habitats, species, those arising from fragmentation and, finally, the
potential cumulative impacts. Within each of these categories a distinction is
made between direct and indirect impacts, and these are further defined as to
whether they are predicted at the construction or operational stage of the
project.
The significance of ecological impacts has been
evaluated based primarily on the criteria set out in Table 1 of Annex 8 of the
TM-EIAO, using the following criteria: habitat quality, species impacted,
size/abundance, duration, reversibility, magnitude and severity.
In addition to the project as a whole, the following
Designated Projects (DPs) have been included in the ecological impact
assessment.
- DP1 – San Tin Highway and Fanling Highway Kwu Tung Section Widening (between San Tin Interchange and Po Shek Wu Interchange) (Major Improvement) and associated new Kwu Tung Interchange (New Road) and Pak Shek Au Interchange Improvement (Major Improvement);
- DP2 – Castle Peak Road Diversion (Major Improvement);
- DP3 – KTN NDA Road P1 and P2 (New Road) and associated new Kwu Tung Interchange (New Road) and Pak Shek Au Interchange;
- DP4 – KTN NDA Road D1 to D5 (New Road);
- DP5 – New Sewage Pumping Stations (SPS) in KTN NDA;
- DP6 – Proposed railway station and associated facilities in KTN NDA (To be conducted under other separated studies);
- DP7 – Utilisation of Treated Sewage Effluent;
- DP8 – Po Shek Wu Interchange Improvement (Major Improvement);
- DP9 – Fanling Bypass Western Section (New Road);
- DP10 – Fanling Bypass Eastern Section (New Road);
- DP11 – Proposed expansion and upgrading of Shek Wu Hui Sewage Treatment Works at FLN NDA;
- DP11 – Reprovision of wholesale market in FLN NDA; and
- DP12 – New Sewage Pumping Stations in FLN NDA.
13.7.2 Baseline conditions
The current conditions of habitats in and around the
Project area are used as the baseline against which impacts of the development
are assessed. This is based on the expectation that ecological conditions in
this area would remain largely unchanged in future in the absence of the
Project.
Future conditions are difficult to predict, being
dependent on changes to habitat conditions, human activity in and around the
area and the population dynamics of species present. The potential ecological
value of the area has been evaluated in Section 13.6 to determine whether this may be expected to
change in the absence of the Project. In most habitats conditions are expected
to remain largely unchanged, albeit with the potential for enhancement in many
habitats if active management measures were implemented or extended. This issue
is of particular relevance in respect to habitats in the Long Valley and Ho
Sheung Heung Priority Site, where a nature conservation MA is in place in parts
of the area. The current MA is scheduled to be completed in February 2015, but
for purposes of this assessment it is assumed that similar MAs (or a similar
successor conservation mechanism) will continue beyond this date. Some other
habitats may be expected to increase in value in future as a result of natural
succession (for example from shrubland into woodland) and maturation (for
example woodland). In such cases where a change in ecological conditions can be
predicted the ecological value of the predicted future conditions is taken into
account in the impact assessment for the relevant habitats.
13.7.3 Impacts on Habitats
In this section the types of direct and indirect
impacts on habitats are described; potential direct and indirect impacts in the
habitats in the assessment area are then predicted and evaluated in accordance
with the requirements of Section 13.4.14.4(vii) of the Study Brief.
13.7.3.1 Habitat
Loss
Direct habitat loss is caused by developments and
their associated infrastructure, and includes temporary construction impacts
and long-term (usually permanent) operational impacts. These are readily
recognized as they take the form of habitat disappearance and are easy to
define, and the magnitude is more easily assessed than some other forms of
impact. The ecological impact is generally a function of the scale of habitat
loss and ecological value of the habitat.
The significance of temporary habitat loss depends to
a degree on the type of habitat; late successional habitats (especially woodland)
take longer and are more difficult to restore than early successional habitats.
Some natural habitats (especially streams) may be difficult to restore to a
natural state, even after completion of construction works.
The areas of habitats predicted to be lost as a
consequence of the Project in the absence of mitigation are summarized in Table 13.57 below. Because of the
nature of the Project, the area of permanent direct habitat loss in the absence
of mitigation of natural, semi-natural and other habitats of ecological value
broadly corresponds to the areas of these habitats not excluded from
development areas under the revised RODP (see Figures 13.14a-c).
This definition obviously does not extend to developed
areas (village areas and, especially, urban/residential areas) where some
areas, such as those in village (V) zones, will not be redeveloped.
Accordingly, these habitats to be ‘lost’ are shown in parentheses in Table 13.57, but
are included in the table as the potential loss of biota in such areas is of
relevance to the evaluation of potential impacts of the project as a whole.
Table 13.57 - Direct Habitat Loss predicted
as a consequence of the project in ha
|
Habitat |
Kwu Tung North |
Fanling North |
Total |
|
Dry
Agriculture |
0.22 |
9.10 |
9.32 |
|
Wet
Agriculture |
- |
0.58 |
0.58 |
|
Grassland |
29.13 |
31.03 |
60.16 |
|
Grassland/
Shrubland |
1.18 |
0.45 |
1.63 |
|
Major
Watercourse |
<0.01 |
0.01 |
0.02 |
|
Minor
Watercourse |
0.37 |
2.06 |
2.44 |
|
Mitigation
Wetland |
0.43 |
2.32 |
2.75 |
|
Mitigation
plantation |
3.69 |
7.07 |
10.75 |
|
Orchard |
2.29 |
5.09 |
7.38 |
|
Plantation |
57.37 |
24.71 |
82.08 |
|
Pond |
2.71 |
0.37 |
3.08 |
|
Seasonally
Wet Grassland |
2.86 |
1.21 |
4.07 |
|
Secondary
Woodland |
0.23 |
0.00 |
0.23 |
|
Shrubland |
1.11 |
0.00 |
1.11 |
|
(Urban/
Residential Area) |
114.16 |
38.36 |
152.52 |
|
(Village
Area) |
25.25 |
8.49 |
33.74 |
|
Waste
Ground |
5.64 |
0.65 |
6.29 |
|
Total |
247.33 |
133.63 |
380.96 |
13.7.3.2 Indirect Impacts
Indirect impacts comprise the secondary effects of
development on habitats or wildlife away from the development footprint. While
direct impacts in the form of habitat loss are relatively easily recognised,
the mechanism and effects of indirect impacts are less straightforward. These
impacts include such secondary impacts as run-off from construction sites that
affects water quality of nearby watercourses, and indirect disturbance impacts
in both construction and operation phases that do not prevent a species from
using an area (as habitat loss does), but may reduce the area’s suitability for
that species. Types of indirect impacts on habitats are further described
below.
Disturbance impacts
These impacts include active disturbance arising from
noise or other human activities, and passive disturbance resulting from
avoidance by fauna of building structures. For fauna species there are two main
reactions to disturbance. The earliest reaction is to become alert, which
usually involves cessation of foraging or roosting; this in itself is
energy-intensive and reduces foraging efficiency. The second reaction is to
move away or (in the case of birds) take flight, or ‘flush’, when it is felt
security is threatened.
Disturbance effects may cause the complete avoidance
of an area because a sense of security is compromised all the time (which is
comparable to habitat loss), reduced densities (where only less-sensitive
individuals utilise an area) or reduced habitat quality (where feeding efficiency
is reduced as a result of increased vigilance). Thus, although a species may be
observed close to a disturbance source, this is not necessarily evidence that
there is no disturbance effect. Ultimately, an organism will only approach a
potential disturbance source up to the point at which the negative effects
prevent achieving sufficient benefits of being there.
Disturbance from roads tends to be fairly low compared
to that from buildings where people are highly visible or where disturbance
events are unpredictable. As with buildings, construction is usually more
disturbing than operation. Mitigation for such disturbance impacts in the form
of visual and noise barriers is, thus, recommended in principle.
Night-foraging or night-roosting birds may be subject
to impacts from glare or direct lighting from buildings, which might make
certain areas unattractive as foraging or roosting sites. The main species
groups affected by disturbance are those such as large waterbirds (cormorants,
egrets and herons) and birds of prey such as owls, as well as mammals. In
general, the larger the species, the greater the distance from a disturbance
source at which an impact occurs.
In Hong Kong, disturbance impacts are most significant
to larger mammals and large birds using open habitats, notably waterbirds and
large raptors. Conversely, woodland fauna other than mammals, smaller birds and
other fauna are relatively insensitive to disturbance.
Faunal surveys in the Study Area have demonstrated
that it does not support significant numbers or diversity of large mammals or
raptors, but that it is important for large waterbirds, with the populations of
these species concentrated in Long Valley and, to a lesser extent, along the
main river channels in the following order of significance: Sheung Yue River,
Ng Tung and Shek Sheung Rivers (Section
13.5.4.3). Within this order, tidal Ng Tung River is of greater
significance than the non-tidal section. Disturbance impacts to large
waterbirds may therefore be of potential significance in these in these
habitats.
Potential disturbance impacts to waterbirds from
construction and operation of development in Hong Kong were analysed and the
resultant predictions of the distance at which waterbird species would be
disturbed (excluded or occurring at reduced densities) were utilised in the EIA
for the LMC Station and Spur Line (Binnie Black & Veatch 2002). Whilst
there are many differences between the projects, the principles followed remain
of relevance and have been utilised in informing the process of assessing the
potential disturbance impacts on the current project. Accordingly, the
predicted disturbance distances of relevance to species occurring regularly in
Long Valley and the river channels are shown in Table 13.58.
The distances within which species were predicted to
be excluded and disturbed which are shown here relate to the construction and
operational phase, which were not distinguished in the analysis. It is assumed
that the predicted distances were the maxima, which, for most disturbance
sources, would be experienced during the construction phase of the project, and
do not allow for the known phenomenon of habituation, whereby birds become more
tolerant of disturbance over a period of time, especially where the activity
causing the disturbance is regular.
Table 13.58. Predicted distances at which waterbird or wetland-associated species were predicted to be disturbed by the operation of the Lok Ma Chau Spur Line (Source: Binnie Black & Veatch 2002).
|
Species |
Lok Ma Chau station complex and viaduct section |
Viaduct track sections only |
Overall disturbance sensitivity |
||
|
Exclusion distance (m) |
Max distance of reduced density (m) |
Exclusion distance (m) |
Max distance of reduced density (m) |
||
|
Grey Heron |
100 |
200 |
100 |
150 |
High |
|
Great Egret |
100 |
200 |
100 |
150 |
High |
|
Little Egret |
20 |
100 |
30 |
100 |
Moderate - High |
|
Chinese Pond Heron |
20 |
30 |
0 |
110 |
Moderate |
|
Cinnamon Bittern |
20 |
20 |
50 |
75 |
Low |
|
Common Teal |
50 |
100 |
50 |
100 |
Moderate - High |
|
Black-winged Stilt |
50 |
50 |
50 |
75 |
Moderate - High |
|
Snipe Gallinago spp. |
30 |
30 |
0 |
60 |
Moderate |
|
Red-billed Starling |
50 |
50 |
50 |
75 |
Moderate |
|
Bluethroat |
20 |
30 |
0 |
50 |
Low |
Note: the table has been amended to include only
species where potentially significant disturbance impacts from the NDA Project
are predicted. Distances assumed the implementation of screen planting, but no
other in situ mitigation, Application
of these distances to impacts on Long Valley is directly comparable in this
respect, as Long Valley is surrounded by mitigation plantation on all sides
which would be impacted by the project, however this is not the case in respect
to impacts on the Ng Tung River in KTN where no such screen planting can be
assumed.
Whilst there are many differences between the
projects, the predicted disturbance from the station and viaduct complex has
some similarities to the predicted disturbance from the construction of large
buildings, as is proposed to the southwest of Long Valley and along the Ng Tung
River in FLN, while predicted disturbance from viaduct track sections has many
similarities with predicted disturbance from roads and bridges over the rivers.
The two most disturbance-sensitive species regularly occurring in Long Valley and in the river channels are Grey Heron and Great Egret, which were both predicted to be disturbed within 200m of the LMC Station and excluded within 100m of the Station. For the viaduct sections the disturbance and exclusion distances were predicted to be 150m and 100m respectively.
However, the numbers of both species foraging in Long Valley and the main river channels are relatively low in comparison with some other ardeids, in particular those of Little Egret and, to a lesser extent, Chinese Pond Heron. Furthermore, both species occur in the Study Area only as non-breeding visitors, unlike Little Egret and Chinese Pond Heron, both of which breed at Ho Sheung Heung and Man Kam To Egretries. Impacts on breeding birds are considered to be more significant than those on non-breeding birds as the former are more restricted in their foraging locations than the latter and have to forage more efficiently, or for longer, to collect sufficient food for themselves and their young, than non-breeding birds which have only to fend for themselves.
For these reasons, whilst acknowledging that this represents a simplification of the severity of disturbance impacts on different species, disturbance and exclusion distances for Little Egret, which is both more disturbance-sensitive and which uses the river channels in larger numbers than Chinese Pond Heron, have been indicated on Figure 11a-b. The disturbance distance of Little Egret was considered to be 100m from both the LMC Station and viaduct sections of the LMC Spur Line, while the exclusion distances were considered to be 20m and 30m from the station and viaduct sections respectively. On a precautionary basis the greater exclusion distance of 30m has been shown in respect to exclusion distances from major additional sources of disturbance arising from the current project (large buildings and new road bridges) in Figure 13.11a-b.
Both the LMC Station and the Spur Line viaduct are large structures. Accordingly Binnie, Black and Veatch (2002) did not address disturbance impacts on birds from minor works and projects. In a number on areas where development will take place under the current project, works will be minor and/or no large structures will be erected. Such areas include open space zones along the rivers and elsewhere, where only landscape works, pipe laying or other works to utilities and erection of minor structures will take place. In addition, experience since 2002 in various places in Hong Kong, for example Tin Shui Wai, the Kam Tin Main Drainage Channel, the San Tin East Drainage Channel and indeed in the Sheung Yue and Ng Tung Rivers, suggests that Binnie, Black and Veatch (2002) over-estimated disturbance and exclusion distances of some species (including ardeids) and that these will forage much closer to disturbance sources than was predicted. This tolerance is both a function of time as birds become habituated to disturbance from a particular source (whether this is a structure or a human activity) and the frequency of occurrence (thus regular disturbance may actually be tolerated more than irregular disturbance in a location where the birds are unfamiliar with the disturbing event).
To take account of both of these factors (i.e. the lower level of disturbance likely to be occasioned by minor works or small structures, and the over-estimation of disturbance and exclusion effects in Binnie, Black and Veatch (2002)), disturbance and exclusion distances have been adjusted in respect to minor works and small structures on Figures 13.11a-b. Accordingly, in these Figures, no exclusion distances are shown/predicted in respect to minor works/structures and only a 30m disturbance zone is shown/predicted in respect to such works/structures.
The consequence of the unmitigated disturbance impact evaluation process described above and shown on Figure 13.11a-b, is summarised below, as follows:
· There are predicted to be disturbance impacts and possible displacement of large waterbirds from the section of the Sheung Yue River to the south of the new bridge which will carry the eastern primary distributor road P2. This area is currently used by moderate numbers of disturbance-sensitive waterbirds;
· There are predicted to be significant, albeit somewhat lower, disturbance impacts on large waterbirds foraging in the section of the Sheung Yue River between the new bridge for Road P2 and the new pedestrian footbridge over the river to the southeast of KTN area D1-5. This area is currently used by moderate numbers of disturbance-sensitive waterbirds;
· There will be some reduction in the carrying capacity of the remainder of the north side of the Sheung Yue River and the fringes of Long Valley north of the Sheung Yue River and west of the Shek Sheung River, especially during the construction phase of works in KTN areas D1-1 to D1-5 and in the open space zones alongside the north side of the Sheung Yue River, the west side of the tidal Ng Tung River and the west side of the Shek Sheung River. This section of the Sheung Yue River (shown in blue in Figure 13.11a) is currently used by large numbers of some waterbird species, including Little Egrets breeding in the Ho Sheung Heung Egretry; the tidal section of the Ng Tung River and the Shek Sheung River are currently used by moderate numbers of waterbirds as foraging areas; the tidal Ng Tung River and its riparian corridor is also utilised as a flight-line by ardeids breeding at Ho Sheung Heung Egretry and provides a linkage for waterbirds to the Deep Bay wetland ecosystem;
· There will be potential disturbance/exclusion impacts on most of the non-tidal Ng Tung River. These will be greatest on the south side of the river to the north of the extension to the Shek Wu Hui Sewage Treatment Works, and on both sides of the river to the east of Sheung Shui Wa Shan; and will be lowest on the north side of the river to the east of FLN area A1-2 and to the east of area A1-8. All of the non-tidal section of the Ng Tung River is utilised by moderate numbers of some species of waterbirds at present. However, the section to the west of the Man Kam To Road Bridge is of greatest significance as it is used as a corridor by some Chinese Pond Herons breeding at the Man Kam To Road Egretry.
The analysis above has been utilised later in this section in evaluating the significance of relevant impacts. It has also been utilised in Section 13.8 in addressing the mitigation of impacts.
Dust Deposition
Unmitigated construction operations create significant levels of dust under certain weather conditions due to the use of haul roads and the phenomenon of wind-blown dust from works areas. This dust is deposited on nearby habitats, which can cause vegetation damage and, as a secondary effect, have an impact on fauna such as insects and birds. Impacts from dust deposition of these types will, however, be temporary and reversible, and standard construction best practices as mitigation measures can be implemented to negate harmful impacts. Dust deposition impacts arising from the Project are not, therefore, considered to be significant in most instances. Accordingly, dust deposition is only elaborated in this section where impacts may be of significance.
Increased Sediment and Nutrient Load
Dust and exposed earth from construction operations may also enter watercourses via run-off, particularly during periods of heavy rain. This can lead to high turbidity from soil particles (which can block the gills of aquatic organisms) and eutrophication as a result of nutrient enrichment. Aquatic macrophytes may be reduced as a result of reduced light penetration or increased free-floating algae populations following eutrophication. Severe eutrophication can lead to oxygen depletion and the impoverishment of aquatic communities, as well as animals that prey on them (e.g. waterbirds). Such effects are usually greatest in the construction phase of a project, though can also occur in the operation phase.
Organisms at a higher trophic level are unlikely to be directly impacted by run-off before their prey (i.e. fish), the availability of which will reduce. In extreme cases, this may lead to abandonment of habitat. Such impacts are most likely to occur during the construction phase, but are also possible in the operational phase.
Additional sediment inputs to watercourses from the Project, while not necessarily significant in terms of the watercourses themselves, may still be of significance further downstream in the intertidal areas of Deep Bay. Increased sedimentation of the inner Deep Bay area in particular could increase the spread of mangrove into the mudflat area, which in turn would reduce the available foraging area for waterbirds, Mitigation measures are required and can be implemented to prevent such adverse impacts.
Impacts from construction site run-off are addressed in Section 5.6.1.1 and are only elaborated in the current section where they are considered to potentially be of particular ecological significance.
Pollution
Pollution of air or water may arise from a large number of different sources and could occur during construction, operation or both. The severity of a pollution event would depend upon the type of pollutant being released, the nature and ecological value of the habitat affected, the size of the habitat affected, the amount of pollutant released, duration of the event and the sensitivity of species potentially affected. Given the number of factors involved, the potential impacts of pollution are difficult to evaluate with a high degree of accuracy. Impacts of water pollution are of particular importance due to the sensitivity of the species involved and the high ecological value of wetland habitats in HK. In contrast, air pollution generally disperses over a larger area and the impacts are evident regionally but mostly do not affect local ecology.
In a HK context air quality issues are of concern generally. However, unless a project has a particular local emissions impact over and above those anticipated from normal urban and infrastructural development, it is not considered that there would be significant marginal impact on flora and fauna. Examples where emissions impacts might be of concern for local ecology are airports, ports and major industrial facilities. Development with regard to the NDA projects is not of this nature. As such, although all fauna and flora are sensitive receivers, the significance of any impacts at an individual species level is not considered significant.
There is potential for toxic pollutants from contaminated mud or storage activities to be disturbed and enter surrounding watercourses. Furthermore, spills and run-off from construction sites can contain high levels of toxic pollutants such as oil, which may cause direct mortality of flora and fauna or sub-lethal impacts (e.g. reduced breeding success, reduced foraging efficiency). Bio-accumulation may also occur should toxic substances be passed up the food chain in increasing concentrations. Such a process would impact top-level predators such as large waterbirds. Although likely to be of lower magnitude, toxic pollutants such as oil or petrol could enter water bodies during the operation phase as a result of run-off from road surfaces.
Impacts from pollution are addressed in Section 5.6.1.1 and are only considered in the current section where they are considered to potentially be of particular ecological significance.
Hydrological disruption
Hydrological disruption as a result of changes to water flow or impacts on the underground water table could impact surrounding water bodies and other habitats. Most habitats which are considered to be potentially sensitive to hydrological disruption are primarily wetlands. These include Long Valley, wet agricultural land, marsh, ponds, mitigation wetlands and seasonally wet agricultural land. Lowland dryland habitats, including dry agricultural land and grassland, may also be sensitive to flooding or an increase in the level of the water table due to changes which impede surface or underground flow of water. All these habitats are considered to be Water Quality Sensitive Receivers (see Section 5.4); potential hydrological impacts on these habitats are assessed in full in Section 5.6, only hydrological impacts of particular relevance to the ecological impacts of the project are addressed specifically in this ecological impact. In practice, hydrological disruption to wetland habitats is likely to be of much greater significance ecologically, especially as most lowland dryland habitats have been evaluated as of low ecological value in the Study Area. Upland dryland habitats are not sensitive to hydrological disruption except at a very local level.
A particular issue, which is of relevance in the NDA Project area, is that of construction phase changes to the management regime of channelised watercourses. Currently the levels of the Ng Tung River in FLN and the Sheung Yue River above the Fanling Highway are controlled by fabridams (Figure 13.4). If that on the Ng Tung River were to be lowered, for example to facilitate construction upstream, there would be impacts on the ecological function of the river. That on the Sheung Yue River is primarily of significance ecologically in that the water which is impounded above the fabridam is the source for the water which is abstracted from the river and which provides Long Valley with some of the water required for irrigation.
One natural, or at least semi-natural, watercourse, Ma Tso Lung Stream may experience hydrological disruption in the section to be diverted and the section downstream from the diverted section. Such hydrological disruption may have significant impacts on stream fauna and on fauna which are associated with habitats which are hydrologically linked to the stream (see also Section 5.6.1.2).
Hydrological impacts on other channels, including the main drainage channels are addressed in Section 5.6.1 (Construction Phase) and Section 5.6.2 (Operational Phase) of this EIA Report, and are not evaluated in detail in the current section. No significant hydrological impacts are predicted.
Fragmentation
Fragmentation is the appearance of discontinuities in habitat that render it less attractive to flora or fauna or isolate populations of a species, potentially leading to reduced viability of a population. This is most easily seen in infrastructural links, where roads and rail lines break up habitat into smaller units, but also arises from disturbance impacts, where organisms avoid certain areas due to secondary impacts from nearby development. Where the infrastructural link prevents mobility of organisms, fragmentation has occurred.
Construction within a large, continuous habitat patch may result in an edge effect reducing the overall value of the habitat. Generally, larger areas of habitat are of higher importance than smaller areas; this is not simply an arithmetical relationship; for example, doubling the area of a particular habitat may result in more than double the ecological value. Many species require a minimum area of a habitat and would not utilise two smaller fragments amounting to the same area. The severity of fragmentation impacts will depend upon the extent to which severance occurs (whether this is partial or total), the relative sizes of resulting fragments, the extent and complexity of previous linkages and the baseline species diversity.
At its most extreme, fragmentation impacts may result in the loss of populations of a species if the remaining fragments are too small to support a viable population. Species most affected by fragmentation impacts are habitat specialists, terrestrial species and species with low mobility. Birds and flying insects are generally less affected than mammals, herpetofauna and non-flying invertebrates.
In the current study, the Project may result in potential fragmentation effect at both a local level, whereby an area of habitat is fragmented into smaller areas or from adjacent areas of habitat with which there are ecological linkages, but also at a macro level, in terms fragmentation of habitats from habitats with which they have significant linkages well outside the assessment area. In this respect, linkages for large waterbirds using Long Valley with the Deep Bay area are of particular significance.
Flight-line impacts are a particular type of fragmentation impacts that affect flying fauna, usually birds or bats. A flight-line can be defined as a route which is regularly followed for local movements of one or more individuals of bird or bat over a period of time (unlike a flight path, which is the route of a single flying bird or bat on a single occasion, or a flyway, which is a broad route followed by a large number of migrating individuals over a long distance). A common example relevant to the NDAs is the flight-line between an egretry and the foraging sites used by breeding egrets; birds will follow such a flight-line regularly over the course of the day to collect food and then return to the nest to incubate or to feed young.
Typically flight-lines involve routes followed between feeding and roosting areas or between feeding and breeding areas. Starting and finishing points of flight-lines may be tightly defined (such as a roost site or a breeding site) or cover a wider area (for example a foraging area covering a wide area of habitat). Geographical features may influence the location of flight-lines; for example waterbirds tend to follow water features such as rivers and may follow valleys even when a route crossing a line of hills would be shorter.
Development located on a flight-line may result in a decrease in the suitability of a foraging, breeding or roosting site by preventing movement to another site or by reducing the efficiency of movement between sites. In an extreme case, this may lead to the total abandonment of one or both sites. There may also be an increased risk of mortality by collision with structures constructed on or close to a flight-line.
Potential significant direct, indirect and fragmentation impacts on habitats in the assessment area in the absence of mitigation are described below. Where any or all of such impacts are not of relevance, for example impacts of hydrological disruption on non-wetland habitats, or not predicted, these are not addressed in this report.
13.7.3.3 Long Valley
There will be no direct habitat loss in Long Valley arising from the Project; the area to the south and east of the Sheung Yue River will be zoned as Other Uses (Nature Park), while the area north and west of Long Valley will retain its current agricultural zoning.
Indirect Impacts
Potential indirect impacts to Long Valley in the absence of mitigation are assessed below. Potential disturbance impacts on Long Valley are considered separately in this section; other potential indirect impacts, which are more closely related, are presented together.
Potential disturbance impacts to Long Valley could arise from development on the west side of the Sheung Yue River in KTN areas B3-1 to B3-16, C1-1 and C1-2, D1-1 to D1-5, D1-7, D1-9 and the roundabout northwest of B3-8, as well as from the construction of two road bridges and a footbridge over the Sheung Yue River and the rechannelisation of the Long Valley Watercourse between the Sheung Yue River and the northeast corner of KTN area C1-1 . In addition, disturbance could also arise from any construction activities along the west side of the river in Open Space zone C2-1 and the subsequent use of the open space zone by people. Of these developments, the bridges, the proposed Commercial, Research & Development complexes in B3-5, B3-8 and B3-12, the developments along the north side of the river at D1-1 to D1-5 and the Open Space zone, and rechannelisation of the Long Valley Watercourse are the largest in scale and/or the closest to Long Valley, and thus have the potential to cause the greatest disturbance during construction and operation. Locations of those proposed developments predicted to cause the greatest disturbance impacts in the absence of mitigation and the areas which would be disturbed are shown in Figure 13.11. Disturbance from most of these sources would occur in both the construction and operational phases of the project but would be significantly greater in the former.
Other development areas are more than 200m from the areas in Long Valley used by significant numbers of large waterbirds (the most disturbance-sensitive receivers occurring in significant numbers in the Study Area) or are separated from Long Valley by intervening existing development, and hence are not predicted to be disturbed significantly by nearby developments.
In addition to disturbance impacts from development, Long Valley may be impacted by increased disturbance from human activities as a consequence of the greater population within the area and the increased ease of access. Currently the areas that receive the greatest number of human visitors are the roads alongside the Sheung Yue and Shek Sheung Rivers, which are used by large numbers of cyclists and walkers and a few vehicles. The farmland areas receive fewer visitors but are disturbed by farmers and birdwatchers.
The intensity of human disturbance within Long Valley compared with the baseline is not predicted to increase during the construction phase of the project. During the operational phase of the project it is assumed that the management of LVNP will, as a minimum, result in disturbance not being greater than at present in LVNP; there may, however, be a small increase in disturbance to the areas north and west of the Sheung Yue River due to the larger number of people living nearby; however these areas are distant from the main population and commercial centres and transport nodes of the NDAs.
Dust deposition may have a localised and short term impact during the construction period, especially in the southwest of Long Valley which is the area closest to major proposed construction activity. This may have a short-term effect on crop growth and food supply for some bird species.
Long Valley is largely made up of wetland habitats and these depend upon rainfall, wells and water supplied from the Sheung Yue River, both directly and that which is extracted to and distributed from the Long Valley Watercourse to the part of Long Valley south and east of the River. Accordingly, increased sediment and nutrient load in, and pollution and hydrological disruption of, the Sheung Yue River, the Long Valley Watercourse or the water table would, have a downstream impact on Long Valley wetland habitats. Effects of increased sedimentation and nutrient load would be minor as Long Valley habitats are already eutrophic and wetlands are turbid, but disruption to interruption of the water supply would be highly significant.
Hydrological impacts on Long Valley would potentially be significant were the water supply to Long Valley from the Long Valley Watercourse to be interrupted unexpectedly and/or for a prolonged period, especially if this occurred during the dry season. The water supply is currently abstracted from the Sheung Yue River above the fabridam located to the south of the Fanling Highway (Figure 13.4). Disruption could occur if this abstraction process were to be interrupted, or if the flow through the watercourse were to be interrupted to facilitate development in the areas to the southwest of Long Valley, especially in KTN area B3-12, or if the flow were to be interrupted to facilitate the proposed rechannelisation of this watercourse as an element of this project.
Table 13.59 - Potential impacts of disturbance and hydrological disruption on Long Valley in the absence of mitigation measures
|
Criteria |
Assessment |
|
|
Habitat Quality |
Large area, a mosaic of wetland habitats of high and very high
ecological value primarily due to high numbers and diversity of waterbirds,
including many species of conservation significance; also of importance for
other wetland-dependent fauna. |
|
|
Species |
High diversity of
wetland bird species, some of which are large waterbirds of conservation
significance sensitive to disturbance; other fauna diversity lower and not
including disturbance-sensitive species in significant numbers. Many of the
species of conservation significance are wetland-dependent, hence would be
affected by impacts of hydrological disruption. |
|
|
Size/Abundance |
Construction Phase disturbance
and hydrological impacts: a large area of habitat potentially impacted, with
high abundance of bird species. |
Operational Phase:
a significantly smaller area would be disturbed from off-site sources; no
impact from on-site disturbance sources predicted in LVNP (as it will be
managed) but casual disturbance from visitors could increase slightly in the
area north and west of the Sheung Yue River. Hydrological
disruption could still affect a large area but contingency plan to mitigate
for impacts should assist in remediation. |
|
Duration |
Construction Phase:
temporary
for construction phase disturbance impacts from development in areas adjacent
to Long Valley (scheduled from 2017-2029). Duration of hydrological impacts dependent upon cause of disruption;
unplanned disruption likely to be short-term and remediation possible. |
Operational Phase: permanent increase in disturbance from human
activities in developed areas once developments are completed; permanent
increase in disturbance during the operational phase from increased human
population in the area to the area north and west of the Sheung Yue River. Duration of hydrological impacts dependent upon cause of disruption;
unplanned disruption likely to be short-term and remediation possible. |
|
Reversibility |
Most impacts of
disturbance and hydrological disruption could be reversed during both
construction and operational phases, but some permanent disturbance due to
increased human activity in the area. |
|
|
Magnitude |
Disturbance: Long Valley is currently disturbed by residents and their
dogs, farming activities and by visitors, and fauna use reflects this. Of
these, the first two sources of disturbance will apply only during the
construction phase of the project and will end when LVNP is operational and
visitor activities will be managed. These changes will offset much of the
increase in disturbance from off-site sources. Accordingly, magnitude of
increase of disturbance from off-site construction activity is predicted to
be low to moderate for large waterbirds (as only a small part of Long Valley
will be affected for a small number of species (Figure 13.11a)), but
low for other fauna; no significant increase in impact from visitors in
managed LVNP; magnitude of impact from increased visitor numbers in
operational phase in the area north and west of the Sheung Yue River is
predicted to be low. Hydrological disruption: magnitude of disruption potentially large if
water supply from the Long Valley Watercourse were to be disrupted for a
prolonged period, especially during in the dry season. |
|
|
Impact Severity |
Disturbance impacts
of Low severity during construction phase as only
part of Long Valley and disturbance-sensitive large waterbirds will be
affected; lower, but still of significance,
during operational phase. Impacts of
hydrological disruption Low to High severity depending upon scale,
duration and time of year. |
|
Table 13.60 - Potential indirect impacts, in addition to disturbance and hydrological impacts, on Long Valley in the absence of mitigation measures
|
Criteria |
Dust deposition and increased sediment and nutrient
load |
Pollution |
|
Habitat Quality |
Large area, a mosaic of wetland habitats of high and very high
ecological value, primarily due to the high numbers and diversity of
waterbirds including many species of conservation significance. |
|
|
Species |
High diversity of
bird species, many of which are dependent on, or associated with wetland
habitats; much of the other flora and fauna is wetland-associated or
dependent. |
|
|
Size/Abundance |
A large area of
habitat potentially impacted, with high abundance of wetland-dependent bird
species and other fauna. |
|
|
Duration |
Risk would be greatest during construction phase and temporary
(scheduled from 2017-2029). No significant impacts during operation
(permanent). |
Risk of impacts would be greatest during construction
(2017-2029); risk small, but not insignificant during operation (permanent);
duration may vary according to the nature of the event. |
|
Reversibility |
Most impacts would
be reversible; dust deposition impacts would be reversed naturally by
rainfall. |
All impacts would
be reversible; but larger events would take longer to remediate. |
|
Magnitude |
Impacts of low magnitude, especially as sedimentation in eutrophic
riparian wetlands is a natural process. |
Magnitude of pollution event depends on type, size and duration of
pollution event. Larger pollution events likely to be detected more quickly,
so duration likely to be shorter. However, most pollution events are likely
to be small, detected less quickly, but to affect smaller areas. Higher
magnitude events unlikely during construction phase as monitoring will be in
place and highly unlikely during operational phase as KTN development will
largely be commercial and residential, hence potential sources for major
events are highly limited. |
|
Impact Severity |
Construction phase: severity of impacts Low as only a small part of the habitat would be affected and
most habitats and species are not sensitive. Operational phase: severity of impacts Low. |
Nature of project is such that sources major pollution sources will
not be present: most events likely to
be of low magnitude, severity of which would be Low to Moderate. Operational phase pollution impacts: although dependent on nature and
scale, most impacts likely to be Low.
|
Fragmentation
Potential fragmentation impacts on Long Valley include both potential fragmentation impacts within Long Valley and potential fragmentation of Long Valley from other habitats with which it has linkages. The avoidance of development within Long Valley does not wholly ensure that fragmentation within Long Valley will be avoided, as such impacts could arise if the Sheung Yue River, which divides the north and west of Long Valley from the south and east, were to be impacted in such a way that fauna species are deterred from crossing between the two areas. The development areas under the Project will not result in any reduction in connectivity between the two areas; however, construction works and increased human activity along the river may have some disturbance effects.
Long Valley has important linkages with the Ho Sheung Heung and Man Kam To Egretries in the form of flight-line links for foraging ardeids.
Table 13.61 - Potential Fragmentation Impacts on Long Valley in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Large area, a mosaic of wetland habitats of high and very high
ecological value, primarily due to the high numbers and diversity of
waterbirds, including many species of conservation significance. |
|
Species |
High diversity of
wetland bird species, many of which are large waterbirds that require or
prefer larger habitat blocks and are absent from fragmented areas.
Individuals of some species move between Long Valley and the Inner Deep Bay
area and utilise the Ng Tung River corridor. Linkages between Long Valley and
the Ho Sheung Heung and Man Kam To Egretries are highly significant for
ardeids breeding at these egretries. Populations of
other wetland fauna (except aquatic fauna able to use the Ng Tung and Sheung
Yue Rivers) are largely already fragmented from wetland fauna elsewhere and,
within Long Valley, by the Sheung Yue River, except for species that are able
to use anthropogenic habitats; hence, there will be little or no increase in
fragmentation for these groups. |
|
Size/Abundance |
A large area of
habitat potentially impacted, with high abundance of bird species potentially
affected by fragmentation impacts of areas on either side of the Sheung Yue
Rive and the Ng Tung River corridor. Lower abundance of
other fauna potentially impacted by fragmentation. |
|
Duration |
Fragmentation impacts from development activity along the Sheung Yue
River will be temporary. Impacts of increased human activity will be permanent. |
|
Reversibility |
Construction phase
impacts would be reversible; operational phase impacts irreversible;
remediation possible in both construction and operational phases. |
|
Magnitude |
Moderate during construction phase; low to moderate during operational
phase for some waterbirds but not significant for most fauna, hence low
overall. |
|
Impact Severity |
Low to Moderate during construction phase, Low during operational phase (except
on some waterbirds in the southwestern part of Long Valley which is closest
to proposed development areas where impact severity will remain Low to Moderate). |
13.7.3.4 Wet Agricultural Land
The ecological value of wet agricultural land in the Study Area has been assessed as Low to Moderate.
Small areas of wet agricultural land will be lost as a result of the Project. These comprise two fragments totalling 0.58ha, on the north and south sides of the Ng Tung River in the west of FLN. Whilst wet agriculture is often a habitat of relatively high ecological value, the value of these fragments is limited by their small size; this is somewhat compensated by linkages with Long Valley in respect to that at KTN and the Ng Tung River for those in FLN.
Wildlife species found are generally common and widespread and present in small numbers, consistent with the small size of the areas, though moderate numbers of amphibians were found in the wet agricultural areas in KTN. Most of these species are common and widespread in Hong Kong, but wetland bird species of conservation significance use these areas in small numbers. However, only seven wetland bird species (Watercock, Pintail Snipe, Swinhoe’s Snipe, Citrine Wagtail, Pallas’s Grasshopper Warbler and Oriental Reed Warbler) are restricted to wet agricultural land and one other wetland habitat (Long Valley). Loss of this habitat will therefore, not be of significance for these species due to the small number of individuals using wet agricultural land relative to Long Valley. Red-billed Starling utilises wet agricultural land in moderate numbers but this is a highly mobile species which forages opportunistically in a large number of wet and dry lowland habitats. Impacts on this species from the loss of small areas of wet agricultural land will, therefore, be insignificant. One butterfly species of conservation significance, Danaid Egg-fly is associated with wet agricultural land (but also occurs around other lowland wetland habitats and in shrubland). However, it was not found in or near any areas which will be impacted. Moderate numbers of amphibians are present in wet agricultural land, but all are common in many wetland habitats and the effect of the loss of the small areas of wet agricultural land will be insignificant at a species level. One amphibian species of conservation significance, Chinese Bullfrog, was found in one of the patches in FLN which will be lost, however this species is common in Hong Kong, hence the impact on this species will not be significant.
In addition to direct impacts on wet agricultural land which are evaluated in Table 13.62, some small areas of wet agricultural land in outside the boundary of the FLN NDA may experience some indirect impacts from the Project (Table 13.62a).
Table 13.62 - Potential Direct Ecological
Impacts on Wet Agricultural Land in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small areas of wet agriculture of Low to Moderate ecological value;
partly fragmented from similar habitats, but with some linkages with nearby
wetland habitats. |
|
Species |
Largely common and
widespread fauna species, but including bird species of conservation
significance, all in small numbers, and only seven species of which are
restricted to wet agricultural land and Long Valley habitats; numbers in Long
Valley are greater for all species. A moderate number and diversity of
amphibians is present but all species are found in several wetland habitats.
One individual of an amphibian species of conservation significance, Chinese
Bullfrog, was found in an area of wet agricultural land which will be lost in
FLN. |
|
Size/Abundance |
Small area (0.58ha)
will be permanently lost; small numbers of most animals but moderate numbers
of amphibians in patches in FLN. However, all species (including Chinese
Bullfrog, are common in Hong Kong, and impacts of displacement will be minor
as these species are able to utilise a variety of wetland habitats. |
|
Duration |
Permanent loss. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low to Moderate in both construction and operational
phases, primarily due to impacts on amphibians. |
Table 13.62a - Potential Indirect and
Fragmentation Impacts on Wet Agricultural Land in the absence of mitigation
measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small areas of wet agriculture of Low to Moderate ecological value
north and south of the non-tidal Ng Tung River; partly fragmented from
similar habitats, but with some linkages with nearby wetland habitats. |
|
Species |
Largely common and
widespread fauna species, but including bird species of conservation
significance, all in small numbers, and only seven species of which are
restricted to wet agricultural land and Long Valley habitats; numbers in Long
Valley are greater for all species. Moderate numbers and diversity of
amphibians are present but all species are found in several wetland habitats.
One individual of an amphibian species of conservation significance, Chinese
Bullfrog, was found in an area of wet agricultural land which may be
disturbed, but this species is not disturbance-sensitive. |
|
Size/Abundance |
Small area may be
disturbed by noise and human activity, dust and hydrological changes; small
numbers of most animals but moderate numbers of amphibians. However, all
species (including Chinese Bullfrog, are common in Hong Kong, and impacts of
disturbance are likely to be minor as
any impacts will be low and these species are able to utilise a variety of
wetland habitats and are not sensitive to most types of disturbance impacts. |
|
Duration |
Disturbance form noise and human activity will be permanent but
probably lower during the operational phase; dust and sediment run-off
largely during the construction phase; hydrological impact could be temporary
or permanent depending upon cause. |
|
Reversibility |
Mostly reversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low in view of small area, likely low magnitude and small number of
sensitive receivers. |
13.7.3.5 Dry Agricultural Land
The ecological value
of wet agricultural land in the Study Area has been assessed as Low.
Direct Impacts
The small areas of dry agricultural land that will be lost in KTN are highly fragmented and not used by significant numbers or diversity of fauna. A larger area of dry agricultural land will be lost in FLN, mainly between the existing urban area and Ng Tung River. The dry agricultural fields that will be lost in this area are highly fragmented by village areas. While areas of dry agricultural land may be ecologically linked to lowland grasslands; lowland grassland habitat has also been assessed as of Low ecological value as it too does not support significant numbers and diversity of species. Further, none of the species using lowland grassland are restricted to this, or this and a small number or area of other habitats. Nevertheless, small numbers of several fauna species of conservation significance have been recorded in dry agricultural land in this area. However, none of these species are dependent upon or strongly associated with dry agricultural land, and most are birds and amphibians that occur in higher numbers and more regularly in wet agricultural land or other habitats. Only one species, Bull-headed Shrike, is largely restricted to a small number of habitats (it also utilises wet agricultural land and Long Valley habitats). This species only just meets the criterion of regularly occurring in the Study Area, with, at most, a handful of individuals likely to be present, and as a non-breeding visitor. This species is of marginal occurrence in Hong Kong, which is at the extreme south of its wintering range, the impacts of displacement of one or two individuals into other areas would be insignificant.
Indirect
and Fragmentation Impacts
There will be no significant indirect and fragmentation impacts on dry agricultural land in KTN; one parcel of dry agricultural land in FLN to the east of Fanling is close to the Fanling Bypass and may be indirectly affected by dust and run-off during the construction phase and disturbance and fragmentation during the construction and operational phase of the project (Table 13.64).
Table 13.63 - Potential Direct Ecological Impacts on Dry Agricultural Land in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small, fragmented and disturbed areas individually but a moderate area
overall (9.33ha, all except 0.22ha of which are in FLN) of Low ecological
value. |
|
Species |
Low abundance and
diversity of wildlife, largely common and widespread fauna species not
restricted to this or a small number of habitats, but including a small
number of species and individuals of some species of conservation
significance, only one of which, Bull-headed Shrike, is distributed in this
and a small number of other habitats. A large area of suitable habitat not
affected by the project is present in the Study Area for these species. None
of these species are present in numbers which would result in direct impacts
causing a significant reduction in the carrying capacity of the areas to be
lost such that any displaced individuals would not be able to be absorbed
within the carrying capacity of unimpacted dry agricultural land or other
habitats suitable for the species. |
|
Size/Abundance |
A moderate area
totalling 9.33 ha; numbers of organisms are low. |
|
Duration |
Permanent loss. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low as area is
disturbed and fragmented, number of organisms is small and few, if any, are
dependent on this habitat. |
|
Impact Severity |
Low. |
Table 13.64 - Potential Indirect and Fragmentation Impacts on Dry Agricultural Land in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small area (4.59ha) of Low ecological value. |
|
Species |
Low abundance and
diversity of wildlife, largely common and widespread fauna species not
restricted to this or a small number of habitats, but including a small
number of species and individuals of some species of conservation
significance, only one of which, Bull-headed Shrike, is distributed in this
and a small number of other habitats. A large area of suitable habitat not
affected by the project is present in the Study Area for these species. None
of these species are present in numbers which would result in indirect
impacts causing a significant reduction in the carrying capacity of the areas
to be impacted such that any displaced individuals would not be able to be
absorbed within the carrying capacity of unimpacted dry agricultural land or
other habitats suitable for the species. |
|
Size/Abundance |
Small area; low
numbers of fauna due to small size. |
|
Duration |
Any impacts from dust deposition and run-off would be short term and
only during part of the construction phase; disturbance impacts would be
permanent but reduced during the operational period. |
|
Reversibility |
Construction phase
impacts mostly reversible; operational phase impacts irreversible; remedial
measures to reduce impacts possible in both construction and operational
phases. |
|
Magnitude |
Low due to small
area impacted and limited scope of disturbance impacts; number of organisms
is small and none are dependent on this habitat. |
|
Impact Severity |
Disturbance and
fragmentation impacts both Low as
both area and number of individuals affected are small. |
13.7.3.6 Pond
Direct Impacts
A total of 3.08ha of pond habitat, all but 0.37ha of which is in KTN, will be directly impacted by the Project. Most of the ponds in KTN are small and isolated both from each other and habitats with which they might have ecological linkages, and support few wetland faunal species, although the fish fry ponds at Fung Kong attract some ardeids and two ponds at Ho Sheung Heung, though largely surrounded by developed areas, have linkages with Long Valley habitats.
At FLN NDA, one small inactive fish pond located to the west of the Man Kam To Road, to the north of Ng Tung River, will be directly impacted. Being close to Ng Tung River, this and nearby ponds have some linkages with the river for more vagile fauna, especially birds, and also have a role in maintaining linkages for waterbirds with Long Valley. Thus, although the ponds generally attract few wetland species, they have been assessed as being of Moderate ecological value. Diversity of fauna in ponds along the Ng Tung River was assessed as low to moderate, however, due to its small size, fauna diversity in this one pond is low.
Indirect Impacts
In addition to the single pond directly impacted, the other ponds in this area are potentially indirectly impacted by construction noise, increased sediment and nutrient load and hydrological disruption arising from the development of the proposed Police Driving and Traffic Training Complex in FLN area A1-8 to the east, proposed WSD facilities in FLN area A1-2, Open Space in FLN area A1-4, and the Sewage Treatment Works Extension in FLN area A2-3.
Table 13.65 - Potential Direct Ecological Impacts on Ponds in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small areas of Low (0.59ha in KTN), Low to Moderate (2.12ha in KTN)
and Moderate (0.37ha in FLN) ecological value; largely fragmented by urban
habitats and somewhat disturbed by human activities. |
|
Species |
Small numbers and
diversity of floral species in active ponds, more floral diversity in
inactive ponds but with many exotic herb species, low diversity of fauna but
small numbers of waterbird species of conservation significance occur
occasionally. |
|
Size/Abundance |
Habitat area is
small (3.19ha) and faunal abundance is low. |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low for ponds small scattered ponds in KTN but Low to Moderate for pond at Fung Kong, those near Ho Sheung Heung
and that in FLN due to use by some wetland fauna and linkages with other
wetland habitats. |
Table 13.66 - Potential Indirect and Fragmentation Impacts on Ponds in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small area (2.75ha) of Moderate ecological value; somewhat fragmented
by developed areas and somewhat disturbed by human activities. |
|
Species |
Floral diversity
low with many exotic herb species; low diversity of fauna in ponds where
disturbance may occur (ponds with low to moderate diversity of fauna will not
be disturbed) but small numbers of waterbird species of conservation
significance occur occasionally. Some of these species are largely restricted
to pond and Long Valley habitats in the Study Area; however, these largely
occur in ponds along the Ng Tung River, not the ponds which will be
disturbed. One species of conservation significance, Little Grebe, may occur
regularly in the disturbed ponds; however this waterfowl species tolerates
relatively high levels of disturbance, including noise, presence of humans
and human activities. |
|
Size/Abundance |
Habitat area is
small and faunal abundance is low. |
|
Duration |
Temporary in respect of construction impacts, permanent in respect of
operational impacts. |
|
Reversibility |
Mostly reversible;
but operational phase disturbance irreversible; remedial measures possible in
both construction and operational phases. |
|
Magnitude |
Low for impacts of run-off and hydrological disruption; moderate for
construction phase disturbance, low to moderate for operational phase
disturbance, low for fragmentation. |
|
Impact Severity |
Construction stage disturbance impact of Low to Moderate severity and operational phase disturbance impact of Low severity; severity of run-off,
hydrological disruption and fragmentation Low in both construction and operational phase. |
Marsh
There will be no direct impacts to marsh habitat arising from the Project.
Indirect and Fragmentation Impacts
Marsh areas outside the KTN NDA boundary at Ma Tso Lung may be indirectly impacted by development to the south.
Potential disturbance impacts to the marsh at Ma Tso Lung from development nearby are not predicted as the marsh area is not used by significant numbers of disturbance-sensitive species; however, since the marsh is downstream of development areas of the Project, impacts of run-off and hydrological disruption during the construction and, to a lesser extent, the operational phase of the Project may occur. However, the marsh is a moderate area of habitat which currently experiences seasonal fluctuations in water levels and turbidity; hence impacts of run-off and hydrological disruption are likely to be of low significance.
Fragmentation impacts on this habitat are addressed as an element of fragmentation impacts on the Ma Tso Lung Stream and its riparian corridor of which this habitat constitutes an element.
Table 13.67 - Potential Indirect Ecological Impacts on Marsh in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Moderate area (4.16ha) of Low to Moderate ecological value; somewhat
fragmented by developed areas and somewhat disturbed by human activities. |
|
Species |
Floral diversity
low; several wetland fauna species, including one amphibian, one butterfly
and one dragonfly of conservation significance. |
|
Size/Abundance |
Habitat area is
moderate but faunal abundance is low. |
|
Duration |
Temporary in respect of construction impacts, permanent in respect of
operational impacts. |
|
Reversibility |
Mostly reversible
but operational phase disturbance impacts irreversible; remedial measures
possible in both construction and operational phases. |
|
Magnitude |
Low during construction and operational phases in respect to impacts
of run-off and hydrological disruption. Low during both construction and operational phases in respect to
disturbance impacts. |
|
Impact Severity |
Impact severity of
run-off, hydrological disruption and pollution Low; severity of disturbance impacts Low. |
13.7.3.7
Mitigation Wetland
Potential ecological
impacts on mitigation wetland parcels, other than the parcels in Long Valley
which were considered as an element of assessment of impacts on Long Valley
habitats, are assessed below.
Direct Impacts
Three mitigation wetland parcels alongside the Sheung Yue River and seven on the Ng Tung River will be directly impacted by the Project. The areas are small (2.75ha in aggregate), but the parcels alongside the Sheung Yue River form an element of the Long Valley wetland complex, albeit they are somewhat fragmented from the main area of that wetland by non-wetland habitats; both these and the parcels along the Ng Tung River have linkages with the adjacent river channels.
One mitigation wetland parcel on the Sheung Yue River is 140m upstream of the Project Area boundary and is unlikely to be used by significant numbers of the more disturbance sensitive waterbirds. No significant impacts on this wetland parcel are predicted.
Indirect Impacts
One mitigation wetland parcel on the north side of the Ng Tung River in FLN area A1-7 is proposed to be retained as wildlife habitat and zoned as Conservation Area (CA) in the revised RODP. Indirect impacts to this parcel could arise from construction and operation of the Police Driving and Traffic Training Complex (in FLN A1-7) just over 100m to the east, and any landscape works along the Ng Tung River, as well as increased human activity during the operational phase of the Project. The Sewage Treatment Works Extension is 200m to the west of A1-7 so disturbance impacts from this source are not considered to be significant. However, a new footbridge to be constructed over the Ng Tung River is within 50m and hence is a potential source of disturbance during construction. Dust deposition may have a localised and temporary impact on this parcel during the construction period. This may have a short-term effect on plant growth and food supply for some species of fauna. Water supply to the wetland is from the Ng Tung River but this supply will not be affected by the project as no works requiring this to be interrupted are proposed; further, works are not predicted to result in any hydrological disruption. However, increased sediment and nutrient load in, and pollution of, the Ng Tung River would have an impact on the habitat. Effects of increased sedimentation and nutrient load would be minor, as water in the habitat is already eutrophic and turbid.
Fragmentation Impacts
Potential fragmentation impacts to this mitigation meander could arise from interruption of linkages to adjacent wetland habitat (the Ng Tung River) or with nearby wetland habitat with which it has linkages (Long Valley). Linkages with the Ng Tung River would be affected by construction work on the road and by increased use of the road by vehicles or pedestrians during the operational period. Linkages with Long Valley will not be impacted significantly permanently, as the single development in the intervening area (Sewage Treatment Works Extension) will only slightly increase the development area and mass relative to the existing Sewage Treatment Works.
Table 13.68 - Potential Direct Ecological Impacts on Mitigation Wetlands in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Small areas of semi-natural pond and marsh habitat, somewhat
fragmented, but those along the Sheung Yue River have linkages with Long
Valley and all parcels have linkages with the adjacent river channels.
Parcels along the Sheung Yue River (0.43ha) are considered to be of Moderate
ecological value as an element of the Long Valley wetland complex; those
along the Ng Tung River (2.32ha) are more fragmented from other wetland habitats
and are used by smaller numbers of fauna, hence are of Low to Moderate
ecological value. |
|
Species |
Parcels along the
Sheung Yue River are used by many of the pond and marsh-associated fauna of
Long Valley wetland; those along the Ng Tung River have a low diversity of
wetland birds and most fauna, but a moderately diverse dragonfly community,
including one species of conservation significance, Dingy Dusk-hawker, albeit
this species is common in Hong Kong. |
|
Size/Abundance |
Habitat area is
small (2.75ha in aggregate) and abundance of fauna is low. |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low to Moderate severity. |
Table 13.69 - Potential Impacts of Disturbance and Hydrological Disruption on Mitigation Wetland in FLN A1-7
|
Criteria |
Disturbance |
Hydrological Disruption |
|
Habitat Quality |
Small area (0.34ha) of wetland of Moderate ecological value with some
linkages to the Ng Tung River and Long Valley. |
|
|
Species |
Low diversity of
species due to the small size of this one parcel, but some wetland flora and
small numbers of wetland birds of conservation significance. |
|
|
Size/Abundance |
Area of habitat and
fauna numbers are both small. |
|
|
Duration |
Temporary for construction phase impacts from nearby development.
Permanent from human activities in these areas once developments are
completed. Permanent increase in disturbance during the operational phase
from increased human population in the area causing number of visitors to
increase. |
Temporary for construction phase impacts from
nearby development. |
|
Reversibility |
Mostly reversible,
but operational stage disturbance impacts irreversible; remedial measures
possible in both construction and operational phases. |
Reversible. |
|
Magnitude |
Magnitude of increase of disturbance is predicted to be low (see Figure
13.11b). |
Only minor works under the project are predicted nearby and interruption
to water supply is not planned and is unlikely to occur accidentally. |
|
Impact Severity |
Low severity. |
Low severity. |
Table 13.70 - Potential impacts of dust deposition, increased
sediment and nutrient load and pollution on mitigation wetland in FLN A1-7 in
the absence of mitigation measures
|
Criteria |
Assessment in respect of dust deposition,
increased sediment and nutrient load to, pollution of, or hydrological
disruption to the water supply |
|
Habitat Quality |
Small area of wetland of Low to Moderate ecological value with some
linkages to the Ng Tung River and Long Valley. |
|
Species |
Low diversity of
species but some wetland flora and small numbers of wetland birds of
conservation significance. |
|
Size/Abundance |
Area of habitat and
fauna numbers are both small. |
|
Duration |
Temporary for changes to water quality. |
|
Reversibility |
Mostly reversible
and remedial measures may be possible. |
|
Magnitude |
Low. |
|
Impact
Severity |
Low during construction, not significant during operation. |
Table 13.71
- Potential fragmentation Impacts on mitigation wetland in FLN A1-7 in the
absence of mitigation measures
|
Criteria |
Assessment in respect of fragmentation |
|
Habitat Quality |
Small area of wetland of Moderate ecological value with some linkages
to the Ng Tung River for more vagile wetland fauna. |
|
Species |
Low diversity of
species but some wetland flora and small numbers of wetland birds of
conservation significance. |
|
Size/Abundance |
Area of habitat and
fauna numbers are both small. |
|
Duration |
Temporary for any construction impacts. Impacts of increased human
activity will be permanent. |
|
Reversibility |
Mostly irreversible
but remedial measures may be possible. |
|
Magnitude |
Construction phase impacts of low to moderate magnitude; operational
phase impacts of low magnitude. |
|
Impact Severity |
Low to Moderate during construction phase, Low during operational phase. |
13.7.3.8 Direct, Indirect and Fragmentation impacts on the Major Channelised Watercourses
Two new road bridges and one new footbridge
will be constructed over the Sheung Yue River; one new footbridge will be
constructed over the tidal Ng Tung River and two new road bridges and three new
footbridges will be constructed over the non-tidal Ng Tung River. In addition,
four footbridges and one road bridge will be upgraded
on the non-tidal Ng Tung River. Bridge construction will result in a small
direct loss of habitat in the major channelised watercourses as a consequence
of the construction of piers in the river beds. The area occupied by the piers
will be very small, both in absolute terms and in relation to the size of the
rivers; it is estimated that approximately 60m2 will be lost on the
Sheung Yue River, 10m2 and 80m2 will be lost on the Ng
Tung River, assuming that the new bridges are of a similar design to existing
bridges.
Construction of the new bridges will require
the creation of temporary cofferdams in many or all cases. The direct impact of
the temporary habitat loss will be of low significance, as will hydrological
impacts as the areas required for cofferdams will be small and will not affect
the rivers hydrologically (see Section
5.6.1.2), Disturbance and fragmentation impacts of pier construction will
not be materially different from those of bridge construction as the
disturbance and fragmentation will affect the same sensitive receivers (large
waterbirds) as other elements of the construction process. Locations of new
bridges over the channels are shown on Figure 13.11a-b.
In addition to impacts of hydrological disruption, there may be indirect impacts on the three main channelised watercourses from disturbance, pollution, sedimentation, increased nutrient load and fragmentation. In the following impact evaluations direct and disturbance impacts, which are similar in nature in respect to this habitat are considered together; as are other indirect impacts (including hydrological impacts). Fragmentation impacts on large waterbirds utilising this habitat are addressed separately, as these are somewhat different in nature in that they only affect a limited number of species, but may be relatively significant for some of these.
The Sheung Yue River is used by some species of waterbirds on a regular basis, though the numbers are insignificant in a Hong Kong context; while the Ng Tung and the tidal lower section of the Shek Sheung River are used by moderate numbers of the same species. Grey Heron and Great Egret are the most disturbance sensitive of these species, but they are not known to rely significantly on the water channels. The waterbird species usually present in the largest numbers is Little Egret. The species and circumstances for which the foraging habitat is considered to be of most significance are Little Egret and Chinese Pond Heron during the breeding season, as they are most likely to be reliant on this habitat.
Roads alongside the rivers are currently used by local residents, small numbers of vehicles, but considerable numbers of cyclists and pedestrians. Accordingly, birds using the river channels are already exposed, and hence habituated, to moderate amounts of disturbance in the area. However, disturbance levels will increase significantly on the Sheung Yue and Ng Tung Rivers as a consequence of the Project, both through construction activity adjacent to the channels and increased population within the NDAs during the operational period. Disturbance is predicted to increase most along the southern section of the Sheung Yue River, especially in the south where there will be development on both sides and along much of the non-tidal section of Ng Tung River in FLN (Figure 13.11). There will be no significant disturbance impacts to the Shek Sheung River during the construction phase of the project, but disturbance may increase during the operational phase.
Disturbance impacts to the rivers are predicted to be greatest to the Sheung Yue and Ng Tung Rivers during the construction phase, but will be lower, especially along the tidal section of Ng Tung River, during the operational phase as much of the land adjacent to the river will be zoned as open space, in which disturbance impacts will be largely restricted to disturbance from human recreational and leisure activities.
Development adjacent to, or upstream of, the watercourses may result in increased sedimentation, nutrient load, pollution or hydrological disruption. Any assessment of potential impacts from these sources must, however, be set in the context of the large size of the rivers (length, width and, in the case of the Ng Tung River, water volume) and their current eutrophic, turbid and relatively polluted state.
Fragmentation Impacts
Potential fragmentation impacts to major channelised watercourses include additional barriers to the movement of aquatic fauna, especially in the sections with unimpeded flow at present, and bridges or other structures that would impede flying birds. Additional barriers to water movement are not proposed under the Project, but a new road bridge and footbridge will be built over the Sheung Yue River and the Ng Tung River.
Fragmentation impacts may also be caused if the movement corridors along the rivers are narrowed by development or activities in adjacent areas and/or if movement corridors along or across the rivers are impacted by development or activities along the rivers such that fauna are deterred from using them.
In the case of the Sheung Yue River, there are two movement corridors; that along the river, which extends upriver beyond the Study Area, and that across the river between the areas north and west and south and east of the river. The first of these corridors is primarily used by waterbirds foraging in the river; the second by waterbirds moving between wetland habitats in Long Valley on either side of the river and by ardeids flying between Long Valley south and east of the river and Ho Sheung Egretry. Both of these corridors are used by moderate numbers of waterbirds; the latter is of particular significance for breeding ardeids. In the case of the Shek Sheung River, the river corridor is used primarily by waterbirds foraging in the river, and hence is used by fewer waterbirds.
The corridor along the Ng Tung River in FLN is used by waterbirds foraging along the river and by ardeids breeding at Man Kam To Road Egretry; while that along the Ng Tung River north of the confluence with the other rivers and Area C2-2 of KTN NDA, form an important ecological linkage, especially for waterbirds, to Hoo Hok Wai and the Deep Bay wetland ecosystem. Again, the species and circumstances for which fragmentation impacts are considered of potential significance are Little Egrets and Chinese Pond Herons foraging in this habitat during the breeding season and breeding at Ho Sheung Heung and Man Kam To Egretries.
Table 13.72 - Potential Direct Ecological Impacts and Disturbance Impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Habitat is artificial and has been created by entirely remodelling
former river channels. However, Sheung Yue River and the tidal section of the
Ng Tung River are of Moderate ecological value, and the non-tidal section of
the Ng Tung River and the Shek Sheung River are of Low to Moderate ecological
value, primarily because of their importance to some waterbird species. |
|
Species |
Low floral
diversity; low to moderate diversity of fauna species on Sheung Yue River,
low diversity of fauna species on the other rivers. Of significance to some
waterbird species; however, all species of conservation significance use a
variety of wetland habitats and all occur more regularly and usually in
larger numbers, in Long Valley. |
|
Size/Abundance |
Habitat area is
large (total length of approximately 9,500m). Sheung Yue River and tidal
section of Ng Tung River used by moderate numbers, non-tidal section of Ng
Tung River by low to moderate numbers, Shek Sheung River
by low numbers of waterbirds. Low abundance of other fauna of
conservation significance. |
|
Duration |
Permanent in respect of direct habitat loss and operational phase
impacts, temporary in respect of construction phase impacts. |
|
Reversibility |
Construction phase
impacts of small area occupied by cofferdams for bridge piers mostly reversible;
permanent habitat loss for bridge piers irreversible; construction stage
disturbance impacts mostly reversible. Remedial measures possible during both
construction and operational phases. |
|
Magnitude |
Direct habitat loss of very low magnitude during operation, larger,
but still low relative to the size of the rivers, during construction. Construction phase disturbance to the Sheung Yue River moderate; to
the non-tidal section of the Ng Tung River and the Shek Sheung River would be
of low to moderate magnitude; and to the tidal section of the Ng Tung River,
low. Operational phase disturbance to large waterbirds on the Sheung Yue
River and non-tidal section of the Ng Tung River would be of low to moderate
magnitude but all other disturbance impacts on the habitat and species would
be of low magnitude or not significant; operational phase disturbance to the
non-tidal section of the Ng Tung River and the Shek Sheung Rivers would not
be significant as all significant ecological functions would be restored. |
|
Impact Severity |
Impact of direct
habitat loss of Low severity
during both construction and operational phases, as area is small, relative
to the size of the rivers. Construction phase: Moderate severity on Sheung Yue
River due to the relatively large number of waterbirds present; Low to Moderate severity
on non-tidal section of the Ng Tung River; Low severity on tidal section of the Ng Tung River and on the
Shek Sheung River. Operational phase: Low severity (in view of small number
of species and single foraging function) on waterbirds in the Sheung Yue
River and the non-tidal section of Ng Tung Rivers but all other habitat
functions and functions for fauna would be restored; not significant
elsewhere as only a small number of species (the most disturbance-sensitive
large waterbirds) will be affected and other ecosystem functions will be restored. |
Table 13.73 - Potential Impacts of increased sediment and nutrient load, pollution and hydrological disruption on Ng Tung, Sheung Yue and Shek Sheung Rivers in the absence of mitigation measures
|
Criteria |
Increased
sediment and nutrient load and pollution |
Hydrological disruption |
|
Habitat Quality |
Habitat is artificial and has been created by entirely remodelling
former river channels. However, Sheung Yue River and the tidal section of the
Ng Tung River are of Moderate ecological value, and the non-tidal section of
the Ng Tung River and the Shek Sheung River are of Low to Moderate ecological
value, primarily because of their importance to some waterbird species. |
|
|
Species |
Low floral
diversity; low to moderate diversity of fauna species on Sheung Yue River,
low diversity of fauna species on the other rivers. Of significance to some
waterbird species; however, all species of conservation significance use a
variety of wetland habitats and all occur more regularly and usually in
larger numbers, in Long Valley. |
|
|
Size/Abundance |
Habitat area is
large (total length of approximately 9,500m. Sheung Yue and Ng Tung Rivers
are used by moderate numbers and Shek Sheung River by low numbers of
waterbirds. Low abundance of other fauna of conservation significance. |
|
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
Temporary and only during construction phase. |
|
Reversibility |
Construction phase
impacts mostly reversible; operational phase impacts irreversible; remedial
measures possible during both construction and operational phases. |
Reversible. |
|
Magnitude |
Magnitude mostly low, due to potential scale of impacts relative to
the size of the channels; some pollution events could be of moderate
magnitude. |
Magnitude low: pier construction will utilise cofferdams which will
not have significant effects on hydrology of rivers (see Section 5.6.1.2). |
|
Impact
Severity |
Low in
most circumstances, but some construction phase pollution impacts could be of Moderate severity. |
Low. |
Table 13.74 - Potential Fragmentation Impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers in the absence of mitigation measures
|
Criteria |
Assessment in respect to fragmentation |
|
Habitat Quality |
Habitat is artificial and has been created by entirely remodelling
former river channels. However, Sheung Yue River and the tidal section of the
Ng Tung River are of Moderate ecological value, and the non-tidal section of
the Ng Tung River and the Shek Sheung River are of Low to Moderate ecological
value, primarily because of their importance to some waterbird species. |
|
Species |
Of potential
significance to bird species if linkages between the rivers and Long Valley
are affected, or linkages along the rivers to other habitats with which Long
Valley has ecological linkages are affected. There are no significant
linkages between the rivers and other habitats for other fauna. |
|
Size/Abundance |
The tidal section
of the Ng Tung River is large and is used by moderate numbers of waterbirds,
including breeding egrets, as a movement corridor. However, the movement corridor is
considerably wider than the river itself and includes a relatively wide riparian
corridor, much of which contains wetland habitats, and which is largely
unobstructed by development. The non-tidal
section of the Ng Tung River is large; moderate numbers of waterbirds use the
river as a movement corridor to Long Valley and perhaps the Sheung Yue River.
The Sheung Yue
River is moderate in size; moderate to large numbers of waterbirds move
between the river and Long Valley, but relatively few birds use the Sheung
Yue River as a movement corridor as there is little suitable habitat upstream
of the Fanling Highway. The Shek Sheung
River is small; a small number of birds move between this river and Long
Valley but the river itself is not a significant movement corridor. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Fragmentation
impacts caused by construction activity largely reversible but impacts due to
avoidance of structures largely irreversible; some remediation possible for
construction phase impacts. |
|
Magnitude |
Not significant for impacts on linkages between the Sheung Yue and
Shek Sheung Rivers and Long Valley as these linkages will largely be
unaffected; low to moderate for impacts on linkages between the non-tidal Ng
Tung River and Long Valley during both construction and operational phases as
number of birds is moderate but few species are involved in significant
numbers, low for impacts on linkages along the tidal Ng Tung River during the
construction phase as development area is small relative to the corridor
width; not significant during the operational phase as no significant
increase in sources of fragmentation. |
|
Impact Severity |
Low to Moderate severity in
respect to impacts on linkages between the non-tidal Ng Tung River and Long
Valley during construction and operation; Low severity in respect to impacts on linkages along the tidal Ng
Tung River during the construction phase, but not significant during the
operational phase. |
13.7.3.9 Minor Watercourse/Stream
Ma Tso Lung Stream
There will be no direct impacts on the mid/upstream section of the Ma Tso Lung Stream where a Three-banded Box Terrapin was found during surveys conducted for this project.
Ma Tso Lung Stream will be impacted directly by construction of the Eastern Link Road to LMC Loop. The road will cross the stream on viaduct, though a section of 130m of the stream will be diverted and the 30m wide riparian corridor on either side of this section will be narrowed to between 15m and 30m on the west side of the stream. One minor tributary will be diverted for a combined length of 120m in its upper reaches in order to avoid proposed development areas in KTN areas E1-2 (Primary School). This stream section is disturbed by adjacent developed areas at present.
Where the road is on viaduct over the stream, no direct impact on the stream is predicted.
However, Ma Tso Lung Stream may be indirectly impacted downstream of the viaduct and at-grade sections by run-off and hydrological disruption arising from the road construction and diversion and the stream and the riparian corridor may receive fragmentation impacts from these sources. In addition, both the stream and its tributary, Ma Tso Lung San Tsuen Stream, may be indirectly impacted and experience fragmentation impacts as a consequence of development in KTN area F1-1, proposed for Sports Ground/Sports Complex, F1-2 proposed for a Sewage Pumping Station, and F1-3 proposed for Research and Development in Support of Lok Ma Chau Loop Development.
Fragmentation impacts on the stream and riparian corridor are primarily of concern if the project element which may cause impacts severs continuous areas of a habitat or severs habitats which have significant ecological linkages. In the case of Ma Tso Lung Stream and tributaries, these comprise the natural and semi-natural habitats of the riparian corridor, as well as the stream itself. The riparian corridor is largely wooded in the middle and upstream sections and grassland, seasonally wet grassland and marsh in the downstream section. The alignment of the road is such that it will cross the stream approximately 320m upstream of the northern boundary of the Project Area, then will run parallel and to the west of the stream (including the section to be diverted) as far as the limits of the Study Area. As a consequence fragmentation impacts could arise in one of three ways: fragmentation where the stream crosses the road; fragmentation, if disturbance impacts on the corridor deter fauna from using the corridor where this parallels the road; and fragmentation of linkages between stream corridor habitat and other areas of the same or ecologically linked habitat on the western side of the road.
Of these three types of fragmentation impact, the first, the severance of the stream corridor where the road crosses the stream is potentially the most severe impact; disturbance of the corridor also has the potential to be a severe impact if it deters fauna of conservation significance which are reliant on the riparian corridor habitats from using the corridor. The third type of fragmentation impact is likely to be of lower severity to fauna using the riparian corridor, but may be of significance for fauna moving between habitats on either side of the corridor, or moving between the corridor and non-riparian habitats to the west.
Table 13.75 - Potential Direct Ecological Impacts on Ma Tso Lung Stream and tributaries in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Ma Tso Lung Stream is of Moderate to High
ecological value as the watercourse within the Study Area is natural or
semi-natural and supports stream fauna of conservation significance); the section of
minor tributary which will be diverted is disturbed by neighbouring
development and is of Low ecological value. |
|
Species |
Flora diversity is
low but fauna includes three wetland-dependent species of conservation
importance in or near the stream including the globally Critically Endangered
Three-banded Box Terrapin (though the latter is unlikely to utilise the area
of stream which will be impacted on a regular basis as this species prefers
wooded habitats which are not present in the section of Ma Tso Lung Stream
which will be diverted and its downstream riparian corridor, while the
tributary section to be diverted is disturbed at present and is located some
way from where the terrapin was recorded). |
|
Size/Abundance |
Both diverted sections of streams are small
as compared to the total length of the stream and tributaries (6600m).
Numbers of fauna which may be impacted are small. |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Moderate. |
|
Impact Severity |
Moderate in respect of diversion of lower stream course, Low in respect of disturbed minor tributary. |
Table 13.76 - Potential Indirect Ecological Impacts on Ma Tso Lung and Ma Tso Lung San Tsuen Streams in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Ma Tso Lung Stream and Ma Tso Lung San Tsuen
Streams are of Moderate to High ecological value as the watercourses within
the Study Area are natural or semi-natural and support stream fauna of
conservation significance. The section of minor tributary to be diverted is
disturbed by neighbouring development and is of Low ecological value. |
|
Species |
Flora diversity is
low but fauna includes seven wetland-dependent species of conservation
importance in or near the stream, including the globally Critically
Endangered Three-banded Box Terrapin (though the latter is unlikely to utilise
the area of stream which will be impacted on a regular basis as this species
favours wooded habitats which are not present in the section of Ma Tso Lung
Stream which will be diverted and its downstream riparian corridor, while the
tributary section to be diverted is disturbed at present and is located some
way from where the terrapin was recorded). None of these species are highly
disturbance-sensitive, but reptile species (including Three-banded Box
Terrapin) may be displaced from potential habitat by disturbance. Two aquatic species
(Somanniathelphusa zanklon and
Small Snakehead) and two species with partially aquatic life cycles (Chinese
Bullfrog and Ruby Darter) of conservation significance may be impacted by
pollution, though all four species are relatively tolerant of high turbidity
and organic pollutants. |
|
Size/Abundance |
Both streams are
small (but the total length of the stream and tributaries is large (6600m);
the length that might be impacted is moderate due to potential downstream
hydrological disruption and impacts of pollution and disturbance impacts on
riparian fauna. Numbers of fauna which may be impacted are small but include Somanniathelphusa zanklon
and Small Snakehead. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Construction phase
impacts mostly reversible; operational phase impacts irreversible; remedial
measures to reduce disturbance possible in both construction and operational
phase. |
|
Magnitude |
Disturbance: moderate during both construction and operational phases Run-off and hydrological disruption: moderate during construction
phase, low during operational phase. |
|
Impact Severity (Disturbance) |
Low during
construction phase; Low during
operational phase, in respect of main stream; Low during construction and Low
during operation in respect of the tributary. |
|
Impact Severity (Pollution and Hydrological
Disruption) |
Moderate during construction phase; Low
to Moderate during operational
phase, in respect of both the main stream and the tributary, due to the
relatively large area which may be affected downstream. |
Table 13.77 - Potential Fragmentation Impacts on Ma Tso Lung Stream and tributaries and riparian corridor in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Ma Tso Lung Stream and Ma Tso Lung San Tsuen
Streams are of Moderate to High ecological value as the watercourses within
the Study Area are natural or semi-natural and support stream fauna of
conservation significance. |
|
Species |
Terrestrial fauna
may be affected by fragmentation of the stream corridor or of linkages
between habitats on either side of the riparian corridor. Such fauna includes
seven wetland-dependent species of conservation importance in or near the
stream, including the globally Critically Endangered Three-banded Box
Terrapin. Of these species, two
(Three-banded Box Terrapin and Chinese Bullfrog) may be affected by fragmentation
of the riparian corridor. Also of relevance is Red Muntjac, found to the west
of the stream, as this species may cross the riparian corridor. All aquatic fauna
of conservation significance was found downstream of the area where
fragmentation impacts may occur so impacts on the species are predicted to be
small at most. |
|
Size/Abundance |
Both streams are
small, but fragmentation has the potential to impact a large area. Numbers of
fauna which may be impacted are small. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible;
though remedial measures possible during operational phase. |
|
Magnitude |
Low to moderate as number of species and
individuals which will be affected are both small. |
|
Impact Severity |
Moderate on Ma Tso Lung Stream during
both construction and operational phases as number of individuals is small
but ecological importance of potentially impacted fauna (in particular
Three-banded Box Terrapin) is high. Low on
tributaries during construction and operation. |
Pak Shek Au and Chau Tau Watercourse
This watercourse is a concrete-lined drainage ditch alongside Castle Peak Road. It has only intermittent flow and supports no fish or stream fauna. Road improvement works will directly impact the whole watercourse.
Chau Tau Watercourse is a small partly-channelised polluted stream located in the east of Chau Tau Village. Small numbers of the crab, Somanniathelphusa zanklon, which is of conservation significance, have been found in this watercourse. The watercourse is outside the Project Area boundary and is upstream of any areas where impacts are predicted.
Table 13.78 - Potential Ecological Impacts on Pak Shek Au and Chau Tau Watercourses in the absence of mitigation measures
|
Criteria |
Pak Shek Au Watercourse |
Chau Tau Watercourse |
|
Habitat Quality |
Man-made habitat of Low ecological value. |
Partially channelised but largely natural bed
and sides; polluted. |
|
Species |
No fish or stream
fauna. |
Somanniathelphusa zanklon present in small
numbers. |
|
Size/Abundance |
Very small with
intermittent flow. |
Stream is small;
numbers of Somanniathelphusa
zanklon appear to be small. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
No impacts on the stream or stream fauna area predicted. |
|
Reversibility |
Irreversible. |
N/A. |
|
Magnitude |
All of watercourse will be impacted but very
small; therefore low. |
N/A. |
|
Impact Severity |
Low. |
No impacts
predicted. |
Tung Fong/Shek Tsai Ling Watercourse and Kwu Tung Watercourse
These small, connected watercourses fall entirely within the development area of the Project in KTN. They are largely channelised but a short upstream section of Tung Fong Watercourse has a semi-natural stream course, though this is highly disturbed and flow is intermittent in this section. One crab species of conservation significance, Somanniathelphusa zanklon, was found in a channelised section of the Tung Fong Watercourse and may also be present in the semi-natural section. This species is present in a number of streams in the area and is tolerant of polluted conditions; only one individual was found in this stream and there is little suitable habitat present.
Table 13.79 - Potential Ecological Impacts on Tung Fong/Shek Tsai Ling Watercourse and Kwu Tung Watercourse in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Largely man-made habitat of Low ecological
value; a small semi-natural upstream section is highly disturbed and polluted
and flow is intermittent; this section also of Low ecological value. |
|
Species |
One individual of a
crab species of conservation significance, Somanniathelphusa zanklon is present. This species is of
conservation significance however has been recorded in a number of
watercourses in the northern New Territories and occurs in a variety of lotic
wetlands. This species is not significantly restricted by either geographical
or habitat constraints to the impacted habitat. |
|
Size/Abundance |
Small, limited
habitat for Somanniathelphusa
zanklon present. Only one individual found suggesting that the population in the
impacted is small and unlikely to be significant |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible. |
|
Magnitude |
All of watercourses will be impacted but
small; therefore low. |
|
Impact Severity |
Low as Somanniathelphusa zanklon is
present in several watercourses in the area, population in the impacted
habitat is likely to be small and this stream does not provide significant
areas of suitable habitat for this species. |
Fung Kong and Ho Sheung Heung Watercourses
These small, connected, watercourses fall entirely within the development area of the Project in KTN. They are channelised but a part of Fung Kong Watercourse is not concrete-lined. The watercourses are highly disturbed and polluted and no fish or stream species of conservation significance have been recorded.
Table 13.80 - Potential Ecological Impacts on Fung Kong and Ho Sheung Heung Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Man-made habitat of Low ecological value. |
|
Species |
No species of
conservation significance recorded. |
|
Size/Abundance |
Small area; small
numbers of stream fauna. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible. |
|
Magnitude |
All of watercourses will be impacted but
small; therefore low. |
|
Impact Severity |
Low |
Tsung Yuen, Lo Wu and Ngam Pin Watercourses
These small watercourses do not fall within, and are not downstream of any areas which will be developed under, the Project, and no impacts arising are predicted.
Long Valley Watercourse
The middle and downstream sections of this watercourse are irrigation ditches within Long Valley. No stream fauna (fish or invertebrates) of conservation significance occurs in the watercourse, though it is utilised by species of conservation significance using Long Valley.
However, this watercourse delivers water to Long Valley, and thus it has an important hydrological function. The upstream channelised section does not support stream fauna of ecological significance, but run-off from construction activity and hydrological disruption to this watercourse from the Project are potentially of significance.
The upstream section of the watercourse which flows through KTN Areas B3-12 and forms the boundary between the proposed LVNP and KTN area C1-4 will be re-channelised as an element of the project. Ecological impacts of rechannelisation works will be limited; however construction phase hydrological disruption to Long Valley could be significant if the water supply is disrupted for longer than the water storage capacity of ponds in Long Valley, especially if such disruption took place in the dry season and/or unexpectedly. The design and scheduling of rechannelisation works and construction works in developments areas through which the Long Valley Watercourse flows at present should, therefore, take account of the predicted hydrological impacts on Long Valley in the absence of mitigation.
Table 13.81 - Potential Ecological and Hydrological Impacts on Long Valley Watercourse in the absence of mitigation measures
|
Criteria |
Ecological Impacts |
Hydrological Impacts |
|
Habitat Quality |
Upstream section is a man-made habitat flowing
through developed areas; lower sections are a man-made network of irrigation
ditches. Stream is of Low to Moderate ecological value, primarily due to its
linkages with other wetland habitats. |
|
|
Species |
It
does not support any stream fauna of conservation significance but it is
utilised by many wetland-dependent species of conservation significance in
Long Valley. |
|
|
Size/Abundance |
Small area; small
numbers of stream fauna. However it is used by many wetland-dependent
species. In addition, many more wetland-dependent species and large numbers of
individuals are partly dependent on water from this channel to maintain
suitable conditions in their required habitats. |
|
|
Duration |
Construction phase only. |
Temporary in both construction and operational phases. |
|
Reversibility |
Reversible and
remedial measures possible. |
Reversible in both
construction and operational phases, though restoration of habitats may take
some time if disruption is prolonged. Remedial measures easy to implement but
advance planning to avoid requirement for emergency remediation measures. |
|
Magnitude |
Magnitude small as area is small and few
individuals or species would be affected. |
Magnitude small if disruption is short term or
occurs in the wet season; moderate if long-term and in the dry season. |
|
Impact Severity |
Low. |
Low if short term and during the wet season; Moderate if long-term and in the dry season. |
Cheung Po Tau and Fu Tei Au Watercourses
The upstream section of Cheung Po Tau Watercourse is semi-natural but seasonal, and supports no stream fauna of conservation significance. This section could be impacted by run-off during construction of the proposed Fanling North Freshwater Service Reservoir in FLN area A3-1. The downstream section of these linked watercourses, the Fu Tei Au Watercourse, flows through FLN area A1-8, which is proposed to be developed as a Police Driving and Traffic Training Complex. This section could be directly impacted and could also be hydrologically disrupted and/or impacted by construction run-off. However, this downstream section is entirely channelised and no fauna of conservation significance have been found in this section.
Table 13.82 - Potential Ecological Impacts on Cheung Po Tau and Fu Tei Au Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Upstream section of Cheung Po Tau Watercourse
is natural but seasonal; downstream sections of this watercourse and Fu Tei
Au Watercourse are man-made. Upstream section of Cheung Po Tau Watercourse is
of Low to Moderate ecological value; other sections are of Low ecological
value. |
|
Species |
No species of
conservation significance found in the watercourses but two protected orchid
species found in riparian corridor of the Cheung Po Tau Watercourse. |
|
Size/Abundance |
Small area; small
numbers of stream fauna. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Habitat loss
irreversible, other construction phase impacts reversible; operational phase
impacts irreversible but remedial measures possible. |
|
Magnitude |
Magnitude of loss and disturbance impacts both
low due to small size of stream and intermittent stream flow. |
|
Impact Severity |
Direct habitat
loss, disturbance, hydrological and run-off impact severity all Low. |
Sheung Shui Wa Shan Watercourses
The upstream sections of these watercourses are outside the Project Area boundary and no significant impacts are predicted. One crab species of conservation significance, Somanniathelphusa zanklon was found in the eastern watercourse, again upstream of the Project Area; hence, no significant impacts on this species are predicted.
The downstream sections of these streams may be impacted by the Fanling Bypass and development in FLN area B1-2 (Open Space). These stream sections are channelised and no stream fauna of conservation significance have been found. No significant impacts on these stream sections from the Project are predicted.
Table 13.83 - Potential Ecological Impacts on Sheung Shui Wa Shan Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Largely channelised, highest upstream sections
are semi-natural but seasonal. The watercourses are considered to be of Low
to Moderate ecological value due to the presence of Somanniathelphusa
zanklon. |
|
Species |
One individual of a crab species of conservation significance, Somanniathelphusa zanklon, was found
in the eastern channel, upstream of the potentially impacted stream sections.
|
|
Size/Abundance |
Small area; small
numbers of stream fauna. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible,
though remedial measures possible in operational phase. |
|
Magnitude |
Magnitude of loss and disturbance impacts both
low due to small size of stream. |
|
Impact Severity |
Direct habitat
loss, disturbance, hydrological and run-off impact severity all Low. |
Siu Hang San Tsuen Watercourse
This watercourse is in a concrete-lined channel in its lowest section where it joins the Ng Tung River, but upstream the channel, though highly modified by agricultural activities, has natural sides and bottom. This stream supports populations of three wetland-dependent species of conservation significance, Predaceous Chub, Blue Sprite and Emerald Cascader. Direct impacts to this stream will be avoided (construction of a pipe and pipe cap would be required within 10m of the stream in its downstream section but not in the watercourse), and much of it is outside the NDA boundary, while the Fanling Bypass will cross the lower section of the stream on a viaduct. However, the lower section may be impacted by disturbance and run-off during the construction and operational phases of the Project by the Fanling Bypass and development and use of the area around this stream section as an Open Space zone (FLN area D1-3).
Table 13.84 - Potential Impacts on Siu Hang San Tsuen Watercourse in the absence of mitigation measures
|
Criteria |
Assessment |
|
|
Habitat Quality |
A man-made habitat; however, upstream section
(outside the Project Area) has banks and bed of natural materials, albeit
channel highly modified by agricultural activities. The upstream section has
been assessed as of Moderate ecological value due to the presence of three
faunal species of conservation significance; the downstream channelised
section (within the Project Area) has been assessed as of Low to Moderate
ecological value. Downstream section only will be disturbed by Fanling Bypass
construction and will be permanently shaded by the Bypass structure during
operation. |
|
|
Species |
Three
wetland-dependent species of conservation significance present in the
upstream section. None of these species are present in the section of stream
which will be disturbed. |
|
|
Size/Abundance |
Habitat area is
small and stream length is short. Fauna numbers are low to moderate. |
|
|
Duration |
Construction phase: temporary |
Operational phase: permanent |
|
Reversibility |
Construction Phase:
construction phase disturbance and run-off impacts are all reversible and
remediation is possible. |
Operational
Phase: shading of the stream by the
viaduct would be permanent. However, any loss of vegetation cover could be
remediated. |
|
Magnitude |
Construction phase: low magnitude as impacts would be localised to the
downstream stream section and effects would be minor, |
Construction phase; low magnitude as area which would be shaded is
small and effects of shading would be minor. |
|
Impact
Severity |
Construction
Phase: construction phase re-channelisation,
run-off and disturbance impacts of Low
severity. |
Operational phase:
shading impacts of Low severity;
no other impacts of significance. |
Man Kok Village, Ting Ping Shan Tsuen, Shek Wu San Tsuen and Ma Shi Po Watercourses
These four watercourses, located to the north of Sheung Shui/Fanling and south of the Ng Tung River, will all be directly impacted by the Project. All are channelised, largely in concrete-lined channels, but part of Tin Ping Shan Tsuen Watercourse, which passes through farmland, has sides and bed of natural materials. A crab species of conservation significance, Somanniathelphusa zanklon, was found in this watercourse. This species is present in a number of streams in the area and is tolerant of polluted conditions; only one individual was found in this stream and there is little suitable habitat present.
Table 13.85 - Potential Ecological Impacts on Man Kok Village, Ting Ping Shan Tsuen, Shek Wu San Tsuen and Ma Shi Po Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Man-made habitat of Low ecological value. |
|
Species |
One individual of a
crab species of conservation significance, Somanniathelphusa zanklon was recorded in Tin Ping Shan Tsuen
Watercourse. |
|
Size/Abundance |
Small, limited
habitat for Somanniathelphusa
zanklon is present. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible. |
|
Magnitude |
All watercourses will be impacted but remains
of small magnitude; therefore low. |
|
Impact Severity |
Low as Somanniathelphusa zanklon is
present in several watercourses in the area and this stream does not provide
significant areas of suitable habitat for this species. |
Ma Wat River
This is much the largest of the smaller watercourses considered and is channelised throughout its length in the Study Area; the river downstream of the point where it is crossed by the Fanling Highway is highly disturbed and has been assessed as of Low ecological value. However, the section upstream of this point has some natural features and includes a section near Nam Wa Po that has been designated as an EIS on account of its fish community, including species of conservation significance. This upstream section has been assessed as of Moderate ecological value.
A 700m length of the river will be rechannelised upstream of the point where it crosses the Sha Tau Kok Road, and the mid and downstream sections of the river will be crossed by the Fanling Bypass viaduct in a number of, and hence will be indirectly impacted by the Project; no impacts are predicted to the section of the Ma Wat River upstream of the Fanling Highway, which is outside the Project Area.
In addition to the fish species of conservation significance known to be present in the upstream section of the river, a crab species of conservation significance, Somanniathelphusa zanklon, is also present. This is the only species of conservation significance known to have been found in the section of the watercourse impacted by the Project; however, fish species of conservation significance known to be present in the upstream section may occur on occasion, albeit the habitat conditions are such that numbers are unlikely to be of significance.
Table 13.86 - Potential Ecological Impacts on Ma Wat River in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Man-made habitat; mid and downstream sections
of Low ecological value; section above the Fanling Highway crossing point of
Moderate ecological value. |
|
Species |
Two fish species of
conservation significance known from the upstream section. No impacts from
the project are predicted on the stream section where these fish species are
present. |
|
Size/Abundance |
River is of
moderate length (approx. 3.5km) and size; fish are relatively abundant in the
upstream section but exotic species are numerically dominant. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Reversible and
remedial measures possible. |
|
Magnitude |
Construction phase disturbance impacts of low
magnitude, construction phase run-off may be of moderate magnitude;
operational phase magnitude low. |
|
Impact Severity |
Re-channelisation impact Low. Low to Moderate for construction phase run-off and
hydrological impacts, Low for
construction phase disturbance and operational phase disturbance and
operational impacts. |
San Uk Tsuen, Ma Wat Wai and Tong Hang Watercourses
These three watercourses all drain into the Ma Wat River. All are channelised, lie in developed areas and were assessed as of Low ecological value. None of these watercourses will be directly impacted by the Project, but the Tong Hang Watercourse may be indirectly impacted by the construction and operation of the Fanling Bypass viaduct.
Table 13.87 - Potential Ecological Impacts on San Uk Tsuen, Ma Wat Wai and Tong Hang Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Largely man-made habitat but with some
semi-natural sections upstream. San Uk Tsuen and Tong Hang Watercourses were
assessed as of Low ecological value; however Ma Wat Wai Watercourse has been
assessed as of Low to Moderate ecological value due to semi-natural upstream
sections and presence of Sommaniathelphusa
zanklon. |
|
Species |
Sommaniathelphusa zanklon recorded from the Ma Wat
Wai Watercourse; no other species of conservation significance known. |
|
Size/Abundance |
Streams are small. A
single specimen of Sommaniathelphusa
zanklon was found. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low for both disturbance and run-off impacts
in both construction and operational phases in the Tong Hang Watercourse; no
significant impacts on other watercourses. |
|
Impact Severity |
Low at Tong Hang Watercourse, no significant impacts on other watercourses
or on Sommaniathelphusa zanklon are
predicted. |
Kau Lung Hang Watercourses
The Kai Lung Hang Lo Wai, Kau Lung Hang San Wai and Yuen Leng Watercourses are designated as an EIS due to the presence of stream fish of conservation significance. Some of the upper reaches of these streams are natural, but the sections within the Study Area are wholly or largely channelised. Two fish species of conservation significance, Acrossocheilus parallens and Small Snakehead, have been found in these streams. The sections of streams designated as EIS are entirely outside the Project Area; however, a downstream section of the Kau Lung Hang Watercourses near Kiu Tau, where the streams join before discharging into the Ma Wat River, may be indirectly impacted by the construction and operation of the Fanling Bypass viaduct.
Table 13.88 - Potential Ecological Impacts on Kau Lung Hang Watercourses in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Man-made habitat of Moderate ecological value
in the Study Area. |
|
Species |
Two fish species of
conservation significance known: Acrossocheilus
parallens and Small Snakehead. |
|
Size/Abundance |
Streams are small
individually but combined length of the stream system is moderate. Acrossocheilus parallens
is abundant; numbers of Small Snakehead are probably small. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low for both disturbance and run-off impacts
in both construction and operational phases as impacts would only affect a
short downstream section of the stream system. |
|
Impact Severity |
Low |
Nam Wa Po Watercourses
These short seasonal tributaries of Ma Wat River have been assessed as of Low ecological value. None will be directly impacted or significantly indirectly impacted by the Project
13.7.3.10 Upland Grassland
Direct
Impacts
A small area of upland grassland (6.95ha) will be directly impacted by the Project. As upland grassland is maintained by periodic fires, it has low floral diversity and is dominated by fire-tolerant grass species. Faunal numbers and species diversity are low and few species are dependent on this habitat in the Study Area. However, one grassland and shrubland associated bird species of conservation significance, Grey Nightjar, has been found at Cheung Po Tau and at Wa Shan, and another species associated with these habitats, Eurasian Eagle Owl, has occurred in the Chau Tau area in the past. Other grassland species of conservation significance found in this habitat (Golden-headed Cisticola found outside the breeding season and Small Three-ring which is not restricted to this or a small number of habitats) are not considered to be impacted by loss of this habitat to a significant extent.
Eurasian Hobby forages over upland grassland but is only sensitive to disturbance at breeding sites (which are always in an elevated abandoned nest of another species (usually a corvid) hence would not breed in grassland.
No direct loss of upland grassland will occur from the Project at Chau Tau and Wa Shan, but a small area will be lost at Cheung Po Tau other areas of significance noted above.
Indirect Impacts
Disturbance impacts on upland grassland fauna will be relatively limited as few disturbance-sensitive species (mammals and larger birds) utilise this habitat in the Study Area. However, there will be some disturbance during the construction phase of the Project and the increased human population in the area during the operational phase is likely to result in increased recreational use of upland grassland areas. Such disturbance is likely to be concentrated along footpaths, where it may result in localized disturbance to fauna and erosion; however, if greater visitor use increases the frequency of hill fires the impacts would be greater.
Eurasian Eagle Owl is potentially sensitive to disturbance, but the area in which it may occur is on the edge of the Study Area and disturbance impacts on this area from the Project are not predicted.
Table 13.89 - Potential Direct Ecological Impacts on Upland Grassland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Upland grassland is largely undisturbed but
supports low diversity of flora and diversity and density of fauna. The
ecological value of upland grassland in the Study Area is Low in general, but
that at Cheung Po Tau is considered to be of Low to Moderate ecological value
due to the presence of Grey Nightjar. |
|
Species |
Low diversity of
fauna and flora species; one bird species (Grey Nightjar) of conservation
significance known to occur near a directly impacted area at Cheung Po Tau,
but it is unlikely to be nesting in the impacted area, which forms a small
part of this habitat in the area. |
|
Size/Abundance |
A small habitat
area (6.95ha) in relation to the area of this habitat in the Study Area.
Fauna occurs at low densities and is dispersed. |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Magnitude moderate overall, but magnitude of
loss in the Cheung Po Tau area is small. |
|
Impact Severity |
Severity Low as upland grassland is a very
common habitat in the Study Area and the New Territories, and supports few
species and a low number of organisms at low densities. |
Table 13.90 - Potential Indirect Ecological Impacts on Upland Grassland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Upland grassland is largely undisturbed but
supports low diversity of flora and diversity and density of fauna. The
ecological value of upland grassland in the Study Area is Low in general, but
that north of Chau Tau is considered to be of Low to Moderate ecological
value due to the possible presence of Eurasian Eagle Owl, and that above
Sheung Shui Wa Shan is considered to be of Low to Moderate ecological value
due to the presence of Grey Nightjar. |
|
Species |
Low diversity of
fauna and flora species; most fauna species not very disturbance sensitive;
of two bird species of conservation significance known to be/may be present
in this habitat, Eurasian Eagle Owl is relatively disturbance sensitive; Grey
Nightjar relies on camouflage when roosting (during the day) and nesting is
relatively insensitive to disturbance. |
|
Size/Abundance |
Area which would be
disturbed is small relative to the area present. Fauna occurs at low
densities and is dispersed. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Construction phase
impacts reversible; operational phase impacts irreversible but remedial
measures may be possible. |
|
Magnitude |
Low except for fires covering large areas of
upland grassland which would be of moderate magnitude. |
|
Impact Severity |
Low as no increase in disturbance to upland grassland in the area where
Eurasian Eagle Owl may occur is predicted and Grey Nightjar is not
particularly sensitive to disturbance. |
13.7.3.11 Lowland Grassland
Direct
Impacts
A total of 53.21ha of lowland grassland, largely formed by vegetation succession on abandoned agricultural land, will be directly impacted by the Project. Unlike upland grassland, which is relatively unfragmented in the Study Area, lowland grassland is fragmented by other habitat types. Fauna using this habitat in the Study Area are largely habitat generalists that also utilise other modified or man-made lowland habitats, including agricultural land, waste land and urbanized and village areas. No species of conservation significance found in the Study Area are dependent upon, or strongly associated with this habitat, though small numbers of wetland bird species and amphibian species will use this habitat opportunistically.
Indirect Impacts
Only small areas of lowland grassland, largely on the north side of the Ng Tung River in FLN will be disturbed by the Project. Disturbance impacts on lowland grassland fauna will be limited as few disturbance-sensitive species (mammals and larger birds) utilise this habitat in the Study Area on a regular basis and this habitat is not of importance for disturbance-sensitive waterbird species.
Table 13.91 - Potential Direct Ecological Impacts on Lowland Grassland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Disturbed and fragmented habitat around
villages and urban areas of Low ecological value. |
|
Species |
Low diversity of
flora species and low diversity of fauna species, most of which are habitat
generalists; habitat is not utilised preferentially by any fauna of
conservation significance in the Study Area, but may be used
opportunistically by small numbers of some species. |
|
Size/Abundance |
A moderate area
(53.21ha) in total; fauna abundance is low to moderate. |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low as lowland grassland is a very common habitat in the Study Area and
the New Territories, supporting low to moderate numbers and diversity of
species that are habitat generalists. |
Table 13.92 - Potential Indirect Ecological Impacts on Lowland Grassland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Disturbed and fragmented habitat around
villages and urban areas of Low ecological value. |
|
Species |
Low diversity of
flora species and low diversity of fauna species, most of which are habitat
generalists; not utilised preferentially by any fauna of conservation
significance in the Study Area, but may be used opportunistically by small
numbers of some species. |
|
Size/Abundance |
A small area
(additional to that which will be lost); fauna abundance is low to moderate. |
|
Duration |
Permanent in respect of operational impacts, temporary in respect of
construction impacts. |
|
Reversibility |
Construction phase
impacts reversible; operational phase impacts irreversible; remedial measures
possible in both construction and operational phases. |
|
Magnitude |
Low. |
|
Impact Severity |
Low |
13.7.3.12 Seasonally Wet Grassland
Direct Impacts
Small areas of seasonally wet grassland are impacted by the Project near Ma Tso Lung Stream and in two areas near Ng Tung River in FLN. None of these areas is floristically diverse, while the latter does not support significant numbers of fauna species. However, that at Ma Tso Lung is utilised by low numbers of marsh fauna in season, including Chinese Bullfrog, and is connected to other wetland habitats.
Indirect Impacts
An additional area of seasonally wet grassland at Ma Tso Lung immediately to the north of the KTN NDA may be indirectly impacted by construction activity, including construction of the Eastern Connection Road for the LMC Loop, both within and just outside the Project Area.
Potential indirect impacts to the seasonally wet grassland on the north side of Ng Tung River in FLN are predicted to be small, as the areas are small and they are not utilised by significant numbers of disturbance-sensitive fauna.
Fragmentation impacts on this habitat are addressed as an element of fragmentation impacts on the Ma Tso Lung Stream and its riparian corridor of which this habitat constitutes an element.
Table 13.93 - Potential Direct Ecological Impacts to Seasonally Wet Grassland in the absence of mitigation measures
|
Criteria |
Ma Tso Lung |
Along Ng Tung River in FLN |
|
Habitat Quality |
Seasonally wet grassland at Ma Tso Lung is
floristically poor but is used by small numbers of marsh fauna when wet and
has some ecological linkages with Ma Tso Lung marsh. The ecological value is Low to Moderate. |
Two small areas of seasonally wet grassland
near the Ng Tung River are likewise floristically poor and support limited
wetland fauna due to lack of microhabitat diversity, small area and disturbed
condition. Ecological value is Low. |
|
Species |
Low diversity of
fauna and flora species; may be utilised by species of conservation
significance present in the areas but not a habitat used preferentially by
such species. |
|
|
Size/Abundance |
Habitat area is
small (2.86ha). A low number of individuals of fauna species are present. |
Habitat area is
small comprising two areas totalling 1.24ha. A low number of individuals of
fauna species are present. |
|
Duration |
Permanent. |
|
|
Reversibility |
Irreversible. |
|
|
Magnitude |
Low |
Low |
|
Impact Severity |
Low to Moderate |
Low |
Table 13.94 - Potential Disturbance Impacts on Seasonally Wet Grassland in the absence of mitigation measures
|
Criteria |
Ma Tso Lung |
Along Ng Tung River in FLN |
|
Habitat Quality |
Seasonally wet grassland at Ma Tso Lung is
floristically poor but is used by small numbers of marsh fauna when wet and
has some ecological linkages with Ma Tso Lung marsh. The ecological value of these areas is Low to
Moderate. |
Areas of seasonally wet grassland on the north
side of the Ng Tung River which will be indirectly impacted are floristically
poor and support limited wetland fauna due to lack of microhabitat diversity,
small area and disturbed condition. Ecological value is Low. |
|
Species |
Low diversity of
fauna and flora species; may be utilised by species of conservation
significance present in the areas but not a habitat used preferentially by
such species. |
|
|
Size/Abundance |
Habitat area is
small. A low number of individuals of fauna species are present. |
|
|
Duration |
Permanent in respect of operational
impacts, temporary in respect of construction impacts.
|
|
|
Reversibility |
Construction phase
disturbance reversible but operational phase disturbance is irreversible;
remedial measures are possible in both construction and operational phases. |
|
|
Magnitude |
Low to moderate in construction phase, low in
operational phase. |
Low in construction and operational phases. |
|
Impact Severity |
Low to Moderate in construction phase. Low in operational phase. |
Low
in construction and operational phases. |
Table 13.95 - Potential Impacts of increased sediment load, pollution, or hydrological disruption on seasonally wet grassland in the absence of mitigation measures
|
Criteria |
Ma Tso Lung |
Along Ng Tung River in FLN |
|
Habitat Quality |
Seasonally wet grassland at Ma Tso Lung is
floristically poor but is used by small numbers of marsh fauna when wet and
has some ecological linkages with Ma Tso Lung marsh. The ecological value of these areas is Low to
Moderate. |
Areas of seasonally wet grassland on the north
side of the Ng Tung River which will be indirectly impacted are floristically
poor and support limited wetland fauna due to lack of microhabitat diversity,
small area and disturbed condition. Ecological value is Low. |
|
Species |
Low diversity of
fauna and flora species; may be utilised by species of conservation
significance present in the areas but not a habitat used preferentially by
such species. |
|
|
Size/Abundance |
Habitat area is
small. A low number of individuals of fauna species are present. |
|
|
Duration |
Permanent in respect of
operational impacts, temporary in respect of construction impacts. |
|
|
Reversibility |
Mostly reversible. |
|
|
Magnitude |
Low to moderate in construction phase, low in
operational phase. |
Low in both construction and operational phases. |
|
Impact
Severity |
Low
to Moderate in construction phase. Low in operational phase. |
Low in
both construction and operational phases. |
13.7.3.13 Grassland / Shrubland
Direct Impacts
Grassland/shrubland habitats are an intermediate stage in vegetation succession, resulting from the spread of shrubland species into grassland habitats. Small areas of this habitat, all in lowland areas and often close to sources of human disturbance, will be lost to development. Lowland grassland/shrubland in the Study Area is floristically poor and woody species often include a high proportion of invasive exotic species. Fauna species in lowland grassland/shrubland are largely habitat generalists that utilise a variety of lowland habitats, including farmland, grassland, plantation and urban and village areas, though may include some woodland associated species in small numbers. No fauna species in the Study Area are dependent on this habitat or use it preferentially.
No significant indirect impacts are predicted to the small areas of grassland/shrubland in the assessment area.
Table 13.96 - Potential Direct Ecological Impacts on Grassland/Shrubland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Habitat is of Low ecological value due to
small size and high levels of disturbance. |
|
Species |
No species use this
habitat preferentially; some species of conservation significance may occur
in this habitat on occasion but it is not of significance for any species. |
|
Size/Abundance |
A small area
(1.63ha) |
|
Duration |
Permanent. |
|
Reversibility |
Irreversible. |
|
Magnitude |
Low. |
|
Impact Severity |
Low |
13.7.3.14 Shrubland
This is a very common habitat type in Hong Kong, but little shrubland is present in the development areas for the Project. Small patches of disturbed shrubland of Low ecological value on the fringes of settlements in KTN will be lost to development.
Direct and Indirect Impacts
A large area of shrubland of Moderate ecological value on Crest Hill is close to the proposed Kwu Tung North Fresh Water Service Reservoir in KTN area G1-5 and a small area of shrubland is present within the footprint of this development. The direct habitat loss will be small; however, the larger area may be disturbed during the construction phase of the Project. However, most species for which shrubland is of importance at Crest Hill (butterflies and, to a lesser extent, smaller bird species) are relatively tolerant of disturbance, but breeding Eurasian Hobby may be disturbance-sensitive depending on location of the nest site relative to the disturbance source. Danaid Egg-fly, found in shrubland on the east side of Crest Hill is not disturbance-sensitive and the area where it was found will not be disturbed.
Eurasian Hobby, which has bred in an abandoned corvid nest on a pylon in shrubland in the past, is sensitive to disturbance when nesting (see Table 13.58), especially if construction activity commences after a nest site has been selected. There is a large area of shrubland habitat where this species may nest; hence it is statistically unlikely that a nest site, if present, would be located in or close to area G1-5. However, should such a co-incidence occur, impact on this species may be significant.
No significant fragmentation impacts on shrubland areas of ecological significance are predicted, as the habitat will not be fragmented in itself or from habitats with which there exist significant linkages.
Table 13.97 - Potential Direct Ecological Impacts on Shrubland in the absence of mitigation measures
|
Criteria |
Shrubland on Crest Hill |
Small areas of shrubland on fringes of KTN
developed area |
|
Habitat Quality |
Large continuous area of shrubland of
Moderate ecological value. |
Patches are small and disturbed and of Low
ecological value. |
|
Species |
Diverse butterfly
community, including Danaid Egg-fly of conservation significance, other
species of conservation significance recorded in the past; one bird species
of conservation significance, Eurasian Hobby has bred in the past in this
habitat was found in the area during the current study. |
A low number of
species present, none of which are of conservation significance in this
habitat. |
|
Size/Abundance |
Habitat area is
small (0.07ha) and fauna numbers are low. |
Habitat area is
small (1.04ha) and fauna numbers are low. |
|
Duration |
Permanent. |
|
|
Reversibility |
Irreversible. |
|
|
Magnitude |
Low. |
|
|
Impact Severity |
Most likely Low, but Low to Moderate in
the unlikely event that a Eurasian Hobby nest site is in the Project Area. |
|
Table 13.98 - Potential Indirect Ecological Impacts on Shrubland in the absence of mitigation measures
|
Criteria |
Shrubland on Crest Hill |
Small areas of shrubland on fringes of KTN
developed area |
|
Habitat Quality |
Large continuous area of shrubland of
Moderate ecological value |
Patches are small and disturbed and of low
ecological value. |
|
Species |
Diverse butterfly
community, which may include species of conservation significance, however
butterfly species are not sensitive to disturbance unlikely to be affected
by indirect impacts of the project; one bird species of conservation
significance, Eurasian Hobby has bred in the past in this habitat was found
in the area during the current study. |
A low number of
species present, none of which are of conservation significance in this
habitat. |
|
Size/Abundance |
Habitat area which
may be impacted is moderate; fauna numbers are low to moderate. |
Small area with
low abundance of fauna. |
|
Duration |
Permanent in respect of
operational impacts, temporary in respect of construction impacts. |
|
|
Reversibility |
Construction phase
impacts are reversible, operational phase impacts are irreversible;
remediation possible in both construction and operational phases. |
|
|
Magnitude |
Low to moderate in construction phase, low in
operational phase. |
Low in both construction and operational
phases. |
|
Impact Severity |
Construction
phase: most likely Low, but Low to Moderate in the unlikely event that a Eurasian Hobby nest site
is in the Project Area. Operational phase: Low. |
Low. |
13.7.3.15 Fung Shui Woodland
No fung shui woodland will be directly impacted by the Project.
Indirect and Fragmentation Impacts
Fung shui woodland at Kam Tsin and Tsung Pak Long are remote from project development areas, but that at Ho Sheung Heung is adjacent to proposed residential development in KTN D1-7. Direct impact from development has been avoided. Fragmentation impacts on terrestrial fauna have also been avoided, as both linkages between fung shui woodland and the adjoining secondary woodland, and linkages between these habitats and woodland and shrubland on Crest Hill, with which they are linked ecologically, will not be affected by the project. However, potential impacts in the absence of mitigation include indirect impacts from dust deposition and disturbance. Habitat linkages for birds will not be impacted significantly, especially during the operational period of the Project. In general, small bird species are not very disturbance-sensitive and most are not restricted to this habitat.
Table 13.99 - Potential Indirect Ecological Impacts on Ho Sheung Heung fung shui woodland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Semi-natural mature woodland assessed as of
Moderate ecological importance. |
|
Species |
Flora is
moderately rich. Flora species of conservation importance and protected
flora species in fung shui
woodland and adjoining secondary woodland include Ailanthus fordii, Aquilaria
sinensis, Gnetum luofuense and
Pavetta hongkongensis. Some mammal
species of conservation significance may occur in small numbers; diverse
butterfly community including many woodland-associated species; species of
conservation significance recorded in the past and may still be present. Of
these species only flora is a significant receiver of impacts of dust
deposition and only birds and mammals are significant receivers of
disturbance impacts. However, smaller woodland bird species are relatively
insensitive to disturbance impacts. |
|
Size/Abundance |
Area is small
(4.57ha); fauna numbers low. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Dust deposition
would be reversed naturally by rainfall. Construction phase
disturbance reversible; operational phase disturbance irreversible;
remediation possible in both construction and operational phases. |
|
Magnitude |
Low to moderate during construction phase,
low during operational phase. |
|
Impact Severity |
Low to Moderate on mammals during construction phase, Low during construction phase on
flora and other fauna; Low during
operational phase. |
Table 13.100 - Potential Fragmentation Impacts on Ho Sheung Heung fung shui woodland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Semi-natural mature woodland assessed as of
Moderate ecological importance. |
|
Species |
Some mammal
species of conservation significance may occur in small numbers. However,
fragmentation impacts on these species will be small as there will be no
fragmentation of the most important linkages for mammals; those between the fung shui wood and the adjoining
secondary woodland and between these habitats and Crest Hill woodland and
shrubland. |
|
Size/Abundance |
Area is small;
fauna numbers low. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Some construction
phase impacts reversible; operational phase impacts largely irreversible;
some remediation possible during both construction and operational phases. |
|
Magnitude |
Low for terrestrial fauna during construction
and operational phases. |
|
Impact Severity |
Low during construction phase and
Low during operational phase, as numbers of fragmentation-sensitive
fauna are small and most important linkages will not be affected. |
13.7.3.16 Secondary Woodland
The ecological value of woodland patches present is dependent to some extent upon their linkage to other areas of similar habitat and upon the age of the woodland. Since secondary woodland is a relatively rare habitat in the north and west of the New Territories, this limits the potential value of woodland in the area, but also means that these patches are potentially of significant ecological value by providing a refuge for woodland species.
Crested Serpent Eagle has been recorded in secondary woodland (and plantation woodland) in the Study Area. This species is listed as of Local Concern as by breeding species by Fellowes et al. (2002) and as Vulnerable in the CRDB. This species ranges widely and is frequently recorded over habitat where it does not breed such as shrubland and developed areas. The is no suggestion that it breeds in any areas which would be directly or indirectly impacted by the project, hence it is not considered further in the evaluation of the significance of potential impacts of the project.
Direct Impacts
A small area (0.23ha) of secondary woodland will be lost near Ho Sheung Heung due to proposed residential development in KTN area D1-11. As discussed in Section 13.1.4.6, alternatives to avoid and minimise loss of secondary woodland were adopted where feasible. However, at the current (RODP) stage, unavoidable loss of 0.23ha of secondary woodland is predicted, in the absence of mitigation.
Indirect and Fragmentation Impacts
Few secondary woodland patches in the Study Area are in direct or close proximity to development areas of the Project; very often, as in the area to the south of Pak Shek Au, Fu Tei Au, Sheung Shui Wa Shan and southeast of Fanling, they are separated and buffered from disturbance and other indirect impacts by areas of plantation and/or village habitat at least 100m in width. Indirect impacts on woodland habitats and fauna in these areas will not be significant as very few woodland fauna species would be disturbed at distances of more than 100m from the sources of disturbance. The buffering effect of the intervening habitat will be greater in areas where there is also a significant difference in elevation between the source of disturbance and the woodland area; such a difference applies in woodland areas south of Pak Shek Au, west of Nam Wa Po and east of Kau Lung Hang – the latter area being that where larger mammals, the most disturbance-sensitive woodland fauna, are most likely to be present in significant numbers.
However, there are two locations in the Study Area where secondary woodland areas are in direct proximity with, or are relatively close to, potential sources of disturbance. These areas are Ho Sheung Heung, where secondary (and fung shui) woodland) are located close to development areas in KTN; and to the west of Siu Hang San Tsuen where secondary woodland is close to the proposed Fanling Bypass.
Secondary woodland patches present in the Study Area are very frequently linked with plantation and shrubland areas; thus consideration of indirect and, especially, fragmentation impacts requires assessment of to what extent an area of wooded habitats as a whole may be impacted by the Project. Taking such linkages into account; potential fragmentation impacts of significance are predicted only at Ho Sheung Heung; other secondary woodlands will not be fragmented or fragmented from other wooded habitats
Table 13.101 - Potential Direct Ecological Impacts on Secondary Woodland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Secondary woodland at Ho Sheung Heung is of
moderate ecological value and shares species, including some of conservation
significance, with the adjacent fung
shui wood; habitat assessed as of Moderate ecological value. |
|
Species |
Flora is moderately rich, and species of conservation importance and
protected plant species in secondary woodland and linked fung shui woodland include Ailanthus
fordii, Aquilaria sinensis, Gnetum luofuense and Pavetta hongkongensis, though none of
these are believed to be present in the area directly impacted. Some mammal
species of conservation significance may occur in small numbers; diverse
butterfly community, including many woodland-associated species; species of
conservation significance recorded in the past may still be present. |
|
Size/Abundance |
Habitat area is
small (0.23ha) and faunal abundance is low. |
|
Duration |
Permanent. |
|
Reversibility |
Not reversible;
compensation is feasible but woodland takes a long time to become mature. |
|
Magnitude |
Low. |
|
Impact Severity |
The area is small
but the woodland is of moderately high quality, hence impact severity is Low to Moderate. |
Table 13.102- Potential Indirect Ecological Impacts on Secondary Woodland in the absence of mitigation measures
|
Criteria |
Ho Sheung Heung |
West of Siu Hang San Tsuen |
Elsewhere in the Study Area |
|
Habitat Quality |
Moderate ecological value due to age and
presence of fauna of conservation significance. |
Moderate ecological value, primarily due to
relatively large area. |
Moderate ecological value at Ma Tso Lung, Chau
Tau and on hill slopes southeast of Fanling; Low to Moderate ecological value
elsewhere. |
|
Species |
Protected plant
species present; small numbers of mammals of conservation significance may be
present; high diversity of butterfly species, possibly including some of
conservation significance. Of these species, only flora is a significant
receiver of impacts of dust deposition and only birds and mammals are
significant receivers of disturbance impacts. However, smaller woodland bird
species are relatively insensitive to disturbance impacts. |
No
woodland-dependent species of conservation significance recorded. Of these
species, only flora is a significant receiver of impacts of dust deposition
and only birds and mammals are significant receivers of disturbance impacts.
However, smaller woodland bird species are relatively insensitive to
disturbance impacts. No mammal species of conservation significance are known
to be present but potential impacts are evaluated on a precautionary basis. |
Protected plant and
woodland fauna of conservation significance present in secondary woodland and
ecologically linked plantation in wooded areas southeast of Fanling; other
areas not of significance for woodland-dependent fauna. Of these species, only flora is a significant
receiver of impacts of dust deposition and only birds and mammals are
significant receivers of disturbance impacts. However, smaller woodland bird
species are relatively insensitive to disturbance impacts. |
|
Size/Abundance |
Small (2.74ha),
abundance of fauna low. |
Moderate in size
(27.10ha); abundance of fauna is low. |
Moderately large
area (83.02ha); abundance of fauna low. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
||
|
Reversibility |
Dust deposition
would be reversed naturally by rainfall. Construction phase
disturbance reversible; operational phase disturbance irreversible;
remediation possible in both construction and operational phases. |
||
|
Magnitude |
Impact of dust deposition low during
construction phase and not significant during operational phase. Disturbance impact on fauna low during both
construction and operational phases. |
Low during construction and operational
phases. |
|
|
Impact Severity |
Low to Moderate during construction phase, Low during operational phase. |
Low during construction phase, Low
during operational phase. |
Low during both construction and operational phases. |
Table 13.103 - Potential Fragmentation Impacts on Ho Sheung Heung Secondary Woodland in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Semi-natural mature woodland assessed as of
Moderate ecological importance. |
|
Species |
Some mammal species of conservation significance may occur in small
numbers. However, fragmentation impacts on these species will be small as there
will be no fragmentation of the most important linkages for mammals; those
between the fung shui wood and the
adjoining secondary woodland and between these habitats and Crest Hill
woodland and shrubland. |
|
Size/Abundance |
Area is small; fauna numbers low. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Some construction phase impacts reversible; operational phase impacts
largely irreversible; some remediation possible during both construction and
operational phases. |
|
Magnitude |
Low for terrestrial fauna during construction
phase, low during operational phase. Small numbers of individuals impacted
and most important linkages not affected. |
|
Impact Severity |
Low during construction phase, Low during
operational phase; because numbers of fragmentation-sensitive fauna are
small. |
13.7.3.17 Plantation
Direct Impacts
An area of 80.56ha of plantation will be directly impacted by the Project. Much of the area to be lost comprises habitat fragments alongside roads and in villages and other developed areas. This applies, in particular, to loss of plantation in the largely developed areas in KTN and to the south of the Ng Tung River in FLN. These plantation areas are highly disturbed, contain a high proportion of exotic tree and shrub species, and are of limited ecological value. Associated wildlife largely comprises widespread species tolerant of high levels of disturbance and which are common in such areas throughout Hong Kong.
Hillside plantations within the Project Area often contain some semi-natural vegetation and in some locations support a moderate diversity of faunal species, including some woodland-associated bird and butterfly species. No fauna species of conservation significance are strongly associated with, or utilise this habitat preferentially; however, it may be utilised by woodland-dependent or associated species in small numbers. Such plantation areas are considered to be of low to moderate ecological value (Figure 13.11), and this value has the potential to increase as native species colonise.
Such plantations are present in the northwest of KTN, south of the Fanling Highway in KTN, north of the Ng Tung River in KTN and to the east and south of Fanling along the Ma Wat River. In addition to their intrinsic ecological values, some of these plantation areas provide a corridor for the movement of woodland species through habitats which would otherwise be unsuitable.
Plantation south of the Fanling Highway and east and south of Fanling will not be directly impacted by the Project, but some areas of plantation will be lost due to development in the north and west of KTN and north of the Ng Tung River in FLN (Figure 13.14a-c).
The Man Kam To Road egretry is located in roadside plantation habitat situated between the Man Kam To Road and an open storage area in FLN NDA. The plantation was damaged by site clearance activity in the open storage area in 2012. Despite this damage, the egretry was re-occupied in April 2013.
This egretry site will be directly impacted by the interchange of the Fanling Bypass and the Man Kam To Road. Although this area of plantation is highly disturbed and otherwise of low ecological significance, the presence of the egretry raises its value due to its importance as a breeding site for Chinese Pond Herons and Little Egrets.
Crested Serpent Eagle has been recorded in plantation (and secondary woodland) in the Study Area. This species is listed as of Local Concern as by breeding species by Fellowes et al. (2002) and as Vulnerable in the CRDB. This species ranges widely and is frequently recorded over habitat where it does not breed such as shrubland and developed areas. The is no suggestion that it breeds in any areas which would be directly or indirectly impacted by the project, hence it is not considered further in the evaluation of the significance of potential impacts of the project.
Indirect and fragmentation Impacts
Roadside and urban plantation fragments are already highly disturbed and subject to pollution, and hence are utilised by wildlife species relatively insensitive to indirect and fragmentation impacts. However, even small areas of plantation habitat may provide short-term refugia for more vagile woodland-associated fauna such as birds, providing habitat ‘islands’ or ‘stepping stones’ permitting movement through areas that are otherwise unsuitable. Loss of such plantation areas may, therefore, increase habitat fragmentation even if the areas lost are small and otherwise of little ecological significance.
Hillside plantation will not be fragmented significantly by the Project, nor will it be fragmented significantly from habitats with which it has important ecological linkages; however, some areas of hillside plantation and associated fauna will receive disturbance impacts from the Project.
The Ho Sheung Heung Egretry is located in plantation and orchard to the northeast of Lo Wu Correctional Institution. This plantation/orchard is disturbed by adjacent residential and industrial areas; however, the egretry is large in a Hong Kong context and hence of high ecological significance. This egretry will not be directly impacted by the Project but may experience disturbance and/or fragmentation impacts.
Table 13.104 - Potential Direct Ecological Impacts on Plantation in the absence of mitigation measures
|
Criteria |
Hillside Plantation Northwest of KTN and
North of the Ng Tung River in FLN |
Roadside and Urban Plantation |
Man Kam To Road Egretry Plantation |
|
|
Habitat Quality |
Plantation blocks, small to moderate in size,
often with linkages to other habitats, including secondary woodland and
shrubland, which permit movement of fauna and colonisation by native species.
Such plantation, 8.65ha of which will be lost, is assessed as of Low to
Moderate ecological value. |
Fragmented and highly disturbed by human
activities with a high proportion of exotic trees; assessed as of Low
ecological value. There is a large area (73.43ha) of such plantation. |
Roadside plantation of 0.27ha assessed as of
Low to Moderate ecological value due to presence of egretry. Habitat is
disturbed and the plantation was damaged in 2012 due to construction
activity. |
|
|
Species |
Species diversity
low to moderate; may be utilised by woodland-associated fauna of conservation
significance in small numbers. |
Species diversity
is low and species are common and widespread habitat generalists highly
tolerant of disturbance. |
Plantation at Ma
Kam To Road Egretry supports two ardeid species (Chinese Pond Heron and
Little Egret). |
|
|
Size/Abundance |
Patches are small
in size but aggregate area is moderate. Fauna density is low. |
Fauna occurs at low
density but aggregate numbers may be moderate. |
Habitat area is
small; number of breeding ardeids at Man Kam To Road Egretry is small in a
Hong Kong context. |
|
|
Duration |
Permanent. |
|||
|
Reversibility |
Irreversible. |
|||
|
Magnitude |
Low magnitude overall as number of organisms
impacted would be small. |
Low magnitude overall as number of organisms
impacted would be moderate and these are highly disturbance-tolerant. |
Egretry is relatively small in a Hong Kong
context and relocation of egretries is not infrequent; however, egretry would
be entirely lost therefore magnitude of loss would be low to moderate. |
|
|
Impact Severity |
In view of the low
number of organisms, impact severity is
Low. |
Fauna is highly
tolerant of disturbance, hence impact severity is Low. |
Egretry is small in
a Hong Kong context and the ardeids could relocate to another site, hence
impact severity is Low to Moderate. |
|
Table 13.105 - Potential Indirect Impacts on Plantation in the absence of mitigation measures
|
Criteria |
Hillside Plantation |
Roadside and Urban Plantation |
Ho Sheung Heung Egretry Plantation |
|
|
Habitat Quality |
Plantation blocks, moderate in size, often
with linkages to other habitats, including secondary woodland and shrubland
which permit movement of fauna and colonisation by native species. Assessed
as of Low to Moderate ecological value. |
Fragmented and highly disturbed by human
activities with a high proportion of exotic trees, assessed as of Low
ecological value. |
Relatively disturbed plantation and orchard,
but assessed as of Moderate to High ecological value due to presence of
egretry. |
|
|
Species |
Species diversity
low to moderate; utilised by woodland-associated fauna of conservation
significance in small numbers. |
Species diversity
is low and species are common and widespread habitat generalists. |
Three ardeid
species of conservation significance breed regularly and one other species
has bred in the past. |
|
|
Size/Abundance |
Patches that may be
indirectly impacted are moderate in size. Fauna density is low. |
Patches are small
in size, but aggregate area is moderate. Fauna occurs at low density but
aggregate numbers of some disturbance-tolerant groups, including birds and
butterflies may be moderate. |
Habitat area is
small; number of breeding ardeids at Ho Sheung Heung Egretry is large in a
Hong Kong context. |
|
|
Duration |
Permanent
in respect of operational phase impacts; temporary in respect of construction
phase impacts. |
|||
|
Reversibility |
Construction
phase impacts largely reversible; operational phase impacts irreversible;
remediation possible for both construction and operational phase impacts. |
|||
|
Magnitude |
Low to moderate magnitude overall as number of
organisms impacted would be relatively small and most are not
disturbance-sensitive. |
Low magnitude overall as organisms are not
disturbance-sensitive. |
Egretry site is distant (>500m) from
development areas of the Project and areas where human activity will increase
significantly, therefore magnitude of disturbance will be low. |
|
|
Impact Severity |
Relatively low
number of disturbance-sensitive species but utilised by small numbers of some
species of conservation significance; thus, impact severity is Low to Moderate. |
Habitat is abundant
and organisms impacted are common, widespread and not disturbance sensitive;
thus, impact severity is Low. |
No significant
increase in disturbance is predicted, hence impact severity is Low. |
|
Table 13.106 - Potential Fragmentation Impacts on Plantation in the absence of mitigation measures
|
Criteria |
Hillside Plantation |
Roadside and Urban Plantation |
Ho Sheung Heung Egretry Plantation |
|
|
Habitat Quality |
Plantation blocks, moderate in size, often
with linkages to other habitats, including secondary woodland and shrubland
which permit movement of fauna and colonisation by native species. Assessed
as of Low to Moderate ecological value. |
Fragmented and highly disturbed by human
activities with a high proportion of exotic trees, assessed as of Low
ecological value. |
Relatively disturbed plantation and orchard,
but assessed as of Moderate to High ecological value due to presence of
egretry. |
|
|
Species |
Species diversity
low to moderate; utilised by woodland-associated fauna of conservation
significance in small numbers. |
Species diversity
is low and species are common and widespread habitat generalists. |
Three ardeid
species of conservation significance breed regularly and one other species
has bred in the past. |
|
|
Size/Abundance |
Patches which may
be fragmented indirectly impacted are small in size. Fauna density is low. |
Patches are small
in size, but aggregate area is moderate. Fauna occurs at low density but
aggregate numbers of some disturbance-tolerant groups, including birds and
butterflies may be low to moderate. |
Habitat area is
small; number of breeding ardeids at Ho Sheung Heung Egretry is large in a
Hong Kong context. |
|
|
Duration |
Permanent
in respect of operational phase impacts; temporary in respect of construction
phase impacts. |
|||
|
Reversibility |
Construction
phase impacts largely reversible; operational phase impacts irreversible;
remediation possible for both construction and operational phase impacts. |
|||
|
Magnitude |
Low magnitude overall areas and number of
organisms impacted would be small. |
Low magnitude overall as number of organisms
impacted would be small, most are not disturbance-sensitive and intrinsic
ecological value of patches is small. |
Breeding egrets are dependent upon linkages to
foraging areas. Some of those breeding at Ho Sheung Heung forage in the
Project Area, notably in Long Valley and the Sheung Yue River, both of which
may be disturbed
by the Project in the absence of mitigation. However, flight-lines and
foraging areas to the north and east will not be impacted, impacts to the
flight-line between the egretry and the Sheung Yue will be small and there
will be no significant structures erected along the flight-line, a new
footbridge over the Ng Tung River being the largest project element in this
area. This footbridge is not on the main flight-line. Further, Long Valley
foraging areas will be retained by the project. Accordingly magnitude may be
low to moderate. |
|
|
Impact Severity |
Low |
In view of the
abundance of this habitat in Hong Kong and the low number of organisms and
their low sensitivity to disturbance, impact severity is Low. |
Potential
fragmentation impact on flight-lines could have an impact of breeding
ardeids. Accordingly potential impact severity is Low to Moderate. |
|
13.7.3.18 Mitigation Plantation
A number of small areas of mitigation plantation will be impacted along the Ng Tung, Sheung Yue and Shek Sheung Rivers. These mostly comprise corridors of plantation managed as mitigation for impacts arising from channelisation of the rivers and to be reprovisioned under the Cycle Track Projects. Existing tree species are largely exotic, though some native species and bamboos are present. Their ecological value as wildlife habitat is limited, but they are assessed as of Low to Moderate ecological value due to their function as a screen to reduce disturbance to fauna using the adjacent river channels. Mitigation plantation around Long Valley performs a similar function and would be retained under the NDA project where feasible; potential impacts on mitigation plantation around Long Valley were addressed along with those on other Long Valley habitats.
Table 13.107 - Potential Direct Ecological Impacts on Mitigation Plantation in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Plantations largely of exotic species,
fragmented and lacking in understorey vegetation other than grasses. Wildlife
diversity and abundance is low but they screen wildlife using the river
channels from disturbance. Ecological value is Low to Moderate as a
consequence of this screening function. |
|
Species |
Low floral and
faunal diversity, but may be utilised by species of conservation importance,
including species using the adjacent wetlands, in small numbers. |
|
Size/Abundance |
Areas be lost are
small individually but total area is moderate (10.75ha). Faunal numbers are
low. |
|
Duration |
Permanent |
|
Reversibility |
Irreversible |
|
Magnitude |
Loss of individual patches would be of low
magnitude but the cumulative magnitude would be moderate. |
|
Impact Severity |
Low, as in-situ ecological
value is limited. |
Table 13.108 - Potential Indirect Ecological Impacts on Mitigation Plantation in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Plantations largely of exotic species,
fragmented and lacking in understorey vegetation other than grasses. Wildlife
diversity and abundance is low but they screen wildlife using the river
channels from disturbance. Ecological value is Low to Moderate as a
consequence of their screening function. |
|
Species |
Low floral and
faunal diversity; but may be utilised by species of conservation importance,
including species using the adjacent wetlands, in small numbers. |
|
Size/Abundance |
Areas impacted are
small individually but total area is moderate. Faunal numbers are low. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Construction phase
impacts largely reversible; operational phase impacts irreversible;
remediation possible for both construction and operational phase impacts. |
|
Magnitude |
Disturbance of individual patches would be of
low magnitude but the cumulative magnitude would be moderate. |
|
Impact Severity |
Low, as disturbance impact on mitigation plantation has limited impact on
its ecological function in mitigating disturbance impacts on other habitats
and species. |
Table 13.109 - Potential Fragmentation Impacts on Mitigation Plantation in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Plantations are fragmented but they provide
some habitat linkages for woodland species and help to maintain linkages for
species using the rivers by reducing disturbance. Ecological value is Low to
Moderate. |
|
Species |
Utilised by
woodland species in small numbers and help to maintain linkages along rivers. |
|
Size/Abundance |
Areas impacted are
small individually but total area is moderate. Faunal numbers that benefit
from role in maintaining linkages are moderate and include some species of
conservation significance. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Construction phase
impacts largely reversible; operational phase impacts irreversible;
remediation possible for both construction and operational phase impacts. |
|
Magnitude |
Fragmentation impacts on individual patches
would be of low magnitude but the cumulative magnitude would be moderate. |
|
Impact Severity |
Low, as in-situ ecological
value is limited. |
13.7.3.19 Orchard
Several small orchard areas, generally located close to villages, will be lost to development. These orchards are fragmented from other woodland habitats, usually have a closed canopy with little understorey vegetation and are regularly disturbed by human activity. Accordingly both floral and faunal diversity is generally low.
Table 13.110 - Potential Ecological Impacts on Orchard in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Ecological value is low due to small size,
low vegetation and faunal diversity and relatively high levels of
disturbance. |
|
Species |
Vegetation
dominated by a small number of fruit trees. No species of conservation
importance recorded. |
|
Size/Abundance |
Small total
habitat area (7.38ha) and low numbers of fauna present. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Construction phase
impacts largely reversible; operational phase impacts irreversible;
remediation possible for both construction and operational phase impacts. |
|
Magnitude |
Low. |
|
Impact Severity |
Low |
13.7.3.20 Village, Urban/Residential, Waste Ground
Much of the land in each NDA
comprises developed land, including village areas, urban/residential
development and waste ground. Vegetation diversity is low and many species are
exotic. Faunal diversity in these areas is also low and species present are
habitat generalists tolerant of human activities which are common and
widespread in Hong Kong. .
Table 13.111 - Potential Ecological Impacts on Developed Land (Village Areas, Waste Ground and Urban/Residential) in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Low ecological value. |
|
Species |
Faunal diversity is low and species present
are habitat generalists tolerant of human activities that are common and
widespread in Hong Kong. Displacement of the fauna would not have a
significant effect on these species, and as a consequence of the long
duration of the project, the number of individuals which will be displaced at
any one time will be small. Further, as the project proceeds the area where
development has been completed (and hence is available for re-occupation)
will increase; accordingly there will be no cumulative increase in the number
of displaced individuals as the project progresses. |
|
Size/Abundance |
Habitat occupies a
large part of the Study Area. Not utilised by any species of conservation
significance except incidentally. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Largely
irreversible during the construction phase but reversible in the operational
phase. |
|
Magnitude |
Habitat is of low ecological value and no
fauna of conservation significance utilises this habitat other than
incidentally. Further, the area impacted at any one time will be a minor
element of the habitat available to these species as they are not restricted
to a few habitats or area. Accordingly, magnitude of impact is low. |
|
Overall Impact Severity |
Low |
13.7.3.21 Impacts on Deep Bay Ecosystem
Pollution
The Project Area is located within the catchment for rivers feeding into Deep Bay via the Shenzhen River. Water discharging from the Project Area will thus flow into habitats of very high ecological value in Deep Bay, including intertidal mudflats and extensive mangrove ecosystems. These habitats are at risk of pollution as a result of discharge of untreated or partially-treated domestic effluent, discharge of industrial chemicals or surface runoff of pollutants from paved areas. Such pollution could prove toxic to important wildlife or could lead to eutrophication of local watercourses and the wider Deep Bay ecosystem. Such pollution could occur during either the construction or the operational phases of the Project.
A related risk will arise during the construction phase of the Project as a result of increased sedimentation from exposed soil.
An increase in the paved area present as a consequence of the Project would lead to a higher rate of stormwater runoff from road surfaces and other pollutant sources. Ultimately this stormwater could carry pollutants from road surfaces in the project area into the bay.
The most ecologically important habitats in Deep Bay are located well downstream from the Project Area. This increases the chance that any pollution event is detected prior to this reaching the bay, and thus reduces the risk of pollution of the bay arising from the NDA.
Most non-tidal wetland areas around Deep Bay (primarily the fish pond areas surrounding the bay) have no direct hydrological links to the Project Area and would not be impacted by the proposed development, although a small number of fishponds at Hoo Hok Wai may import water directly from Ma Tso Lung Stream.
Table 13.112 - Potential Indirect Ecological Impacts on the Deep Bay Catchment in the absence of mitigation measures
|
Criteria |
Impacts from Sedimentation |
Impacts from Pollutant Run-off |
|
Habitat Quality |
Deep Bay intertidal mudflats and mangrove
habitats are of High ecological value and of international importance. |
|
|
Species |
A high abundance
and diversity of species in intertidal areas, many of which are of
conservation significance regionally or globally. |
|
|
Size/Abundance |
Deep Bay covers a
large area and contains very extensive areas of intertidal mudflats and of
mangroves. Large numbers of birds, fish and invertebrates are present. |
|
|
Duration |
Risk of impacts would be greatest during
construction and would be temporary. |
Risk of impacts would be greatest during
construction phase but some impacts could remain into the operational phase.
Duration may very depending on the nature of the pollution event. |
|
Reversibility |
Siltation would be
largely incorporated into natural processes. |
Smaller-scale
pollution events would be easier to contain and reverse. Large-scale
pollution events would be more difficult to reverse. |
|
Magnitude |
Sedimentation is a natural process and impacts
would be of low magnitude. |
Magnitude of impacts would be dependent upon
the nature and quantity of pollutant; chemical pollution (especially oil)
would have a serious impact to a large number of species. More significant
pollution events are likely to be detected sooner, so of shorter duration. Magnitude of most events likely to be low due
to the large size of Deep Bay and its distance from the Project Area. |
|
Impact Severity |
Construction phase
impacts of Low to Moderate
severity. Operational phase
impacts of Low severity. |
Construction phase:
certain pollution events (e.g. oil spills or other chemical pollution) have
potential for High severity
depending on nature and scale; most pollution events likely to be of Low to Moderate severity as magnitude
likely to be small. Operational phase:
although dependent on nature and scale, most likely to be Low. |
13.7.4 Impacts on species of conservation importance
Impacts to species, other than those arising as a consequence to direct impacts on their habitats, which were assessed in Section 13.7.3, are considered in this section. These include direct mortality of fauna and species level impacts to flora and fauna, in particular species of conservation significance including potential flight-line impacts to birds.
13.7.4.1 Flora:
death/mortality and damage of individuals
Direct impacts on species of flora arise from vegetation clearance and felling of trees required as part of development works. While transplanting or replanting of species affected can be carried out, the feasibility of such measures depends on the specimens affected, their age/size, the tolerance of any time lag required for growth to maturity and the availability of suitable relocation sites.
The protected tree, Aquilaria sinensis, is present in fung shui woodland/secondary woodland at Ho Sheung Heung, Ma Tso Lung, south of Pak Shek Au, east of Tong Hang Tung Chuen and east of Wo Hop Shek. Three other flora species of conservation significance, the trees Ailanthus fordii and Pavetta hongkongensis, and the climber Gnetum luofuense (which is common in Hong Kong) have been recorded in fung shui woodland/secondary woodland at Ho Sheung Heung. Gnetum luofuense is also present in secondary woodland near Siu Hang Tsuen. The fern Cibotium barometz is present near the Ngam Pin Watercourse and two protected orchid species, Pecteilis susannae and Spathoglottis pubescens, are present in plantation near the Cheung Po Tau Watercourse, Sha Ling.
None of the specimens found are located in areas that will be directly impacted by the Project, or are in areas where significant indirect impacts are predicted; however, Ho Sheung Heung fung shui and secondary woodland is immediately adjacent to development areas and may be indirectly impacted by dust deposition and disturbance by site staff during the construction phase of the Project.
Table 13.117 - Potential death/mortality or damage to plant specimens in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Woodland at Ho Sheung Heung is of Moderate
ecological value for flora. |
|
Species |
Flora species of
conservation significance and protected flora species. |
|
Size/Abundance |
Gnetum luofuense is common; only a few sapling specimens of
Aquilaria sinensis were found
during surveys for the current study; Ailanthus
fordii and Pavetta hongkongensis
found previously and in this woodland and may still present but are likely to
be rare. |
|
Duration |
Construction phase. |
|
Reversibility |
Dust deposition
will be reversed by rainfall; damage by site staff may be irreversible but
remediation possible. |
|
Magnitude |
Magnitude low as the area does not support
significant populations of these species. |
|
Impact Severity |
Dust deposition of Low severity; damage/death of
specimens of protected species of Low
severity; but damage/death of species of conservation significance would be
of Low to Moderate severity. |
13.7.4.2 Fauna:
mortality of individuals
Direct mortality involves the death of organisms as a result of the development. Animals may be hit and killed or injured by rapidly-moving vehicles or by collision with stationary objects such as buildings or noise barriers. Birds and mammals appear to be most susceptible (Van der Grift and Kuijsters 1998), though herpetofauna are also prone. Should roads pass through areas of high animal population density, or cut across regular lines of movement, such mortality is likely to be greater. The risk of animal mortality arising from road kill and collision with buildings, windows or transparent noise barriers is likely to be greater in rural areas than in already developed, urban areas, as wildlife populations are higher in the former.
Numerous studies have documented avian mortality associated with buildings, usually the result of collision with tall buildings or windows. Long-term studies have documented the chronic nature of collision mortality associated with some buildings. Over a three-year period in Toronto, Ontario, Ogden (1996) counted 5,454 dead birds at 54 tall glass buildings. Inclement weather during the migration seasons is known to exacerbate nocturnal collision mortality, as birds become disorientated in such weather conditions. The combination of strong night-time lighting emitted from a tall building or structure is a particular source of mortality.
Collisions also occur in daytime, though the causes are generally related to the nature of the building exterior (glass being the prime culprit), and the key risk factors are transparency and reflectivity. Building façades that constitute transparent glass appear not to present an obstacle to flight and birds may strike windows as they attempt to access potential perches, plants, food and water sources or other lures seen through the glass. Design features such as glass skywalks joining buildings, glass walls around planted atria and windows installed perpendicularly at building corners are dangerous as birds perceive these an unobstructed route.
In addition, materials that reflect surrounding natural vegetation impart the appearance of being suitable for foraging or perching. Where nearby vegetation is limited in extent, even extensive glass surfaces may produce only a few collisions per year; but where vegetation is extensive and “mirrored glass exteriors” face “forested patches” (O’Connell 2001), high collision rates may occur. Glass windows in the lower storeys of a building are, typically, a much greater threat as they are more likely to reflect trees and other landscape features that attract birds. Windowed courtyards and open-topped atria, especially if heavily planted, are also hazardous. Birds fly down into such areas, but may try to leave by flying directly towards reflections on walls. Gelb and Delacretaz (2009) found that in New York the combination of open space, vegetation and large windows greater than 1m x 2m are more predictive of bird mortality than building height. The angling of glass up toward the sky also appears to confuse birds (Klem 1990) and constitute an exacerbating factor.
In the same manner, noise barriers are problematic if they are transparent, and thus appear to allow clear passage to suitable habitat on the far side, or are reflective of surrounding habitats. A particular complicating factor is that if a surface is not obviously impenetrable from some distance, it may be difficult for birds to take evasive action at a closer range. Birds, whether by instinct or morphology, often cannot rapidly reduce flight speed as it results in stalling, and a fall from the air; thus, if there is insufficient distance to avoid a barrier by flying over or around, collision is inevitable (Martin 2011). Consequently, surfaces that appear to be solid only at close range (for example, where a pattern such as hatching is not visible at longer range) may still cause significant mortality.
Birds have evolved to fly through tree canopies at speed. As a result, such measures as the placing of falcon silhouettes, owl decals and large eye patterns do not reduce strike rates by a statistically significant level (Kruuk 1995). Such objects have to be distributed sufficiently densely across the problem surface so as to break the glass swaths to less than 4” vertically or 2” horizontally (San Francisco Planning Dept. 2011) in order to be effective. Such a density is unlikely to be considered aesthetically pleasing on buildings, though may be acceptable for roadside noise barriers.
Direct mortality of fauna may occur during the construction and operational phase of the Project as a consequence of such fauna being accidentally or deliberately killed by human agency, by displacement from required habitat as a consequence of loss or disturbance to that habitat and by fragmentation of habitat such that the remaining habitat fragments are too small to meet the ecological requirements of all the individuals isolated in the fragments. Direct mortality may also occur as a result of a combination of these factors when individual factors are not, in themselves, sufficient to cause mortality; a well-known example of factors acting in concert resulting in direct mortality is the death of amphibians on roads as they try to move between terrestrial habitats, occupied for much of the year by adults, to wetlands utilised when breeding.
Terrestrial Mammals and Herpetofauna
Terrestrial mammal numbers in the Study Area are low. As a consequence, mortality of mammals during the construction and operational phases of the Project is likely to be small. However, mortality may still be of significance at a population level, especially in respect of slower breeding and rarer species. These include Eurasian Otter, which has been recorded once in the north of the Study Area and occurs regularly in areas to the north.
Some herpetofauna species may be slow-moving, especially when temperatures are low, and some species may utilise road surfaces to assist in maintaining body temperatures. Some species may also find it difficult or impossible to climb out of vertical or steep-sided artificial structures such as drainage channels. As with other fauna, mortality of species of conservation significance as a direct or indirect consequence of the Project may be of importance if this is sufficient to affect populations at a local or higher level.
As indicated above, most of the Project Area mortality of terrestrial fauna, and especially terrestrial fauna of conservation significance, is unlikely to be of significance. However, the Eastern Connection Road is located in close proximity the riparian corridor of Ma Tso Lung Stream where Three-banded Box Terrapin is present, as are other herpetofauna species of conservation significance. Though not known from the Study Area, it is possible that Eurasian Otter may occur in this area. Accordingly, it is considered that mortality impacts on terrestrial fauna may be of conservation significance in this area.
Table 13.113 - Potential mortality
impacts on Terrestrial Mammals and Herpetofauna in the absence of mitigation
|
Criteria |
Assessment |
|
Habitat Quality |
Most mammal species in the Study Area use
woodland habitats, especially larger and older woods; Bandicoot Rat occurs in
lowland habitats around Long Valley and Eurasian Otter utilises wetland,
including riparian corridors; reptiles occur in a variety of habitats, with
wetlands and the Ma Tso Lung area of greater significance; amphibians are
wetland-dependent. |
|
Species |
All species of
conservation significance recorded in the Study Area. |
|
Size/Abundance |
The areas of
preferred habitat (wetlands and older/larger woodlands) are relatively small,
but other habitats may be utilised on occasion. The Study Area does not
support any mammal populations of significance in a Hong Kong context, but
populations of some herpetofauna are of importance; that of Three-banded Box
Terrapin may be globally significant. Mortality of any individuals of species
of conservation importance could be significant at a local level. |
|
Duration |
Permanent in respect of operational phase
impacts; temporary in respect of construction phase impacts. |
|
Reversibility |
Not reversible; but
remediation measures possible. |
|
Magnitude |
Generally low but could be low to moderate in
the Ma Tso Lung area. |
|
Impact Severity |
Low in the Project Area as a whole but Low to Moderate in the Ma Tso Lung area for riparian fauna of
conservation significance and Moderate
to High for any mortality of Three-banded Box Terrapin. |
Bats
Bats are not significantly impacted by most potential causes of direct mortality potentially arising from the Project; however, they may be vulnerable to direct mortality from destruction of roost sites, especially those occupied by nursing females or by winter bat roosts. Potential impacts on bat roosts are considered below.
Table 13.114 - Potential Mortality
Impacts on Bat Roosts in the absence of Mitigation
|
Criteria |
Assessment |
|
Habitat Quality |
Variable, roost locations may be in habitats
such as villages that are otherwise of limited ecological value. |
|
Species |
Bat species of
conservation significance known to occur in the Study Area include
Short-nosed Fruit Bat, Brown Noctule and Lesser Yellow Bat; given their
vagility, other species may occur. All bats are protected under the Wild
Animals Protection Ordinance. |
|
Size/Abundance |
Large area of
potential habitat; bat roosts are likely to occur in most habitats where
roost requirements are met, including anthropogenic habitats. Bats are
abundant in lowland agricultural and wetland areas impacted by the Project. |
|
Duration |
Impacts would only be of significance during
the construction stage of the Project. |
|
Reversibility |
Irreversible; but
remediation possible. |
|
Magnitude |
Low as period of vulnerability will be short
and localised. |
|
Impact Severity |
Low as population level impacts highly unlikely. |
Birds
Like bats, birds will be able to avoid most direct impacts of the Project. However, birds are vulnerable to direct mortality, especially of eggs or nestlings, when breeding. Potential mortality to breeding birds is assessed below.
Table 13.115 - Potential Direct
Mortality Impacts on Breeding Birds in the absence of Mitigation
|
Criteria |
Assessment |
|
Habitat Quality |
Variable, breeding locations do not
necessarily reflect the habitat quality of the immediate area. |
|
Species |
Moderate diversity
of wetland-dependent bird species and others of conservation significance
breed in the area, including ardeid species at two locations. |
|
Size/Abundance |
Large; some
breeding birds are present in all habitats; abundance higher in woodland and
wetland habitats and lower in grassland and developed areas; ardeid nests are
concentrated at two locations. |
|
Duration |
Construction phase. |
|
Reversibility |
Irreversible but
remediation possible. |
|
Magnitude |
Generally low as period of vulnerability at
any one location will be short and localised. Moderate if egretry locations
were to be cleared during the breeding season. |
|
Impact Severity |
Generally Low severity but potentially Moderate if egretry locations were to
be cleared during the breeding season. |
Collision mortality on birds from buildings or other barriers is potentially of significance from the Project. The height of some buildings in the Project Area will be substantial, and as modern buildings tend to have large areas of glass, avian mortality is possible. Much depends on the nature of the glass, however, with highly reflective surfaces causing greater mortality, especially if adjacent to dense areas of shrubs or trees.
Collision frequency is also related to the number of birds present, with numbers of birds in an area increasing the likelihood of collision, irrespective of other factors. Similarly, the risk of collision is increased if development is located across a flight-line regularly utilised by birds in significant numbers. In the assessment area significant concentrations of birds occur in Long Valley and, to a lesser extent, along the major river channels. However, the most significant flight-line is that used by large waterbirds (which, as a group, are not particularly prone to collision with structures) linking Long Valley northwards along the Ng Tung River to the Shenzhen River and Deep Bay; also of significance for waterbirds is the flight-line along the Ng Tung River eastwards, although this is used by smaller numbers and fewer species. A flight-line for some soaring species follows the hills in the north of the Study Area, though this is of much less significance in terms of the number of individuals using it and this flight-line is also elevationally separated from development areas.
In any location, species involved in collisions will generally reflect the habitats in the immediate vicinity. The development areas of the project will be planted with trees and shrubs that will attract the typical common and widespread species that have adapted to this habitat in Hong Kong. Some species using adjacent areas of shrubland and secondary woodland will opportunistically use such habitats in the developed areas, but in relatively small numbers. Consequently, any mortality in these areas is not anticipated to be different in nature to that which occurs in other areas of Hong Kong.
Data from the only study of mortality of birds caused by noise barriers in Hong Kong, which was not systematic, are presented on the website of the Hong Kong Bird Watching Society. Though informal, the data suggest that mortality from transparent noise barriers alongside roads can be significant. Most of the species suffering collision at the study site were small in size due to the nature of habitats in the surrounding area. The issue at this and similar sites concerns birds flying between separate patches of wooded or shrubland habitat, where the transparent glass imparted an impression of unobstructed passage.
The larger species present in Hong Kong are less prone to such impacts as they tend to fly more slowly and at greater heights in more open areas, away from roads and buildings. Consequently, it is not anticipated that larger species, in particular the large waterbirds which are common in the Study Area, will be significantly impacted in this way, given appropriate selection of building materials and design. The main issue for these larger species, including the largely nocturnally-foraging Grey Heron and Black-crowned Night Heron, and migratory birds in general is probably lighting. Certain types of lighting, especially in tandem with poor weather, may impose an impact.
The part of the Project Area where the risk of mortality of birds from buildings is of most significance is the area to the southwest of Long Valley, where a concentration of non-residential buildings is proposed to be constructed close to an area with a concentration of birds.
Areas where noise barriers are most likely to be of concern in respect to mortality of birds are areas where barriers are planned between sensitive noise receivers and wooded areas; however since experience has shown that almost any transparent noise barrier has the potential to cause bird mortality, it is recommended to avoid transparent noise barriers throughout the Project Area.
Table 13.116 - Potential collision mortality
impacts on bird species in the absence of mitigation
|
Criteria |
Assessment |
|
Habitat Quality |
Wetlands of high ecological value at Long Valley and along the main
river channels which support a large number of waterbirds; other habitats of
lower value elsewhere in the Study Area support small numbers of waterbirds
and small to moderate numbers of landbirds. |
|
Species |
Species of conservation value, wetland-dependent species and a diverse
variety of landbirds are present in the area. Susceptibility to mortality
more dependent upon size than habitat preferences with larger species being
less susceptible; however, species of the same size which typically utilise
closed habitats tend to be more susceptible than species of the same size
which typically utilise open habitats. |
|
Size/Abundance |
Abundance of birds is high, especially in Long Valley, while the area
of buildings and roads that could potentially cause mortality is large. |
|
Duration |
Construction phase impact will be short-term but operational phase
impacts are long-term. |
|
Reversibility |
Irreversible but can be remediated to some extent reversible via
installation of measures to minimise impacts. |
|
Magnitude |
Probably of low magnitude for larger bird species, including larger
species of conservation significance; number of smaller birds impacted may be
larger but this is balanced by their generally larger populations, fecundity
and shorter generation times, hence of low magnitude at a species level. |
|
Impact Severity |
Low, mainly in relation to
small to medium-sized birds, but also including smaller numbers of
waterbirds, especially along the Ng Tung River in KTN. |
13.7.4.3 Impacts at Species Level
Mammals
The following terrestrial species of conservation significance: Greater Bandicoot Rat, East Asian Porcupine, Masked Palm Civet, Leopard Cat and, at least historically, Red Muntjak, have been recorded in the Long Valley and Ho Sheung Heung areas in wetland and woodland habitats, and may be impacted by the Project indirectly, or experience fragmentation or cumulative impacts, in these areas. In addition, Eurasian Otter, a species of global conservation concern, has been recorded on the east side of the Ng Tung River near Sha Ling and has been reported regularly just to the north of the Study Area at Hoo Hok Wai and may occasionally occur within the area in the Ma Tso Lung area. Accordingly, this species may also be impacted by the project.
All bat species are protected in Hong Kong but the only species of conservation significance that has been reported from the assessment area with certainty is Brown Noctule, recorded in Ho Sheung Heung village during the current study. In addition, Pomona Leaf-nosed Bat was tentatively recorded in KTN during the Hong Kong Biodiversity Survey (Dudgeon and Corlett (2001), and hence is treated as a species which may be significantly affected by the project on a precautionary basis. However, in view of the difficulties involved in observing and identifying bats and their mobility, it is not unlikely that additional species of conservation significance occur.
Table 13.118 - Potential Ecological Impacts on Mammals in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
The habitat value of the mosaic of wetland
habitats in Long Valley is High; Ho Sheung Heung woodland is of Moderate
value, while shrubland at Crest Hill, which may also be utilised by some
mammal species, is of Moderate to High value. Riparian habitats in the Ma Tso
Lung area are of variable ecological value but the combined habitats are of
ecological significance for a number of fauna species. Bats may be found in a variety of habitats,
and location of roosts (where bats are most vulnerable to impacts) may not be
related to habitat quality in the immediate area. |
|
Species |
Mammal species of
conservation significance of which Greater Bandicoot Rat (found at Long
Valley) and Eurasian Otter (found near the Ng Tung River at Sha Ling and to
the north of the Study area at Hoo Hok Wai) have restricted distributions in
Hong Kong. |
|
Size/Abundance |
Except for some bat
species, which are abundant in lowland areas, mammal populations in the
assessment area are probably low in a Hong Kong context. |
|
Duration |
Construction phase impacts will be temporary
but operational phase impacts will be permanent. |
|
Reversibility |
Mostly
irreversible, but remedial measures are possible in both construction and
operational phases. |
|
Magnitude |
Magnitude likely to be low as the area does
not appear to support significant populations of species of conservation
importance. |
|
Impact Severity |
Construction phase:
Low in respect to mortality and
Low in respect to fragmentation due to potential for greater disturbance and
fragmentation impacts from construction activities. Operational phase: Low to Moderate in the Ma Tso Lung
area, primarily due to the potential fragmentation impacts of the LMC Loop
Eastern Connection Road, but Low
in the Long Valley and Ho Sheung Heung areas and elsewhere as habitats of
significance to mammals will be retained, habitat linkages will be retained,
and disturbance will decrease. |
The assessment area is of high importance to wetland bird species of conservation importance, supporting both a high diversity of wetland bird species and high numbers of some of these species. Both species diversity and numbers are highest in Long Valley, which is particularly important in a Hong Kong context to species that favour freshwater wetland and wetland agriculture. The Sheung Yue River and, to a lesser extent, the Ng Tung and Shek Sheung Rivers are also of importance to wetland birds, though numbers, and especially, diversity are lower than in Long Valley and species using these rivers are not restricted to these habitats or these and a small number of other habitats. Other wetland areas in the assessment area are small and scattered and not used by any wetland bird species in significant numbers.
Open or largely open-canopy dryland habitats in the assessment area, especially those away from Long Valley, are of much lower significance in a Hong Kong, national, or international context. Two species of conservation significance in Hong Kong have been recorded in upland grassland and shrubland habitat in the Study Area in circumstances meeting the criteria used in this assessment and in Fellowes et al. (2002): Eurasian Hobby and Grey Nightjar. Of these species, Eurasian Hobby, has bred at Crest Hill in the past (Carey et al. 2001), and was recorded in the same area during the current study, and Grey Nightjar was recorded in upland grassland (a suitable breeding habitat) near Cheung Po Tau and Wa Shan, again during the current study. In addition, Eurasian Eagle Owl, though not of certain occurrence in the Study Area, may be present in upland grassland north of Chau Tau.
Other species of open dryland habitats recorded in the Study Area, such as Japanese Quail, Zitting Cisticola, Golden-headed Cisticola, Chestnut-eared Bunting, Yellow-breasted Bunting and Grey-capped Greenfinch are either not of regular occurrence in the Study Area, not of regular occurrence in such habitats, or are not restricted to a single habitat, or a few habitats or areas in the Study Area. Red-billed Starling and Chinese Grosbeak are found in a variety of open country habitats, including both wetland and dryland habitats and developed areas. Both species are primarily non-breeding visitors to Hong Kong and occur in flocks which forage opportunistically where food sources are temporarily abundant; Red-billed Starling is generally commonest in wetland habitats, whereas Chinese Grosbeak is often found in trees in or near village areas, perhaps because Cinnamomum camphora trees, the seeds of which are a favoured food source, are often planted in such areas. Numbers of both species in the Study Area as a whole may be significant in a Hong Kong context; however, as both species occur in a wide variety of habitats, including developed areas and forage in mobile flocks, impacts on these species from the project are not considered to be significant. White-shouldered Starling, which is largely a breeding summer visitor or passage migrant through Hong Kong, has similar habitat requirements to Red-billed Starling, but is perhaps more closely associated with wooded habitats and is even more closely associated with developed areas, where it breeds in man-made structures. This species is listed by Fellowes et al. (2002) as restricted as a breeding species, albeit numbers have increased in Hong Kong in the past ten years (M.R. Leven pers. obs.). Impacts of the project on this species are also not considered to be significant.
Whilst not of significant intrinsic habitat value, plantation and orchard east of Ho Sheung Heung and plantation at Man Kam To Road north of the Ng Tung River are of significance as egretry locations. In some years Ho Sheung Heung Egretry is one of the largest in Hong Kong.
Mature secondary woodland which meets the habitat requirements of woodland-dependent bird species is rare in the assessment area; the largest area of older secondary woodland and contiguous fung shui woodland in the Study Area lies to the west of Ho Sheung Heung.
Crested Serpent Eagle has been recorded over wooded areas (including shrubland). This species, which is listed by Fellowes et al. (2002) as a restricted breeding species, breeds in wooded areas in the New Territories (Carey et al. 2001). It has been recorded from a number of areas and habitats in the Study Area but there is no evidence that it breeds in any of the areas which may be impacted by the project. White-throated Kingfisher, listed by Fellowes et al. (2002) as of Local Concern as a breeding species, has been recorded in or near some woodland areas and may breed in at least some of these; however, again there is no evidence that it breeds in any locations which will be significantly affected by the project. Also recorded in wooded areas away from Long Valley are Brown-headed Thrush (a rare winter visitor to Hong Kong), and Black-naped Oriole (a former common breeding species which has now largely disappeared (as a breeding species) from Hong Kong.
Table 13.119 - Potential Ecological Impacts on Wetland-dependent Birds in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Long Valley habitat is of High to Very High
ecological value for wetland-dependent birds, including many species of
conservation importance. Sheung Yue River is of Moderate ecological value for
a much smaller number of wetland-dependent bird species, but including some
species of conservation significance; tidal Ng Tung River is of Moderate
ecological value and non-tidal Ng Tung River and Shek Sheung River are of Low
to Moderate ecological value for wetland-dependent birds as they support,
moderate and small numbers, respectively, and a more limited diversity of
wetland-dependent species. Other wetland habitats and non-wetland habitats
are of low ecological value to wetland bird species other than habitats used
by breeding egrets. |
|
Species |
A high diversity of
wetland-dependent species, including many species of conservation importance,
is present in Long Valley. Main river channels support a low to moderate
diversity of wetland-dependent bird species; wetland habitats elsewhere and
non-wetland habitats are not of significance for wetland-dependent bird
species. |
|
Size/Abundance |
Long Valley is a
large area of freshwater wetland in a Hong Kong context; Ng Tung and Sheung
Yue Rivers are large areas of channelised river habitat, while the Shek
Sheung River is a moderate area of this habitat; other areas are small.
Abundance of wetland-dependent species is high in Long Valley and moderate on
the Ng Tung and Sheung Yue Rivers and low elsewhere. |
|
Duration |
Loss of wetland habitats and associated birds
would be permanent. Disturbance impacts would be permanent but would be
reduced during the operational phase. Duration of construction phase impacts
will vary due to phasing of the project: those on Long Valley will be highest
during the Advance Works Phase; those on the Sheung Yue River will be
greatest during road bridge construction by which time there will be no
significant disturbance impacts on Long Valley as a whole. Fragmentation
impacts on flight-lines of wetland-dependent waterbirds, in particular
breeding ardeids, would be permanent in respect to linkage between Long
Valley and the non-tidal Ng Tung River; other fragmentation impacts would be
lower from other sources and largely in later phases, as the main
flight-lines would not be affected by development in their path. |
|
Reversibility |
Direct loss of
wetland habitat and fragmentation of linkage between Long Valley and Ng Tung
River would be irreversible; disturbance impacts from structures would be
irreversible; remedial measures possible to reduce disturbance and other
fragmentation impacts would be possible during both construction and
operational phases. |
|
Magnitude |
Construction phase: magnitude of direct
habitat loss low, magnitude of disturbance impacts on birds using Sheung Yue
River north of the new footbridge and tidal Ng Tung River low to moderate
during Advance Works period then low thereafter; magnitude on birds using
southern section of Sheung Yue River low to moderate during early part of the
construction phase but high during road bridge construction, and during
development of areas on either side of the river. Magnitude of disturbance impact on birds using
the non-tidal Ng Tung River moderate to high throughout overall, but related
to phasing of individual project elements. Magnitude of disturbance on birds using the
Shek Sheung River low to moderate during Advance works phase, low thereafter. Magnitude of impact on Long Valley low
throughout but low to moderate on areas along the river channels during
Advance Works phase. Overall trend for magnitude of impact to
decline over time due to habituation. Overall magnitude of construction phase
disturbance low to moderate as impacts on most species and on most
individuals low or low to moderate. However, magnitude of impact on foraging
habitat for some species using Sheung Yue River may be moderate, especially
in the case of Little Egret and Chinese Pond Heron breeding at Ho Sheung
Heung Egretry and foraging in the river. Magnitude of fragmentation impact on
linkage between Long Valley and Deep Bay wetland ecosystem low, magnitude of
fragmentation impact on linkage between Long Valley and non-tidal Ng Tung
River low as few individuals and species are involved. Operational phase: low except for disturbance
impact which would be low to moderate on birds using the Sheung Yue River and
low to moderate on birds using non-tidal sections of the Ng Tung River;. |
|
Overall Impact Severity |
Impact of direct
habitat loss: Low. Construction phase: Low to Moderate on most species
using Sheung Yue River but Moderate
on breeding individuals of Little Egret and Chinese Pond Heron; Low to Moderate on birds using
non-tidal Ng Tung Rivers; Low on
birds elsewhere including Long Valley. Operational phase: Low on birds using Sheung Yue River,
Low to Moderate on birds using non-tidal Ng Tung River; not significant
on birds using Long Valley and tidal Ng Tung Rivers; not significant or Low on wetland birds elsewhere. |
Table 13.120 - Potential Ecological Impacts on Non Wetland-dependent birds in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Most lowland dryland habitats are disturbed by
human activity and do not support important bird communities and are of Low
ecological value. Dry agricultural land in FLN is of Low to Moderate
ecological value; this habitat/area is used by some bird species of
conservation significance in small numbers but it is not regularly used by
significant numbers of these species. Upland grassland and
grassland/shrubland are largely of Low ecological value; however, that at
Cheung Po Tau, Wa Shan and Chau Tau are considered to be of Low to Moderate
ecological value due to the presence and suspected presence, respectively, of
Grey Nightjar and Eurasian Eagle Owl. Upland shrubland at Crest Hill is of
Moderate to High ecological value, partly as a consequence of the presence of
Eurasian Hobby, and that at Ma Tso Lung is of Low to Moderate ecological
value. Most woodlands areas are too small and/or young and fragmented to
support woodland-dependent bird species, but Ho Sheung Heung fung shui woodland and secondary
woodland and Siu Hang Tsuen woodland, both of Moderate ecological value,
support a few woodland-dependent species which are unusual in the Study Area.
|
|
Species |
A moderate
diversity of species but most are common and widespread in Hong Kong. Small
numbers of some bird species of conservation importance are found in dry
agricultural land in FLN and in woodland habitats. Eurasian Hobby has bred on
a pylon in shrubland at Crest Hill and is known still to occur in this area
during the breeding season. As noted above, Grey Nightjar occurs at Cheung Po
Tau and Wa Shan and Eurasian Eagle Owl may occur at Chau Tau, however the
area where it may occur will not be affected by the project. |
|
Size/Abundance |
Areas of upland
grassland, lowland grassland, hillside plantation and roadside and urban
plantation and developed land are large, areas of other dryland habitats are
low to moderate. Abundance of species of conservation importance is low all
habitats. |
|
Duration |
Loss of habitat is permanent; disturbance
impacts are largely restricted to the construction phase, but some
disturbance impacts would be permanent. |
|
Reversibility |
Loss of habitat
would be irreversible; remedial measures possible to reduce disturbance
impacts would be possible during both construction and operational phases. |
|
Magnitude |
Magnitude of loss of, and disturbance to, dry
agricultural land in FLN is large, but magnitude of impact is low to
moderate, as bird species of conservation significance occur in low numbers
and this is not their preferred habitat. Magnitude of loss of, and disturbance to,
wooded habitats is large, but magnitude of impact is low to moderate, as bird
species of conservation significance occur in low numbers. Magnitude of impact on Grey Nightjar at Cheung
Po Tau and Wa Shan potentially moderate during construction phase if a
breeding site is within a works area and occupied at the time of commencement
of construction, but low during operational phase as area of direct habitat
loss is small and operational phase disturbance impacts would be low. Magnitude of impact on Eurasian Hobby at Crest
Hill potentially moderate to high during construction phase in the relatively
unlikely event that a breeding site is close to any works area but low during
operational phase as no direct habitat loss and operational phase disturbance
impacts would be low. Magnitude of impacts on birds in other
habitats low as habitats not regularly utilised by non-wetland bird species
of conservation significance. |
|
Overall Impact Severity |
Construction phase:
Low on species using dry agricultural
land in FLN and wooded habitats; Low to Moderate on Grey Nightjar and Low to Moderate on Eurasian Hobby depending upon proximity of any nest
location to works areas. Operational phase: Low. |
Egretries and Egret Flight-lines
The egretry at Ho Sheung Heung is one of the largest egretries present in Hong Kong. The Man Kam To Road egretry which was first discovered in 2009, is located near Man Kam To Road, north of the Ng Tung River. Both Egretries are currently located immediately adjacent to open storage areas and subject to some level of disturbance. While no direct impact on Ho Sheung Heung Egretry is envisaged under the NDA development, the Man Kam To Road egretry would be unavoidably and directly impacted by the interchange at the western terminus of the Fanling Bypass. Alternative alignments for the Bypass and roundabout connection were considered, but the constraints imposed by the existing Mam Kam To Road alignment, the Boundary Control Point and the Ng Tung River rendered these unfeasible (Section 13.4.1.3 and Section 2.4.1.5). This egretry will thus be unavoidably lost as a consequence of the Project if it is still occupied when site clearance work for the Western Section of the Fanling Bypass commences in August 2025. It may also be indirectly affected by site formation for Advance Works elements of the project which will commence in July 2018 and a new footbridge to the west for which construction is scheduled to commence in August 2024. The size of the egretry was smaller in the early part of the 2013 breeding season, which may have occurred in response to previous damage to the site. Given the transient nature of some egretries, it is possible that other changes might occur that would result in increase, decrease or relocation of the egretry. For this reason, the impact assessment in respect of this should be reviewed before commencement of works and amendments to mitigation agreed with relevant authorities (see Section 13.5.4.5)
Ardeids breeding in both egretries are required to fly to nearby wetland habitats in order to forage for themselves and their chicks. These birds could be impacted by the loss of wetland habitats within the Project Area or the presence of obstacles along the route between breeding and foraging sites, which may make wetland sites unavailable to foraging birds or reduce foraging efficiency by forcing birds to fly further. In addition, disturbance could occur to breeding or foraging birds as a result of increased human activity in the area.
Flight-line surveys conducted at the egretries suggest that Long Valley and Sheung Yue River provide important foraging sites for birds breeding at Ho Sheung Heung. The height at which ardeids fly between breeding and foraging sites is also relevant; especially along the flight-line between Ho Sheung Heung Egretry and the Sheung Yue River and Long Valley. Currently, most birds follow routes that take them lower than the overhead electricity wires which intersect the flight-line, and hence any development that reduced or eliminated the airspace between the ground and the wires would present a significant obstacle to birds, especially if it created a wide obstacle around which birds could not easily fly.
Development along the flight-lines between Ho Sheung Heung Egretry and Long Valley and the Sheung Yue River has largely been avoided; however, minor Advance Works elements of the project will be undertaken in the Open Space zone in KTN area C2-1 comprising minor site formation, utility laying and construction of open space. These works will be perpendicular to the flight-lines hence birds using them will have to fly over the works area to reach the Sheung Yue River and Long Valley. In addition, a new pedestrian footbridge will be constructed over the tidal section of the Ng Tung River, albeit this will be located to the east of the major portion of the flight-line. Other flight-lines from this egretry to the north and east will not be affected. Foraging areas to the north and east will also not be affected by the project and the area of Long Valley north and west of the Sheung Yue River will retain its current agricultural zoning, though this area will also be affected by works in KTN area C2-1 as well as pipe laying between this area and the Lo Wu Correctional Institution. In addition to impacts on flight-lines, foraging areas of breeding birds along the Sheung Yue River and, to a smaller degree, those in parts of Long Valley will be disturbed, especially during the construction phase of the Project.
Until the site of Man Kam To Road Egretry is cleared in order to permit construction of the western terminus of the Fanling Bypass, the flight-line from this egretry to Long Valley may be affected by upgrading of a footbridge between FLN area A2-1 and area A1-2 which is scheduled to commence in March 2019. This flight-line will also be affected by the extension to Shek Wu Hui Sewage Treatment Works and associated development within the footprint of the existing Sewage Treatment Works which is scheduled to commence in March 2015 and two new footbridges over the Ng Tung River. The first of these, which will link FLN area A1-3 and A2-3, is scheduled to be constructed between March 2021 and February 2023; construction of the second, which will be located just to the west of FLN area A1-7, will commence in August 2024.
Table 13.121 - Potential Ecological Impacts on egretries and flight-lines of breeding ardeids in the absence of mitigation measures
|
Criteria |
Impacts on Ho Sheung Heung Egretry |
Impacts on Man Kam To Road Egretry |
|
Habitat Quality |
The egretry is located in plantation/orchard
northeast of Ho Sheung Heung. The habitat is of Low intrinsic ecological
value but has been assessed as of Moderate to High ecological value because
of the egretry. |
The egretry is located in plantation east of
Man Kam To Road. The habitat is of Low intrinsic ecological value but has
been assessed as of Low to Moderate ecological value because of the egretry.
This plantation was disturbed by site clearance works in an adjacent open
storage/industrial site in 2012 and this assessment takes this damage, as
well as the small size of the habitat into account. |
|
Species |
Three species
breeding in recent years: Little Egret, Cattle Egret and Chinese Pond Heron.
Breeding sites of all three species are of conservation significance. |
Two species
recorded breeding: Little Egret and Chinese Pond Heron breeding in 2012.
Breeding sites of both species are of conservation significance. |
|
Size/Abundance |
One of the larger
egretries in Hong Kong, with up to 119 active nests since 2007, but declined
to 49 nests in 2012. The egretry was re-occupied in 2013. |
Up to 27 nests (in
2012), since the egretry was discovered in 2009. However, the site was partly
cleared in 2012, and only nine nests (all of Chinese Pond Herons) were
present in April 2013. |
|
Duration |
Impacts would occur during the ardeid breeding
season (March to July). Construction phase impacts would be temporary;
(operational phase impacts would be permanent. |
Loss of egretry site will be permanent.
Disturbance to the egretry and to flight-lines will also be permanent as this
will continue until the egretry site is developed. . |
|
Reversibility |
Operational phase
impacts would be irreversible; most construction phase impacts would be
reversible. Remediation possible during both construction and operational
phases. |
Irreversible. |
|
Magnitude |
Construction phase: magnitude of indirect
impacts on egretry site would be low as no development is proposed in the
vicinity. Magnitude of impacts on flight-lines would be low to moderate.
Magnitude of disturbance impacts on foraging areas at Sheung Yue River would
be moderate and on foraging areas in Long Valley would be low to moderate
during the Advance Works phase and low subsequently. No disturbance impacts
on foraging areas to the north and east. Operational phase: magnitude of impacts on
egretry site would be low at most; magnitude of impacts on flight-lines to
the south would be low,
no impacts on other flight-lines. Magnitude of disturbance to
foraging areas at Sheung Yue River would be low to moderate, impacts on other
foraging areas would be low or not of significance. |
Construction phase: until site is cleared
magnitude of disturbance impacts and impacts on flight-lines would be low to
moderate. Los of egretry site would be a low to moderate impact as egretry
would be lost but egretry is small, heavily disturbed and partly cleared, and
egrets could relocate. |
|
Overall Impact Severity |
Low to Moderate during construction phase due to
combination of impacts on flight-lines and foraging areas; Low during operational phase for the
same reasons. |
Low to Moderate severity as egretry is relatively small in
a Hong Kong context and changes in the location of egretries are not
infrequent. |
Disturbance impacts on
birds from increased levels of lighting and glare
Disturbance impacts arising from increases in lighting and associated
glare could have night-time impacts on birds. Experience elsewhere in Hong Kong
suggest that ardeids do not avoid roost sites in well-lit urban areas, as can
be seen by the examples of year-round roosts at Victoria Park, Penfold Park and
Tai Po Market.
Nocturnal or partially nocturnal birds may be adversely impacted if
light levels cause them to avoid areas, either because they are more vulnerable
to predation or their foraging efficiency is reduced. Conversely, some
nocturnal birds, such as nightjars and smaller owls, may forage around light sources
as these attract their insect prey. There has been no research on the
significance of avoidance or attraction effects in Hong Kong; accordingly,
following the precautionary principle, it is assumed that additional light and
glare is not beneficial to nocturnal bird species.
Light and glare is also known to adversely affect birds migrating at
night, causing them to become disorientated and, in some cases, to be killed if
they fly into obstacles or land in inappropriate locations. Rails are
particularly prone to such disorientation, but other species that migrate at
night, including many passerine birds, may also be affected.
Currently, the urban area of Sheung Shui and Fanling is brightly lit at
night, but light levels to the west and north of Long Valley are significantly
lower. With the implementation of the Project, brightly lit areas will,
potentially, extend to the west and northwest of Long Valley. Migrating birds
approaching the Long Valley area from these directions would, therefore,
additional disturbance impacts from light and glare in these areas.
Table 13.122 Potential
impacts from increased lighting or glare on large waterbirds, nocturnal birds
and migratory bird species in the absence of mitigation
|
Criteria |
Assessment |
|
Habitat Quality |
Wetlands of high ecological value support high numbers of waterbirds;
other habitats are of variable quality but all support some birds. |
|
Species |
Large waterbirds, nocturnal birds and migrant birds. |
|
Size/Abundance |
Numbers of large waterbirds in Long Valley are high, nocturnal bird
numbers are low but include species of conservation significance; numbers of
migratory birds in Long Valley are high and most habitats support at least
some migrant bird species. |
|
Duration |
Construction phase impacts will be short-term but operational phase
impacts are long-term. |
|
Reversibility |
To some extent reversible via installation of measures to minimise
impacts. |
|
Magnitude |
Impacts probably of low magnitude in terms of larger waterbirds and
nocturnal birds but may be low to moderate for migrant birds. |
|
Impact Severity |
Low for waterbirds, probably
Low for nocturnal birds, but may
be Low to Moderate from the main
commercial /business area to the west of Long Valley on migrating birds. |
Reptiles
Sixteen reptile species of conservation importance have been recorded in the Study Area: three Chelonians, four lizards and nine snakes.
The record of Three-banded Box Terrapin is of particular significance because the global population of this species is Critically Endangered. This species is associated with hill streams, usually where there is diverse and mature riparian woodland, in which the terrapins spend some of the time. The species could be significantly impacted by impacts on the Ma Tso Lung Stream, including impacts to the stream bed from channelisation, increased pollution load in the stream or damage to the riparian woodland.
Impacts on Reeve’s Terrapin are predicted to be low as the habitat where this species has been found (Long Valley) will not be developed and impacts on this habitat are not considered to be of significance for this species. Impacts on Chinese Soft-shelled Turtle are also predicted to be low as the habitats where this species has been found (Long Valley and the downstream tidal section of the Ng Tung River) will not be developed and other impacts on these habitats are not considered to be of significance for this species.
Five-striped Blue-tailed Skink is known from the Study Area on the basis of an observation from a local naturalists group and there is no other information on the status of the species in the Study Area. However, whilst there is no reason to doubt the report, the reported location of the observation (Ma Shi Po) is not typical of the usual forest or upland habitat of this species. Accordingly, any population in this area is likely to be small and not of significance at a species level. Accordingly, impacts on this species are predicted to be low on a precautionary basis.
Habitat where Burmese Python has been reported in KTN will not be developed, however the site where Burmese Python was recorded in FLN is not certain. As this species is widespread in Hong Kong, a single record of this species is of limited conservation significance, despite this species being of conservation importance. Accordingly, impacts on this species are predicted to be low on a precautionary basis.
Chinese Cobra was reported from active agricultural land in KTN (Maunsell 2003), but the location was not stated. An observation of a single record of this widespread species is of limited conservation significance, despite this species being of conservation importance. Accordingly, impacts on this species are predicted to be low on a precautionary basis.
Single observations of Banded Krait and Indo-chinese Rat Snake and two observations of Common Rat Snake have been made during surveys conducted for this and other projects or studies, and Buff-striped Keelback has been reported by local naturalists, in areas which will be developed under the project. All of these species are widespread in Hong Kong and there are large areas of habitat in the Study Area which are suitable for these species and which will not be affected by the project; however impacts on these species are predicted to be of low severity on a precautionary basis.
Observations of Indian Forest Skink, Copperhead Racer, Many-banded Krait, and King Cobra have been made where no works are proposed and that no significant disturbance impacts on reptiles, are predicted. No significant impacts are predicted on these species.
Records of Tokay Gecko and Common Water Monitor are considered to relate to escaped or released individuals, hence impacts on these species are not considered to be of significance.
Impacts on reptiles which may be of significance are summarized below.
Table 13.123 - Potential ecological impacts to reptiles in the absence of mitigation measures.
|
Criteria |
Assessment |
|
Habitat Quality |
Long Valley, habitats around Ma Tso Lung and
wooded habitats in the southeast of the Study Area are all of ecological
significance to reptiles. Lowland non-wetland habitats support some
habitat-generalist species at low densities. |
|
Species |
Reeve’s Terrapin,
Three-banded Box Terrapin and Chinese Soft-shelled Turtle are of Global
Conservation Concern; other species of conservation significance present. Of
these species, Three-banded Box Terrapin, Reeve’s Terrapin, Chinese
Soft-shelled Turtle, Five-striped Blue-tailed Skink, Burmese Python, Common
Rat Snake, Banded Krait, Chinese Cobra and Buff-striped Keelback may be
affected by the project. |
|
Size/Abundance |
Numbers generally low but detection is difficult. |
|
Duration |
Operational phase impacts will be permanent; construction phase
impacts will be temporary |
|
Reversibility |
Operational phase impacts irreversible; some construction phase
impacts reversible; some remediation possible in both phases. |
|
Magnitude |
Magnitude of impacts moderate as area is large
but numbers are small; magnitude of impact on Three-banded Box Terrapin also
moderate as impacts on preferred habitat relatively low. |
|
Overall Impact Severity |
Impacts on
Three-banded Box Terrapin Moderate due
to potential impacts on Ma Tso Lung Stream and stream corridor; Impacts on other
species Low or not significant. |
Amphibians
Amphibians are common in much of the Study Area, especially in wetland habitats and in the lowlands. Most species are common and widespread in Hong Kong and occur in a variety of habitats, though wetland habitats, or wet areas in other habitats are required for breeding and the larval (tadpole) stage of their life cycles. None of these common and widespread species are restricted to a few habitats or sites in the Study Area and in Hong Kong; hence species level impacts from the project are not considered to be significant.
Four amphibian species of conservation significance have been recorded in the Study Area and a fifth species, Short-legged Toad, has been found near Wo Hop Shek Crematorium, either within the Study Area or just outside it. Chinese Bullfrog has been found widely, albeit in low numbers in a variety of habitats both within and outside the Project Area; most observations are from the Ma Tso Lung Stream catchment. This species is relatively common in the northern New Territories. Two-striped Grass Frog has been recorded in Long Valley, and Lesser Spiny Frog and Brown Wood Frog have been found in plantation near Wo Hop Shek. A fifth species, Short-legged Toad has also been found in the Wo Hop Shek area and may occur in the Study Area. No impacts are predicted on habitats and species in this area which is outside and upstream of the Project Area boundary.
Table 13.124 - Potential Ecological Impacts
to amphibians in the absence of
mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Long Valley is of High ecological value; other
wetland habitats are of lower ecological value. Woodland habitat at Wo Hop
Shek supports three species of conservation significance. |
|
Species |
Lesser Spiny Frog
and Short-legged Toad are of Global Conservation Concern, Chinese Bullfrog is
of Potential Regional Concern, Brown Wood frog and Two-striped Grass Fog are
of Local Concern. Other species are not of conservation concern. |
|
Size/Abundance |
Chinese Bullfrog is
widespread, but numbers are low; numbers of other species of conservation
concern appear to be small. Species which are not of conservation concern are
common in much of the Study Area, especially in lowland wetlands. |
|
Duration |
Permanent for operational phase impacts;
temporary for construction phase impacts. |
|
Reversibility |
Operational phase
impacts would be irreversible; some construction phase impacts reversible;
remediation possible in both phases. |
|
Magnitude |
Magnitude would be low to moderate on Chinese
Bullfrog as area of habitat impacted is large, but numbers are small and
species is widespread in the New Territories. Magnitude of impact on other
species of conservation significance is low or no impact is predicted, as
impacts on amphibians in habitats/areas where these species are present are
small or no impacts are predicted. Magnitude of impacts on other species is
low as species are common and widespread in the Study Area and in Hong Kong |
|
Overall Impact Severity |
Impact on Chinese
Bullfrog Low to Moderate as
relatively common in Hong Kong and number of individuals impacted will be
relatively low. Impacts on other species Low
or not significant. |
Butterflies
Butterfly diversity is relatively high in the Study Area and fifteen species of conservation significance have been found. Most of these have been found in the Ho Sheung Heung area, Crest Hill and in the area around Long Valley (including Tsung Pak Long). Elsewhere in the Study Area there do not appear to be any habitats and areas of particular significance for butterflies; four butterfly species of conservation significance (Pale Palm Dart, Spotted Angle, Danaid Egg-fly and Small Three-ring) have been found in the Ma Tso Lung area in scattered locations. All of these species are largely associated with non-woodland habitats, including grassland and wetlands. The most important habitats for butterflies in the Study Area are woodland and shrubland at Ho Sheung Heung and Crest Hill, which support a high diversity of butterfly species in addition to a high proportion of the species of conservation significance found in the Study Area. This high diversity is likely to be due to the relatively high diversity of plant species found in this habitat, providing food plants for butterfly larvae and nectar sources for adult butterflies. In comparison, agricultural land and lowland grassland are species-poor habitats, but a few species of conservation significance have been recorded in Long Valley and in FLN.
Habitats supporting a high diversity of butterflies, woodland and grassland in the Ho Sheung Heung and Crest Hill areas, will only experience limited impacts from the Project, and impacts on butterflies in these habitats are predicted to be small. Impacts on butterflies from the project in other areas are predicted to be small, as species are not present in numbers of significance in a Hong Kong context.
Of species of conservation significance, one species associated with woodland and orchards, Peacock Royal, was recorded in upland plantation near Fung Kong Shan in KTN. Most of this plantation area will not be directly impacted by the project, though a small area will be lost due to road construction and development in open space zone KTN E1-7. Since little habitat will be lost, impacts on this species are predicted to be low. Another species, Commander, was found in a development area north of Ma Shi Po. This is primarily a species of hillside shrubland and woodland (Lo and Hui 2010); consequently impacts are considered to be low at a species level. Habitat loss for other butterfly species is not predicted to be significant, so impacts on all other species from the project are predicted to be low or insignificant.
Table 13.125 - Potential Ecological Impacts
to butterflies in the absence of
mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Woodland and shrubland at Ho Sheung Heung and
Crest Hill are of high ecological importance for butterflies. The habitats
in the Ma Tso Lung area are of low to moderate ecological importance. Other
habitats are of lower quality for this group. |
|
Species |
Fifteen species of
conservation significance recorded, most in the Ho Sheung Heung area. Of
these species, there will be low impacts or no impacts on habitats and areas
of significance for these species; hence impacts on these species are
predicted to be low or insignificant. One species, Commander, found near Ma
Shi Po was found in atypical habitat, species level impacts on this species
are predicted to be low. Impacts on all other butterfly species are
predicted to be low as habitat loss is not predicted to be of significance
for this group. |
|
Size/Abundance |
Area of woodland
habitat at Ho Sheung Heung is small and area of shrubland at Crest Hill is
moderately large. However, areas where impacts will be of significance to
butterflies are small. Butterfly numbers in the Study Area as a whole are
not considered unusual in a Hong Kong context. |
|
Duration |
Construction phase impacts would be temporary
but habitat loss would be permanent. |
|
Reversibility |
Operational phase
impacts would be permanent; some construction phase impacts reversible;
remediation possible in both phases. |
|
Magnitude |
Magnitude of construction phase impacts small
as a small area of habitat would be impacted. Magnitude of operational phase
impacts small or very small. |
|
Overall Impact Severity |
Construction phase
impacts of Low severity,
operational phase impacts of Low severity
or are not significant. |
Dragonflies
Eight dragonfly species of
conservation significance have been recorded in the Study Area, Blue Sprite,
Orange-backed Threadtail, Dingy Dusk-hawker, Blue Chaser, Ruby Darter, Sapphire
Flutterer, Scarlet Basker and Emerald Cascader. Of these, Dingy Dusk Hawker,
found in a mitigation wetland in FLN is the only species predicted to be
directly impacted by the Project. However, this species is common in Hong Kong
and tends to be under-recorded during surveys as it is a crepuscular species
and hence impacts of habitat loss on this species are not predicted to be
significant. All species may, however, be impacted by run-off or pollution
impacts on water bodies utilised for breeding. Such
impacts may be of significance on one species, Ruby Darter, which occurs
downstream of the section of Ma Tso Lung Stream which will be diverted.
Table 13.126 - Potential Ecological Impacts to dragonflies
in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Pond and stream habitats required by
dragonflies are widespread but unpolluted streams are few, hence most
species present are found in lentic water bodies. Siu Hang San Tsuen Stream,
streams in the Kau Lung Hang EIS and Ma Tso Lung Stream are all relatively
clean and support dragonfly species of conservation significance. However,
the species present at Ma Tso Lung Stream, Ruby Darter, is a species of
lotic waters. |
|
Species |
Dragonfly species
are wetland-dependent for part of their life cycle; wetlands in the Study
Area support a moderate diversity of dragonflies; most are species of lotic
waters. Eight species of conservation significance are known from the Study
Area; two of these species, Dingy Dusk-hawker and Ruby Darter occur in
habitats where impacts from the project are predicted in the absence of
mitigation. However, Dingy Dusk-hawker is considered to be common in Hong
Kong and Ruby Darter is tolerant of sediments and organic pollutants. |
|
Size/Abundance |
Areas utilised by
species of conservation significance are small, hence number of individuals
probably relatively low. In other wetland habitats, dragonflies occur in
numbers typical of such habitats in Hong Kong; since wetland habitats are
relatively common in the Project Area, it follows that the number of
dragonflies in the Project Area is proportionate. However, the area of
wetland habitats in the Project Area which will receive impacts of
significance to dragonflies is small; a proportionate impact of the project
on dragonfly numbers is, therefore, predicted. |
|
Duration |
Operational phase impacts would be permanent;
construction phase impacts would be permanent. |
|
Reversibility |
Operational
impacts will be permanent. Construction phase impacts will be permanent and
include loss of mitigation wetland; some remediation possible for
construction phase impacts. |
|
Magnitude |
Small for all species,
especially during the operational phase of the project |
|
Overall Impact Severity |
Low severity or are not significant during both
construction and operational phases of the project. |
Aquatic Fauna (including Fish)
Fish and freshwater invertebrates in the Study Area are fairly typical of wetland areas in Hong Kong. As many wetlands in the Study Area are disturbed, and water is lotic or polluted, fish and invertebrate fauna in many of these areas is dominated by species which are tolerant of pollution and/or low oxygen levels. The Siu Hang San Tsuen Stream, streams in the Kau Lung Hang Watercourses and the Ma Tso Lung Stream have relatively good water quality and the fish and invertebrate community in these streams reflects this.
Three species of fish and the crab Somanniathelphusa zanklon are the only aquatic fauna of conservation significance that have been recorded in the Study Area. Somanniathelphusa zanklon has been found in Ma Tso Lung San Tsuen Stream, Chau Tau Watercourse, Tung Fong Watercourse, Sheung Shui Wa Shan Eastern Watercourse, Tin Ping Shan Tsuen Watercourse and in the Ma Wat Wai Watercourse. Single individuals were found in all these locations except in Ma Tso Lung San Tsuen Stream where a total of five individuals were found at two locations. This species is listed as globally Endangered; however, it is found in a wide variety of lotic water bodies including paddies and is tolerant of organic pollution. Surveys conducted for the LMC Loop Study also found this species at another location outside the area covered by the current study (Hoo Hok Wai); it seems that this species may not be highly restricted in its distribution in Hong Kong.
Tung Fong and Tin Ping Shan Tsuen Watercourses, which are largely engineered, will be lost as a consequence of the project; and Ma Tso Lung San Tsuen Stream may be impacted by run-off from the development of KTN area F1-4 in the absence of mitigation measures. No impacts of relevance to Somanniathelphusa zanklon are predicted at Sheung Shui Wa Shan Watercourses and the Ma Wat Wai Watercourse as the locations where it was found in these streams were upstream of the short sections of the lower streamcourses which will be affected by this project. No impacts on the Chau Tau Watercourse, which is outside the boundary of the Project Area, are predicted. However, impacts on Somanniathelphusa zanklon due to pollution and potential hydrological disruption on the Ma Tso Lung Stream system during the construction phase may be of Moderate significance in the absence of mitigation.
The fish species, Acrossocheilus parallens, Predaceous Chub and Small Snakehead, are all native, though some of the individuals of the last of these species may be of captive origin. Impacts on Small Snakehead in the Ma Tso Lung San Tsuen Stream, due to run-off arising from development of adjacent areas entering the stream, are predicted to be of Moderate significance in the absence of mitigation. Acrossocheilus parallens is widespread and Small Snakehead is present in streams in the Kau Lung Hang EIS; while Predaceous Chub is common in the upper reaches of the Siu Hang San Tsuen Watercourse. All locations where these fish species of conservation significance have been found in these streams are well upstream of locations where impacts from the project are predicted.
Table 13.127 - Potential Ecological
Impacts on fish and other aquatic fauna in the absence of mitigation measures
|
Criteria |
Impacts to Fish |
Impacts to aquatic fauna |
|
Habitat Quality |
Siu Hang San Tsuen Stream (where Predaceous
Chub present) is of Moderate ecological value; streams in the Kau Lung Hang
Stream Watercourses (where Acrossocheilus
parallens and Small Snakehead are present) are of Moderate ecological value and
Ma Tso Lung San Tsuen Stream (where Small Snakehead is present) is of
Moderate to High value. |
Tolerant of pollution and found in streams of varying quality: Ma Tso
Lung San Tsuen Stream is of Moderate to High ecological value; Tung Fong and
Tin Ping Shan Tsuen Watercourse are
of Low ecological value. Sheung Shui Wa Shan Streams and the Ma Wat
Wai Watercourses where Somanniathelphusa zanklon was found are all engineered but evaluated
as of Low to Moderate ecological value due to the presence of this species. |
|
Species |
Acrossocheilus parallens is of Global Concern;
Predaceous Chub is of Regional Concern, and Small Snakehead is of Local
Concern. Other species are not of conservation significance. |
Somanniathelphusa zanklon is listed as Globally
Endangered but evidence from this and the LMC Loop Study suggest that this
species is fairly widespread in streams in the northern New Territories. |
|
Size/Abundance |
Streams where
species of conservation significance were found are small; however both the
Ma Tso Lung and Kau Lung Hang Stream systems are moderate in size. Acrossocheilus
parallens and Predaceous Chub found in large numbers where present;
numbers of Small Snakehead are probably small. |
Ma Tso Lung Stream
system is moderate in size; other streams are small. Single individuals of Somanniathelphusa
zanklon at each location except in Ma Tso Lung San Tsuen Stream where several
individuals were found and population is likely to be larger. |
|
Duration |
Construction phase impacts will be temporary
and operational phase impacts will be permanent on the Ma Tso Lung Stream
system. No significant impacts are predicted to
stream sections occupied by fish species of conservation significance at Siu
Hang San Tsuen Stream and streams in the Kau Lung Hang Watercourses. |
Tung Fong and Tin Ping San Tsuen Streams will
be permanently lost. Construction phase impacts will be temporary
and operational phase impacts will be permanent on the Ma Tso Lung Stream
system. No impacts of significance are predicted on stream habitat utilised
by Somanniathelphusa zanklon at Sheung Shui Wa Shan and Ma Wat
Wai Watercourses as all impacts will be downstream of areas which are
suitable for this species. |
|
Reversibility |
Reversible and
remediation measures possible. |
Reversible and
remediation measures possible at Ma Tso Lung San Tsuen
Stream; loss of Tung Fong and Tin Ping San Tsuen Watercourses
will be irreversible. |
|
Magnitude |
Magnitude on Small Snakehead low as this species is relatively
tolerant of sediment load and organic pollution. |
Magnitude low to moderate at Tung Fong and Tin Ping San Tsuen
Watercourses as these will be lost, however area of suitable habitat for Somanniathelphusa
zanklon is small and population of this species appears to be
low. Magnitude of indirect impacts on
other streams low as this species is tolerant of turbid conditions and
organic pollutants. |
|
Overall Impact Severity |
Construction phase
impact on Small Snakehead at Ma Tso Lung San Tsuen Stream Moderate and Low to Moderate during operational phase, no other significant
impacts. |
Low at Tung Fong and Tin Ping San Tsuen Streams as number of individuals which may be directly impacted is likely to
be small. No impacts of significance are predicted on stream habitat
utilised by Somanniathelphusa zanklon at Sheung Shui Wa Shan and Ma Wat
Wai Watercourses. Low to Moderate impact at Ma Tso Lung San
Tsuen Stream during construction and operational phases, due to potential
pollution and hydrological impacts, as population in this stream is very
likely larger and of more significance than at the other streams where it
may be impacted. |
13.7.5 Cumulative Impacts
13.7.5.1 Potential geographical scope of impacts
The Project is entirely within the catchment of the Deep Bay area wetland ecosystem, with which it has direct linkages through the hydrological connection of the Ng Tung River and the Ma Tso Lung Stream via the Shenzhen River. Functional linkages also exist with wetland habitats in the Deep Bay wetland ecosystem for wetland-dependent birds. In addition there are also more localized linkages through the connection of the Ng Tung and the Shenzhen Rivers, through the riparian corridor of the Ma Tso Lung Stream and, perhaps, in the Pak Shek Au area, some of which is within the catchment area of the Eastern Main Drainage Channel for San Tin.
Linkages are also present in respect of terrestrial upland habitats, mainly grassland, to the north and west of the Study Area as far west as Chau Tau, and in grassland, shrubland and plantation/woodland to the east of the Ng Tung River as far north as the HKSAR boundary and as far east as Ping Yuen River. Linkages to the east are much less significant due to the existing developed areas of Fanling.
Linkages to the south are, in general, much less significant as the existing urban area of Sheung Shui, Fanling and the Fanling Highway form a major ecological barrier. The exception to this relates to the extreme southeast of the Study Area, where upland habitats to both the southwest and southeast of Fanling Highway are connected directly with those in upland areas beyond. Linkages for lowland habitats are largely severed by the urban area of Fanling as the riparian corridor is developed; however, the channelised Ma Wat River is directly linked to the ecologically important Kau Lung Hang Streams.
With regard to specific sites of conservation importance outside the Study Area, these are all part of the Deep Bay wetland ecosystem, and are thus covered below in consideration of potential impacts on the latter and its wetland habitats.
13.7.5.2 Significance of Cumulative Impacts
Cumulative impacts are those arising from a development in combination with other developments in the area, and include those that are incremental, synergistic or interactive. The first of these comprises the straightforward, additional marginal impact of further development, while the second involves two impacts for which the whole effect is greater than the sum of its parts. The third involves impacts that arise in other areas, which then have knock-on effects in further areas, or in the original area. Such impacts may or may not reach a new equilibrium depending on the nature of the impacts. In terms of this Project, developments for which the cumulative impacts require to be addressed were detailed in Section 13.2.
It is important to note that the existence of other developments in an area means that further developments may impose proportionately greater impacts, as the initial impact already imposes stresses on the ecosystem. For example, should a flight-line have already been impacted by disturbance impacts of a development, the marginal effect of a relatively minor further source of disturbance may be sufficient to cause substantial loss of flight-line function due in large part to the impact of the initial disturbance source.
Cumulative Direct, Indirect Impacts and
Fragmentation impacts on Wetland habitats (including the Deep Bay ecosystem)
and Fauna
The major residential projects in the Deep Bay area listed in Section 13.2.3 all have the potential to impact wetland habitats, at least indirectly. These development projects will, however, be guided by the EIAO process and Town Planning Board Planning Guideline No.12B, and direct loss of wetland habitat should not occur. Accordingly, no cumulative impacts of significance are predicted in respect to direct impacts most wetland habitats. The one exception to this is in respect to cumulative loss of seasonally wet grassland arising from the current project and the LMC Loop project at Ma Tso Lung. A loss of 2.86ha of this habitat is predicted under the current project and 0.19ha is predicted to be lost under the LMC Loop project. The significance of the cumulative impact of this loss is evaluated below.
Most indirect impacts of other planned and concurrent
projects on wetland habitats are expected to be kept within acceptable levels
by the EIA and planning systems and hence cumulative impacts are not predicted
to be of significance, especially in view of the geographical distance of most
projects, which have the potential to cause indirect impacts on wetland
habitats, from the NDA Project Area. This applies, in particular, to
disturbance impacts and impacts of hydrological disruption and pollution, most
of which are localised to the vicinity of the source of the impact.
However, there are two potential exceptions to this
which apply in respect to the current project and the LMC Loop project: the LMC
Loop Eastern Connection Road, which is an element of both the current project
and the LMC Loop project, which has the potential to result in significant
indirect impacts on Ma Tso Lung Stream and ecologically linked riparian wetland
habitats and their fauna; and the LMC Loop project as a whole, which has the
potential to result in significant hydrological and pollution impacts on the
Deep Bay ecosystem - cumulative impacts with the current project may be of
significance as both projects are upstream of the ecosystem and are
hydrologically linked to it.
In addition, potential cumulative indirect impacts may
arise from the current project and the construction of Cycle Tracks and
Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River on Long
Valley and the Sheung Yue, Ng Tung and Shek Sheung Rivers.
Potential cumulative indirect impacts may arise from
the current project and the Liantang/Heung
Yuen Wai Boundary Control Point and Associated Works project on the Ma Wat
River and the Kau Lung Hang Stream system.
Lastly, potential cumulative impacts on the Tsung Yuen Watercourse may arise from the current
project and the channelization works to this stream proposed to be carried out
by Drainage Services Department (DSD).
Fragmentation of linkages between wetland habitats
cumulative with the Project is not considered to be of significance in respect
to most projects, as the NDAs are at the southeastern limit of the geographical
scope of ecological linkages and these projects do not lie between the Project
area and the main Deep Bay wetland area. However, the LMC Loop project lies
between the NDA Project Area and the main wetland area of Deep Bay, and hence
there is the potential for this linkage to be interrupted, either by
development within the LMC Loop or to the north of Long Valley.
In this regard, as no significant development north of Long Valley is proposed, the only source of cumulative impact on this linkage appears to be that in relation to birds that fly over the LMC Loop to/from Long Valley. While there are significant linkages for waterbirds between Long Valley and the Deep Bay wetlands, these are primarily to the areas to the east of the LMC Loop and the number of individuals moving between Long Valley and areas to the west of the Loop is unlikely to be large. Although Black-faced Spoonbill is known to be one species which does move between the two areas, the number of individuals visiting Long Valley is small relative to the numbers in Deep Bay and hence any impacts on the Hong Kong wintering population are predicted to be minor.
Cumulative indirect impacts, in particular disturbance to waterbird species of conservation significance, are potentially also of significance should a reduction in numbers occurring in the area of the Project impose greater strain on other parts of the Deep Bay wetland ecosystem. In this respect, disturbance to Long Valley and the Ng Tung, Shek Sheung and Sheung Yue Rivers, which support moderate to large numbers of some of these species in a Deep Bay context, could contribute to cumulative adverse disturbance impacts in the absence of mitigation. Given that the Deep Bay wetland ecosystem is largely undeveloped, as long as effective mitigation for impacts on these large channelised watercourses is put in place by this Project, then cumulative impacts are not predicted to occur elsewhere.
Also of potential cumulative significance is the type of wetland that would be lost. Long Valley is unusual compared to other wetland habitats within the Deep Bay catchment in that it comprises a large contiguous area of managed freshwater wetland habitats, including wet agricultural land, in a complex microhabitat mosaic. As a consequence, while all the species of conservation importance in Long Valley, in particular large waterbirds, are also present and comparatively abundant in Deep Bay wetland habitats, and that the composition of the wetland bird community in Long Valley differs significantly, as the latter is of particular importance for species with a habitat preference for one or more of the freshwater wetland habitats present there. Accordingly, no significant cumulative adverse impacts to these species are anticipated so long as appropriate mitigation measures are in place.
In addition to cumulative fragmentation impacts on
linkages for birds between wetland habitats in the Deep Bay ecosystem,
cumulative impacts on terrestrial fauna using wetland habitats in the Ma Tso
Lung area may arise from the impacts of the current project and the LMC Loop
projects. Such impacts are addressed in the evaluation of cumulative impacts on
the Ma Tso Lung Stream and its riparian corridor below.
Cumulative Impacts of the Current Project and
the LMC Loop Project on Ma Tso Lung Stream, its riparian corridor and Fauna
Ma Tso Lung Stream and its riparian corridor (including Ma Tso Lung Marsh), support, or potentially support, a number of wetland-dependent or associated species of conservation significance, notably Three-banded Box Terrapin (recorded in its natural upstream/midstream section), and a number of species that have been found in and around the partially channelised downstream section of the stream and its tributaries, and in Ma Tso Lung marsh, just within the northwestern boundary of the Study Area for this project.
However, the section of the Ma Tso Lung Stream and the stream corridor where significant cumulative impacts may occur is not likely to be of major importance to Three-banded Box Terrapin, which favours more wooded riparian areas, but it is possible that it may utilise the area on occasion. Furthermore, the area where significant cumulative impacts are predicted in the absence of mitigation is of importance, or potential importance, for other species of conservation significance. Accordingly, the combined potential adverse cumulative impacts on this area and its fauna from the two projects have the potential to be significant in the absence of mitigation, especially during the construction and operational phases of the road and the construction phase of other elements of the NDAs project.
Potential cumulative impacts on Ma Tso Lung Stream and its corridor are addressed in Table 13.127a below.
Table 13.127a – Severity of Cumulative Impacts on Ma Tso Lung
Stream and Riparian Habitats in the absence of mitigation measures
|
Habitat |
NDA
Project |
LMC
Loop Project |
Cumulative
Impact |
|
Ma Tso Lung Stream and tributaries |
Disturbance: Low
during construction and operation. Run-off and
hydrological disruption: Moderate during construction and Low to Moderate
during operation. Fragmentation:
Moderate during construction and operation. |
Disturbance: Low. Run-off: Moderate
in lower section during construction and Low to Moderate during operation in
lower section. Hydrological
disruption: potentially Moderate. Fragmentation: of
potential significance for mammals and herpetofauna. |
Disturbance: Low during construction and
operation. Run-off: Moderate during construction
and Low to Moderate during operation as most impacts are partly on different
stream sections. Hydrological
disruption: Moderate during
construction and operation. Fragmentation: Moderate during construction and
operation. |
|
Ma Tso Lung Marsh |
Disturbance, hydrological disruption and run-off
impacts all Low during both construction and operation. |
Disturbance, hydrological disruption and run-off
impacts all Low during both construction and operation. |
Disturbance, hydrological disruption and run-off
impacts all Low during both construction and operation. |
|
Seasonally wet grassland |
Direct impact:
permanent loss of 2.86ha (Low to Moderate). Disturbance, run-off and hydrological disruption:
Low to Moderate during construction and Low during operation. |
Direct impact: loss
of 0.19ha (Low to Moderate). Disturbance, run-off and hydrological disruption:
Low during construction and operation. |
Direct impact
permanent loss of 3.05ha (Low to Moderate as combined area is low). Disturbance, run-off and hydrological disruption: Low to Moderate during construction Low during operation. |
|
Deep Bay Ecosystem |
Run-off impacts of
Low to Moderate severity during construction and Low during operation. Impacts of most pollution events most likely Low to
Moderate during construction and Low during operation but dependent on nature
and scale of event. Fragmentation impacts on linkages for large
waterbirds: Low during construction and not significant during operation. |
Combined effect of sedimentation (Low to Moderate)
and pollutant run-off (Low to High, depending on nature of event). |
Cumulative run-off
impacts of Low to Moderate severity during construction
and operation. Cumulative impact of pollutant run-off Low to High depending on location of
event and type of pollutant. Cumulative fragmentation impacts not of
significance as low construction phase impacts on linkage between LMC Loop /
Hoo Hok Wai area and Ho Sheung Heung and Long Valley are not cumulative with
any fragmentation impacts of the LMC Loop project as different species/birds
are involved. |
|
Fauna of conservation
significance |
Moderate
fragmentation impact on fauna using the main stream during construction and
operation. Low impact on fauna using the tributaries during construction and
operation. Combined impacts on
Three-banded Box Terrapin Moderate during construction and operation. Combined impacts on Small Snakehead and Somanniathelphusa zanklon Moderate
during construction and Low to Moderate during operation. |
Combined impacts on
mammals, largely due to fragmentation, Moderate during construction, Low to
Moderate during operation. Low to Moderate or
Moderate combined impact of fragmentation and habitat loss on herpetofauna
during construction; Low to Moderate combined impact of habitat loss and
fragmentation on other herpetofauna. Moderate from combined impacts during
construction and operational phases on Three-banded Box Terrapin. Combined impacts on Small Snakehead and Somanniathelphusa zanklon Moderate
during construction and Low to Moderate during operation. |
Moderate during construction and
operation on mammals and herpetofauna, but perhaps Moderate to High on Three-banded Box
Terrapin during construction and operation and on Small Snakehead and Somanniathelphusa zanklon during
construction |
Cumulative
Impacts of the Current Project and the Cycle Tracks and associated supporting
facilities from Sha Po Tsuen to Shek Sheung River on Long Valley and the Sheung
Yue, Ng Tung and Shek Sheung Rivers and their Fauna
An EIA Report has been approved for the construction of the Cycle Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River project. This project will result in a cycle track being constructed along the west bank of the Sheung Yue River, across the Sheung Yue River (utilising an existing bridge), and along the west bank of the Shek Sheung River. Mitigation measures to address potential impacts of this project, including restrictions on construction phase working during the ardeid (and Greater Painted-snipe) breeding season, and screen planting are included in the Environmental Permit for this project. With the implementation of the recommended mitigation measures, no significant residual impacts are anticipated under the Cycle Track project.
Works under the current project will, therefore, have to be undertaken in such a way that the mitigation measures for the cycle track project are not compromised. In addition, any cumulative increase in disturbance and fragmentation impacts will have to be addressed under the current project. Of most significance in this respect is any increase in disturbance and fragmentation impacts on ardeids breeding at the Ho Sheung Heung Egretry and foraging in Long Valley and on the Sheung Yue River. Other bird species breeding in Long Valley and/or foraging on the Sheung Yue, Shek Sheung and Ng Tung Rivers may also be affected, albeit to a lesser extent.
The Cycle Tracks project is scheduled to be completed well ahead of the commencement of the NDAs project. Accordingly, so long as mitigation measures implemented under the Cycle Tracks project are not impacted by the NDAs project, no significant cumulative impacts are predicted.
Cumulative Impacts of the Current Project and
the Liantang/Heung Yuen Wai
Boundary Control Point and Associated Works project on the Ma Wat River
and Kau Lung Hang Watercourses
Cumulative impacts of hydrological disruption and sedimentation and impacts on stream and riparian fauna could arise during the construction and operational phases of the current project and Liantang/Heung Yuen Wai Boundary Control Point and Associated Works project on the Ma Wat and Kau Lung Hang Watercourses. The ecological value of the sections of these watercourses potentially impacted has been assessed as low in both studies. Ecological impacts of hydrological disruption have been assessed as negligible in the EIA Report for the Liantang/Heung Yuen Wai Boundary Control Point and Associated Works project and as Low to Moderate during construction and Low during operation under the current study. Accordingly, there are no significant cumulative impacts on these channels.
Cumulative
Impacts of the Current Project and the DSD Project to Channelise the Tsung Yuen
Watercourse
Tsung Yuen Watercourse will not be impacted by the current Project but is scheduled to be channelised by DSD in 2013 to 2016. The section to be channelised is already artificial in that it has been ‘informally’ channelised by residents. There will, therefore, be no cumulative loss of natural watercourses arising from the current Project and the DSD project. Other significant impacts arising from the DSD channelisation works (if identified) will require to be addressed by that project.
Cumulative Impacts on Woodland Habitats
Implementation of the current project will result in a substantial area loss of wooded habitats (93.06ha), albeit much of this comprises roadside plantations of low ecological value (73.43 ha). In addition, however, 8.65ha of hillside plantation of low to moderate ecological value, 10.75ha of mitigation plantation and 0.23ha natural secondary woodland would be lost. Loss of woodland of considerable significance can be mitigated under the Project either by provision of ecological compensation woodland or landscape planting (detailed in Chapter 12). In addition, the consolidation of the proposed ecological compensation woodland into two large blocks will, once sufficient maturity is reached, result in a net ecological benefit as moderately large areas of contiguous secondary woodland are currently absent from the Study Area (see Section 13.8).
In terms of cumulative loss in regard to other projects, the LMC Loop Project would lead to very limited woodland loss (1.26ha). This loss will be fully mitigated under the Project via compensatory planting at or near the site of loss.
Loss of woodland arising from other projects in the area is of relatively low magnitude, and is compensated by replacement planting. Loss associated with Construction of Cycle Tracks and associated supporting facilities from Sha Po Tsuen to Shek Sheung River, and at Nam Sang Wai, Yuen Long (Atkins China 2008) comprises a total of 1.15ha of plantation and woodland (0.78ha of which is mitigation plantation along the Sheung Yue and Shek Sheung Rivers). This will also be compensated by replacement planting under relevant projects.
Total loss arising from development of the Liantang/Heung Yuen Wai Boundary Control Point and associated works is 6.2ha, the majority of which is located 170m away from the NDA Project boundary, while woodland compensation comprises 18.6ha (Mott MacDonald 2010). In regard to the Provision of Cremators at Wo Hop Shek Crematorium, total woodland loss is 0.25ha, while compensation constitutes 0.28ha (Hyder 2008). No significant residual impacts are envisaged under these concurrent projects.
In summary, combined woodland loss from the other projects is small and will be fully mitigated. Accordingly, cumulative loss of woodland with other projects is evaluated as acceptable with mitigation.
Cumulative impacts on Upland Grassland and Shrubland
Both upland grassland and shrubland are very common
and widespread habitats in the northern New Territories. None of the concurrent
and planned projects will have more than a low quantitative and quantitative
impact on these habitats individually, and the cumulative loss is likewise
small relative to the overall habitat area. Accordingly, cumulative impact on
these habitats is not considered to be of significance.
Cumulative impacts on Eurasian Otter
The Hong Kong population of globally-threatened Eurasian Otter is likely to be of regional significance. Although there is only a single observation of Eurasian Otter within the Study Area for the Project (at Sandy Ridge, distant from the development footprint), and no direct, indirect or fragmentation impacts on the species are predicted from the Project on the area where the sighting was made, Eurasian Otter has regularly been recorded at Hoo Hok Wai, and it may occasionally occur in the Ma Tso Lung valley as it has been seen in similar closed wetland habitats of marsh or vegetation-choked watercourse elsewhere in the northern New Territories (Study Team pers. obs.).
Accordingly, cumulative impacts of loss of habitat and disturbance impacts on Eurasian Otter are not predicted, as the additional habitat loss and potential disturbance arising from this Project will be insignificant. Direct mortality as a consequence of Eurasian Otters being killed on any at-grade sections of the Eastern Connection Road within the NDA project area is possible. However, in view of the lack of open water habitats in the Ma Tso Lung area, both otter abundance and frequency of occurrence are likely to be low; hence the potential impact of direct mortality is predicted to be of low severity.
No significant cumulative impacts on other habitats or other fauna are predicted to arise from the current project and other planned or concurrent projects.
Cumulative impacts on Sommaniathelphusa zanklon
Impacts on this species that might be cumulative are relevant only in respect of the LMC Loop Project, under which study the species was recorded. However, the impacts on the species were assessed as of low significance, as they are under this Study. Consequently, it is not predicted that significant cumulative impacts will result.
13.8.1 Summary of Ecological Impacts
In Section 13.7 potential ecological impacts were presented and categorised as to whether these were impacts to habitats or species. Assessment of potential impacts to habitats took into account which species or species groups were found to be associated with, or dependent on, these habitats. Likewise, assessment of potential impacts to species took into account the habitats in which these species were found and their association with or dependence on these habitats and their connectivities.
In this section, the total impacts of all elements (except cumulative impacts which were addressed in Section 13.7.5) are presented (quantitatively where possible), and their severity is assessed in the absence of mitigation.
Table 13.128
- Potential Total Direct, Indirect and Fragmentation and Impacts on Habitats
and their severity in the absence of mitigation measures
|
Habitat |
Direct Impacts |
Indirect and Fragmentation Impacts |
|
Long Valley |
·
No
direct impact. |
·
Disturbance
of Long Valley habitats (Low Severity during construction and
operation). ·
Dust
deposition, increased sediment and nutrient load: construction phase Low during construction and
operational phase. ·
Hydrological
disruption of Long Valley habitats (Low
to High during both
construction and operational phases depending on duration and season). ·
Pollution
of Long Valley habitats dependent upon type, but most likely Low to Moderate during construction
and Low during operation. ·
Fragmentation
impact on Long Valley Low to Moderate during
construction and Low during
Operation except on some waterbirds in the southwestern part of Long Valley
which is closest to proposed development areas where impact severity will
remain Low to Moderate. ·
Combined
disturbance and fragmentation impacts Low
to Moderate during construction and Low
during operation. |
|
Wet Agricultural land |
·
Permanent
loss of 0.58ha (Low to Moderate) |
·
Low during construction/operation. |
|
Dry Agricultural Land |
·
Permanent
loss of 9.33ha (Low). |
·
Low during construction/operation. |
|
Pond |
·
Permanent
loss of 3.08ha. Low for small
fragmented ponds (0.82ha) and Low to
Moderate (0.59ha) and Moderate (0.37ha) for larger ponds and/or with
significant ecological linkages. |
·
Disturbance
of pond (Low to Moderate during
construction and Low during
operation. ·
Run-off,
hydrological disruption and fragmentation (Low during construction and operation. ·
Combined
impacts Low to Moderate during construction and Low during operation. |
|
Marsh at Ma Tso Lung |
·
No
direct impact. |
·
Disturbance
(Low during construction and
operation). ·
Run-off
and hydrological disruption (Low
during construction and operation. ·
Combined
impacts Low during construction
and operation. |
|
Mitigation Wetland (other than area in Long Valley) |
·
Loss
of 2.75ha (Low to Moderate. |
·
Disturbance
on FLN area A1-7 (Low during
construction and operation). ·
Run-off,
hydrological disruption and pollution on FLN area A1-7: Low during construction and not significant during operation. ·
Fragmentation
impacts on FLN area A1-7) Low to
Moderate during construction; Low
during operation. ·
Combined
impacts Low to Moderate during construction and Low during operation. |
|
Major Channelised Watercourse |
·
Permanent
loss of < 0.02ha (Low
severity); construction phase loss due to cofferdam construction also of Low severity as area will be small
relative to the size of the rivers. |
·
Disturbance
impacts on Sheung Yue River (3300m): Moderate
during construction, Low during
operation. ·
Disturbance
impacts on non-tidal Ng Tung River (4000m): Low to Moderate during construction and Low during operation. ·
Disturbance
impacts on tidal Ng Tung River (650m): Low
during construction and not significant during operation. ·
Disturbance
impacts on Shek Sheung River (2300m): Low
during construction and not significant operation. ·
Fragmentation
impact between non-tidal Ng Tung River and Long Valley Low to Moderate during
construction and Low during operation;
Low on tidal section during
construction but not significant during operation; fragmentation impacts on
other rivers not of significance. ·
Hydrological
impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers (Low severity); ·
Run-off
and pollution impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers (Low during construction and operation
for most events but certain construction stage pollution events could be of Moderate severity). ·
Combined
impacts on Sheung Yue River Moderate
during construction and Low to
Moderate during operation. ·
Combined
impacts on tidal section of the Ng Tung River Low during construction and not significant during operation. ·
Combined
impacts on non-tidal Ng Tung River Low
to Moderate during construction and Low
during operation. ·
Combined
impacts on Shek Sheung River Low
during construction and operation and not significant during operation. |
|
Ma Tso Lung Stream and tributaries and riparian corridor (including
fragmentation impacts on marsh and seasonally wet grassland) |
·
Diversion
of 130m of Ma Tso Lung Stream in its lower reaches (Moderate) and 120m of tributaries in their upper reaches (Low). |
·
Disturbance
impacts on Ma Tso Lung Stream: Low during
construction and operation. ·
Run-off
and hydrological impacts on Ma Tso Lung Stream Moderate during construction and Low to Moderate during
operation. ·
Fragmentation
impact on Ma Tso Lung Stream and riparian corridor (Moderate during construction and operation). ·
Low fragmentation impact for minor upper
tributaries. ·
Combined
impacts Moderate during
construction and operation. |
|
Pak Shek Au Watercourse |
·
Re-channelisation
(Low). |
·
No
significant indirect impacts. |
|
Tung Fong/Shek Tsai Ling Watercourse & Kwu Tung Watercourse |
·
Re-channelisation
(Low). |
·
No
significant indirect impacts. |
|
Fung Kong & Ho Sheung Heung Watercourses |
·
Re-channelisation
(Low). |
·
No
significant indirect impacts. |
|
Long Valley Watercourse |
·
Re-channelisation
(Low). |
·
Run-off
and hydrological impacts on Long Valley: most likely Low during construction and operation but could be Moderate if hydrological disruption
is prolonged and during the dry season. |
|
Cheung Po Tau & Fu Tei Au Watercourse |
·
Re-channelisation
(Low). |
·
No
significant indirect impacts. |
|
Sheung Shui Wa Shan Watercourses |
·
Re-channelisation
of approx. 80m length of both watercourses (lowest reaches) (Low). |
·
No
significant indirect impacts. |
|
Siu Hang San Tsuen Watercourse |
·
Re-channelisation
of approx. 180m length of lowest reaches (Low). |
·
Disturbance
impacts not significant during construction and operation). ·
Run-off
and hydrological impacts (Low
during construction). ·
Combined
impacts Low to Moderate during
construction and Low during
operation. |
|
Man Kok Village, Tin Ping Shan Tsuen, Shek Wu San Tsuen & Ma Shi
Po Watercourses |
·
Re-channelisation
(Low). |
·
No
significant indirect impacts. |
|
Ma Wat River |
·
Re-channelisation
of approx. 700m of lower stream course (Low). |
·
Disturbance
impacts on approx. 3000m of channelised stream course (Low during construction and operation). ·
Run-off
and hydrological impacts on channelised stream course (Low to Moderate during construction and Low during operation). ·
Combined
impacts Low to Moderate during
construction and Low during
operation. |
|
San Uk Tsuen, Ma Wat Wai & Tong Hang Watercourses |
·
No
direct impact. |
·
Disturbance
impacts on approx. 100m of Tong Hang Watercourse during construction of
Fanling Bypass (Low). ·
No
significant impacts on other watercourses. |
|
Kau Lung Hang Watercourses |
·
No
direct impact. |
·
Disturbance
impacts on approx. 50m during construction of Fanling Bypass (Low) |
|
Upland Grassland |
·
Loss
of 6.95ha (Low). |
·
Disturbance
(Low during construction and
operation). |
|
Lowland Grassland |
·
Loss
of 53.21ha (Low). |
·
Disturbance
during construction and operation (Low). |
|
Seasonally Wet Grassland |
·
Loss
of 2.86ha near lower stream reaches of Ma Tso Lung Stream (Low to Moderate) and elsewhere 1.21ha
(Low). |
·
Disturbance,
run-off and hydrological disruption impacts on seasonally wet grassland at Ma
Tso Lung (Low to Moderate during
construction and Low during
operation). |
|
Grassland/Shrubland |
·
Loss
of 1.63ha (Low). |
·
Disturbance
during construction and operation (Low). |
|
Shrubland |
·
Loss
of 1.11ha (Low). |
·
Disturbance
impacts on shrubland at Crest Hill (most likely Low but Low to Moderate
during construction in the unlikely event that a Eurasian Hobby nest site is
within or close to the works area for KTN area G1-5 and Low during operation); Low
during construction and operation elsewhere. |
|
Ho Sheung Heung Fung Shui Woodland
& Secondary Woodland |
·
Loss
of 0.23ha of secondary woodland (Low
to Moderate). |
·
Disturbance
of fung shui and secondary woodland
(Low to Moderate, mainly on
mammals, during construction and Low during
operation). ·
Dust
deposition on vegetation during construction (Low). ·
Fragmentation
impact on woodland (Low during
construction and operation). ·
Combined
impacts (Low to Moderate during
construction and Low during
operation). |
|
Secondary Woodland west of Siu Hang San Tsuen |
·
No
direct impact. |
·
Disturbance
(Low during construction and
operation). ·
Dust
deposition on vegetation (Low during
construction and operation). ·
Combined
impacts (Low during construction
and operation). |
|
Other Secondary Woodland |
·
No
direct impact. |
·
Disturbance
and dust deposition during construction, and disturbance during operation (Low). |
|
Hillside Plantation |
·
Loss
of 8.65ha (Low). |
·
Disturbance
during construction and operation (Low
to Moderate). ·
Fragmentation
impacts on hillside plantation during construction and operation (Low). ·
Combined
impacts on hillside plantation Low to
Moderate during construction and operation. |
|
Roadside and Urban Plantation |
·
Loss
of 73.43ha Low. (Loss of 0.27ha of plantation supporting Man Kam
To Egretry is addressed under ‘Egretries and Egretry flight-lines’ below, Low to Moderate due its functional
value as egretry site) |
·
Disturbance
during construction and operation (Low). |
|
Mitigation Plantation |
·
Loss
of 10.75ha (Low). |
·
Disturbance
impacts on mitigation plantation (Low). ·
Fragmentation
impacts on mitigation plantation (Low). ·
Combined
impacts Low to Moderate during construction and
operation. |
|
Orchard |
·
Loss
of 7.38ha (Low). |
·
Disturbance
impacts on orchard (Low). |
|
Golf Course |
·
No
direct impact |
·
None. |
|
Village, Urban/Residential Areas & Waste Ground |
·
Habitat
is of low ecological value (Low). |
·
Disturbance
impacts on developed areas will not increase significantly. |
|
Deep Bay Wetland Ecosystem |
No direct
impacts. |
·
Run-off
and pollution impacts on Deep Bay ecosystem likely to be Low to Moderate severity during construction and Low in operation phase. ·
Although
impact of pollution events on Deep Bay ecosystem are dependent on nature and
scale, there is the potential for High
severity; however, most events likely to be of Low to Moderate severity during construction and Low severity during operation. ·
Combined
impacts Low to High, depending on
nature and scale. |
Table 13.129
- Potential Total Direct, Indirect and Fragmentation Impacts of the Project on Species
Groups and Species, and their severity in the absence of Mitigation Measures
Note: in the table below the
severity of impacts are presented hierarchically and inclusively, but
repetition has been avoided for the purposes of clarity. For example, the
severity of combined impacts on Three-banded Box Terrapin is predicted to be
Moderate: the severity of this combined impact has been predicted by combining
the severities of relevant impacts on all fauna, herpetofauna, reptiles and
this species.
|
Sensitive Receiver |
Severity of Impact |
|
All
flora and fauna |
·
Direct and indirect loss of habitats in the Project Area as a whole of
Low Severity. |
|
Flora
of conservation significance |
·
Construction phase impacts at Ho Sheung Heung fung shui and secondary woodland: dust deposition of Low Severity, damage or death of
species of conservation significance and protected species of Low to Moderate Severity. |
|
Mammals
|
·
Mortality impacts: Low in the Project Area as a whole but Low to
Moderate in Ma Tso Lung area.. |
|
Bat
Roosts |
·
Roost destruction during site clearance works: Low. |
|
Birds
|
·
Mortality impacts on breeding birds during site clearance works:
generally Low, but Moderate if an egretry site was to be
cleared during the breeding season. ·
Mortality impacts arising from collision: Low, largely smaller birds. ·
Increase in lighting and glare: probably Low for most species but may be Low to Moderate on migrating birds from the commercial/business
district in KTN on migrating birds. ·
Combined impacts: Low
(except as noted above). |
|
Wetland-dependent bird species |
·
Direct
loss of wetland habitats: Low. ·
Indirect
loss of wetland habitats: Low to Moderate on bird species using Sheung
Yue River, but Moderate on Little
Egret and Chinese Pond Heron; Low to
Moderate on bird species using Long Valley and the non-tidal Ng Tung
River, but Low elsewhere during
construction phase, Low on birds
using Sheung Yue and non-tidal Ng Tung Rivers, but not significant elsewhere
during operational phase. ·
Fragmentation
impact: impact on linkage between Long Valley and non-tidal Ng Tung River Low to Moderate during construction
and operation; impact on linkage between Long Valley and the Deep Bay wetland
ecosystem along the non-tidal Ng Tung River of Low severity during construction and not significant during
operation; no other significant fragmentation impacts. ·
Combined
impacts: Low overall, but Low to Moderate for freshwater wetland/wet agricultural land
habitat-specialist species and species using Sheung Yue River in significant
numbers). |
|
Non wetland-dependent bird species |
·
Direct
loss of habitats: Low. ·
Indirect
loss of habitats: Low. ·
Fragmentation
impact: Low. ·
Combined
impacts: Low. |
|
Bird species utilising dry agricultural land and woodland |
·
Direct
loss of habitats: Low. ·
Indirect
loss of habitats: Low. ·
Fragmentation
impact: Low. ·
Combined
impacts: Low. |
|
Eurasian Hobby |
·
Combined
impacts: Low to Moderate depending
on proximity of any nest site in Crest Hill area to works areas. |
|
Grey Nightjar |
·
Combined
impacts: Low to Moderate depending
on proximity of any nest site area to works areas. |
|
Egretries and Egretry Flight-lines |
·
Direct
loss of Man Kam To Road Egretry: Low to Moderate. ·
Disturbance
impacts on Ho Sheung Heung Egretry: Low. ·
Disturbance
and fragmentation impacts on Man Kam To Road Egretry
and flight-lines: Low to Moderate prior to clearance of
egretry site then not relevant. ·
Disturbance
and fragmentation impacts on flight-lines between Ho Sheung Heung Egretry and
foraging areas: Low to Moderate during
construction phase and Low during
operational phase. ·
Combined
impact on egretries: Moderate
during construction and Low during
operation. |
|
Herpetofauna |
·
Mortality impacts: Low to
Moderate in Ma Tso Lung area and Moderate to High for Three-banded Box
Terrapin; Low elsewhere. |
|
Reptile
species |
·
Direct loss of habitats: Low. ·
Indirect loss of habitats: Low. ·
Fragmentation impact: Low. ·
Combined impacts: Low. |
|
Three-banded
Box Terrapin |
·
Combined impacts: Moderate. |
|
Amphibian
species |
·
Combined impacts: Low. |
|
Chinese
Bullfrog |
·
Combined impacts: Low to
Moderate. |
|
Butterflies |
·
Combined impacts: Low. |
|
Dragonflies |
·
Combined impacts: Low. |
|
Fish |
·
Combined impacts: Low. |
|
Small
Snakehead |
·
Combined impacts: Moderate
during construction phase and Low
to Moderate during operational
phase of Ma Tso Lung Stream diversion works, Lok Ma Chau Eastern Connection
Road and other developments in the Ma Tso Lung area; otherwise Low. |
|
Somanniathelphusa zanklon |
·
Combined impacts: Moderate and Low to Moderate
during construction and operational phases of Ma Tso Lung Stream diversion
works, Lok Ma Chau Eastern Connection Road and other developments in the Ma
Tso Lung area; otherwise Low. |
13.8.2 Proposed Mitigation Measures
Mitigation measures to avoid, minimise or compensate for the potential significant ecological impacts identified in Tables 13.128 – 13.129 are detailed below. As stated in the EIAO-TM, proposed mitigation should give priority to avoidance of impacts. For the NDA project, avoidance of impacts was followed wherever possible during the study process. Alternatives that were considered and addressed during the study process in accordance with Section 3.4.14.4(x) of the Study Brief are described in Section 13.1.4. The principal planning and design alternatives adopted are summarized below, together with the outcomes of this consideration and assessment.
Alternatives to safeguard the conservation value of Long Valley: it is proposed to designate the area of highest ecological value (37.17ha), the largely wetland area south and east of the Sheung Yue River and south and west of the Shek Sheung River, as Other Uses (OU) Nature Park (area C1-9 in KTN) and retain the agricultural (AGR) zonings of the area west and north of the Ng Tung and Sheung Yue Rivers and east of Ho Sheung Heung (C2-2), and the area south and east of area C1-9 and east of Yin Kong (C1-6) (Section 13.1.4.1);
Alternatives to avoid potential impacts of the
Kwu Tung Interchange on Long Valley: it is proposed to locate the new
grade-separated interchange, proposed as the major access from the Fanling
Highway to the KTN NDA at about 400m east of the Sheung Yue River, thus
avoiding Long Valley (Section 2.5.1.2
and 13.1.4.2)
Alternatives to avoid potential impacts of the Fanling Bypass on habitats of ecological significance: it is proposed that the western terminus of the Fanling Bypass will be at the point where it meets Man Kam To Road in FLN, and the road network of KTN and FLN will be designed and constructed in such a way that a bypass west of this point is not required, and hence has avoided habitats of ecological significance including Long Valley and Ho Sheung Heung fung shui wood (Section 13.1.4.3);
Alternatives to avoid, minimise and compensate for potential impacts to Man Kam To Road Egretry: alternative alignments for the Fanling Bypass and its interchange with Man Kam To Road were considered but were found to be impractical due to engineering constraints and requirements (Sections 2.5.2.9 and 13.1.4.4). Mitigation measures to compensate for this loss are therefore proposed;
Alternatives to avoid, minimise and compensate for potential impacts to the Ma Tso Lung Stream and marsh, its riparian corridor and fauna of conservation significance: avoidance of all significant impacts proved impractical due to engineering constraints and requirements (Sections 2.4.1.8 and 13.1.4.5). Mitigation measures to minimise and compensate for unavoidable impacts are therefore proposed.
Alternatives to avoid, minimise and compensate
for potential impacts to the main river channels: the main river channels are almost entirely
avoided in terms of habitat loss, the only direct impact constituting a loss of
less than 0.02ha for bridge piers; areas adjacent to the river channels have
been largely avoided by development, especially the tidal section of the Ng
Tung River, which is bordered by Long Valley Nature Park or Open Space zoning.
With regard to non-tidal sections of the Ng Tung River, Open Space zones occur
along the channel.
Figure 13.12 shows the areas where the revised RODP has avoided impacts on habitats and species of conservation significance through avoidance, either by exclusion from the NDA boundaries or by zoning that would afford protection from development (Other Uses (Nature Park), Conservation Area, Green Belt and Agriculture).
Where avoidance is not possible, the EIAO-TM states that it is preferable to mitigate for impacts ‘on-site’ wherever possible. As discussed in Section 13.1.4.7, alternatives for the identification of mitigation sites were considered, and it was resolved that in many cases in situ compensation at the exact site where the identified impact has been predicted was not appropriate, both because of the large scale of the development areas involved and because this would result in compensation areas being ecologically fragmented and of limited ecological value. In these cases the consolidation of mitigation measures at locations elsewhere within the Project Area was chosen as the most practical, feasible and effective alternative.
13.8.2.1 Mitigation for Direct Loss of Habitats of Ecological Importance
Direct loss of habitat of ecological significance (i.e. habitat areas identified as being of at least low to moderate ecological value) for which compensation for direct habitat loss is required is detailed in Table 13.130 below. Mitigation for permanent loss of a very small area (<0.02ha of main channelised river and temporary construction stage loss of a small area of this habitat is addressed along with mitigation for disturbance and fragmentation impacts on this habitat
Table 13.130 - Direct Habitat loss arising from the Project requiring mitigation measures.
|
Habitat |
Area (ha) |
|
Wet Agricultural Land |
0.58 |
|
Pond |
2.49 |
|
Mitigation Wetland |
2.75 |
|
Seasonally wet grassland at Ma Tso
Lung |
2.86 |
|
Main River Channel |
<0.02 |
|
Total Wetland Loss requiring mitigation |
8.70 |
|
Secondary Woodland |
0.23 |
|
Hillside Plantation |
8.65 |
|
Total Woodland Loss requiring mitigation |
8.88 |
Mitigation
for loss of wetland habitats (wet agricultural land, pond and mitigation
wetland)
A total of 5.82ha of wet agricultural land, pond and mitigation wetland, (0.58ha of wet agricultural land and 2.12ha of ponds of Low to Moderate ecological value, 0.37ha of ponds of Moderate ecological value and 2.75ha of mitigation wetland of Low to Moderate ecological value) of ecological significance will be directly impacted by the Project. As is discussed in Section 13.1.4.6, an outcome of the review of alternatives for compensation of habitat loss arising from the Project was the decision to consolidate compensatory wetland habitat provision in LVNP.
The area of Long Valley proposed to be zoned as LVNP and shown in Figure 13.13 has been assessed as of High to Very High ecological value; however, it has been demonstrated from monitoring of bird diversity and distribution undertaken under the previous and current MAs that management with nature conservation objectives has the potential to increase both numbers and diversity of fauna (Table 13.131 and Appendix 13.10).
Table 13.131 -
Ratios of bird numbers in managed to unmanaged fields in the Long Valley and Ho
Sheung Heung Priority Site, 2007 to 2011. (Source: Hong Kong Bird Watching Society[3])
|
Year |
Spring |
Summer |
Autumn |
Winter* |
|
2007 |
0.7 |
1.6 |
0.9 |
1.5 |
|
2008 |
2.3 |
5.6 |
3.8 |
3.3 |
|
2009 |
1.9 |
2.3 |
3.6 |
2.4 |
|
2010 |
2.10 |
1.3 |
2.1 |
2.9 |
|
2011 |
1.8 |
1.5 |
2.4 |
2.2 |
|
Mean |
1.7 |
2.5 |
2.6 |
2.5 |
*Note that seasons are
as follows: Spring (March to May), Summer (June to August), Autumn (September
to November) and Winter (December to January) Thus Winter 2007 in the table
refers to the period from December 2007 to February 2008.
At the present time MAs in Long Valley are voluntary and do not cover
the whole of Long Valley; the managed area within the boundary of the proposed
LVNP is approximately 10ha. There is, therefore, considerable scope to increase
the extent of the managed area, approximately 70% currently not being under
conservation management.
In addition, however, studies undertaken by CA and HKBWS have shown that of the different cultivation treatments adopted, less intensively managed wet agricultural land and shallow ponds have higher species richness than other habitats. Survey findings have also shown that, at least in shallow pond habitat, the attractiveness of such habitat to birds begins to decline after about four years; thus rotation of habitats is an important ongoing element of conservation management (see Appendix 13.10).
Accordingly, long-term and strategic management (i.e. provision of
specific wetland types, periodic habitat changes and adoption of crop rotation)
will be required to maintain and enhance the wetland function. These management
issues are discussed further in the Preliminary Management Plan for the LVNP (Appendix
13.10).
Designation of the LVNP will offer an appropriate location for measures
to mitigate for wetland loss and will secure the long term future of this
important area. In the Hong Kong context, this achieves a valuable conservation
objective, and allows the management of Hong Kong’s largest continuous and contiguous
area of freshwater wetland habitats for the purposes of nature conservation.
While the MAs grant considerable conservation/ecological benefits, the
opportunity to manage the entire 37ha to the south of the Sheung Yue and Shek
Sheung Rivers for nature conservation will considerably add to the achievable
enhancements of ecological function. This benefits both flora and fauna, and
particularly those wetland-dependent species which distinguish Long Valley from
other Hong Kong areas managed for nature conservation.
The boundary of the LVNP corresponds to area defined in Section 13.6.1.1 of this report as Long Valley south and east of the Sheung Yue River and includes all areas of more or less continuous and contiguous wetland in this location. Except for the plantations around the periphery, all of this area is currently wetland or is topographically similar (hence could easily be flooded) but is currently occupied by dryland habitats.
Mitigation for
loss of seasonally wet grassland at Ma Tso Lung
An area of 2.86ha of seasonally wet grassland adjoining the lower reaches of Ma Tso Lung Stream will be lost as a consequence of the Project. Mitigation for loss of this area will be incorporated in the habitat restoration measures proposed for the Ma Tso Lung Stream corridor, which will be required following diversion of the stream to permit construction of the LMC Loop Eastern Connection Road (see below).
Mitigation for loss of woodland habitats
It is proposed that loss of woodland and hillside plantation of considerably value be compensated by planting of native tree and shrub species. In accordance with the principles adopted for mitigation habitat provision described in Section 13.1.4.7, suitable locations to consolidate compensatory habitat provision were identified within the Project Area boundary. Consideration was also given to the locations of habitat loss (largely in KTN). Based on these principles, areas currently of low habitat value on hillside (grassland and grassland/shrubland) were reviewed and suitable sites identified (see Figure 13.14 and plates in Appendix 13.11). In accordance with this principle, appropriate locations (currently upland grassland of low ecological value) as shown on Figure 13.14 and areas are detailed in Table 13.132.
Table 13.132 – Proposed Areas for Compensatory Planting in NDAs (Site Locations for the revised RODP)
|
Site
Location |
KTN
(ha) |
|
E1-8 |
7.75 |
|
G1-3 (south) |
3.28 |
|
G1-3 (north) |
5.00 |
|
Total |
16.03 |
The area of 16.03ha allocated for compensatory woodland planting is almost twice the area to be lost. In part, this extra provision allows for the fact that it will take some time for the compensatory planting to achieve the ecological function and value of the area to be lost. In addition, it allows for the fact that not all of the areas identified for planting will prove to be suitable, by virtue of topography and ground conditions, or other site constraints such as poor soil conditions. In addition, localised areas within the proposed planting areas already show evidence of natural regeneration, and it would clearly be inappropriate to damage such areas by cultivation.
Although areas where fires have occurred in the past, including existing permitted burial grounds, were avoided when identifying the compensation areas, fire control measures shall be incorporated in the woodland management plan. There are many examples around Hong Kong to demonstrate that so long as active management is undertaken, fire risk can be reduced considerably. Within the Study Area the successful establishment of plantation around Wo Hop Shek, which now supports woodland dependent amphibian species of conservation significance, provides an example of the feasibility and benefits of woodland restoration; adequate resources for management and maintenance are, however, an essential prerequisite.
Species proposed for planting are pioneer native tree and shrub species often present in natural woodlands in Hong Kong, including a number of shrub species known to be of value in providing fruit for native fauna, in particular birds. Details of the compensatory planting plan including the planting materials would be formulated during the detailed design stage and included in the Woodland Planting and Management Plan (Section 13.9.3).
Table 13.133 – Native Tree and Shrub Species for Compensatory Planting Areas
|
Trees |
Shrubs |
|
Ailanthus fordii |
Diospyros
vaccinioides |
|
Bischofia
javanica |
Gardenia
jasminoides |
|
Castanopsis
fissa |
Ixora
chinensis |
|
Celtis
sinensis |
Ligustrum
sinense |
|
Cinnamomum
burmannii |
Litsea
rotundifolia |
|
Cinnamomum
camphora |
Melastoma
malabathricum |
|
Xanthoxylum
avicennae |
Melastoma
dodecandrum |
|
Liquidambar
formosana |
Atalantia
buxifolia |
|
Sapium
discolor |
Rhodomyrtus
tomentosa |
|
Schefflera
heptaphylla |
Rhaphiolepis
indica |
|
Ilex
rotunda |
Rhododendron
simsii |
In addition, it is recommended that the layout and
development footprint of KTN area D1-11a should be reviewed at the detailed
design stage in order to avoid or minimise loss of secondary woodland arising
from the development of this area.
Mitigation for loss of mitigation plantation
This habitat largely comprises strips along the main river channels and is dominated by exotic species, though some native species are present. It has limited intrinsic ecological value for fauna; however, certain areas have a role in buffering areas of ecological importance (the river channels and habitats around Long Valley) from disturbance, and hence has been assessed as of Moderate ecological value. Mitigation for loss of this habitat serving as screen planting along the main river channels is, therefore, addressed in the following sections.
13.8.2.2 Mitigation for Indirect Impacts on Habitats of Ecological Importance
In addition to direct habitat loss, indirect impacts to habitats will occur as a consequence of the Project. Habitat or site-specific mitigation requirements to avoid or minimise disturbance to habitats are proposed below.
Measures to avoid or minimise disturbance and hydrological impacts on Long Valley and on fauna of conservation significance, in particular disturbance-sensitive bird species of conservation significance
The ecological function of parts of Long Valley may be affected by the development which is proposed to the southwest of Long Valley and on, and alongside, the main river channels, especially in areas abutting the Sheung Yue River (Section 13.7.3.3 and Figure 13.11a). It is predicted that the numbers of the more disturbance-sensitive bird species utilising this part of Long Valley will be reduced in the absence of mitigation measures, as these species might avoid this area in response to visual and aural disturbance. The species most sensitive to such disturbance are large waterbird species, of which the most sensitive regularly occurring in Long Valley are Grey Heron and Great Egret. However, the species for which disturbance impacts are potentially most significant are species for which Long Valley supports a significant proportion of the Hong Kong population (in particular Greater Painted-snipe, albeit this species is not particularly disturbance-sensitive) and/or breeding species for which Long Valley is an important breeding site or foraging area (again including Greater Painted-snipe, but also Little Egrets, Cattle Egrets and Chinese Pond Herons breeding at the Ho Sheung Heung Egretry and, in the case of Little Egrets and Chinese Pond Herons, the Man Kam To Road Egretry).
In addition, these species, and ardeids using the flight-line between Ho Sheung Heung Egretry and Long Valley, would potentially be disturbed by construction phase works in Open Space areas along Sheung Yue River (i.e. C2-1 in KTN). Such disturbance, although not of significant magnitude in view of the minor scale of works in the Open Space areas, will be greatest during the construction phase of the project, and will continue at a lower magnitude during the operational phase. Other birds and most other fauna will not be affected significantly, but there may be some disturbance impact on mammals, again as a consequence of their avoiding areas where construction is underway and human activity is higher than at present as a consequence of the project.
Possible measures to minimise construction phase impacts were considered, and the following were feasible and effective. Accordingly, it is recommended to minimise construction phase disturbance impacts by erection of noise/visual barriers along the frontage of any development zone abutting or within line of sight at ground level of Long Valley and only carry out works in KTN area C2-1 during 1st August to 28th/29th February, outside the ardeid and Greater Painted-snipe breeding seasons. Disturbance impacts on these and other species outside the breeding season are considered to be of lower significance as non-breeding birds have a greater ability to change their foraging areas in response to disturbance. Further, in respect to ardeids, all species occurring in Long Valley also occur in the Deep Bay area in larger numbers, hence impacts on the wintering populations in Long Valley are of lower significance at a Hong Kong level than impacts on the breeding population, for which Ho Sheung Heung Egretry is of significance at a Hong Kong level.
In order to minimise construction and operational phase impacts, it is recommended that development above ground level in area B3-12 (Commercial, Research and Development) adjoining Long Valley Nature Park (LVNP) should be set back 30m from the LVNP boundary. Similarly, it is recommended that a bund should be formed along the northern and northeastern boundaries of KTN area C1-1 (Open Space) and planted with trees and that any structures should be set back 15m from these boundaries.
In addition, it is recommended that the working hours for construction of the new pedestrian bridge over the Sheung Yue River south of KTN area D1-1 should be restricted to 09.00 to 17.30 during 1st March to 31st July (the ardeid breeding season).
In addition, as soon as is practical and before any works other than those required under the advance works phase (which are relatively minor, as noted below), visitor numbers in LVNP should be controlled by fencing the site and managing visitor numbers and access prior to the commencement of any construction activities which may result in disturbance impacts on Long Valley and the main river channels (see Appendix 13.10).
Further, as an element of the adaptive management of Long Valley (see Appendix 13.10) it is recommended to give consideration to redistribution of habitats in Long Valley by increasing the area of open water habitat suitable for foraging ardeids in those parts of Long Valley which will be less disturbed by construction and other human activity and increasing the area of closed habitats (such as marsh and reed marsh) which would be suitable for less disturbance-sensitive birds and other fauna in the more disturbed areas.
Although relatively minor in scale, the Advance Works Phase of the project will result in some disturbance impacts on large waterbirds foraging in Long Valley before its full operation (see Figure 13.11a). It is recommended to stock suitable areas of Long Valley during the advanced works phase with fish fry and or ‘trash fish’ (unwanted by-catch of fish of low commercial value) to provide additional food for ardeids and other piscivorous species as an advanced mitigation measure. Depending upon the progress of land resumption for the Project, the mitigation meanders within Long Valley and ponds along river channels on government land and other suitable areas could be used as stocking locations in the event that other areas were not yet available for this purpose. Details of the above would be further formulated and implemented before commencement of Advanced Works Phase. It is recommended to minimise operational phase impacts to LVNP by erecting a solid noise/visual barrier along the interface between LVNP and adjacent areas on the southeast side of the Sheung Yue River. In addition, the detailed Habitat Creation and Management Plan (HCMP) for LVNP will examine the need for additional buffer planting along the fringes of the LVNP, taking into account the need to avoid loss of wetland area.
In order to mitigate for cumulative impacts of this project and the Construction of Cycle Tracks and the Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River and at Nam Sang Wai, Yuen Long project on Long Valley, it is recommended that screen planting areas implemented as mitigation measures for landscape impacts of the cycle track project should be preserved as far as practicable. Should unavoidable felling of the screen planting under the current Project be identified at the detailed design stage, measures to mitigate for any impacts of such interference should be formulated and incorporated in the design and implementation of the relevant NDA project elements.
In order to minimise constructional and operational phase impacts on fauna in the area of Long Valley north and west of the Sheung Yue River; this area (KTN area C2-2) will retain its agricultural zoning. The area south and east of Long Valley and east of Yin Kong (KTN area C1-6) will also retain its agricultural zoning. In order to minimise disturbance impacts on these areas, and fragmentation impacts on the flight-line between Ho Sheung Heung Egretry and Long Valley and the Sheung Yue River and the flight-line between Long Valley and Hoo Hok Wai and the Deep Bay wetland ecosystem along the Ng Tung River, it is recommended that more stringent planning control be exercised in this area and that this intention should be clearly stated in the Explanatory Statement of the relevant Layout Plan.
The Long Valley Watercourse will be rechannelised under the Project as far north as the northeastern corner of KTN area C1-4. Since this watercourse is one of the principal sources of water for Long Valley, it is recommended that construction and operational phase hydrological impacts are avoided by ensuring that there is no reduction in the quality and quantity of water supplied to Long Valley during the construction period for the rechannelisation works. Accordingly, it is recommended that the detailed design for the rechannelisation works should incorporate measures to ensure and monitor the continuity of the water supply to Long Valley, in particular for the duration of the rechannelisation works. In addition, the HCMP for the LVNP should incorporate a contingency plan to prepare for any unexpected or planned hydrological disruption to the water supply to the LVNP. The preparation of this contingency plan should include a review of options available to secure an alternative water source and if such a source is found to be feasible, the measures required to secure such a source should be detailed and implemented if appropriate.
Measures to minimise disturbance and fragmentation impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers, and to minimise fragmentation impacts on ecological linkages with the Deep Bay wetland ecosystem
A number of wetland-dependent bird species of conservation importance forage in the Sheung Yue, Shek Sheung and Ng Tung Rivers (Section 13.6.1.6). The Sheung Yue River, in particular, is an important foraging area for these species and is regularly utilised by ardeids (especially Little Egrets) breeding at Ho Sheung Heung Egretry. The tidal Ng Tung River is also a flight-line corridor between Long Valley and Ho Sheung Heung Egretries and the Deep Bay wetland ecosystem, while the non-tidal section of the river provides a flight-line linkage between the Man Kam To Road Egretry and Long Valley and elsewhere.
While these rivers are currently somewhat disturbed by users of their access roads, a significant increase in disturbance impacts on larger waterbirds foraging in these rivers and on fragmentation impacts on larger waterbirds using the flight-line corridors is predicted in the absence of mitigation, especially during the construction phase of the Project (Figure 13.11a). As is the case with regard to impacts on large waterbirds using Long Valley, it is considered that impacts on foraging ardeids breeding at the Ho Sheung Heung Egretry (and to a lesser extent, due to the much smaller numbers involved) the Man Kam To Road Egretry, are of relative significance. Impacts on other species, and on species outside the breeding season, are of lower significance as these species occur in lower numbers and/or are not present during the breeding season. Accordingly, the birds which may be displaced elsewhere are likely to be less dependent on the rivers and the foraging opportunities which they provide.
After consideration of those that are both practical and effective, it is recommended that the mitigation measures described below are implemented in order to avoid, minimise and mitigate for construction phase impacts on larger waterbirds foraging in the Sheung Yue, Shek Sheung and Ng Tung River and using the flight-line along the Ng Tung River towards Hoo Hok Wai and Deep Bay.
It is recommended that noise/visual barriers be erected and maintained throughout the construction period along the boundaries of all works areas adjacent to these rivers (Figure 13.15).
It is recommended that the working hours for construction of the new pedestrian bridge over the Sheung Yue River south of KTN area D1-1 should be restricted to 09.00 to 17.30 during 1st March to 31st July (the ardeid breeding season). A temporary halt of works was considered, but proved impractical.
Similarly, it is recommended that the working hours for construction of the new pedestrian bridge over the tidal Ng Tung River between KTN C2-1 and FLN A2-1 should be restricted to 09.00 to 17.30 during 1st March to 31st July (the ardeid breeding season). Avoidance of works entirely during the breeding season did not prove feasible.
In order to mitigate for cumulative impacts of this project and the Construction of Cycle Tracks and the Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River and at Nam Sang Wai, Yuen Long project on Long Valley, it is recommended that construction activities and works of the NDAs project should avoid clearance or interference with any mitigation measures (including screen planting areas) implemented as mitigation measures for impacts of the cycle track project. Should the need for such works under the current project be identified at the detailed design stage of the NDAs project, additional measures to mitigate for any impacts of such interference should be formulated and incorporated in the design and implementation of the relevant element of the NDA project.
Further, as an element of the adaptive management of Long Valley (see Appendix 13.10) it has been recommended to give consideration to redistribution of habitats in Long Valley by increasing the area of open water habitat suitable for foraging ardeids in those parts of Long Valley which will be less disturbed by construction and other human activity. These measures would also serve to provide compensatory habitat for habitat lost to large waterbirds on the main river channels due to the project.
Although relatively minor in scale, Advance Works Phase of the project will result in some disturbance impacts on Long Valley before its full operation (see Figure 13.11a). In order to mitigate for loss of foraging habitat arising from this source, it is recommended to stock suitable areas in LVNP with fish fry and or ‘trash fish’ (unwanted by-catch of fish of low commercial value) to provide food for ardeids and other piscivorous species. Depending upon the progress of land resumption for the project, the mitigation meanders currently managed by AFCD could be used as stocking locations in the event that other areas were not yet available for this purpose.It is proposed that the area of Long Valley north and west of the Sheung Yue River and east of the tidal section of the Ng Tung River (KTN area C2-2) will retain its agricultural zoning. In order to minimise disturbance impacts on this area, and fragmentation impacts on the flight-line between Ho Sheung Heung Egretry and Long Valley and the Sheung Yue River and the flight-line between Long Valley and Hoo Hok Wai and the Deep Bay wetland ecosystem along the Ng Tung River, it is recommended that more stringent planning control be exercised in this area and that this intention should be clearly stated in the Explanatory Statement of the relevant Layout Plan.
In addition, it is recommended that the design of new bridges should be reviewed at the detailed design stage of the project to determine the optimum design to minimise construction and operational phase impacts on the rivers and on large waterbirds and other fauna using the rivers. Design and construction parameters should be reviewed to address the following requirements and objectives:
· Minimisation of the height of bridges especially along those sections of river which are movement corridors of relative significance for birds: the tidal Ng Tung River and the non-tidal Ng Tung River west of the Man Kam To Road;
· Minimisation of the need form cofferdams to form bridge piers;
· Avoidance and minimisation of changes to the hydrological regime of the rivers; including avoidance of changes to flow of rivers, the tidal regime, and the level of impounded river sections;
Minimisation of the duration of construction phase impacts, especially for the footbridges over the Sheung Yue and Ng Tung Rivers, by giving consideration to off-site prefabrication of bridges and bridge elements. Further, construction of each bridge will be scheduled so as there is no overlap, in order to reduce disturbance impacts. As noted above, as well as mitigating for disturbance impacts on the rivers, the proposed measures are also necessary to minimise fragmentation impacts on ecological linkages for birds, especially waterbirds and ardeids breeding at Ho Sheung Heung Egretry, along the Ng Tung River corridor with the Hoo Hok Wai area and areas elsewhere within the Deep Bay wetland ecosystem.
In addition, it is recommended that all wetland bird species of conservation significance using the river on a regular basis in significant numbers (including Little Egret, Chinese Pond Heron, Black-winged Stilt, Little Ringed Plover and Wood Sandpiper and any other bird species found to be using the rivers in significant numbers during pre-construction phase monitoring (see Section 13.11)) be included as target species for the design and management of LVNP. Although Grey Heron regularly occurs, the numbers are not significant in a Hong Kong context. As noted above, it is considered that species breeding in the Study Area (in particular breeding Little Egrets and Chinese Pond Herons) should be regarded as a priority in the design and implementation of mitigation measures. All species of conservation importance regularly utilising the rivers also regularly use habitats in Long Valley, with the exception of Great Cormorant (which only occurs regularly on the tidal section of the Ng Tung River north of the confluence with the Sheung Yue). However, impacts of the project on Great Cormorant are not considered significant even in the absence of mitigation as numbers of this species in the Study Area are very small relative to the large population in Deep Bay.
Finally, it is recommended that detailed design of the Open Space zones along the Ng Tung, Sheung Yue, Ng Tung and Shek Sheung Rivers should include, where practical and consistent with other design parameters and operational constraints, planting buffers between the rivers and areas that will be used intensively by people and/or are located between such areas and the rivers. This recommendation applies, in particular, to the southwestern section of the Sheung Yue River and the south side of the Ng Tung River between FLN area B2-2 and B3-7 where the river corridors and likely to be most heavily disturbed. Greening opportunities and the proposed provision of building set-back along the river channels would be optimized during the detailed design stage by further refinement of the development layout. Where feasible, existing trees should be retained and incorporated into the detailed design of these areas.
Measures to avoid disturbance and hydrological impacts on Ma Tso Lung Stream, tributaries and riparian corridor habitats
As was noted in Section 13.1.4.5 and Section 2.4.1.8, alternatives to minimise impacts to Ma Tso Lung Stream to find the optimum balance between minimising impacts on the stream and minimising impacts on the riparian corridor have been considered. Protection of the integrity of the natural stream and surrounding riparian vegetation at Ma Tso Lung Stream and its tributary the Ma Tso Lung San Tsuen Stream is important in protecting this habitat and stream corridor of moderate to high ecological importance and the fauna of conservation significance, including the globally critically endangered Three-banded Box Terrapin. Studies in North America have recommended the use of development buffers around streams to protect riparian habitat for freshwater turtles. The proposed buffer width varies according to site and species: proposed values from North America include 150m (Bodie 2001), 275m (Burke & Gibbons 1995) and 123 – 287m (Semlitsch & Bodie 2003). The width of riparian woodland at Ma Tso Lung Stream is not as wide or as continuous as the sites which were the subject of these recommendations, so these estimates are not appropriate in this case.
Other reviews of the optimum width of stream buffers for a diversity of wildlife have recommended buffer widths of approximately 30m to 195m (Robins 2002) and approximately 18 to 33 meters (Klapproth & Johnson 2001). For trapping and removing pollutants, recommended buffers include approximately 22m (Robins 2002) and 30m (Haycock & Muscutt 1995). Based on these, a 30m buffer is recommended for Ma Tso Lung Stream and its tributaries within the Project Area. In some areas development already exists within this distance from the stream; this is not inconsistent with the concept of a buffer, but further development or deterioration of the habitat should be prevented to protect the terrapin.
The most important part of Ma Tso Lung Stream corridor is the middle and upper section, where the woodland favoured by Three-banded Box Terrapin in the corridor is more extensive. This area will be protected by Green Belt zoning, with a presumption against development. However, the downstream section of the stream is also of moderate to high ecological importance due to its wetland-dependent fauna of conservation importance, although the ecological value of the riparian corridor vegetation (seasonally-wet grassland and Ma Tso Lung marsh) is low to moderate.
Accordingly, it is recommended to protect the stream corridor by designating a buffer zone on each side of the stream in that part of the Project Area where the riparian corridor is not protected by the Green Belt zoning, subject to the constraint that the buffer zone and stream will be crossed by the proposed LMC Loop Eastern Connection Road. In this location, a section of stream approximately 130m in length will be diverted and a buffer zone of minimum 15m width on the western side of the stream and 30m width on the eastern side of the stream is recommended.
It is proposed that the areas of the buffer zone further from the stream in this section be planted with native riparian tree and shrub species in order to increase its suitability as a corridor for fauna species of conservation significance and other fauna. Meanwhile, the section of the restored stream corridor closest to the diverted stream will be profiled such that an area of marsh habitat with shallow pools can be formed adjacent to the stream, thus compensating for the loss of the seasonally wet grassland by creation of a habitat with similar characteristics but higher ecological function than the area lost, further enhancing connectivity of riparian habitats, and ensuring that the requirement to minimise flooding risk is satisfied.
Vehicles using the at-grade section of the LMC Connection Road may cause mortality impacts on terrestrial fauna and these are predicted to be of low to moderate severity if impacts are on species of conservation significance, and of moderate to high severity if impacts are on Three-banded Box Terrapin. In order to minimise such impacts a permanent solid barrier 1.2m in height with a lip projecting outwards from the road is proposed. Barriers of this type and height have been demonstrated to be highly effective in minimising mortality of herpetofauna, especially testudeans (Dodd et al. (2004).
An indicative cross-section and plan of the diverted section of stream following restoration are shown in Figure 13.16a-b.
It is recommended that construction-phase impacts to the stream are minimised by ensuring that the hydrological linkage between sections of the stream is maintained and a buffer zone on either side of the stream is designated and protected by a solid barrier, 2m in height, to prevent any construction or other materials being deposited in the stream. The solid barrier should be placed 30m from the stream or at the edge of the essential works area, whichever distance is the greater. In addition to minimising impacts on the riparian corridor, the barrier will also serve to minimise mortality of terrestrial fauna in the works area. Measures to avoid construction phase impacts from run-off and drainage are detailed in Sections 5.7.1.1 and 5.7.1.2.
Run-off and pollution impacts on the stream will be minimised in the following ways during the operational period. Run-off from the LMC Loop Eastern Connection Road will be collected and piped to a discharge point downstream where no significant impacts (including cumulative impacts with the LMC Loop project) are predicted. Meanwhile surface-water run-off from the Sports Ground/ Sports Complex in KTN area F1-1 and the Research and Development Facility in F1-3 be collected, sediment will be trapped and the clean water will be discharged into the stream in area F1-3. No significant pollution and hydrological impacts are predicted to the stream or the Deep Bay catchment (see Section 5.7.2.3). There will be a small net ecological benefit in that the surface water run-off can be incorporated into the design of the restored wetland, where it will add microhabitat diversity (see Figure 13.16b).
Connectivity of the riparian corridor for terrestrial fauna will be maintained by virtue of the fact that the road will cross Ma Tso Lung Stream on viaduct to the south of the section of stream to be diverted. In addition to spanning the stream the viaduct section will be of sufficient width for a faunal underpass to be formed alongside the stream (Figure 13.16b). The viaduct abutment would be approximately 30m north of the point at which it crosses the stream; the road would then continue at-grade to beyond the Project Area to the north. Potential impacts of the road in this area on fauna linkages are reviewed in Section 13.8.2.8 below.
Detailed design of the restored stream corridor as well as the barrier and underpass design should be submitted to and agreed by the relevant government departments during the detailed design stage of the project.
Measures to avoid disturbance and hydrological impacts on Siu Hang San Tsuen Watercourse
Siu Hang San Tsuen Watercourse, which flows into the Ng Tung River, is channelised, but the upstream section, which flows through agricultural land, has banks and bed of natural materials. One fish species of conservation significance, Predaceous Chub has been found in this stream section and three further wetland-dependent fauna species have been found in the riparian zone. Within the Project Area the watercourse is modified and evaluated as of low to moderate ecological value. Much of the stream course would be located underneath the viaduct for the proposed Fanling Bypass.
It is recommended that construction-phase impacts to the stream are minimised by ensuring that the hydrological linkage between the stream and the Ng Tung River is maintained and a 10m wide buffer zone on either side of the stream is designated and protected by a 2m-high solid barrier to prevent any construction or other materials being deposited in the stream. A 10m wide buffer zone on either side of a stream to ensure that pollution of the stream course is avoided follows recommended international best practice (e.g. Gilliam et al. 2001, Harris and Foster 2001, Uusi-Kamppa et al. (2001)).
It is currently proposed that the clear headroom under the bypass will be at least 5.1m, while the width is proposed to be 20m. However, the design (including the headroom) has not yet been finalized. The resulting height/width ratio of 0.25 would result in a significant reduction in the light levels under the bridge (Clements 2003). Accordingly, it is recommended that replanting with shade-tolerant native shrub and herb species is undertaken, with details to be formulated at the detailed design stage.
It is further recommended that following completion of the Fanling Bypass, a 10m wide buffer zone is designated throughout the stream (see Figure 13.17).
Measures to minimise disturbance impacts on Ma Wat River
A section of the Ma Wat River between will be re-channelised by the Project. This section is of Low ecological value and standard measures to minimise impacts to the watercourse will be sufficient to meet ecological mitigation requirements (see 13.8.2.4 below).
Measures to minimise disturbance impacts on areas of ecological importance
Where not otherwise addressed above, disturbance to all habitats/areas identified as being of ecological importance as habitats or of importance to species should be minimised by erecting solid dull green faunal barriers at least 2m high between such sites and any construction stage works areas. Locations where such barriers should be erected prior to the commencement of construction phase and maintained for the duration of the works period are detailed in Figure 13.15. Where feasible, barriers should be erected in phases to minimise fragmentation impacts. A phasing plan for barrier erection and dismantling should be designed at the detailed design stage of the relevant project element.
While no significant impacts are predicted to these streams arising from the Project, any such impacts should be avoided by avoiding construction works within the streambeds, minimising any works within the streambeds and preventing pollutants or other construction materials from entering the streams.
Direct encroachment upon areas of ecological significance will be
further avoided and minimized during the detailed design stage. Any temporarily
works area, particularly those on natural habitats, would be reinstated upon
completion of works.
13.8.2.3 Mitigation for Impacts of Dust Deposition on Habitats, Flora and Fauna
Impacts of dust deposition on habitats, flora and fauna are generally localised and reversed naturally by rainfall. However, dust deposition can adversely affect plant growth and hence availability of shelter and food for fauna and directly impact specimens of plant species of conservation significance/protected plant species. Good construction site practice to minimise dust generation should therefore be followed on all construction sites. Measures to avoid, minimise and mitigate for impacts on air and water quality are detailed in Sections 4, 5 and 15 of this report.
13.8.2.4 Mitigation for Impacts of Construction Run-off on water bodies in the Study Area and in the Deep Bay Catchment
Impacts during the construction phase of the Project could impact water bodies in the Study Area and also downstream in the Deep Bay Catchment. Construction run-off is potentially destructive to aquatic communities.
Construction work for this Project could generate surface run-off containing lubricants, chemicals and pollutants. In order to prevent these contaminants entering water bodies, a standard drainage system along with silt traps, oil traps and gullies should be installed at required sites, and collection to proper receivers should occur. Drainage systems should be maintained routinely to prevent blockage. Sewage from construction areas should be properly collected to treatment facilities.
The following measures are adopted by most local projects to mitigate the impacts of construction run-off, and are recommended as mitigation for this Project.
• Temporary sewerage and drainage to be designed and installed to collect wastewater and prevent it from entering water bodies;
• Proper locations well away from nearby water bodies should be used for temporary storage of materials (i.e. equipment, filling materials, chemicals and fuel) and temporary stockpiles of construction debris and spoil, and these should be identified before commencement of works;
• To prevent muddy water entering nearby water bodies, work sites close to nearby water bodies should be isolated, using such items as sandbags or silt curtains with lead edge at bottom and properly supported props. Other protective measures should also be taken to ensure that no pollution or siltation occurs to the water gathering grounds of the work sites;
• If temporary access along a riverbed is unavoidable, this should be kept to the minimum in width and length. Temporary river crossings should be supported on stilts above the river bed;
• Stockpiles of construction materials, if necessary, should be properly covered and located away from nearby water bodies;
• Construction debris and spoil should be covered and/or properly disposed of as soon as possible to avoid these being washed into nearby water bodies;
• Construction effluent, site run-off and sewage should be properly collected and/or treated. Wastewater from any construction site should be minimised via the following, in descending order: reuse, recycling and treatment;
• Proper locations for discharge outlets of wastewater treatment facilities well away from sensitive receivers should be identified (i.e. treated wastewater should not be discharged into natural streams, other streams of ecological significance, marsh, mitigation meanders, wet agricultural land, and active or inactive fish ponds);
• Adequate lateral support should be erected where necessary in order to prevent soil/mud from slipping into water bodies;
• Site boundaries should be clearly marked and any works beyond the boundary strictly prohibited;
• Regular water monitoring and site audit should be carried out at adequate points along any watercourses where construction works are underway upstream within their catchments and also on the Ng Tung, Sheung Yue and Shek Sheung Rivers. If the monitoring and audit results show that pollution occurs, adequate measures including temporarily cessation of works should be considered;
• Excavation profiles should be properly designed and executed with attention to the relevant requirements for environment, health and safety;
• Where soil to be excavated is situated beneath the groundwater table, it may be necessary to lower the groundwater table by installing well points or similar means;
• Excavation should be carried out during the dry season as far as possible to minimise contaminated runoff from contaminated soils;
• Stockpiling sites should be lined with impermeable sheeting and bunded. Stockpiles should be properly covered by impermeable sheeting to reduce dust emission during dry season or contaminated run-off during rainy season. Watering should be avoided on stockpiles of contaminated soil to minimise contaminated runoff;
• Supply of suitable clean backfill material after excavation, if require;
• Vehicles containing any excavated materials should be suitably covered to limit potential dust emissions or contaminated run-off, and truck bodies and tailgates should be sealed to prevent any discharge during transport or during wet season;
• Speed control for the trucks carrying contaminated materials should be enforced; and
• Vehicle wheel washing facilities at construction sites’ exit points should be established and used.
Operational phase run-off should be minimised by the use of modern road drainage systems. Should there be any discharge to watercourses, appropriate use of oil interceptors and silt traps should be made so as to minimise potential impacts on water quality.
Measures to avoid, minimise and mitigate for impacts on water quality are detailed in Section 5 and Section 15 (EM&A Manual) of this report.
13.8.2.5 Mitigation for Impacts of Pollution in the Study Area and in the Deep Bay Catchment
Accidental spillage events, whether during the construction or operational phases of the Project, could potentially have a large impact on nearby habitats and habitats downstream including the ecologically highly important Deep Bay ecosystem. Therefore, an emergency contingency plan should be established and implemented by the Project Proponent or its delegate prior to the commencement of any construction. This should then be in place at all times during the construction and operational phases. The plan should include, but need not be limited to, the following:
• Potential emergency situations;
• Chemicals or hazardous materials used on sites (and their location);
• Emergency response team;
• Emergency response procedures;
• List of emergency telephone hotlines;
• Locations and types of emergency response equipment;
• Training plan and testing for effectiveness.
Detailed plans should be prepared and implemented by the Project Proponent or its delegate at later stages during both construction and operational phases.
Surface runoff during the operational phase from developed areas within Project Area could also affect nearby and downstream habitats. Modern drainage systems along with silt traps, oil traps and gullies should be installed at required sites, and collection to proper receivers should take place. Drainage system should be maintained routinely to prevent blockages. With such systems in place, surface runoff is unlikely to affect nearby or downstream habitats significantly.
Measures to avoid, minimise and mitigate for impacts on water quality are detailed in Section 5 and Section 15 (EM&A Manual) of this report.
13.8.2.6 Mitigation for Impacts on Species
Mitigation for impacts on all fauna and flora
Where not otherwise stated, mitigation measures described in Sections 13.8.2.1 to 13.8.2.6 should be applied, where relevant and appropriate, as mitigation of impacts of the Project on flora and fauna, and areas/habitats utilised by flora and fauna of conservation significance. Proposed mitigation measures are recommended below to supplement these measures in respect to potential impacts on species and species groups.
Mitigation for impacts on flora species of conservation significance
Flora specimens of conservation significance/protected plant species Aquilaria sinensis, Ailanthus fordii, Pavetta hongkongensis and Gnetum luofuense (albeit this species is common in Hong Kong) found in fung shui and secondary woodland at Ho Sheung Heung may be indirectly impacted during the construction phase of the Project. Measures to mitigate for disturbance, dust deposition, run-off and other pollution described above should be applied at construction sites adjacent to Ho Sheung Heung fung shui and secondary woodland should be applied to minimise impacts on protected plant species in these woodlands.
Additional measures should be adopted in consultation with AFCD should individuals of flora species of conservation significance, particularly any mature specimens, be identified during the course of the NDA project.
With the implementation of the above, flora specimens of conservation significance/protected plant species found at other locations in the Study Area are not predicted to be directly impacted or indirectly impacted significantly by the Project.
Mitigation for mortality and fragmentation impacts on terrestrial fauna mammal species
Low mortality and fragmentation impacts on mammals and herpetofauna are predicted over the Project Area as a whole, but low to moderate combined mortality and fragmentation impacts on mammals and herpetofauna are predicted in the Ma Tso Lung and Ho Sheung Heung wooded areas in the absence of mitigation. Measures to mitigate for potential construction phase impacts on habitats/areas of ecological importance and construction and operational phase impacts on Ma Tso Lung Stream, tributaries and riparian corridor habitats should be applied to mitigate for mortality impacts on terrestrial fauna. These measures include habitat restoration and provision of a faunal barrier and underpass at Ma Tso Lung Stream in accordance with international best practice for minimising mortality impacts and maintaining connectivity for terrestrial meso-fauna (e.g. Clevenger et al. (2001) and, more specifically, follow the recommendation of Smith (2003) that the maximum recommended distance between crossing structures to maintain connectivity for meso-mammals, carnivores, herpetofauna, and small mammals should not be more than 325m in ‘core conservation areas and habitat corridors’. This distance is achievable here, so long as an underpass is located immediately to the north of the Project Area in the section of the LMC Loop Eastern Connection Road to be constructed under that project.
Mitigation for mortality impacts on bats
Bats are vulnerable to mortality at roosts, especially if the roosts are being utilised by nursing females. Some insectivorous bat species utilise abandoned buildings as roost sites, whilst Short-nosed Fruit Bats often form roosts in Livistona chinensis in village areas.
Mortality impacts on bats are predicted to be low in the absence of mitigation. However, as bats are a relatively little known group and identification is difficult, it is recommended that on a precautionary basis, prior to the demolition of buildings or felling or transplanting of trees, sites should be checked for the presence of bat roosts by a suitably qualified ecologist. If roosts are found to be occupied by nursing females or winter roosts (where bats are also particularly sensitive to disturbance) are found, a review should be carried by a suitably-qualified ecologist, in consultation with AFCD, to determine the most appropriate course of action. For example, it might be possible to avoid and cordon off the roost site and continue works in surrounding areas.
Mitigation for
mortality impacts on birds
The scale of mortality impacts on birds are primarily related to size and whether species utilise closed or open habitats. Accordingly, the measures detailed below apply to all bird species, and are not related to whether species are wetland-dependent or not.
The siting of noise barriers alongside roads has already been identified as a contributor to avian mortality in Hong Kong, and the magnitude of this impact is inevitably greater should these structures be placed in otherwise largely rural areas. In view of evidence to suggest that the placing of predator images on transparent surfaces may not be effective in reducing avian mortality (Klem 1990) and that barriers that appear to be transparent at even short distances are not effective (Martin 2011), potential impacts of collision mortality will be minimised by the use of opaque noise barriers, through which it is obvious there is no passage, and in which no reflection of the surrounding environment is created.
In terms of non-residential building design the following design guidelines for glass and façades should be noted during the detailed design process.
Glass should provide as low a degree of reflectivity as possible, in order that surrounding natural environments are not replicated, thereby enticing birds to fly into the building exterior. Further, careful consideration should be given at the design stage as to whether the appearance of unobstructed passage is imparted by any glass feature of a building or other structure. If so, design should be amended.
Appropriate glass and facade treatments should be used to minimise collision mortality, especially in areas where the glass façade faces natural vegetation. These include the following:
i.
Fritting, or the
placement of ceramic lines or dots on glass, which has little effect on the
human-perceived transparency of the window but creates a visual barrier to
birds outside. This treatment also has the advantage of reducing air
conditioning loads by lowering heat gain, while still allowing light
transmission for interior spaces. It is most successful when the frits are
applied on the outside surface. Frosted glass has similar effects;
ii.
Angled glass should be used only for smaller panes
in buildings with a limited amount of glass;
iii.
Use of glass that reflects UV light (primarily
visible to birds, but not to humans) acts to reduce collision and should be
used where possible;
iv.
Use of lightweight external screens added to
windows or as a façade element of larger buildings are suitable where
non-operable windows are prevalent, which is often the case in modern buildings
in Hong Kong. Use of such screens should be considered where appropriate.
In terms of reducing night-time mortality impacts, eliminating unnecessary lighting is one of the easiest methods, and has the added advantage of saving energy and expense. Potential impacts of nocturnal avian collision with buildings should be minimised by not creating sky glow from the use of night-time lighting at or near the top of buildings or other structures. In addition to avoiding uplighting, light spillage should be minimised, while green and blue lights should be used where possible. As far as possible, building operations should be managed in such a way as reduce or eliminate night-lighting near windows. The potential advantages of removing unnecessary lighting in terms of reducing the carbon footprint of the NDAs development are obvious.
Mitigation for impacts on wetland-dependent bird species
All but one wetland-dependent bird species of conservation significance recorded regularly in the Study and Project Areas occur regularly in Long Valley. Mitigation measures to address impacts on these species will be addressed as an element of the mitigation measures proposed for that area described above. The one species of conservation significance that does not occur regularly is Great Cormorant. In the Study Area this species occurs regularly only on the tidal downstream section of the Ng Tung River. Numbers using this section are small (typically fewer than 10 individuals) relative to the population of approximately 10,000 birds of this species which occurs in Deep Bay in winter. Furthermore, much of this section of the Ng Tung River will not be disturbed by the Project. Accordingly, potential impacts on this species are not considered to be significant.
Mitigation for impacts on non-wetland dependent bird species
Direct, indirect and fragmentation impacts on non-wetland dependent bird species are predicted to be Low in the absence of mitigation, but combined impacts are predicted to be Low to Moderate. Such impacts as will arise are largely a consequence of predicted impacts on wooded habitats, including loss of secondary woodland and plantation and construction phase disturbance to secondary woodland and plantation at Ho Sheung Heung and Crest Hill.
Impacts on these species will thus be addressed as an element of measures to mitigate for impacts described above.
Some open country bird species are predicted to be impacted by loss of such habitats, especially dry agricultural land in FLN. Many of these species occur in larger numbers in wetland habitats and hence impacts on these species will be addressed as an element of mitigation measures to compensate for wetland habitat loss. Mitigation for impacts on those few species that require or prefer dryland habitats will be addressed as an element of the enhancement of dryland habitats in the LVNP habitat mosaic.
Mitigation for impacts on Eurasian Hobby
In the event that Eurasian Hobby should nest at a location on Crest Hill, it may be disturbed significantly, depending upon the proximity of any nest to a Project works area. Distance from any works area, the height of any nest site and proximity to other disturbance sources would all be relevant: birds using a nest high on a pylon (the site known to have been used in the past at Crest Hill) may tolerate disturbance relatively close to a nest site, whilst many raptor species are relatively tolerant of disturbance that was present when nest site was selected but are intolerant of new sources of disturbance.
Measures to mitigate for potential disturbance to Crest Hill habitats will mitigate for most potential additional disturbance to the potential breeding area. Pre-construction phase monitoring should be undertaken in the breeding season (April to August) to check for presence and identify any nest site if present. If such a site is found and/or Eurasian Hobbies are found and behave in a fashion that breeding activity is in progress, a review should be carried by a suitably-qualified ecologist, in consultation with AFCD, to determine the most appropriate course of action; such review should include the option to postpone works or some types of works or works in some locations until after the completion of breeding activity. Remedial actions should then be formulated and implemented.
Furthermore, Eurasian Hobby is a migratory species and is absent from Hong Kong in the dry season. Site clearance during the early dry season (October to January) would not have a significant impact on this species, so it is recommended that site clearance works in the area be scheduled for these months.
Mitigation for impacts on Grey Nightjar
Grey Nightjar was found in the breeding season close to the proposed Freshwater Service Area in FLN area A3-1. This species nests on the ground in grassland and grassland/shrubland and may have a preference for regenerating burnt areas, as many of the observations have come from such areas (M.R. Leven pers. obs.). It is a nocturnal species and roosts/rests during the day. It relies on camouflage when roosting and nesting and will tolerate close approach by people during the day.
In view of the large area of habitat present, it is unlikely that a nest site will be selected that is within or very close to the Project works area. Pre-construction phase monitoring should be undertaken in the early breeding season (March to May), and if a nest site is found any site clearance works should be postponed. Furthermore, this is known to be a migratory species and may not be present, or present in low numbers, in the dry season. Site clearance during the early dry season (October to February) would not have a significant impact on this species, so it is recommended that site clearance works in the area be scheduled for these months.
Mitigation for impacts on egretries
Man Kam To Egretry is located in plantation in the northern part of the FLN NDA. The site of the egretry would be impacted directly by the proposed Fanling Bypass and roundabout connection to Man Kam To Road. Avoidance of impacts to the egretry has been considered by realignment of the Bypass, but the road design is constrained by existing infrastructure (roads and Ng Tung River channel) and it is not possible to realign the Bypass to avoid the egretry.
Currently, the Man Kam To Road Egretry is subject to heavy disturbance and suitable nesting substrate was partly cleared in 2012. The unavoidable loss of this breeding site is therefore evaluated of low to moderate significance.
Unavoidable clearance of Man Kam To Road Egretry and construction of Fanling Bypass roundabout (western section) should be scheduled outside the breeding season.
Loss of this breeding site would be significant. It is proposed therefore that loss of the egretry should be mitigated by appropriate planting of trees and bamboo to provide compensatory habitat for breeding ardeids, with the intention that this could provide an alternative nesting site for birds from the Man Kam To Road Egretry.
Relocation of an egretry has not previously been successfully achieved in Hong Kong. Creation of egretries has been successful overseas, however (Hafner 2000, White et al. 2008), and there is no apparent reason to suppose that this approach should not also be possible in Hong Kong. Trees and bamboo have been planted at the wetland mitigation area provided for MTRC Lok Ma Chau Spur Line Extension and at Mai Po Nature Reserve with the intention of attracting breeding ardeids to these sites.
Provision of compensatory planting aiming to attract breeding egrets requires that a suitable location should be found. This should have low levels of direct human disturbance, be close to suitable foraging locations and preferably also close to the site of the existing egretry. It is considered that the most suitable location for this would be in area A1-7 in FLN NDA. This land contains a former meander that was isolated from the Ng Tung River during channelisation of the river. The meander is currently maintained by AFCD and DSD as mitigation for the ecological impacts of river channelisation. The area is proposed to be zoned as Conservation Area (CA) under in the revised RODP. Both of the adjacent areas (A1-3 and A1-9) are zoned for Agriculture in the revised RODP.
The
landform and hydrological regime of the proposed compensation site is broadly
suitable for the creation of a tree and bamboo clump in the centre of the
former meander (see Appendix 13.10 Plate 19),
however some earthmoving works will be required to create appropriate
conditions for planting of trees and bamboos. During the design process it is
recommended to consider the merits and disadvantages of adjusting levels such
that the central planting area, which is currently surrounded on three sides by
the oxbow of the former meander, is turned into an island. DSD should be consulted regarding
the technical feasibility.
As mentioned above, there are no previous examples of the successful provision of an artificial egretry in Hong Kong. Reprovision of potential nesting locations should follow overseas practice for the creation of artificial nesting sites (for example Hafner 2000, White et al. 2008). It is likely to take several years after planting before the vegetation is of sufficient maturity to be suitable for breeding egrets. In principle, the provision of suitable nesting locations should be relatively easy to achieve through planting appropriate species of trees and, especially, bamboo (Bambusa eutuldoides particularly favoured by breeding egrets).
Avoidance of human (and other) disturbance is of great importance, either through fencing of the area to prevent human access or by surrounding the site with water.
Judging from flight-line observations, the main foraging sites for Chinese Pond Herons breeding at Man Kam To Road are apparently in the wetland habitats in and around Long Valley. Birds from the egretry were often observed flying along Ng Tung River in the direction of the proposed location for compensatory planting in A1-7, which is closer to the foraging sites than the existing egretry. Measures to minimise disturbance to Ng Tung, Sheung Yue and Shek Sheung Rivers and other areas described in Section 13.8.2.2 should be applied to this site and the flight-line corridor between it and Long Valley.
A detailed plan covering all aspects of design and implementation and monitoring requirements of these measures should be prepared in consultation with AFCD and implementation of site preparation, planting and commencement of habitat management should be included as an element of the Advance Works Package of the First Phase of Infrastructure and Development of the project (see also Section 13.9 and Section 13.11).
Mitigation for disturbance and fragmentation impacts on Ho Sheung Heung Egretry were addressed as an element of required measures to mitigate for impacts on habitats of ecological importance, above.
The possibility that egretry locations may change and that new egretries may be established before or during the construction phase of the project should be taken into account. If any new egretry, or partially or wholly relocated egretry, is identified before or during the construction phase, measures required to avoid, minimise and compensate for impacts on the egretry should be formulated and implemented, as appropriate. The appropriate measures will vary depending on the location of the egretry relative to predicted sources of direct, indirect and fragmentation impacts and the time at which the egretry is found relative to the project construction programme. However, the relevant measures detailed in Table 13.144 (Mitigation of impacts on wetland-dependent bird species of conservation significance) and Table 13.147 (Mitigation of impacts on egretries and egretry flight-lines), together with whichever other mitigation measures are necessary in order to mitigate for any unacceptable impacts on the egretry and the ardeids using it, should be implemented as required.
Mitigation for
impacts on herpetofauna
Mitigation for mortality impacts on herpetofauna has been addressed above.
Low to Moderate impacts on reptile species of conservation significance are predicted as a consequence of loss of habitat and habitat fragmentation, and Low impacts are predicted due to disturbance; combined impacts are predicted to be Low to Moderate. Impacts to amphibians from all sources are predicted to be Low, except for impacts on Chinese Bullfrog, impacts on which from all sources are predicted to be Low to Moderate.
Measures to mitigate for loss of wetland and woodland habitats and minimise indirect impacts to Long Valley, woodland habitats, habitats in Ma Tso Lung and habitats of ecological importance will address impacts on herpetofauna utilising these habitats/areas.
A small number of reptile and amphibian species of conservation significance, of which Chinese Bullfrog is the most frequently detected species, are known to be present (or have been reported in the past) in farmland and other habitats in the area between the urban area of Sheung Shui and Fanling and the Ng Tung River. Whilst this area, and habitats in this area, are not considered to be of importance or contain preferred habitats of any of these species, on a precautionary basis it is recommended that these areas be surveyed by a suitably qualified ecologist prior to the commencement of any building demolition or site clearance, and any individuals of species of conservation importance found should be caught if possible and relocated to suitable receptor sites within LVNP or outside the development areas of the Project, depending on the habitat requirements of the species (see Section 13.9 and Section 13.11).
The above recommendation also applies in respect to works in the Ma Tso Lung Stream area. However, in this area consideration should be given as to whether immediate relocation to a suitable location within the Ma Tso Lung Stream catchment would be appropriate, taking into account the habitat and other ecological requirements of the species, their vagility, and whether release locally would still leave the individuals exposed to impacts from the project and/or sources. In such instances the individuals should be held temporarily in captivity, pending consultation with AFCD as to whether relocation to a protected area, such as a Country Park, would be more appropriate. This consideration applies, especially, should any individuals of Three-banded Box Terrapin be found (see Section 13.9 and Section 13.11).
Mitigation for impacts on butterflies
Impacts on butterflies are predicted to be of low severity in the absence of mitigation. However, butterflies may be affected slightly by the indirect consequences of dust deposition on larval food plants. Measures to avoid and minimise impacts of dust deposition on fung shui and secondary woodland at Ho Sheung Heung would serve to reduce such impacts in this area of importance to butterflies.
In addition, adjustments to the development footprint and works areas should be considered in order to avoid or minimise encroachment onto shrubland on Crest Hill during the detailed design stage for project elements in this area. Any temporary works areas should be restored by planting native shrub species, species selection should be made by a suitably qualified plant ecologist/botantist.
While it is not considered that impacts on any butterfly species are of significance, it is recommended to consider inclusion of the grass species Ischaemum barbatum and Miscanthus sinensis (the larval food plants of Small Three-ring and Pale Palm Dart, which are butterfly species of conservation significance which have been found in wetlands in the area) in the restoration planting of the Ma Tso Lung Stream riparian corridor in order to benefit these species. The other larval food plant of Pale Palm Dart, Pennisetum purpureum is not recommended as it is an exotic species, though it may well colonise without assistance.
Mitigation for impacts on dragonflies
Combined impacts on dragonflies are predicted to be Low during both construction and operational phases, and no specific measures are required to address impacts on dragonfly species in addition to measures to address impacts to wetland habitats described above.
Mitigation for impacts on stream fauna (fish and invertebrates)
Impacts on most fish and stream invertebrates are predicted to be of Low severity. However, these will be addressed by measures to avoid stream habitats or minimise disturbance and pollution impacts on stream habitats by described above.
Construction phase impacts on Small Snakehead are predicted to be Moderate in the absence of mitigation; due to impacts arising from the diversion of a section of Ma Tso Lung Stream and disturbance to adjacent riparian habitats. Measures to minimise impacts to this species are addressed as an element of the measures to avoid, minimise and compensate for impacts on this stream and stream fauna.
Impacts from the project are predicted on the crab, Sommaniathelphusa zanklon, in Ma Tso Lung San Tsuen Stream, and Tung Fong and Tin Ping Shan Tsuen Watercourses. Only single individuals were found in Tung Fong and Tin Ping San Tsuen Streams, both of which will be rechannelised. There is very limited suitable habitat for these species in these streams, and it is most unlikely that it is present in significant numbers. Further, surveys for this and the LMC Loop Study and observations in the area south of Yuen Long and near Ngong Ping, Lantau (Study Team pers. obs.) suggest that this species is relatively widespread in the New Territories and it is tolerant of pollution. Impacts on this species from the Project are, therefore, predicted to be Low, except for those in Ma Tso Lung San Tsuen Stream (see below).
However, since Tung Fong and Tin Ping San Tsuen Streams will be replaced by drainage systems, there will be no habitat for displaced individuals in these streams following completion of construction works. Accordingly, it is recommended that both of these streams are searched by an appropriately qualified ecologist, prior to the commencement of construction works. Any specimens of Sommaniathelphusa zanklon found should be caught and translocated to an appropriate relocation site, such as Ma Tso Lung San Tsuen Stream where this species is known to be present. In addition, consideration could be given to translocation to the LVNP, where conditions in the watercourse are not dissimilar to other locations where this species has been found.
Capture and field identification of this species is not problematic, when undertaken by an appropriately qualified ecologist (Study Team pers. obs.).
As noted above in respect of mitigation measures to address impacts of the project on Small Snakehead, measures are proposed to address impacts of the project on Ma Tso Lung San Tsuen Stream and stream fauna, including Sommaniathelphusa zanklon.
Mitigation for cumulative impacts
Cumulative impacts on wetland dependent bird species of conservation significance that require, or are associated with, freshwater wetland habitats are addressed as an element of the measures to compensate for wetland habitat loss and to avoid, minimise and compensate for disturbance and fragmentation impacts on waterbirds using Long Valley.
Likewise cumulative impacts on habitats and fauna in the Ma Tso Lung area are addressed as an element of the measures to compensate for loss of wetland and riparian habitats and disturbance and fragmentation impacts to fauna in this area described above. There are no other cumulative impacts of significance arising from the Project.
13.8.2.7 Impacts of Mitigation Provision
Proposed wetland habitat enhancement measures in LVNP will have some impact on habitats and species in Long Valley. However, the enhancement measures proposed will be similar in nature and scale to those which are currently undertaken on a regular basis under the MA and, furthermore, are similar to those which regularly occur in all agricultural areas. Accordingly, significant adverse impacts are not predicted.
Faunal barriers to minimise disturbance and other impacts to Long Valley, the main river channels and other sites of ecological importance may act as barriers which increase fragmentation impacts on terrestrial fauna.
Such impacts will largely be avoided as in most cases barriers are proposed to be erected along the edge of works areas; not around areas of ecological importance. Where barriers are required between works areas and areas of ecological importance, the areas of ecological importance will not be completely surrounded by works areas, and hence will not be surrounded by barriers (thus retaining connectivity with other areas/habitats); in particular, barriers will not be required between Ho Sheung Heung woodland and Crest Hill and between the LVNP and KTN areas C1-4 (village) and C1-6 (Agriculture) or between the part of Long Valley north and west of the Sheung Yue River and areas to the north and west. Detailed design and deposition of the barriers with a view to minimize impacts on animal movements are to be reviewed during the detailed design stage.
Mortality to terrestrial fauna can be minimised by ensuring that there are periodic gaps in barriers or sections where a space is left under the barrier. In practice, it is rare for such barriers to be continuous for long distances; however, it is recommended that measures to permit one-way fauna movement in locations where mortality or disruption to life cycles might occur should be included at the detailed design stage of the Project.
Barriers to prevent disturbance to fauna will not result in fragmentation impacts on birds as their height will be much less than other habitat elements, notably trees. However, mortality impacts on birds may increase if they collide with barriers. Such mortality can largely be avoided by ensuring that barriers are bird-friendly and of non-transparent material of subdued or neutral tones (dull green or dull brown).
Permanent faunal barriers proposed to be formed along the at-grade section of the LMC Loop Eastern Connection Road at Ma Tso Lung will be designed in order to ensure that terrestrial fauna is not killed by vehicles on the road, and so will act as a barrier to movement. The most significant linkages are along the riparian corridor; these will not be fragmented within the Project Area during the operational phase of the Project, as the road will cross the stream on viaduct and will not directly impact the stream and its banks which will remain.
However, for some fauna, linkages with habitats further from the stream may be of some significance. Accordingly, it is proposed to provide an underpass at Ma Tso Lung Stream in accordance with international best practice for minimising mortality impacts and maintaining connectivity for terrestrial meso-fauna (e.g. Clevenger et al. (2001) and, more specifically, follow the recommendation of Smith (2003) that the maximum recommended distance between crossing structures to maintain connectivity for meso-mammals, carnivores, herpetofauna, and small mammals should not be more than 325m in ‘core conservation areas and habitat corridors’. This distance will be achieved so long as the most southerly underpass beneath the LMC Loop Eastern Connection Road proposed as a mitigation measure of the LMC Loop project is located immediately to the north of the NDA Project Area boundary.
During the construction stage of the road, temporary faunal barriers are proposed to minimise disturbance and fragmentation impacts to fauna during the construction period. As these will be orientated in parallel with the riparian corridor, the most important linkages will not be fragmented, but some construction phase impact to linkages with habitats further from the stream will take place.
Construction and operational phase impacts of measures to mitigate for indirect impacts and fragmentation impacts on the Ma Tso Lung riparian corridor and fauna are evaluated below. Impacts of faunal barriers in other locations and other impacts of mitigation measures are not considered to be significant.
Table 13.134 - Potential indirect and fragmentation impacts on the Ma Tsung Lung Stream corridor from construction and operational phase faunal barriers in the absence of mitigation measures
|
Criteria |
Assessment |
|
Habitat Quality |
Ma Tso Lung Stream and tributaries are of
Moderate to High ecological value. The riparian corridor, while containing a
variety of habitats of varying ecological value is mainly of importance in
maintaining linkages for fauna of conservation importance using habitats in
along the stream. |
|
Species |
Flora diversity is low but fauna includes wetland-dependent species of
conservation significance in or near the stream including the globally
Critically Endangered Three-banded Box Terrapin (though the latter is
unlikely to utilise the area of stream which will be impacted on a regular
basis as it favours wooded habitats). |
|
Size/Abundance |
The
length of stream along which fragmentation will take place is relatively
short and the barriers will be parallel to the movement corridor along the
stream, but some fragmentation impact on movement of fauna perpendicular to
the corridor will occur. |
|
Duration |
Construction phase only, mitigated at operational stage by underpasses
proposed as mitigation measures for this project and the LMC Loop project. |
|
Reversibility |
Impacts
mostly reversible in operational phase. |
|
Magnitude |
Low as movement perpendicular to the riparian corridor is unlikely to
involve many species or individuals |
|
Impact Severity |
Low during
construction phase, mitigated at operational stage by underpasses. |
This
section addresses 3.4.14.4 (xi) of the Study Brief, which requires the
evaluation of the feasibility and effectiveness of the recommended mitigation
measures and definition of the scope, location, implementation arrangement,
subsequent management and maintenance of such measures.
13.9.1
Guiding principles for mitigation measures
13.9.1.1 Guiding
principles for mitigation measures in the LVNP
The guiding principles upon which the mitigation proposals in the LVNP have been created are as follows:
· Protection and enhancement of 37ha of Long Valley to have it managed as a whole to provide on-site mitigation measures to compensate for the wetland loss due to the project and to mitigate for some impacts on fauna which will not be mitigated in situ;
· Recognition that faunal targets for the mitigation areas should be based upon clear conservation objectives and the need to mitigate for any potential adverse impacts of any development on habitats, flora or fauna of conservation importance and any broader ecological enhancement opportunities presented;
· Need to maintain the integrity of existing ecological linkages between the LVNP and adjacent wetland habitats;
· Need to ensure that there is no net loss of wetland function in the LVNP as a consequence of the mitigation measures proposed and/or as a consequence of the project;
· Recognition of the success of the current and past MAs in Long Valley in increasing both the numbers of and diversity of wetland bird species, and the importance of mitigation flexibility and the need for active management of the habitat mosaic in order to achieve this success;
· Recognition of the importance of active management of agricultural land (including active management of ponds) and the important role of current stakeholders in the management of Long Valley (including farmers, the CA and HKBWS) in achieving this success, and recognition of their continuing role in the plan preparation process and in potential future implementation management and maintenance;
· Recognition that wetland enhancement has a proven track record both in Long Valley and elsewhere in Hong Kong (relevant examples here include wetland rehabilitation or enhancement for the Lok Ma Chau Spur Line, West Rail, the Hong Kong Wetland Park and the Yuen Long Bypass Floodway).;
· Recognition of the importance of sustainability and environmental stability;
· Recognition of the importance of maintenance of a continuous water supply, especially during the dry season;
· Requirement that hydrological changes as part of the wetland enhancement must not increase the flood risk to other basin users;
· Acknowledgement of the importance of an understanding of the habitat requirements of target species, the feasibility of the provision of the required habitats and a realistic assessment of the likelihood that the habitats will be utilised once they are created;
· Recognition of the ecological value of any existing habitats on site, whilst acknowledging that wetland restoration may require significant alterations to other habitats that are of lower ecological value at present;
· Recognition that monitoring is essential in order to assess the success or otherwise of the mitigation measures and to guide management decisions.
13.9.1.2 Guiding Principles for Other Mitigation
Measures
The guiding principles upon which other mitigation proposals have been designed are as follows:
· Recognition that the mitigation measures should be feasible and effective in meeting the need to mitigate for any potential adverse impacts of any development on habitats, flora or fauna of conservation importance;
· Requirement that mitigation measures involving hydrological changes must not increase the flood risk to other basin users;
· Requirement that mitigation measures involving the provision of compensatory habitats should be largely self-sustaining: once the compensatory habitats are established, management should largely be limited to maintenance work. This should still allow for adaptive management, whereby management practices change in response to on-site conditions (especially in response to any failures to meet mitigation objectives);
· Recognition that monitoring is essential, in order to assess the success or otherwise of the rehabilitated wetlands, and to guide management decisions.
Habitats, areas of habitats and fauna and flora groups that primarily determine and define the scope, type and location of proposed mitigation measures were described in Section 13.8; key species, and groups of species that are targets of mitigation measures are detailed below.
13.9.2
Key Mitigation for Target Species
Following a review of the baseline data, the key species (and groups of species) for which mitigation measures are required in order avoid, minimise and compensate for impacts of the project were identified. It is these key species (and groups of species) for which mitigation measures will be primarily designed and which will form the basis for determination of construction and operational phase targets for the project.
Key Species, and groups of species, are those which fulfill the following requirements:
· Species of conservation significance based upon criteria detailed in Section 13.4.3.8 that have been reported in the impacted areas/habitats in numbers considered to be of significance since 1998; or
· Any species that, although not of conservation significance, has been recorded in the impacted areas/habitats in numbers sufficiently high to indicate that the distribution and abundance in Hong Kong or assessment area as a whole would be significantly impacted by the proposed development.
During the assessment process the baseline ecological data were reviewed and the species that meet these requirements were identified. Reasons for the identification of key species, the areas where these species will be impacted significantly and the locations where mitigation measures will be applied, together where these species are present and the mitigation measures required to meet these impacts are included in Table 13.135.
Table 13.135 – Key species and
groups of species requiring mitigation measures
|
Species and Species Groups |
Basis of qualification |
Area where significant impacts predicted |
Area for mitigation for which species is a Key Target |
Mitigation measures for Key Target species/ Habitat requirements |
|
Larger Ardeids
(Eastern Cattle Egret, Grey Heron, Great Egret, Intermediate Egret, Little Egret, Chinese Pond Heron, and Black-crowned
Night Heron). |
All are species of
conservation significance occurring in the Study Area in significant numbers;
Eastern Cattle Egret, Little Egret and Chinese Pond Heron breed at Ho Sheung
Heung Egretry, the latter two species also breed at Man Kam To Road egretry. |
Long Valley foraging
areas; flight-lines from Ho Sheung Heung egretry to foraging areas, foraging
areas along main river channels; also Man Kam To egretry in respect to Little
Egret and Chinese Pond Heron. |
Long Valley foraging
areas; flight-lines from Ho Sheung Heung egretry; FLN area A1-7. |
Early provision or enhancement of foraging ground before and during the
advance stage work. Enhancement of wetland habitats and non-wetland habitats in Long
Valley; compensatory egretry habitat provision at FLN area A1-7 for Little
Egret and Chinese Pond Heron. Measures to minimize disturbance impacts Open and lightly vegetated wetland habitats. |
|
Smaller Ardeids (Yellow Bittern, Von Schrenck’s Bittern, Cinnamon Bittern,
and Ruddy Crake) This last species is not an ardeid but is included here due
to a shared requirement for well-vegetated wetlands |
All are species of conservation significance occurring in the
Study Area in significant numbers. |
Long Valley. |
Long Valley. |
Enhancement of
wetland habitats and non-wetland habitats in Long Valley. Measures to minimize
disturbance impacts Well-vegetated wetland habitats. |
|
Eurasian Teal |
Species of conservation significance occurring in the
Study Area in significant numbers. |
Long Valley. |
Long Valley. |
Enhancement of
wetland habitats and non-wetland habitats in Long Valley. Measures to minimize
disturbance impacts Open wetland habitats (night)/ secure areas (day) |
|
Japanese Quail |
Species of conservation significance occurring in the
Study Area in significant numbers. |
Long Valley. |
Long Valley. |
Enhancement of
non-wetland habitats in Long Valley. Measures to minimize
disturbance impacts Dry agriculture. |
|
Shorebirds, especially species associated with freshwater wetlands
(Pheasant-tailed Jacana, Black-winged Stilt, Pied Avocet, Greater
Painted-snipe, Oriental Pratincole, Pacific Golden Plover, Little Ringed
Plover, Marsh Sandpiper, Common Greenshank, Wood Sandpiper, Swinhoe’s Snipe,
Temminck’s Stint, Long-toed Stint) |
All species of conservation
significance occurring in the Study Area in significant
numbers; except Little Ringed Plover which occurs in the Study Area in
numbers of significance in a Hong Kong context. |
Long Valley, some in
Sheung Yue River. |
Long Valley. |
Enhancement of
wetland habitats in Long Valley. Measures to minimize
disturbance impacts Open and
well-vegetated wetland habitats (also dry agriculture in the case of Little
Ringed Plover). |
|
Pied & White-throated Kingfishers |
Species of conservation significance occurring in the
Study Area in significant numbers. |
Long Valley. |
Long Valley. |
Enhancement
of-wetland habitats in Long Valley. Measures to minimize
disturbance impacts Open wetland
habitats. |
|
Wetland-dependent passerine birds (Citrine Wagtail, Red-throated Pipit,
Pechora Pipit, Buff-bellied Pipit, Bluethroat, Pallas’s Grasshopper Warbler,
Zitting Cisticola, Golden-headed Cisticola) |
Species of conservation significance occurring in Long
Valley significant numbers. |
Long Valley. |
Long Valley. |
Enhancement of
wetland habitats in Long Valley. Measures to minimize
disturbance impacts Wet agricultural
land and other vegetated wetland habitats , |
|
Passerine birds occurring in wet and dryland habitats in Long Valley
(Chestnut-eared Bunting, Yellow-breasted Bunting, Japanese Yellow Bunting) |
Species of conservation significance occurring in Long
valley in significant numbers. |
Long Valley. |
Long Valley. |
Enhancement of
non-wetland habitats in Long Valley. Measures to minimize
disturbance impacts Wet agricultural
land and other vegetated wetland habitats, Dry agricultural land, bunds. |
|
Reptiles recorded from Long Valley (Buff-striped Keelback, Many-banded
Krait, Chinese Cobra, King Cobra |
Species of conservation significance recorded in Long
Valley. |
Long Valley. |
Long Valley. |
Enhancement of
habitats in Long Valley. Relocation prior to
works, if required. Well-vegetated
habitats; cover. |
|
Three-banded Box Terrapin |
Species of conservation significance; only one individual identified
but threat status and potential global significance of Hong Kong population
warrants inclusion as a key species. |
Ma Tso Lung Stream
catchment. |
Ma Tso Lung Stream
catchment. |
Habitat restoration
and enhancement along lower section of Ma Tso Lung Stream. Relocation prior to
works, if required. Clean streams in
wooded areas. |
|
Chinese Bullfrog |
Species of conservation significance, widespread in the Study Area,
albeit not in large numbers. Present in a number of locations where direct or
indirect impacts are predicted. |
Long Valley; Ma Tso Lung; development areas in KTN and
FLN. |
Long Valley
(including translocation from elsewhere); Ma Tso Lung (where in situ mitigation measures are
proposed. |
Enhancement of
wetland habitats in Long Valley. Relocation prior to
works, if required. Well-vegetated
wetland habitats. |
|
Two-striped Grass Frog |
Local Concern; uncommon and restricted to a few sites in Hong Kong. |
Long Valley. |
Long Valley. |
Enhancement of
wetland habitats in Long Valley. Relocation prior to
works, if required. Well-vegetated
wetland habitats. |
|
Sommaniathelphusa zanklon |
Global Concern; has not been found outside Hong Kong. |
Ma Tso Lung San
Tsuen Stream, Tung Fong Watercourse, Tin Ping Shan Tsuen Watercourse. |
Ma Tso Lung Stream,
consider translocation to Long Valley |
Set-back from and
maintenance of hydrological continuity of Ma Tso Lung and Ma Tso Lung San
Tsuen Stream, and restoration as natural stream course. Lotic wetland
habitats, tolerant of organic pollution. Relocation prior to
works, if required. |
13.9.3
Habitat Creation and Management Plans
A Habitat Creation and Management Plan (HCMP) in respect of the LVNP should be drawn up by the Project Proponent, or designate, in advance of the commencement of the Project. This HCMP should address, but need not be limited to, final determination of target species and monitoring protocol; and the objectives, detailed design, implementation, maintenance, management and monitoring requirements for the LVNP.
To facilitate and inform preparation of this HCMP, measurement of the current levels of target species using wetland habitats of importance, or potential importance, for species or species groups of conservation significance that will be impacted by the Project, other than those only using wetland habitats or areas (for example Ma Tso Lung Stream and riparian corridor) for which other site or area-specific mitigation measures are proposed, will be required.
These habitats include wet agricultural land, marsh, pond, and mitigation wetland. In addition, in recognition that there is often a relatively rapid change in the areas of these habitats relative to dry agricultural land and lowland dry grassland and seasonally wet grassland, and in recognition of the use of some of these areas by small numbers of species of conservation significance, any areas of the latter habitats predicted to be impacted by the Project should also be surveyed.
The Preliminary Habitat Creation and Management Plan (HCMP) (Appendix 13.10) will provide the basis for preparation of the HCMP. The Preliminary HCMP also provides additional details of the habitat enhancement mechanism and current conditions in Long Valley relevant to the future management objectives, in particular the experience that has been gained under the current and past MAs and discusses options for management of visitor access, while noting that all these matters require to be considered in more detail at a later stage, as well as explored via engagement with relevant stakeholders.
A Woodland Planting and Management Plan (WPMP) should be prepared for the proposed areas of compensatory woodland in advance of the commencement of the NDAs project by the Project Proponent, or designate, in advance of the commencement of the Project. This WPMP should address the objectives, detailed design, implementation, maintenance, management and monitoringrequirements for the compensatory habitat provision.
An Egretry Habitat Creation and Management Plan (EHCMP) for the creation and management of compensatory habitat required for the proposed area of compensatory egretry habitat in the mitigation wetland at FLN area A1-7 by the Project Proponent, or designate, in advance of the commencement of the Project. This EHCMP should address monitoring protocol, objectives, detailed design, implementation, maintenance and management and monitoring requirements for the compensatory habitat provision and for any egretries existing before or during construction works.
The habitat to be created and enhanced in FLN area A1-7 will also be designed and managed to provide suitable habitat for Dingy Dusk Hawker, a dragonfly species only known in the Study Area from another mitigation wetland in FLN, which will be developed under the project. Measures to be undertaken in respect of this species should also be included in the scope of the EHCMP.
Site specific plans for possible relocation of fauna species of conservation concern and for additional mitigation for flora of species of concern identified before and during the construction phase.
13.9.4 Implementation, management and maintenance of recommended mitigation measures to avoid, minimise and compensate for ecological impacts
The tables below address the Study Brief requirement to define the scope, type, location, implementation arrangement, subsequent management and maintenance of measures required in order to avoid, minimise and compensate for the ecological impacts due to the implementation of the project. Cross-reference is made back to where this measure is proposed in Section 13.8 of the EIA and forward to the EM&A Log Ref. (Project Implementation Schedule (PIS) Reference) in the Common Mitigation Measures Schedule of the EM&A Manual Appendix 2.2. Locations where construction phase barriers are required to mitigate for disturbance impacts are shown in Figure 13.15 and are also specified, with reference to the revised RODP areas, in the EM&A Manual Appendix 2.2.
Note that where ‘N/A’ is stated in this table, this refers to the measure not been of relevance to the applicable stage of the project; maintenance and management agents are identified wherever these are required.
Measures to minimise hydrological, dust and water pollution impacts are dealt with in the relevant sections of the EIA Report.
13.9.4.1 Impacts on habitats of ecological importance
Table 13.136 - Mitigation for direct loss of wetland and woodland
habitats
|
Mitigation Measure
No./ Section Ref./PIS
Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
1.1/13.8.2.1 |
Mitigation for direct loss of wetland habitats |
||||
|
1.1.1/ 13.8.2.1/ E4 |
Long Valley Nature
Park (LVNP) designation, design, and implementation. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan (LVNP
HCMP)). |
Project proponent (pre-construction
baseline data collection and evaluation; LVNP HCMP review). |
N/A. |
N/A. |
|
1.1.2/ 13.8.2.1/ E15, E25 |
Enhancement of
wetland habitats in LVNP. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan LVNP HCMP). |
Project proponent (pre-construction
baseline data collection and evaluation; LVNP HCMP review). |
Project proponent
/contractor (implementation of design of mitigation measures). |
AFCD (management,
maintenance and monitoring). |
|
1.2.3/ 13.8.2.1/ E2, E14 |
Compensation for
loss of seasonally wet grassland at Ma Tso Lung by habitat restoration and
enhancement along diverted section of Ma Tso Lung Stream. |
Project proponent (design
of Ma Tso Lung Stream diversion and buffer zone habitat restoration
measures). |
Project proponent (pre-construction
baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
Government land
allocatee. |
|
1.2/13.8.2.1 |
Mitigation for direct loss of woodland habitats |
||||
|
1.2.1/ 13.8.2.1/ E1, E18, E27 |
Compensatory
woodland planting. |
Project proponent
(Woodland Planting and Management Plan WPMP). |
Project proponent
pre-construction baseline data collection and evaluation; WPMP review). |
Project proponent /
contractor (implementation of mitigation measures) for 2 years. |
AFCD (managementand
maintenance) for 9 years, after which the woodland will be handed over to
LandsD for ad hoc maintenance. |
13.9.4.2 Indirect,
fragmentation and cumulative impacts on habitats of ecological importance
Table 13.137 - Mitigation for indirect, fragmentation and cumulative impacts on Long Valley
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
2.1.1 13.8.2.2/ E15, E25 |
Long Valley Nature
Park (LVNP) designation, design, and implementation including measures to
redistribute wetland habitats in LVNP to concentrate closed wetland habitats
(marsh and reed marsh) in areas closest to disturbance sources; and to stock
fish as food to compensate for disturbance to foraging areas in main river
channels and elsewhere. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan (LVNP
HCMP)). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
Project proponent
/contractor (implementation of design of mitigation measures and monitoring
prior to handover to AFCD). |
AFCD (management,
maintenance and monitoring). |
|
2.1.2/ 13.8.2.2/ E5 |
Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung Egretry. |
PlanD (guidelines
for stringent planning control detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
2.1.3/ 13.8.2.2/ E7 |
Building setback
from Long Valley (30m setback from Road D3 in KTN area B3-12) and mounding
and planting in KTN area C1-1. |
PlanD/ LandsD
(detailed and explained in Layout Plan)). |
N/A. |
N/A. |
N/A. |
|
2.1.4/ 13.8.2.2/ E13 |
No construction
during ardeid breeding season (1st March to 31st July)
along Sheung Yue River north and east of KTN area D1-5 and east of D1-9 and
C2-3, including no works under this project within KTN areas C2-1 and C1-8
(Open Space), including any works on or to the bridge over the Sheung Yue
River between areas C2-1 and C1-8, and restriction of working hours on new
pedestrian bridge over the Sheung Yue River to 09.00 to 17.30 during the
ardeid breeding season. |
N/A. |
N/A. |
Contractor. |
N/A. |
|
2.1.5/ 13.8.2.2/ E16, E17 |
Erection of 2m high
solid dull green site barrier fence between works areas and LVNP and Long Valley north and west
of the Sheung Yue River. |
Project proponent
detailed design consultant (formulation of detailed design of the fence) |
N/A. |
Contractor. |
N/A. |
|
2.1.6/ 13.8.2.2/ E11 |
Review design and
construction methods for all bridges especially those on the Sheung Yue and
tidal Ng Tung Rivers and adopt methods which minimise impacts on Long Valley
and disturbance and fragmentation impacts on fauna. |
Project proponent/
detailed design consultant (detailed design of bridges). |
N/A. |
N/A. |
N/A. |
|
2.1.7/ 13.8.2.2/ E11 |
Avoid removal or
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
project. |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
Table 13.138 - Measures to minimise disturbance and fragmentation impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers and to minimise fragmentation impacts on linkages with the Deep Bay wetland ecosystem
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed mitigation
measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
2.2.1/ 13.8.2.2/ E5 |
Stringent planning
control in Long Valley north and east of the Sheung Yue River to minimise
disturbance and fragmentation impacts on large waterbirds foraging and using
the flight-line along the non-tidal section of the Ng Tung River. |
PlanD (guidelines
for stringent planning control detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A |
|
2.2.2/ 13.8.2.2/ E6 |
Planning for
retention of existing trees in Open Space zones along the Sheung Yue, Ng Tung
and Shek Sheung Rivers and incorporation of these in screen planting along
the rivers in the detailed design of these Open Space zones. |
Project proponent/
detailed design consultant (detailed design of Green Corridors along
watercourses and detailed design of Open Space areas and development areas
along river corridors. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Contractor. |
Government land
allocatee/ contractor |
|
2.2.3/ 13.8.2.2 E16 |
Erection of 2m high
solid dull green site barrier fence between river channel and any active
works area along or adjacent to Ng Tung, Sheung Yue and Shek Sheung Rivers. |
Project proponent
detailed design consultant (formulation of
detailed design of the fence) |
N/A. |
Contractor. |
N/A. |
|
2.2.4/ 13.8.2.2/ E7 |
Building setback
from Long Valley (30m setback from road D3 in KTN area B-12), will also
reduce disturbance impact on Sheung Yue River. |
PlanD/LandsD
(detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
2.2.5/ 13.8.2.2/ E13 |
No construction
during ardeid breeding season (1st March to 31st July)
along Sheung Yue River north and east of KTN area D1-5 and east of D1-9 and
C2-3 and restriction of working hours on new pedestrian bridges over the
Sheung Yue River and tidal Ng Tung River to 09.00 to 17.30 during the ardeid
breeding season (1st March to 31st July). |
N/A. |
N/A. |
Contractor. |
N/A. |
|
2.2.6/ 13.8.2.2/ E11 |
Review design and
construction methods for all bridges especially those on the Sheung Yue and
tidal Ng Tung Rivers and adopt methods which minimise impacts on rivers and
disturbance and fragmentation impacts on fauna |
Project proponent/
detailed design consultant (detailed design of bridges). |
N/A. |
N/A. |
N/A. |
|
2.2.7/ 13.8.2.2/ E11 |
Avoid removal or
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
project. |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
Table 13.139 - Measures to avoid disturbance, fragmentation, hydrological and cumulative impacts on Ma Tso Lung Stream and stream corridor habitats
|
Mitigation Measure
No./ Section Ref./PIS
Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
2.3.1/ 13.8.2.2, 13.8.2.7/ E2 |
Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road). |
Project proponent/
detailed design consultant. |
N/A. |
N/A. |
N/A. |
|
2.3.2/ 13.8.2.2/ E14 |
Buffer zone of
15-30m as appropriate on both sides of Ma Tso Lung Stream north of the point
where it is crossed by the LMC Loop Eastern Connection Road, and Ma Tso Lung
Stream diversion during construction of the LMC Loop Eastern Connection Road;
development along lower reaches of Ma Tso Lung Stream and Ma Tso Lung Tsuen
Stream in OU zones in KTN areas F1-2 and F1-3 to be set back beyond buffer. |
PlanD (detailed and explained in Layout Plan)/ Project proponent/ Detailed design
consultant/ building designer. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
N/A. |
|
2.3.3/ 13.8.2.2/ E14 |
Construction and
maintenance of permanent 1.2m high solid faunal barrier at all at-grade
sections of LMC Loop Eastern Connection Road north of junction with road D4
within 15-30m as appropriate of Ma Tso Lung Stream buffer and construction of
faunal underpass beneath road. |
Project proponent/ Detailed design
consultant. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
N/A. |
|
2.3.4/ 13.8.2.2/ E17 |
Erection of a 2m
high dull green site barrier fence at interface between active works areas
and riparian corridor of Ma Tso Lung Stream and tributaries. |
N/A. |
N/A |
Contractor. |
N/A. |
Table 13.140 - Measures to avoid disturbance and hydrological impacts on Siu Hang San Tsuen Watercourse, Mitigation of Impacts on Ma Wat River and Measures to Avoid Hydrological Impacts on Long Valley due to rechannelisation of Long Valley Watercourse
|
Mitigation Measure
No./ Section Ref./PIS
Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
2.4 |
Measures to avoid
disturbance and hydrological impacts on Siu Hang San Tsuen Watercourse |
||||
|
2.4.1/ 13.8.2.2/ E3 |
Detailed design of
works in lower section of Siu Hang San Tsuen Stream to have 10m wide
vegetated buffer in Open Space zone in FLN area D1-3, Fanling Bypass to cross
stream on viaduct, all stream within NDAs to have permanent buffer on either
side of stream. |
PlanD, Project proponent / Detailed design
consultant (explained in Layout Plan/ incorporated in detailed design). |
N/A. |
Contractor. |
Maintenance
authorities. |
|
2.5 |
Mitigation of
Impacts on Ma Wat River |
||||
|
2.5.1/ 13.8.2.2/ E21 . |
Pre-works
commencement check on watercourses to be physically and/or hydrologically
impacted by construction activities for presence of any protected flora and
fauna and flora of conservation significance and bat roosts. If any of these
are found consider adjustments to avoid, minimise and compensate for impacts;
including adjustments to design, timing of works, transplantation and
translocation. Seek agreement of AFCD in respect of proposed measures then
implement. |
N/A |
Project Proponent/ Contractor/ Ecologist. |
Contractor. |
N/A. |
|
2.5a |
Avoidance of Hydrological Disruption to Long Valley Watercourse |
||||
|
2.5a.1/ 13.8.2.2/ E11 |
Measures to ensure
no hydrological disruption to Long Valley Watercourse and water supply to
Long Valley to be designed at the detailed design stage for the
rechannelisation of the Long Valley Watercourse and the development of areas
through which it passes, including KTN area B3-12. Contingency plan to
address any disruption to be included in LVNP HCMP |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
Table 13.141 – Mitigation of Impacts on Habitats of Ecological Importance
|
Mitigation Measure
No./ Section Ref./PIS
Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
2.6 |
Avoidance and minimization of habitat loss; mitigation of disturbance
impacts on habitats of ecological importance not specified above (including
ponds along the Ng Tung River in KTN and FLN; mitigation wetland at FLN area;
shrubland at Crest Hill; fung shui
and secondary woodland at Ho Sheung
Heung; secondary woodland at Siu Hang San Tsuen; hillside plantation; mitigation plantation) |
||||
|
2.6.1/ 13.8.2.2/ E17 |
Erection of 2m high
solid green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including any roads adjacent to or penetrating into areas/habitats of
ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier) |
N/A. |
Contractor. |
N/A. |
|
2.6.2/ 13.8.2.2/ E6 |
Retention of
existing mitigation plantation trees in Open Space zones along the Sheung
Yue, Ng Tung and Shek Sheung Rivers and incorporation of these in screen
planting along the rivers in the detailed design of these Open Space zones. |
Project proponent/
detailed design consultant (detailed design of Green Corridors along
watercourses and detailed design of Open Space areas and development areas
along river corridors). |
Project proponent
(pre-construction baseline data collection and evaluation). |
Contractor. |
Government land
allocatee/ contractor |
|
2.6.3/ 13.8.2.1/ E10 |
Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland at Ho Sheung
Heung and Crest Hill. |
Project proponent/
Detailed design consultant. |
N/A. |
N/A. |
N/A. |
|
3.1 |
Mitigation of ecological impacts of loss of village, urban/residential
areas and waste ground habitats |
||||
|
3.1.1/ 13.8.2.3/ LV7, LV11, LV12. |
As no significant
ecological impact predicted, ecological mitigation is not required. However,
planning for compensation for landscape and visual impact of loss of trees,
woodland and shrubland by compensatory planting in open spaces, amenity
areas, open areas in streetscapes and open areas in development lots (LV7);
screen planting (LV11) and road greening (LV12). |
Project proponent/
detailed design consultant. |
N/A. |
N/A. |
N/A. |
|
4.1 |
Mitigation of impacts of dust, construction run-off and pollution
impacts on habitats/areas of ecological significance, watercourses and the
Deep Bay Catchment |
||||
|
4.1.1/ 13.8.2.5, 13.8.2.6/ E22; D1-4, W1-4. |
Prevention of dust,
run-off and pollutants entering
watercourses and Deep Bay Catchment |
N/A. |
N/A. |
Contractor. |
N/A. |
13.9.4.3 Impacts
on fauna and flora
Table 13.142 – Mitigation of impacts to flora of conservation significance at Ho Sheung Heung fung shui and secondary woodland and elsewhere in the Study Area
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.1.1/ 13.8.2.6/ E17 |
Erection of 2m high solid dull green site barrier fence between active
works areas and all areas/habitats of ecological importance on edge of
development areas, including along any roads adjacent to or penetrating into
areas/habitats of ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier). |
N/A. |
Contractor. |
N/A. |
|
5.1.2/ 13.8.2.6/ E20 |
Pre-site clearance
check on all construction sites and pre-works commencement check on
watercourses to be physically and/or hydrologically impacted by construction
activities for presence of protected plant species/ specimens of conservation
significance. If any of these are found consider adjustments to avoid,
minimise and compensate for impacts; including adjustments to design, timing
of works, transplantation and translocation. Seek agreement of AFCD in
respect of proposed measures then implement. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
|
5.1.3/ 13.8.2.6/ E10 |
Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland at Ho Sheung
Heung and Crest Hill. |
Project proponent/
Detailed design consultant. |
N/A. |
N/A. |
N/A. |
Table 13.143 – Mitigation of mortality impacts on fauna.
|
Mitigation Measure
No./ Section Ref./PIS
Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.2 |
Mitigation of mortality impacts on mammals and
herpetofauna |
||||
|
5.2.1/ E17 |
Erection of 2m high solid dull green site barrier fence between active
works areas and all areas/habitats of ecological importance on edge of
development areas, including along any roads adjacent to or penetrating into
areas/habitats of ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier) |
N/A. |
Contractor. |
N/A. |
|
5.2.2/ 13.8.2.6/ E20, E21 |
Pre-site clearance
check on all construction sites and pre-works commencement check on
watercourses to be physically and/or hydrologically impacted by construction
activities for presence of mammals and herpetofauna of conservation
significance. If any of these are found consider adjustments to avoid,
minimise and compensate for impacts; including adjustments to design, timing
of works, transplantation and translocation. Seek agreement of AFCD in
respect of proposed measures then implement. |
N/A. |
Project Proponent/ Contractor/ Ecologist. |
Contractor. |
N/A. |
|
5.2.3/ 13.8.2.6/ E14 |
Construction of
permanent 1.2m high solid faunal barrier at all at-grade sections of LMC Loop
Eastern Connection Road north of junction with road D4 within 15-30m as
appropriate of Ma Tso Lung Stream buffer and construction of faunal underpass
beneath road. |
Project proponent/ Detailed design
consultant. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
N/A. |
|
5.2.4/ 13.8.2.2/ E17 |
Erection of a 2m
high dull green site barrier fence at interface between active works areas
and riparian corridor of Ma Tso Lung Stream and tributaries. |
Project proponent/
detailed design consultant (detailed design of barrier) |
N/A |
Contractor. |
N/A. |
|
5.3 |
Mitigation of mortality impacts on bats |
||||
|
5.3.1/ 13.8.2.6/ E20, E21 |
Pre-site clearance
check on all construction sites for presence of bat roosts. If any of these
are found consider adjustments to avoid, minimise and compensate for impacts;
including adjustments to design, timing of works, transplantation and
translocation. Seek agreement of AFCD in respect of proposed measures then
implement. |
N/A. |
Project Proponent/ Contractor/ Ecologist. |
Contractor. |
N/A. |
|
5.4 |
Mitigation of mortality impacts on birds |
||||
|
5.4.1/ 13.8.2.6/ E8 |
Preparation and
implementation of Guidelines for building design measures to minimise
mortality and light and glare impacts to fauna. Guidelines to address the
following measures: Use opaque,
non-transparent, non-reflective noise barriers for all developments
associated with the Project. Measures to include
the following: • Fritting, or the placement of ceramic lines or dots on
glass, which has little effect on the human-perceived transparency of the
window but creates a visual barrier to birds outside. This treatment also has
the advantage of reducing air conditioning loads by lowering heat gain, while
still allowing light transmission for interior spaces. It is most successful
when the frits are applied on the outside surface. Frosted glass has similar
effects; • Angled glass to
be used only for smaller panes in buildings with a limited amount of glass; • The use of glass
that reflects UV light (primarily visible to birds, but not to humans) to
reduce collisions; • Film and art
treatment allow glass surfaces to be used a medium of expression, often
related to the nature and use of the building, as well indicating to birds
their impenetrability; • Lightweight
external screens can be added to windows or become a façade element of larger
buildings, and are suitable where non-operable windows are prevalent. |
PlanD/ Project
proponent (roads)/ Detailed design
consultant/ building designer. |
|
|
|
|
5.4.2/ 13.8.2.6/ E28 |
Use opaque,
non-transparent, non-reflective noise barriers for all roads. Unnecessary
lighting should be avoided. Potential impacts of nocturnal avian collision with buildings should
be minimised by not creating sky glow from the use of night-time lighting at
or near the top of buildings or other structures. In addition to avoiding
uplighting, light spillage should be minimised, while green and blue lights should be used where
possible. As far as possible, building operations should be managed in such a
way as reduce or eliminate night lighting near windows. |
N/A. |
N/A. |
N/A. |
Maintenance
authorities/ operator. |
|
5.4.3/ 13.8.2.6/ E20, E21. |
Pre-site clearance
check on all construction sites and pre-works commencement check on
watercourses to be physically and/or hydrologically impacted by construction
activities for presence of birds of conservation significance. If any of
these are found consider adjustments to avoid, minimise and compensate for
impacts; including adjustments to design, timing of works, transplantation
and translocation. Seek agreement of AFCD in respect of proposed measures
then implement. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
Table 13.144 – Mitigation of impacts on wetland-dependent bird species of conservation significance
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.5.1/ 13.8.2.6 E4, E15, E25 |
Long Valley Nature
Park (LVNP) designation, design, and implementation including measures to
redistribute wetland habitats in LVNP to concentrate closed wetland habitats
(marsh and reed marsh) in areas closest to disturbance sources; and to stock
fish as food to compensate for disturbance to foraging areas in main river
channels and elsewhere.. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan LVNP HCMP). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
Project proponent/
Contractor. |
AFCD/ Contractor
(if required). |
|
5.5.2/ 13.8.2.6/ E5 |
Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung Egretry. |
PlanD (guidelines
for stringent planning control detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
5.5.3/ 13.8.2.2/ E7 |
Building setback
from Long Valley (30m setback from Road D3 in KTN area B3-12) and mounding
and planting in KTN area C1-1. |
PlanD/ LandsD
(detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
5.5.4/ 13.8.2.2/ E13 |
No construction
during ardeid breeding season (1st March to 31st July)
along Sheung Yue River north and east of KTN area D1-5 and east of D1-9 and
C2-3 and restriction of working hours on new pedestrian bridge over the
Sheung Yue River and non-tidal section of the Ng Tung River to 09.00 to 17.30
during the ardeid breeding season (1st March to 31st
July). |
N/A. |
N/A. |
Contractor. |
N/A. |
|
5.5.5/ 13.8.2.7/ E6 |
Planning for creation of Green Corridors along larger watercourses and
detailed design of Open Space areas and development areas along river
corridors to provide screening of rivers. |
Project proponent/
detailed design consultant. |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
N/A. |
N/A. |
|
5.5.6/ 13.8.2.6/ E16 |
Erection of 2m high
solid dull green site barrier fence
between river channel and any active works area along or adjacent to Ng Tung,
Sheung Yue and Shek Sheung Rivers. |
Project proponent/
detailed design consultant (detailed design of barrier) |
N/A. |
Contractor. |
N/A. |
|
5.5.7/ 13.8.2.6/ E17 |
Erection of 2m high solid dull green site barrier fence between active
works areas and all areas/habitats of ecological importance on edge of
development areas, including along any roads adjacent to or penetrating into
areas/habitats of ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier) |
N/A. |
Contractor. |
N/A. |
|
5.5.8/ 13.8.2.6/ E21 |
Pre-works commencement check on watercourses to be physically and/or
hydrologically impacted by construction activities for presence of wetland
bird species of conservation significance. If any of these are
found consider adjustments to avoid, minimise and compensate for impacts;
including adjustments to design, timing of works, transplantation and
translocation. Seek agreement of AFCD in respect of proposed measures then
implement. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
|
5.5.9/ 13.8.2.6/ E11 |
Review design and
construction methods for all bridges especially those on the Sheung Yue and
tidal Ng Tung Rivers and adopt methods which minimise impacts on rivers and
disturbance and fragmentation impacts on fauna. |
Project proponent/
detailed design consultant (detailed design of bridges). |
N/A. |
N/A. |
N/A. |
|
5.5.10/ 13.8.2.2/ E11 |
Avoid removal or
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
project. |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
|
5.5.11/13.8.2.2/E11 |
Scheduling to avoid
overlap in construction of bridges over rivers. |
Project proponent/
Detailed design consultant. |
N/A |
Contractor |
N/A |
Table 13.145 – Mitigation of impacts on non wetland-dependent bird species of conservation significance
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.6.1/ 13.8.2.6 E4, E15, E25 |
Long Valley Nature
Park (LVNP) designation, design, implementation and design. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan (LVNP HCMP)
will include formulation of enhancement measures for non-wetland habitats). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
N/A. |
N/A. |
|
5.6.2/ 13.8.2.6/ E5 |
Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung Egretry. |
PlanD (guidelines
for stringent planning control detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
5.6.3/ 13.8.2.7/ E6 |
Planning for creation of Green Corridors along larger watercourses and
detailed design of Open Space areas and development areas along river
corridors to provide screening of rivers. |
Project proponent/
detailed design consultant. |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
N/A. |
N/A. |
|
5.6.4/ 13.8.2.6/ E4, E15, E25 |
Enhancement of
non-wetland habitats in LVNP. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan LVNP HCMP). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
Project proponent
/contractor (implementation of design of mitigation measures). |
AFCD (management,
maintenance and monitoring). |
|
5.6.5/ 13.8.2.6/ E18, E27 |
Compensatory native
woodland planting, management and maintenance. |
Project proponent (formulation
of woodland planting and management plan. |
N/A |
Project proponent/
Contractor for 2 years. |
AFCD (management
and maintenance) for 9 years, after which the woodland will be handed over to
LandsD for ad hoc maintenance). |
|
5.6.6/ 13.8.2.6/ E16, E17 |
Erection of 2m high solid dull green site barrier fence between active
works areas and all areas/habitats of ecological importance on edge of
development areas, including along any roads adjacent to or penetrating into
areas/habitats of ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier |
N/A. |
Contractor |
N/A. |
|
5.6.7/ 13.8.2.2/ E11 |
Avoid removal or
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
project. |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
|
5.6.8/ 13.8.2.6/ E10 |
Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland at Ho Sheung
Heung and Crest Hill. |
Project proponent/
Detailed design consultant. |
N/A. |
N/A. |
N/A. |
Table 13.146 – Mitigation of impacts on Eurasian Hobby and Grey Nightjar
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.7 |
Mitigation of
impacts on Eurasian Hobby |
||||
|
5.7.1/ 13.8.2.6/ E20 |
Pre-site clearance of construction sites in
Crest Hill area (KTN areas D1-7, D1-11 and G1-5) for presence of any breeding
birds/breeding site. If any of these are found consider adjustments to
avoid, minimise and compensate for impacts; including adjustments to design,
timing of works, transplantation and translocation. Seek agreement of AFCD in
respect of proposed measures then implement. |
N/A. |
Project Proponent/ |
Pre-site clearance check on all construction
sites for presence of species of conservation significance. |
N/A. |
|
5.7.2/ 13.8.2.6/ E17 |
Erection of 2m high solid dull green site
barrier fence between active works areas sites in KTN areas D1-7, D1-11 and
G1-5 and all areas/habitats of natural habitat. |
Project proponent/
detailed design consultant (detailed design of barrier |
N/A. |
Contractor |
N/A. |
|
5.8 |
Mitigation of
impacts on Grey Nightjar |
||||
|
5.8.1/ 13.8.2.6/ E20 |
Pre-site clearance of construction site on
Cheung Po Tau (FLN area A3-1) for presence of any breeding birds/breeding
site. If any of these are found consider adjustments to avoid, minimise and
compensate for impacts; including adjustments to design, timing of works,
transplantation and translocation. Seek agreement of AFCD in respect of
proposed measures then implement. |
N/A. |
Project Proponent/ |
Pre-site clearance check on all construction
sites for presence of species of conservation significance. |
N/A. |
|
5.8.2/ 13.8.2.6/ E17 |
Erection of 2m high solid dull green site
barrier fence between active works areas in FLN area A3-1 and all
areas/habitats of natural habitat. |
Project proponent/
detailed design consultant (detailed design of barrier |
N/A. |
Contractor |
N/A. |
Table 13.147 – Mitigation of impacts on Egretries and Egretry Flight-lines
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.9.1/ 13.8.2.6/ E1, E12, E23 |
Egretry Habitat Creation & Management Plan (EHCMP) and
compensatory egretry habitat provision in FLN area A1-7. |
Project proponent/ Detailed design
consultant (EHCMP) |
Project proponent/
detailed design consultant. |
Contractor. |
Maintenance
authority. |
|
5.9.2/ 13.8.2.6/ E5 |
Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung Egretry. |
PlanD (guidelines
for stringent planning control detailed and explained in Layout Plan). |
N/A. |
N/A. |
N/A. |
|
5.9.3/ 13.8.2.6/ E6 |
Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development areas along river corridors. |
Project proponent/
detailed design consultant. |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
N/A. |
N/A. |
|
5.9.4/ 13.8.2.6/ E13 |
No construction during ardeid breeding season (1st
March to 31st July) along Sheung Yue
River north or east of KTN D1-5 and east of D1-9 and C2-3 and restriction of
working hours on new pedestrian bridges over the Sheung Yue and Ng Tung
Rivers to 09.00 to 17.30 during this period. |
N/A. |
N/A. |
Contractor. |
N/A. |
|
5.9.5/ 13.8.2.6/ E11 |
Review design and
construction methods for all bridges especially those on the Sheung Yue and
tidal Ng Tung Rivers and adopt methods which minimise impacts on rivers and
disturbance and fragmentation impacts on fauna. Phasing of so that there is
no overlap in construction timing. |
Project proponent/
detailed design consultant (detailed design of bridges). |
N/A. |
N/A. |
N/A. |
|
5.9.6/ 13.8.2.6/ E4, E15, E25 |
Long Valley Nature
Park (LVNP) designation, design, and implementation including measures to
redistribute wetland habitats in LVNP to concentrate closed wetland habitats
(marsh and reed marsh) in areas closest to disturbance sources; and to stock
fish as food to compensate for disturbance to foraging areas in main river
channels and elsewhere.. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan LVNP HCMP). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
Project proponent/
Contractor. |
AFCD/ Contractor
(if required). |
|
5.9.7/ 13.8.2.6/ E16 |
Erection of 2m high solid dull green site barrier fence between river channel and any active
works area along or adjacent to Ng Tung, Sheung Yue and Shek Sheung Rivers. |
N/A. |
N/A. |
Contractor. |
N/A. |
|
5.9.8/ 13.8.2.2/ E11 |
Avoid removal or
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
project. |
Project proponent/
Detailed design consultant. |
N/A. |
Contractor. |
N/A. |
Table 13.148 – Mitigation of impacts on Three-banded Box Terrapin, Chinese Bullfrog and other herpetofauna
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.10 |
Mitigation for impacts on herpetofauna |
||||
|
5.10.1/ 13.8.2.6/ E17 |
Erection of 2m high
solid dull green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including along any roads adjacent to or penetrating into areas/habitats of
ecological importance. |
Project proponent/
detailed design consultant (detailed design of barrier |
N/A. |
Contractor |
N/A. |
|
5.10.2/ 13.8.2.6/ E21 |
Pre-site clearance check on all construction sites for presence of
reptile species of conservation significance, capture and
translocate to receptor site; review translocation options in respect to
species in Ma Tso Lung area and determine whether release locally or
elsewhere is appropriate.
Seek agreement of AFCD in respect of proposed measures then implement. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
|
5.11 |
Mitigation for impacts on Three-banded Box Terrapin and other reptiles
using Ma Tso Lung Stream |
||||
|
5.11.1/ 13.8.2.2, 13.8.2.7/ E2 |
Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road. |
Project proponent/
detailed design consultant. |
N/A. |
N/A. |
N/A. |
|
5.11.2/ 13.8.2.2/ E14 |
Buffer zone of
15-30m as appropriate on both sides of Ma Tso Lung Stream north of the point
where it is crossed by LMC Loop Eastern Connection Road, and Ma Tso Lung
Stream diversion during construction of the LMC Loop Eastern Connection Road;
development along lower reaches of Ma Tso Lung and Ma Tso Lung San Tsuen
Streams in OU zones in KTN areas F1-2 and F1-3 to be set back beyond buffer. |
PlanD (detailed and explained in Layout Plan)/ Project proponent/ Detailed design
consultant/ building designer. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
N/A. |
|
5.11.3/ 13.8.2.2/ E14, E25 |
Construction and
maintenance of permanent 1.2m high solid faunal barrier at all at-grade
sections of LMC Loop Road north of junction with road D4 within 15-30m as
appropriate of Ma Tso Lung Stream buffer and construction of faunal underpass
beneath LMC Loop Eastern Connection Road. |
Project proponent/ Detailed design
consultant. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
Maintenance
Authorities. |
|
5.11.4/ 13.8.2.2/ E17 |
Erection of a 2m
high dull green site barrier fence at the edge of the works area or 30m from
the Ma Tso Lung Stream and tributaries, whichever distance is the greater. |
Project proponent/
detailed design consultant (detailed design of barrier |
N/A |
Contractor. |
N/A. |
|
5.12 |
Mitigation for impacts on Chinese Bullfrog |
||||
|
5.12.1/ 13.8.2.6/ E4, E15, E25 |
Creation and operation of Long Valley Nature Park and creation
and enhancement of wetland within LVNP. |
Project proponent (formulation
of Long Valley Nature Park Habitat Creation & Management Plan LVNP HCMP). |
Project proponent
(pre-construction baseline data collection and evaluation; LVNP HCMP review). |
Contractor. |
AFCD. |
|
5.12.2/ 13.8.2.6/ E20 |
Pre-site clearance check on all construction sites for presence of
Chinese Bullfrog, translocation to LVNP. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
Table 13.149 – Mitigation for impacts on butterflies
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.13 |
Butterflies |
||||
|
5.13.1/ 13.8.2.6/ E17; D1-4 |
Prevention of dust impact from active works
areas from sites adjacent to Ho Sheung Heung and Crest Hill woodland and
shrubland in KTN areas D1-7, D1-11 and G1-3. |
N/A. |
N/A. |
Contractor |
N/A. |
|
5.13.2/ 13.8.2.6/ E10 |
Review development footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to avoid/minimise direct and indirect impacts on secondary woodland at Ho Sheung Heung and Crest Hill. |
Project proponent/
Detailed design consultant. |
N/A. |
N/A. |
N/A. |
Table 13.150 – Mitigation for impacts on Small Snakehead and Sommaniathelphusa zanklon
|
Mitigation Measure No./ Section Ref./PIS Ref |
Proposed
mitigation measure |
Detailed design
stage |
Pre-construction
Stage |
Construction Stage |
Operational Stage |
|
5.15.1/ 13.8.2.2, 13.8.2.7/ E2 |
Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road. |
Project proponent/
detailed design consultant. |
N/A. |
N/A. |
N/A. |
|
5.15.2/ 13.8.2.2/ E14 |
Buffer zone of
15-30m as appropriate on both sides of Ma Tso Lung Stream north of the point
where it is crossed by the LMC Loop Eastern Connection Road, and Ma Tso Lung
Stream diversion during construction of the LMC Loop Eastern Connection Road;
development along lower reaches of Ma Tso Lung and Ma Tso Lung San Tsuen
Streams in OU zones in KTN areas F1-2 and F1-3 to be set back beyond buffer. |
PlanD (detailed and explained in Layout Plan)/ Project proponent/ Detailed design
consultant/ building designer. |
Project proponent
(pre-construction baseline data collection and evaluation). |
Project proponent
/contractor (implementation of
mitigation measures). |
N/A. |
|
5.15.3/ 13.8.2.6/ E21 |
Pre-works commencement check on watercourses to be physically and/or
hydrologically impacted by construction activities for presence of Small
Snakehead and Sommaniathelphusa
zanklon. Capture any Sommaniathelphusa zanklon found and translocate to Ma Tso Lung Stream/
consider option to translocate to LVNP. |
N/A. |
Project Proponent/ Contractor/ ecologist |
Contractor. |
N/A. |
This section addresses the requirements of Section 3.4.14.4(xi) and (xii) of the Study Brief. As described in the TM-EIAO, in evaluating residual impacts, more weight is given to adverse impacts that occur in areas that are ecologically fragile and/or rare or undisturbed, or which have little resilience to imposed stresses.
Mitigation measures and predicted residual impacts are summarised below in accordance with Section 5.4.5(b) and (c) of Annex 16 of the EIAO TM, residual impacts with on-site mitigation measures are defined, quantified, where possible, and evaluated.
Table 13.151 - Potential Total Residual Direct, Indirect, Fragmentation and Cumulative Impacts on Habitats and their severity
|
Habitat/ Impact |
Mitigation |
Residual Impacts |
|
Long Valley Disturbance of Long
Valley habitats (Low Severity during construction, lower,
but still significant during operation). Dust deposition,
increased sediment and nutrient load: Low
in construction phase, not significant in operational phase. Hydrological disruption
of Long Valley habitats (Low to High) Pollution of Long Valley
habitats dependent upon type, but most likely Low to Moderate during
construction and Low during
operation. Fragmentation impact on
Long Valley Low to Moderate during
construction and Low during
Operation, except on some waterbirds in the southwestern part of Long Valley
closest to proposed development areas where impact severity will remain Low to Moderate. Combined disturbance and
fragmentation impacts Low to Moderate
during construction and Low during
operation. Cumulative disturbance
and fragmentation impacts with the Sha Po Tsuen to Shek Sheung River Cycle
track project Low during
construction and operation with the proper implementation of mitigation
measures. |
Permanent: Designation of area south
and east of the Sheung Yue River as LVNP (37ha); preparation and
implementation of HCMP to enhance wetland and non-wetland habitats (1.1.1 & 1.1.2). Enhancement of wetland
habitats in LVNP, redistribution of wetland habitats to place closed habitats
(marsh and reed marsh) in areas closest to disturbance sources; fish stocking
to compensate for disturbance to foraging areas (1.1.2 & 2.2.1). Screen planting to be
enhanced along river channels, subject to constraint of need to avoid loss of
wetland area or function (2.2.2). Avoidance of interference
with screen planting undertaken by the Sha Po Tsuen to Shek Sheung River
Cycle track project (2.1.7). Visitor management in
LVNP (1.1.2). Stringent planning
requirements in Long Valley north and west of the Sheung Yue River to be
detailed in Layout Plan (2.1.2). Building setback of 30m
from road D3 in KTN area B13-12 and mounding and planting in KTN area C1-1 (2.1.3). Review of design
and construction methods for all bridges especially those on the Sheung Yue
River and adoption of methods which will minimise impacts on Long Valley and
disturbance and fragmentation impacts on fauna in Long Valley and using
flight-lines between Long Valley and elsewhere (2.1.6). Measures to ensure
no disruption to Long Valley Watercourse to be designed at detailed design
stage for rechannelisation of Long Valley Watercourse and areas through which
it flows including KTN area B3-12 and contingency plan to address any
disruption to be included in LVNP HCMP (2.5a.1). Construction: Measures to prevent dust
impact on sensitive receivers (4.1.1). Measures to control
construction run-off and pollution (4.1.1). Measures to ensure
reliable water supply to be required under LVNP HCMP (1.1.1 and 1.1.2) and
to minimise water quality impact due to stream diversion (4.1.1). No works permitted in
ardeid breeding season (1st March to 31st July) north or east of KTN area D1-5 and of D1-9 and
C2-3 and restriction of working hours on new pedestrian bridge over Sheung
Yue River during ardeid breeding season (2.1.4). Erection of 2m high dull
green site boundary fence between Long Valley and any works areas (2.1.5). Enhancement of wetland
habitats in LVNP, redistribution of wetland habitats to place closed habitats
(marsh and reed marsh) in areas closest to disturbance, fish stocking as
supplementary management measure available if required to ensure that there
is no reduction in ecological function for large waterbirds during the
construction phase (1.1.2 & 5.5.1). Review of bridge design
and construction methods during detailed design phase to ensure that
disturbance impacts from these sources are minimised (2.2.6). |
With the designation and
management of LVNP,
the area in Long Valley under active conservation management will increase
from 12ha to 37.17ha. In addition, integrated management of the area as a
whole will significantly increase the effectiveness and value of conservation
management measures. Accordingly, there will be a positive residual impact on
the LVNP area during the operational phase of the Project. Long Valley north and
west of the Sheung Yue River will retain its current ecological function and
value and this will increase once planning measures take effect and if more
land is brought under MAs. Accordingly, there will be a net positive residual
impact on Long Valley during the operational phase of the project. With measures to mitigate
for construction phase impacts from dust, pollution or hydrological
disruption, these will not be of significance during either construction or
operation of the Project. With measures to mitigate
for construction phase disturbance impacts in place there may be some
redistribution of large waterbirds away from the southwest of Long Valley.
Accordingly there may be a Low
residual construction phase impact on larger waterbird species in this part
of Long Valley. Such an impact is considered to be acceptable as there will
be no impact on more disturbance-sensitive species in Long Valley as a whole
and no significant impact on the ecological function of Long Valley habitat arising
from the project. (To further
reduce potential impacts and to strengthen the carrying capacity of Long
Valley area for large waterbirds potentially affected during the advance
works stage before full establishment of the LVNP, supplementary fish stocking to provide food for the most
disturbance-sensitive species which occur in Long Valley in significant
numbers is available as a management tool) |
|
Wet Agricultural land Permanent loss of 0.58ha
(Low to Moderate). Disturbance (Low during construction/operation). |
Permanent Loss of wet agricultural
land would be mitigated by enhancement of wetland habitats (including wet
agricultural land) in LVNP (1.1.1
& 1.1.2). |
With provision of on-site
mitigation measures, the diversity of wet agricultural crops in LVNP will be
increased and the ecological value of wet agricultural land will increase; no
significant residual impact is predicted.
|
|
Dry
Agricultural Land Permanent loss of 9.33ha
(Low). Disturbance (Low during construction/operation). |
Permanent No mitigation required.
However dry agricultural land will be enhanced in LVNP (1.1.1 & 1.1.2). Construction Phase Erection of 2m high dull
green site boundary fence between dry agricultural land north of the Ng Tung
River and any works areas (2.6.1). |
With provision of
mitigation measures, the diversity of dry agricultural crops in LVNP will be
increased and the ecological value of dry agricultural land will increase;
creating a positive residual impact. |
|
Pond Permanent loss of 3.08ha
(Low for small fragmented ponds
(0.59ha) and Low to Moderate (2.12ha)
and Moderate (0.37ha) for larger ponds and/or with
significant ecological linkages). The total loss requiring mitigation is
2.49ha. Disturbance of pond (Low to Moderate during construction
and operation. Run-off and hydrological
disruption (Low during
construction and operation. Combined impacts Low to Moderate during construction and Low during operation. |
Permanent Loss of pond would be
mitigated by enhancement of wetland habitats (including pond) in LVNP (1.1.1 & 1.1.2). Construction Phase Erection of 2m high dull
green site boundary fence between ponds along Ng Tung River and any works
areas (2.2.3). Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). |
With provision of on-site
mitigation measures, the ecological value of pond habitat in LVNP will
increase; creating a positive residual impact. With provision of on-site
mitigation measures, adverse residual indirect impacts on the small areas of
pond habitat are not considered to be of significance and any residual impact
is considered to be acceptable. However, In view of the small size of the
area where residual impacts are predicted, residual impacts on this habitat
in the Study Area as a whole are not of significance. |
|
Marsh at Ma Tso Lung Disturbance (Low during construction/operation). Run-off and hydrological
disruption (Low during
construction and operation. Combined impacts Low during construction and operation. Cumulative impact with
LMC Loop Project Low during
construction and operation. |
Construction Phase Detailed design,
implementation and maintenance of buffer zone along lower reaches of Ma Tso
Lung Stream (2.3.1 & 2.3.2) Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). Pre-works commencement
check on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1). |
With provision of mitigation
measures at source (upstream, where there will be direct and indirect impacts
on Ma Tso Lung Stream), adverse residual impacts will be of Low significance during the
construction period and there will be no significant residual operational
phase impacts. Mitigation measures
proposed will also ensure that there are no significant cumulative residual
impacts with the LMC Loop project. |
|
Mitigation Wetland (other than area in Long
Valley) Loss of 2.75ha (Low to Moderate. Disturbance in FLN area
A1-7 (Low during construction and
operation). Run-off and hydrological
disruption: Low during
construction and not significant during
operation. Fragmentation impacts on
FLN area A1-7) Low to Moderate
during construction; Low during
operation. Combined impacts Moderate during construction and Low during operation. |
Permanent Loss of mitigation
wetlands would be mitigated by enhancement of wetland habitats (including
mitigation wetland, marsh and pond) in LVNP. Preparation and implementation
of EHCMP in mitigation wetland at FLN area A1-7 (5.9.1). Construction Phase Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). Erection of 2m high solid
green site boundary fence between active works areas and the mitigation
wetland (2.2.3). |
With provision of on-site
mitigation measures, the ecological value of mitigation wetland habitat in
LVNP will increase; creating a positive residual impact. The mitigation wetland at
FLN area A1-7 will be enhanced as a compensatory egretry habitat;
implementation of design, management and maintenance measures will increase
the ecological function of this area for ardeids; no adverse residual impacts
on other ecological functions of this area are predicted. l |
|
Major Channelised Watercourse Permanent loss of
<0.02ha and construction phase loss of areas required for construction of
coffer dams: Low during
construction and not significant during operation. Disturbance of Sheung Yue
River (3300m): Moderate during
construction, Low during
operation. Disturbance of non-tidal
Ng Tung River (4000m): Low to Moderate during construction and Low during operation. Disturbance of tidal Ng
Tung River (650m): Low during
construction and not significant during operation. Disturbance of Shek Sheung
River (2300m): Low during
construction and not significant during operation. Fragmentation impact on
non-tidal Ng Tung River: Low to Moderate during construction and
operation. Fragmentation impact on
tidal Ng Tung River: Low during
construction and not of significance during operation. Run-off and pollution
impacts on Ng Tung, Sheung Yue and Shek Sheung Rivers (Low during construction and operation for most events but certain
construction phase pollution events could be of Moderate severity). Combined impacts on
Sheung Yue River Moderate during
construction and Low to Moderate
during operation. Combined impacts on
non-tidal Ng Tung River Low to
Moderate during construction and Low
during operation. Combined impacts on tidal
Ng Tung River Low during
construction and not significant during operation. Combined impacts on Shek
Sheung River Low during
construction and operation. With mitigation measures in place,
cumulative impacts
on Sheung Yue river with the Sha Po Tsuen to
Shek Sheung River Cycle track project Low
during construction and operation. |
Permanent Stringent planning
control in area north and east of the Sheung Yue River (2.2.1). Planning for retention of
existing trees in Open Space zones along the Sheung Yue, Ng Tung and Shek
Sheung Rivers and incorporation of these in the screen planting will reduce
disturbance and fragmentation impacts on rivers and fauna using them (2.2.2). Building setback from
Long Valley (30m setback from road D3 in KTN area B3-12 will setback from
part of Sheung Yue River (2.2.4). Maximisation of building setback and provision of
screen planting along main river channels during the detailed design stage. Review of design and construction methods for all
bridges especially those on the Sheung Yue and tidal Ng Tung Rivers and
adoption of methods which will minimise impacts on rivers and disturbance and
fragmentation impacts on fauna (2.2.6). Provision of alternative foraging site for
waterbirds by establishment of LVNP and stocking of fish at suitable ponds on
government land along river channels and in LVNP during the advanced works
stage. Construction Phase No construction during
ardeid breeding season (1st March to 31st
July) along Sheung Yue River north and east of
KTN area D1-5 and east of D1-9 and C2-3 and restriction of working hours on
new pedestrian bridges over the Sheung Yue River and tidal Ng Tung River to
09.00 to 17.30 during the ardeid breeding season (2.2.5) will reduce disturbance to Sheung Yue River and non-tidal
Ng Tung River during this period. Erection of 2m high dull
green site boundary fence between ponds along Ng Tung River and any works
areas (2.2.3). Avoidance of removal and
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
(2.2.7). Mitigation of dust,
construction run-off and pollution impacts on watercourses (4.1.1). |
With provision of
mitigation measures, there will be no significant adverse residual impacts to
main river channels during the construction phase and no impact during the
operational phase. With the proposed
mitigation measures in place the combined construction phase residual impacts
on waterbird flight-lines will be mitigated to an acceptable level due to the
small number of birds involved, all of which are common and widespread
species in Hong Kong wetlands. Mitigation measures
proposed will also ensure that there are no significant cumulative residual
impacts with the Construction of Cycle tracks and Associated Supporting
Facilities from Sha Po Tsuen to Shek Sheung project. |
|
Ma Tso Lung Stream and tributaries and riparian
corridor Diversion of 130m of Ma
Tso Lung Stream in its lower reaches (Moderate)
and 12m of tributaries in their upper reaches (Low). Disturbance to Ma Tso
Lung Stream: Low during construction and not significant during operation. Run-off and hydrological
impacts to Ma Tso Lung Stream (Moderate
during construction and not significant during operation) Fragmentation impact on
Ma Tso Lung Stream riparian corridor (Moderate
during construction and operation). Low fragmentation
impact for minor upper tributaries. Combined impacts Low to Moderate during construction
and operation. Cumulative disturbance
impacts with LMC Loop Project Low. Cumulative run-off and
hydrological impacts with LMC Loop Project Moderate during construction and Low to Moderate during operation. Cumulative hydrological
disruption impacts with LMC Loop Project Moderate
during construction and operation. Cumulative fragmentation
impacts with LMC Loop Project High during construction and operation Moderate. Cumulative combined
impacts with LMC Loop Project Moderate. |
Permanent Detailed design of
development along lower reaches of Ma Tso Lung and Ma Tso Lung Streams in OU
zones (KTN areas F1-2 and F1-3 and detailed design of LMC Loop Eastern
Connection Road (2.3.1). Designation and
implementation of buffer zone of 15-30m as appropriate on either side of Ma
Tso Lung Stream North of the point where it is crossed by the LMC Loop
Eastern Connection Road, Green Belt zoning elsewhere, and Ma Tso Lung Stream
diversion (2.3.2). Solid faunal barrier
(1.2m) barrier along at-grade section of LMC Loop Eastern Connection Road and
faunal underpass (2.3.3 & 2.3.5). Construction phase Diversion of Ma Tso Lung
Stream and reinstatement of natural stream bed, channel and enhanced riparian
zone (2.3.2). Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). Erection of 2m high
construction phase barrier between active works areas and stream and
tributaries (2.3.4). Pre-works commencement
check on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1). |
With provision of
mitigation measures, construction phase impact will be of Low severity during road
construction, but no significant residual impact due to other elements of the
Project. During the operational
phase the value of the riparian corridor habitat will improve over time such
that a positive residual impact is anticipated after approximately two to
three years. Mitigation measures
proposed will also ensure that there are no significant cumulative residual
impacts with the LMC Loop project. |
|
Pak Shek Au Watercourse Re-channelisation (Low). No significant indirect
impacts. |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of conservation
significance and bat roosts on watercourses to
be physically or hydrologically impacted by construction activities (2.5.1). Formulation and
implementation of practicable and effective mitigation measures, if required,
in consultation with AFCD. |
No residual impact. |
|
Tung Fong/Shek Tsai Ling Watercourse & Kwu
Tung Watercourse Re-channelisation (Low). No significant indirect
impacts. |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of conservation
significance and bat roosts on watercourses to
be physically or hydrologically impacted by construction activities (2.5.1). Formulation and
implementation of practicable and effective mitigation measures, if required,
in consultation with AFCD. |
No significant residual impact. |
|
Fung Kong & Ho Sheung Heung Watercourses Re-channelisation (Low). No significant indirect
impacts. |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of conservation
significance and bat roosts on watercourses to
be physically or hydrologically impacted by construction activities (2.5.1). Formulation and
implementation of practicable and effective mitigation measures, if required,
in consultation with AFCD. |
No significant residual impact. |
|
Long Valley Watercourse Re-channelisation (Low). Run-off and hydrological
impacts on Long Valley: most likely of Low
severity but could be Moderate
if hydrological disruption is prolonged and during the dry season. |
Pre-Construction Phase Pre-works check for presence of
any protected flora and fauna and flora of conservation significance and bat
roosts on watercourse to be physically or
hydrologically impacted by construction activities (2.5.1). Formulation and implementation of practicable and
effective mitigation measures, if required, in consultation with AFCD. Construction Phase Measures to ensure
no disruption to Long Valley Watercourse to be designed at detailed design
stage for rechannelisation of Long Valley Watercourse and areas through which
it flows including KTN area B3-12 and contingency plan to address any
disruption to be included in LVNP HCMP (2.5a.1). Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). |
Measures to maintain
continuity of water supply to Long Valley will be designed at the detailed
design stage for the rechannelisation of the Long Valley Watercourse and will
also be required at the detailed design of any development areas through
which it flows. In addition, the LVNP HCMP will include a contingency plan to
address any unexpected disruption. With these measures in place, there will
be no significant residual impacts; scope to increase ecological value of
section adjacent to Yin Kong village should also be addressed during the
detailed design of the rechannelisation works. |
|
Cheung Po Tau & Fu Tei Au Watercourse Re-channelisation of Fu
Tei Au Watercourse (Low). No significant indirect
impacts. |
Pre-Construction Phase Pre-works check for presence of
any protected flora and fauna and flora of conservation significance and bat
roosts on watercourses to be physically or
hydrologically impacted by construction activities (2.5.1). Formulation and implementation of practicable and
effective mitigation measures, if required, in consultation with AFCD. |
No significant residual impact. |
|
Sheung Shui Wa Shan Watercourses Re-channelisation of
approx. 80m length of both watercourses (lowest reaches) (Low). No significant indirect
impacts. |
Pre-Construction Phase Pre-works check for presence of
any protected flora and fauna and flora of conservation significance and bat
roosts on watercourses to be physically or
hydrologically impacted by construction activities (2.5.1). Formulation and implementation of practicable and
effective mitigation measures, if required, in consultation with AFCD. |
No significant residual impact. |
|
Siu Hang San Tsuen Watercourse Re-channelisation of
approx. 180m length of lowest reaches (Low). Disturbance impacts
during construction and operation not significant. Run-off and hydrological
impacts (Low during construction). Combined impacts Low to Moderate during construction
and Low during operation. |
Permanent Detailed design of Siu
Hang San Tsuen Stream to have 10m wide vegetated buffer in Open Space zone in
FLN area D1-3 (2.4.1). Bypass to cross stream on
viaduct (2.4.1). Any channelisation works
in upstream section not recommended (2.4.1). Pre-Construction Phase Pre-works check for
presence of any protected flora and fauna and flora of conservation
significance and bat roosts on watercourses to
be physically or hydrologically impacted by construction activities (2.5.1).
Formulation and implementation of practicable and effective mitigation
measures, if required, in consultation with AFCD. Construction phase Lower reaches (within
works area) to have 10m wide vegetated buffer on either side of stream (2..1).
Measures to control hydrological disruption, construction run-off and
pollution (4.1.1). |
With provision of
mitigation measures, there will be no significant residual impacts arising
from rechannelisation works. No significant residual
impacts are predicted during operation. |
|
Man Kok Village, Tin Ping Shan Tsuen, Shek Wu San
Tsuen & Ma Shi Po Watercourses Re-channelisation (Low). No significant indirect
impacts |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of
conservation significance and bat roosts on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1).
Formulation and implementation of practicable and effective mitigation
measures, if required, in consultation with AFCD. |
No significant residual impact. |
|
Ma Wat River Re-channelisation of
approx. 700m of lower stream course (Low). Disturbance of approx.
3000m of channelised stream course (Low
during construction and operation). Run-off and hydrological
impacts on channelised stream course (Low
to Moderate during construction and Low during operation). Combined impacts Low to Moderate during construction
and Low during operation. |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of
conservation significance and bat roosts on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1).
Formulation and implementation of practicable and effective mitigation
measures, if required, in consultation with AFCD. |
With scope for minor
adjustments to design, timing of works and measures to minimise impacts on
species of conservation significance, no significant residual impact. |
|
San Uk Tsuen, Ma Wat Wai & Tong Hang
Watercourses No direct impact. Disturbance of approx.
100m of Tong Hang Watercourse during construction of Fanling Bypass (Low). |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of
conservation significance and bat roosts on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1).
Formulation and implementation of practicable and effective mitigation
measures, if required, in consultation with AFCD. |
No significant residual impact. |
|
Kau Lung Hang Watercourses No direct impact. Disturbance of approx.
50m during construction of Fanling Bypass (Low). |
Pre-Construction Phase Pre-works commencement
check for presence of any protected flora and fauna and flora of
conservation significance and bat roosts on watercourses to be physically or hydrologically impacted by
construction activities (2.5.1).
Formulation and implementation of practicable and effective mitigation
measures, if required, in consultation with AFCD. |
No significant residual
impact. |
|
Upland Grassland Loss of 6.95ha (Low). Disturbance (Low during construction and
operation). |
Pre-Construction Phase Pre-site clearance check
on all construction sites for presence of flora and fauna of conservation
significance (5.2.2). |
No significant residual impact. |
|
Lowland Grassland Loss of 53.21a (Low). Disturbance during
construction and operation (Low). |
Pre-Construction Phase Pre-site clearance check
on all construction sites for presence of flora or fauna of conservation (5.2.2). |
No significant residual impact. |
|
Seasonally Wet Grassland Loss of 2.86ha near lower
stream reaches of Ma Tso Lung Stream (Low
to Moderate) and elsewhere 1.21ha (Low).
Only the former requires mitigation. Disturbance, run-off and
hydrological disruption of seasonally wet grassland at Ma Tso Lung (Low to Moderate during construction
and Low during operation); Low during construction and operation
elsewhere. Cumulative impact with
LMC Loop Project Low to Moderate
during construction and operation. |
Construction Phase Loss at Ma Tso Lung of
seasonally wet grassland of limited ecological value due to lack of floral
and structural diversity to be compensated by more floristically and
structurally diverse marsh habitat in restored habitat in Ma Tso Lung Stream
riparian corridor (2.3.1). Pre-site clearance check
on all construction sites for presence of flora or fauna of conservation (5.2.2). |
Ma Tso Lung: with
provision of mitigation measures, impacts during the construction phase
severity are not significant and restored/created habitat expected to be of
significantly higher ecological value than existing habitat, so beneficial
residual impact. Elsewhere: no significant
residual impact. |
|
Grassland/ Shrubland Loss of 1.63ha (Low). Disturbance during
construction and operation (Low). |
Construction Phase Pre-site clearance check
on all construction sites for presence of flora or fauna of conservation (5.2.2). |
No significant residual
impact. |
|
Shrubland Loss of 1.11ha (Low). Disturbance of shrubland
at Crest Hill (most likely Low but
possibly Low to Moderate during
construction if a Eurasian Hobby nest site were to be affected and Low during operation); Low during construction and operation
elsewhere. |
Permanent Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on shrubland (2.6.3). Construction Phase Pre-site clearance check
on all construction sites for presence of flora or fauna of conservation (5.2.2). Disturbance impacts at
Crest Hill to be mitigated by erection of 2m high solid green site barrier
fence between active works areas at KTN areas D1-11, D1-12, G1-4 and G1-5 and
adjacent natural habitats to minimise disturbance impacts on shrubland
habitats (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
With mitigation measures
in place severity of residual impact on shrubland at Crest Hill will be not
significant; there will be no significant residual impact in other areas. |
|
Ho Sheung Heung Fung Shui Woodland & Secondary Woodland Loss of 0.23ha of
secondary woodland (Low to Moderate). Disturbance of fung shui and secondary woodland (Low to Moderate during construction
and Low during operation). Dust deposition on
vegetation during construction (Low). Fragmentation impact on
woodland (Low during construction
and). Combined impacts Low to Moderate during construction
and Low during operation. |
Permanent Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland (2.6.3). Compensatory native
woodland planting in KTN areas E1-8 and G1-3. Construction Phase Erection of 2m high solid
green site barrier fence between active works areas at KTN areas D1-7 and
D1-11 and adjacent natural habitats to minimise disturbance impacts on fung shui woodland and secondary
woodland habitats (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
With mitigation measures
in place severity of residual construction phase impact on secondary fung shui and secondary woodland at Ho
Sheung Heung will not be of significance and any residual impact is
considered to be acceptable. Since woodland takes a
long time to become established, there will continue to be a residual impact
of Low severity until the
compensatory woodland habitat is sufficiently mature that it has a similar
ecological function to areas which will be lost. Subsequently, because of the
larger size of the woodland area planted, relative to the areas which will be
lost, these areas will have a small beneficial impact. |
|
Secondary Woodland west of Siu Hang San Tsuen No direct impact. Disturbance (Low during
construction and operation). Dust deposition on
vegetation (Low during construction and operation). Combined impacts Low during construction and
operation. |
Construction Phase Erection of 2m high solid
green site barrier fence on the northern side of active works areas for the
Fanling Bypass to minimise disturbance impacts on secondary woodland (and
other) habitats (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
With mitigation measures
in place, the severity of the residual construction impact will be not
significant and there will be no significant impact during the operational
phase of the project. |
|
Other Secondary Woodland No direct impact. Disturbance and dust
deposition during construction, and disturbance during operation (Low). |
Construction Phase Erection of 2m high solid
green site barrier fence Bypass to minimise disturbance impacts on secondary
woodland (and other) habitats (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1).
|
With mitigation measures
in place, the severity of residual construction impact on other secondary
woodland will not be significant during the construction and operational
phases of the Project. |
|
Hillside Plantation Loss of 8.65ha (Low). Disturbance during
construction and operation (Low to
Moderate). Fragmentation impacts on
hillside plantation during construction and operation (Low). Combined impacts on
hillside plantation Low to Moderate
during construction and operation. |
Permanent Compensatory native
woodland planting in KTN areas E1-8 and G1-3. Construction Phase Erection of 2m high solid
green site barrier fence between active works and adjacent natural habitats
to minimise disturbance impacts on hillside plantation habitats (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
Since woodland takes a
long time to become established, there will continue to be a residual impact
of Low severity until the
compensatory woodland habitat is sufficiently mature that it has a similar
ecological function to areas which will be lost. After this point there will
be a net positive residual impact as a consequence of the increased
ecological function of the compensatory woodland. |
|
Roadside and Urban Plantation Loss of 73.43ha Low. (Loss of 0.27ha of
plantation supporting Man Kam To Egretry addressed under ‘Egretries and
Egretry flight-lines’ below). Disturbance during
construction and operation (Low). |
Permanent Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development along river corridors (3.1.1). Planning for compensation
for loss of trees, woodland and shrubland by compensatory planting in open
spaces, amenity areas, open areas in streetscape and open areas in
development lots; screen planting and road greening (3.1.2). |
Because of the long
duration of the Project planting undertaken in earlier phases of the Project
will have matured by the time impacts from later phases occur. Regardless of
this point, despite the large scale of habitat loss, both construction and
operational phase impacts are not considered to be of significance
ecologically as the habitat does not have any significant ecological function . Once habitats in the final phases of the
Project have matured, there is expected to be a positive residual impact. |
|
Mitigation Plantation Loss of 10.75ha (Low). Disturbance to species
using mitigation plantation (Low). Fragmentation impacts on
species using mitigation plantation (Low). Combined impacts on
species using Low to Moderate
during construction and operation. |
Permanent Stringent planning
control in area north and east of the Sheung Yue River (2.2.1). Screen planting along Ng
Tung, Sheung Yue and Shek Sheung Rivers (2.2.2). Retention of existing mitigation plantation trees
in Open Space zones along the Sheung Yue, Ng Tung and Shek Sheung Rivers and
incorporation of these in screen planting along the rivers in the detailed
design of these Open Space zones (2.6.2). Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development along river corridors (3.1.1).Planning for compensation for loss of trees, woodland and
shrubland by compensatory planting in open spaces, amenity areas, open areas
in streetscape and open areas in development lots; screen planting and road
greening (3.1.2). Construction Phase Erection of 2m high solid
green site barrier fence to minimise disturbance impacts on mitigation
plantation (2.6.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
Mitigation plantation
along the major watercourses is primarily of ecological importance as a
consequence of the screening function which it provides to adjoining
habitats, including Long Valley, mitigation wetland and the rivers. In
addition, it provides linkages between otherwise more isolated areas of
wooded habitats for some fauna, although most of the species involved are
relatively vagile and not restricted to wooded habitats. During the
construction phase, the screening function of the woodland will be fulfilled
by solid barriers which will provide greater noise attenuation and will form
a more effective visual barrier. Accordingly, impacts of loss of screening
function caused by loss of plantation area will not be significant during the
construction phase. Retention of as much of
the mitigation plantation as is feasible, together with the incorporation of
ecological considerations during the planning of open space zones will
mitigate for most potential fragmentation impacts on fauna species using the
plantation. Accordingly, fragmentation impacts as a result of the loss of
mitigation plantation are not considered to be of significance with
mitigation measures in place during the construction and operational phase of
the project. |
|
Orchard Loss of 8.70ha (Low). Disturbance to orchard (Low). |
No mitigation measures
required under the Project. |
Floral diversity in
orchard areas is low and habitat is utilised by habitat-generalist fauna in
small numbers. No residual impacts of significance. |
|
Village, Urban/Residential Areas & Waste
Ground Habitat is of low
ecological value hence severity of impact is. Disturbance to developed
areas will not increase significantly. |
Permanent Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development along river corridors (3.1.1). Planning for compensation
for loss of trees, woodland and shrubland by compensatory planting in open
spaces, amenity areas, open areas in streetscape and open areas in
development lots; screen planting and road greening (3.1.2). |
No
impacts of significance are predicted. |
|
Deep Bay Wetland Ecosystem Cumulative impact of loss
of wetland habitat in the Project Area and LMC Loop Project Area and possible
development at Hoo Hok Wai (Low Severity). Cumulative disturbance to
wetland habitat (Low). Cumulative fragmentation
impact on linkages in the Deep Bay ecosystem of the Project and the LMC Loop
Project and possible development at Hoo Hok Wai (Low). Run-off impact on Deep
Bay ecosystem likely to be Low to
Moderate severity during construction and Low in operation phase. Impact of pollution
events on Deep Bay ecosystem have potential for High severity, but dependent on nature and scale but most events
likely to be of Low to Moderate severity
during construction and Low severity
during operation. With proper mitigation in
place, cumulative impact of run-off and pollution on the Deep Bay ecosystem
is of Low Severity during
construction and of Low Severity during
operation due to large area and scale of more likely events. |
Permanent: Designation of area south
and east of the Sheung Yue River as LVNP (37ha); preparation and
implementation of HCMP to enhance wetland and non-wetland habitats (1.1.1 & 1.1.2). Screen planting to be
enhanced along river channels, subject to constraint of need to avoid loss of
wetland area or function (2.2.2). Prevention of dust,
run-off and pollutants entering Deep Bay (4.1.1). |
With the implementation
of mitigation measures, all cumulative impacts of the project on the area and
connectivity of wetland habitat in the Deep Bay area will be insignificant. With the implementation
of mitigation measures, there will be no significant cumulative impact of the
project on water quality in the Deep Bay wetland ecosystem w during the
construction phase during the operational phase of the project. No residual impacts are
predicted. |
Table 13.152 - Potential Total Residual Direct, Indirect, Fragmentation and Cumulative Ecological Impacts of the Project on Species Groups and Species
Note: in the table below the severity of impacts are presented hierarchically and inclusively, but repetition has been avoided for the purposes of clarity. For example, the severity of combined impacts on Three-banded Box Terrapin is predicted to be Moderate: the severity of this combined impact has been predicted by combining the severities of relevant impacts on all fauna, herpetofauna, reptiles and this species.
|
Sensitive Receiver |
Severity of Impact |
Mitigation |
Residual Impacts |
|
All flora and fauna |
Direct and indirect loss
of habitats in the Project Area as a whole of Low Severity. |
Measures to mitigate for
impacts on habitats described in Table
13.128 above. |
It is inevitable that a
project of the scale of the NDAs will result in redistribution of flora and
fauna, especially during the construction phase; however no unacceptable
residual impacts on fauna and flora in general or on any species or species
group are predicted during either the construction or operational phases of
the project. |
|
Flora of conservation
significance |
Construction phase
impacts at Ho Sheung Heung fung shui and
secondary woodland: dust deposition of Low
Severity, damage or death of Low
to Moderate Severity. |
Permanent Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland (2.6.3). Additional mitigation
measures (in the order of. preserve on site, transplantation and provision of
compensatory planting) would be formulated and implemented should Individual
of species of conservation concern be identified before and during the
construction stage. Construction Phase Erection of 2m high solid
green site barrier fence between active works areas at KTN areas D1-7 and
D1-11 and adjacent natural habitats to minimise disturbance impacts on fung shui woodland and secondary
woodland habitats (5.1.1). Measures to control dust,
construction run-off and pollution (4.1.1). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Mammals and Herpeto-fauna |
Mortality impacts: Low in the Project Area as a whole but Low to Moderate in the Ma Tso Lung
area for riparian fauna of conservation significance and Moderate to High for any mortality of Three-banded Box Terrapin. |
Construction Phase Erection of 2m high solid
green site barrier fence between active works areas and all areas/habitats of
ecological importance on edge of development areas, including any roads
adjacent to or penetrating into areas/habitats of ecological importance (5.2.1). Pre-site clearance check
on all construction sites and pre-works commencement check on watercourses to
be physically and/or hydrologically impacted by construction activities for
the presence of mammals and herpetofauna of conservation significance (5.2.2). Permanent Construction and maintenance of permanent 1.2m high solid faunal
barrier at all at-grade sections of LMC Loop Road north of junction with road
D4 within 15-30m as appropriate of Ma Tso Lung Stream buffer to prevent
terrestrial fauna mortality and a faunal underpass to mitigate for
fragmentation impacts (5.11.3). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Bat Roosts |
Roost destruction during
site clearance works: Low. |
Pre-site clearance check
on all construction sites for presence of bat roosts (5.3.1). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Birds |
Mortality impacts on
breeding birds during site clearance works: generally Low; Moderate if an
egretry site were to be cleared during the breeding season. Mortality impacts arising
from collision: Low, largely
smaller birds. Increase in lighting and
glare: probably Low for most
species but may be Low to Moderate
for migrating birds. Combined impacts: Low (except as noted above). |
Preparation and
implementation of Guidelines for building design measures to minimise
mortality and light and glare impacts to fauna (5.4.1). Use opaque, non-transparent, non-reflective noise
barriers for all roads. Unnecessary lighting should be avoided. Potential impacts of nocturnal avian collision with
buildings should be minimised (5.4.2). Pre-site clearance check
on all construction sites and pre-works commencement check on egretries and
watercourses to be physically and/or hydrologically impacted by construction
activities for the presence of birds of conservation significance (5.2.2). Unavoidable clearance of
Man Kam To Road Egretry to be scheduled outside breeding season. Experience elsewhere in
the world (and, anecdotally, in Hong Kong) is that ‘black spots’, where a
combination of environmental factors results in high collision mortality, are
likely. Post-construction monitoring should, therefore, be undertaken to
identify any such ‘black spots’ and additional/remedial mitigation measures
should be applied. With such additional measures in place, adverse residual
mortality impacts on birds will not be significant in any location in the
Project Area. |
With implementation of
mitigation measures, adverse residual impacts not significant during
construction phase. With implementation of
mitigation measures, there will be no significant adverse residual impacts on
birds during the construction and operational phases of the project in the
Project Area as a whole. |
|
Wetland-dependent bird
species |
Direct loss of wetland
habitats: Low. Indirect loss of wetland
habitats: Low to Moderate on birds using the Sheung
Yue River and non-tidal Ng Tung River, but Low elsewhere, during the construction phase. Low on birds using the
Sheung Yue River; Low to Moderate on non-tidal Ng Tung Rivers, but not
significant elsewhere, during
operational phase. Fragmentation impact: Low to Moderate Severity during
construction and operation on the linkage between Long Valley and the long
non-tidal Ng Tung River; Low Severity on
the linkage between Long Valley and the Deep Bay wetland ecosystem along the
tidal Ng Tung River during construction but not significant during operation;
no other significant fragmentation impacts. Combined impacts of
habitat loss, disturbance and fragmentation: Low overall but Low to
Moderate for freshwater
wetland/wet agricultural land habitat-specialist species and species using
the Sheung Yue River and non-tidal section of Ng Tung River in significant
numbers (especially breeding Little Egrets and Chinese Pond Herons). |
Long Valley Nature Park
(LVNP) designation, design, implementation and design including
redistribution of wetland habitats in LVNP to concentrate closed wetland
habitats (marsh and reed marsh) in more disturbed areas and to undertake
supplementary stocking of fish to mitigate for any loss of foraging habitat
for large waterbirds in disturbed areas including the Sheung Yue River,
especially during the construction phase (5.5.1). Stringent planning
control in Long Valley north and west of Sheung Yue River, including Ho
Sheung Heung Egretry (5.5.2). Planning for creation of
Green Corridors along larger watercourses, detailed design of Open Space
areas and development areas along river corridors to provide screening of
rivers (5.5.5). Enhancement of wetland
habitats in LVNP (5.5.4). Building setback from
Long Valley (5.5.3). Erection of 2m high solid
dull green site barrier fence between
river channel and any active works area along or adjacent to Ng Tung, Sheung
Yue and Shek Sheung Rivers (5.5.6). Erection of 2m high solid
dull green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including along any roads adjacent to or penetrating into areas/habitats of
ecological importance (5.5.7). Pre-works commencement
check on watercourses to be physically and/or hydrologically impacted by
construction activities for
presence of wetland bird species of conservation significance (5.5.8). Review of bridge design
and construction methods during detailed design phase to ensure that
disturbance impacts from these sources are minimised (5.5.9). Avoidance of removal and
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
(5.5.10). Some phasing of
construction such that bridges over watercourses are not constructed
simultaneously (5.5.11). |
With provision of
mitigation measures, in particular the designation, management and
maintenance of the LVNP, there will be a positive residual impact on most
wetland-dependent bird species from the project; in particular those
freshwater wetland species, including Greater Painted-snipe, for which Long
Valley is of particular significance in a Hong Kong context. There will be residual
impacts, especially during the construction phase, on those large waterbird
species which forage in the main river channels, especially the Sheung Yue
River in significant numbers. All of these species also forage in Long
Valley, none are freshwater wetland specialists, and all occur in much larger
numbers in the Deep Bay area. Accordingly, the residual disturbance impacts
on non-breeding waterbirds are considered not to be of significance in a Hong
Kong context, hence the residual impacts on these birds are acceptable. Numbers of Little Egrets
and Chinese Pond Herons breeding at Ho Sheung Egretry are considered to be
significant; hence loss of foraging habitat may be of significance for these
birds. Accordingly, these species have been identified as Key Target Species
for habitat enhancement and management measures in the LVNP. Management
measures will include the provision of undisturbed foraging habitat and
supplementary provision of fish to compensate for any loss of foraging
habitat in the rivers. With such provision, residual impacts on breeding Little
Egrets and Chinese Pond Herons from loss of foraging habitat will be fully
mitigated. |
|
Non wetland-dependent
bird species (except Grey Nightjar and Eurasian Hobby) |
Direct loss of habitats: Low. Indirect loss of
habitats: Low. Fragmentation impact: Low. Combined impacts: Low. |
Long Valley Nature Park
(LVNP) designation, design, implementation and design (5.6.1). Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung egretry (5.6.2). Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development areas along river corridors to provide screening of
rivers (5.6.3). Enhancement of
non-wetland habitats in LVNP (5.6.4) Compensatory native
woodland planting, management and maintenance (5.6.5).Erection of 2m high solid dull green site barrier fence
between active works areas and all areas/habitats of ecological importance on
edge of development areas, including along any roads adjacent to or
penetrating into areas/habitats of ecological importance (5.6.6). Avoidance of removal and
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
(5.6.7). Review development
footprint and layout of proposed developments in KTN areas D1-11a and G1-5 to
avoid/minimise direct and indirect impacts on secondary woodland at Ho Sheung
Heung and Crest Hill (5.6.8). |
Impacts on non-wetland
bird species are all low in the absence of mitigation. With provision of
mitigation measures, there will be no significant residual impacts on non
wetland-dependent bird species from the project. |
|
Bird species utilising
dry agricultural land and woodland |
Direct loss of habitats: Low. Indirect loss of
habitats: Low. Fragmentation impact: Low. Combined impacts: Low. |
Species utilising dry agricultural land and
woodland Long Valley Nature Park
(LVNP) designation, design, implementation and design will include
enhancement of non-wetland habitats (5.6.1). Enhancement of
non-wetland habitats in LVNP (5.6.4). Erection of 2m high solid
dull green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including along any roads adjacent to or penetrating into areas/habitats of
ecological importance (5.6.6). Avoidance of removal and interference with
screen planting undertaken under the Construction of Cycle Tracks and
Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung (5.6.7). Species utilising woodland Planning for compensation
for loss of trees, woodland and shrubland by compensatory planting in open
spaces, amenity areas, open areas in streetscape and open areas in
development lots; screen planting and road greening (3.1.2). Compensatory native
woodland planting, management and maintenance (5.6.5). |
With provision of
mitigation measures, in particular the designation, management and
maintenance of non-wetland habitats in LVNP for species using dry
agricultural land, and woodland and tree planting for species using wooded
habitats, there will be a no significant residual impact on non
wetland-dependent bird species from the project during either the
construction or operational phase. |
|
Eurasian Hobby |
Combined impacts: Low to Moderate depending on
proximity of any nest site in Crest Hill area to works areas. |
Pre-site clearance of
construction sites in Crest Hill area (KTN areas D1-7, D1-11 and G1-5) for
presence of any breeding birds/breeding site (5.7.1). Erection of 2m high solid
dull green site barrier fence between active works areas sites in KTN areas
D1-7, D1-11 and G1-5 and all areas/habitats of natural habitat (5.7.2). |
With pre-site checking to
confirm if a Eurasian Hobby nest site is present in or near a planned active
works area, adjustment to works programme or area, and/or other mitigation
measures identified depending upon proximity of nest site to works area;
impacts on this species will not be significant. |
|
Grey Nightjar |
Combined impacts: Low to Moderate depending on
proximity of any nest site area to works areas. |
Pre-site clearance of
construction site on Cheung Po Tau (FLN area A3-1) for presence of any
breeding birds/breeding site (5.8.1). Erection of 2m high solid
dull green site barrier fence between active works areas sites in FLN area
A3-1 and all areas/habitats of natural habitat (5.8.2). |
With pre-site checking to
confirm if a Grey Nightjar nest site is present in or near a planned active
works area, adjustment to works programme or area, and/or other mitigation
measures identified depending upon proximity of nest site to works area;
impacts on this species will not be significant. |
|
Egretries and egretry
flight-lines |
Direct loss of Man Kam To
Road Egretry: Low to Moderate. Disturbance to Ho Sheung
Heung Egretry: Low. Fragmentation impact on
flight-lines between Ho Sheung Heung Egretry and foraging areas: Low to Moderate during construction and Low during operation. Fragmentation impact on
flight-lines between Man Kam To egretry and foraging areas: Low to Moderate during construction prior to clearance of egretry site. Combined impact: Moderate during construction and Low during operation. |
Egretry Habitat Creation
& Management Plan (EHCMP) and compensatory egretry habitat provision (5.9.1). Stringent planning
control requirements in Long Valley north and west of Sheung Yue River,
including Ho Sheung Heung Egretry (5.9.2). Planning for creation of
Green Corridors along larger watercourses and detailed design of Open Space
areas and development areas along river corridors (5.9.3). No construction during
ardeid breeding season (1st March to 31st July) along Sheung Yue River north or east of KTN D1-5
and east of D1-9 and C2-3 and restriction of working hours on new pedestrian
bridges over the Sheung Yue River and tidal Ng Tung River to 09.00 to 17.30
during the ardeid breeding season (5.9.4). Unavoidable clearance of
Man Kam To Road Egretry scheduled outside breeding season. Review of bridge design
and construction methods during detailed design phase to ensure that
disturbance impacts from these sources are minimised (5.9.5). Creation and operation of
Long Valley Nature Park and creation and enhancement of wetland within LVNP including redistribution of wetland habitats in
LVNP to concentrate closed wetland habitats (marsh and reed marsh) in more
disturbed areas and to undertake supplementary stocking of fish to mitigate
for any loss of foraging habitat for large waterbirds in disturbed areas
including the Sheung Yue River, especially during the construction phase (5.9.6). Erection of 2m high solid
dull green site barrier fence between
river channel and any active works area along or adjacent to Ng Tung, Sheung
Yue and Shek Sheung Rivers (5.9.7). Avoidance of removal and
interference with screen planting undertaken under the Construction of Cycle
Tracks and Associated Supporting Facilities from Sha Po Tsuen to Shek Sheung
(5.9.8). The condition of egretries before commencement and during works would
be monitored. Additional mitigation measures would be formulated and
implemented if necessary. |
With implementation of
mitigation measures, there will be no significant construction phase impacts
to Ho Sheung Heung Egretry and to flight-lines. Together with measures to
mitigate for impacts on foraging habitat for ardeids breeding at the egretry,
no significant impacts on the egretry and on egrets breeding there are
predicted. The effectiveness of
mitigation measures to compensate for loss of Man Kam To Egretry site by
reprovision is uncertain as, even if suitable habitat is provided at the
compensation site, the birds may nest elsewhere. However, other measures to
address adverse impacts on ardeids will ensure that the environment in the Study
Area will continue to provide suitable breeding sites and foraging areas.
Accordingly, the residual impact of the loss of the current breeding site
will be, at most, of Low severity
for one breeding season, if some individuals do not breed in the first season
after the site is cleared. In the longer term, loss of this site is not
significant in a Hong Kong context, hence this impact is considered
acceptable. Mitigation measures are
proposed to minimise impacts on flight-lines from this egretry prior to the
egretry site being cleared; however there will still be residual impacts on
these flight-lines with mitigation measures in place. However, in view of the
small size of the egretry (nine nests in 2013), this
impact is considered not to be of significance. No significant residual impacts anticipated with the mitigation
measures in place. |
|
Reptile species |
Direct loss of habitats: Low. Indirect loss of
habitats: Low. Fragmentation impact: Low. Combined impacts: Low. |
Erection of 2m high solid
dull green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including along any roads adjacent to or penetrating into areas/habitats of
ecological importance (5.10.1). Pre-site clearance check
on all construction sites for presence of species of conservation
significance (5.10.2). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Three-banded Box Terrapin |
Combined impacts: Moderate. |
Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road (5.11.1). Buffer zone of 15
to 30m as appropriate on both sides of Ma Tso Lung Stream and tributaries
north of the point where it is crossed by the LMC Loop Eastern Connection
Road. Ma Tso Lung Stream diversion during
construction of the LMC Loop Eastern Connection Road; development along lower
reaches of Ma Tso Lung and Ma Tso Lung San Tsuen Streams in OU zones in KTN
areas F1-2 and F1-3 to be set back beyond buffer (5.11.2). Construction and
maintenance of permanent 1.2m high solid faunal barrier at all at-grade
sections of LMC Loop Road north of junction with road D4 within 15-30m as
appropriate of Ma Tso Lung Stream buffer to prevent terrestrial fauna mortality and
a fauna underpass to mitigate for fragmentation impacts (5.11.3). Erection of a 2m high
dull green site barrier fence at interface between active works and riparian
corridor of Ma Tso Lung Stream and tributaries (5.11.4). Pre-site clearance check
on all construction sites for presence of Three-banded Box Terrapin (5.10.2). |
With implementation of
mitigation measures, adverse residual impacts not significant during
construction phase and a positive residual impact once re-provided riparian
habitat matures. |
|
Amphibian species |
Combined impacts: Low. |
Erection of 2m high solid
dull green site barrier fence between active works areas and all
areas/habitats of ecological importance on edge of development areas,
including along any roads adjacent to or penetrating into areas/habitats of
ecological importance (5.10.1). Pre-site clearance check
on all construction sites for presence of species of conservation
significance (5.10.2). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Chinese Bullfrog |
Combined impacts: Low to Moderate. |
Creation and operation of
Long Valley Nature Park and creation and enhancement of wetland within LVNP (5.12.1). Pre-site clearance check
on all construction sites for presence of species of conservation
significance (5.12.2). Construction and
maintenance of permanent 1.2m high solid faunal barrier at all at-grade
sections of LMC Loop Road north of junction with road D4 within 15-30m as
appropriate of Ma Tso Lung Stream buffer to prevent terrestrial fauna
mortality and a faunal underpass to mitigate for fragmentation impacts (5.11.3). |
With implementation of
mitigation measures, adverse residual impacts not significant during
construction phase, positive residual impact during operational phase. |
|
Butterflies |
Combined impacts: Low in construction phase, Low during operational phase. |
Prevention of dust impact from active works areas from sites adjacent to Ho Sheung Heung and Crest Hill woodland and shrubland in KTN areas D1-7, D1-11 and G1-(5.13.1). Review development footprint and layout of
proposed developments in KTN areas D1-11a and G1-5 to avoid/minimise direct
and indirect impacts on secondary woodland at Ho Sheung Heung and Crest Hill.
(5.13.2). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Dragonflies |
Combined impacts: Low. |
Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Fish |
Combined impacts: Low. |
Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
|
Small Snakehead |
Combined impacts: Low to Moderate during construction
phase of Ma Tso Lung Stream diversion works; otherwise Low during construction and operation. |
Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road (5.15.1). Buffer zone of 15
to 30m as appropriate on both sides of Ma Tso Lung Stream and tributaries
north of the point where it is crossed by the LMC Loop Eastern Connection
Road. Ma Tso Lung Stream
diversion during construction of the LMC Loop Eastern Connection Road;
development along lower reaches of Ma Tso Lung and Ma Tso Lung San Tsuen
Streams in OU zones in KTN areas F1-2 and F1-3 to be set back beyond buffer (5.15.2). Pre-works commencement
check on watercourses to be physically and/or hydrologically impacted by
construction activities for presence of Small Snakehead (5.15.3). |
With implementation of
mitigation measures, adverse residual impacts not significant during
construction phase, positive residual impact during operational phase. |
|
Somannia-thelphusa zanklon |
Combined impacts: Low. |
Measures to control
hydrological disruption, construction run-off and pollution (4.1.1). Detailed design of
development along lower reaches of Ma Tso Lung Stream in OU zones (KTN areas
F1-2 and F1-3 and detailed design of LMC Loop Eastern Connection Road (5.15.1). Buffer zone of 15
to 30m as appropriate on both sides of Ma Tso Lung Stream and tributaries
north of the point where it is crossed by the LMC Loop Eastern Connection
Road (5.15.1). Ma Tso Lung Stream
diversion during construction of the LMC Loop Eastern Connection Road;
development along lower reaches of Ma Tso Lung Stream in OU zones in KTN
areas F1-2 and F1-3 to be set back beyond buffer (5.15.2). Pre-works commencement
check on watercourses to be physically and/or hydrologically impacted by
construction activities for presence of Somanniathelphusa
zanklon and translocation to Ma Tso Lung Stream (5.15.3). |
With implementation of
mitigation measures, adverse residual impacts not significant. |
With mitigation measures most ecological impacts of the implementation of the Project will be fully mitigated. In particular, there will be a positive residual impact on wetland-dependent bird species of conservation significance, including all those species associated with freshwater wetland habitats. However, while mitigation measures to reduce disturbance impacts on waterbirds using the main river channels are proposed, disturbance impacts to the more sensitive species on the Sheung Yue and Ng Tung River channels can be mitigated in full by provision of compensatory wetland habitat within LVNP.
The requirement to compensate for impacts on large waterbirds using the main river channels will be greatest during the construction phase of the Project. However, following completion of the Project, the southern section of the Sheung Yue River and the Ng Tung River east of western terminus of the Fanling Bypass will still be subject to some disturbance from developed areas and the activities of people using them. Measures have been proposed to mitigate for these impacts by increased carrying capacity for these species in the LVNP.
Construction phase impacts of Low severity are predicted on some wooded habitats and areas. This is largely a consequence of wooded habitats taking some time to mature.
13.11.1 Ecological Monitoring Programme
The ecological impact assessment has evaluated the predicted ecological
impacts of the NDAs project and has concluded that ecological impacts can be
avoided or reduced to a low and acceptable level with the implementation of
appropriate mitigation measures.
Major mitigation measures proposed include the creation of Long Valley
Nature Park (LVNP) where compensatory wetland habitat will be created or
enhanced; compensatory egretry habitat provision at FLN A1-7; and compensatory
woodland habitat creation.
In addition, mitigation measures to minimise adverse impacts of the
projects on the Ng Tung, Sheung Yue and Shek Sheung Rivers and large waterbirds
using them (including compensatory habitat provision for impacts on large
waterbirds in LVNP are proposed. At Ma Tso Lung Stream a series of measures are
proposed to minimise and mitigate for impacts on the stream and riparian fauna
In addition, in situ
mitigation measures are proposed to address potential impacts on habitats and
fauna of conservation significance in a number of locations, including woodland
at Ho Sheung Hill, shrubland at Crest Hill and elsewhere as noted in Section 13.8 and 13.9 and Chapter 15 of
this report.
The proposed ecological mitigation measures should be checked as an
element of the environmental monitoring and audit programme prior to and during
the project construction stage.
Mitigation measures have been identified and designed in accordance with Annex 16 of the EIAO-TM. The Implementation Schedule for these measures is detailed in Appendix 2-2. Required measures are described in more detail below.
13.11.2.1 Wetland Habitat Loss
Unavoidable loss of 6.12ha of wetland across the two NDAs will be
compensated by creation and enhancement of 37ha of wetland habitat in the LVNP.
Detailed design and proposed management and maintenance of this wetland habitat
will be included in the Detailed Habitat Creation & Management Plan for
LVNP (see also Appendix 13.10).
13.11.2.2 Wetland Habitat Disturbance
Impacts on the Ng Tung, Sheung Yue and Shek Sheung Rivers will occur
during the construction and operational stages of the project. Focus shall be
made on more disturbance-sensitive species of large waterbirds foraging in the
rivers. Impacts are also predicted on Long Valley, in particular disturbance
impacts on large waterbirds, especially in the southwest of the proposed LVNP.
Mitigation measures to address these impacts are proposed to mitigate for
impacts on the river habitats and on the waterbirds using them. The latter will
be mitigated, in part by the provision of compensatory habitat in LVNP.
Mitigation will be provided in part by the enhancement of wetland in Long
Valley described in Section 13.2.1
above and in part by appropriate screen planting in the Open Space zone along
the river banks. During the construction phase disturbance to large waterbirds
in these channels should be minimised by erection of a 2m high, solid dull
green site boundary fence between the channel and any active works area.
Surveys of waterbirds and other species of conservation significance
using Long Valley and the main river channels are required throughout the year
to monitor the effectiveness of the mitigation measures and to inform the
adaptive management of LVNP to meet the needs of target species and species
groups. Should unacceptable disturbance impacts be noted, appropriate measures
to further reduce disturbance impacts should be devised and implemented as is
discussed below and in Chapter
15.
13.11.2.3 Woodland Habitat Loss
Unavoidable loss of 8.88ha of secondary woodland and plantation of
ecological significance will be compensated by planting native tree and shrub
species at an area ratio of at least 1:1. Areas of grassland of low ecological
value comprising 16.03ha have been identified for compensatory planting (Figures
13.14a-c). The area identified for planting is approximately twice the
area of loss, which allows for both the lower initial ecological value of the
areas to be planted relative to the areas lost, and also makes an allowance for
parts of the areas identified being unsuitable for planting (for example due to
topography, soil conditions, existing vegetation or footpaths).
13.11.2.4 Man Kam To Egretry Habitat Loss
A site of 0.14ha in A1-7, FLN has been identified for the planting of
bamboos and trees to compensate for the loss of the site of Man Kam To Road Egretry. The site is on land comprising a former
meander of the Ng Tung River which is currently managed as compensatory wetland
habitat. No loss of wetland will be involved in this compensatory provision
which will be undertaken on dry land within the ox-bow of the meander.
Compensatory planting and measures to attract egrets (decoy models and
broadcast of calls) should be undertaken as advance works for the NDAs project
and well in advance of the existing egretry site being impacted.
It should be noted that compensatory provision of this nature has been
successful overseas but success cannot be assured as it is dependent on the
birds relocating under their own volition.
13.11.2.5 Measures to minimise impacts to the Ma Tso Lung Stream and the Siu Hang San Tsuen Stream
Impacts to the Ma Tso Lung Stream and its tributaries will be avoided by Green Belt zoning except for a section of the lower Ma Tso Lung Stream that will be impacted by the construction of the LMC Loop Eastern Connection Road. Mitigation measures to minimise ecological impacts will include the avoidance of direct impacts at the point where the road crosses the stream by the road being placed on viaduct. A short section of stream (130m in total) will be diverted and a buffer corridor with a minimum width of 15m from the road (and 45mm in total) will be reinstated with natural riparian vegetation and maintained during the operational period of the Project. Detailed mitigation measures will be designed at the detailed design phase of the road.
The lower reaches of the Siu Hang San Tsuen Stream will be crossed by the Fanling Bypass and will lie within Open Space Zone D1-3. The bypass will be on viaduct at this point, which should serve to minimise impacts to the stream and stream fauna. However, measures to reduce any impacts to an acceptable level will be designed at the detailed design stage of the road and the D1-3 zone.
13.11.2.6 Measures to minimise impacts on ecologically sensitive habitats from disturbance and pollution
Mitigation measures to minimise disturbance and pollution of adjacent areas of ecologically sensitive habitats are also pertinent in ensuring that ecological impacts of the project are kept to acceptable levels. These measures include the provision of site hoarding around all construction areas to minimise disturbance to adjacent habitats. Measures required are as detailed in Section 13.9 and in Appendix 2-2.
13.11.3 Monitoring and Audit Requirements
13.11.3.1 Ecological Audit
The
implementation of mitigation measures described above shall be audited
periodically during the implementation of the project. This will cover
implementation of the mitigation measures described in Section 13.9 and in the Environmental Monitoring
& Audit (EM&A) Manual (Chapter 15 of this report) and the Project
Implementation Schedule detailed in Appendix
2-2.
Monitoring
activities described below should be conducted by the Environmental Team (ET)
and supervised by a qualified ecologist who will be a member of the ET.
13.11.3.2
Ecological Monitoring
Monitoring of Construction and Operation of LVNP (including creation of compensatory wetland habitat)
Monitoring measures for the construction of the LVNP, including creation and enhancement of wetland to compensate for wetland loss will be detailed in the LVNP Habitat Creation and Management Plan. After the construction and establishment stages, management and monitoring will be the responsibility of AFCD.
As noted below, monitoring should also be undertaken in all areas where impacts on habitats and fauna may arise as a consequence of the project. This includes LVNP where impacts on disturbance-sensitive fauna are predicted in the absence of mitigation measures (including adaptive management measures in Long Valley). The ecological monitoring protocol to be followed in LVNP should, therefore satisfy three objectives, as follows:
· Monitoring of numbers and distribution of fauna (especially species of conservation significance) relative to adaptive management targets;
· Monitoring of numbers and distribution of fauna (especially species of conservation significance) for which habitat enhancement and other measures in LVNP are required to mitigate for impacts of the project on their use of Long Valley habitats;
· Monitoring of numbers and distribution of fauna (especially species of conservation significance) for which habitat enhancement and other measures in LVNP are required to mitigate for impacts of the project on their use of habitats in the main river channels.
It follows that the monitoring protocol in order to address the second and third of these requirements should be consistent with that described below in respect of monitoring of measures to mitigate for impacts on wetland-dependent fauna using the Ng Tung, Sheung Yue and Shek Sheung Rivers.
Details of monitoring protocol will be included in the HCMP for LVNP. Subject to confirmation following the completion of pre-construction baseline surveys and the adoption and implementation of the HCMP, the following survey methodologies and frequencies are recommended in respect of fauna species and groups of species which are the targets for mitigation measures:
· Mammals: infra-red camera ‘traps’ to be deployed;
· Birds: weekly surveys following similar methodologies to those utilised by HKWBS since 2005 (in order to allow comparability of data), together with any additional surveys required in order to address the need for survey data to be comparable with that collected in respect to bird use of the main river channels, as described below);
· Herpetofauna: monthly transect surveys, including night-time surveys during March to July;
· Butterflies and dragonflies: monthly transect surveys; exuviae monitoring in any areas managed with creation or enhancement of conditions as a breeding site.
Monitoring of Measures to Mitigate for Impacts of the Project on Wetland-dependent Fauna using the Ng Tung, Sheung Yue and Shek Sheung Rivers
Where development under the NDAs project is undertaken within 200m (the maximum distance at which it is predicted there may be some disturbance, and hence a reduction in numbers, of large waterbirds) of the Ng Tung, Sheung Yue and Shek Sheung Rivers and Long Valley (including wetland enhancement measures in LVNP), the monitoring protocol detailed in Table 13.153 should be followed. A transect should be undertaken throughout the sections of the rivers where NDA construction activities are proposed; as the sensitive receivers (large waterbirds) are easily visible, the transect route needs only follow one bank of the rivers. The transect route should remain the same during the different phases in order to ensure that data are comparable. As stated in this report, it is predicted that there will be some construction and operational phase disturbance impacts on large waterbirds using these rivers, and mitigation will in part be provided by enhancement measures for large waterbirds in LVNP. Monitoring of large waterbirds should, therefore, also be undertaken with the same frequency in LVNP (see above). A detailed monitoring plan would be formulated at least one year before the commencement of construction phase.
Table
13.153 - Monitoring of Measures to Minimise Disturbance to Waterbirds on Ng
Tung, Sheung Yue and Shek Sheung Rivers
|
Phase |
Methodology |
|
Pre-construction (Baseline) |
Weekly transect at both high and low tides to identify and enumerate
all bird species utilising the river channels and LVNP area for 12 months
prior to the commencement of construction. |
|
Construction |
Weekly transect at both high and low tides to identify and enumerate
all bird species utilising the river channels and LVNP and identify any
sources of actual or potential disturbance to birds due to construction
activities throughout the construction period. |
|
Post-construction |
Weekly transects at both high and low tides to identify and enumerate
all bird species utilising the river channels and LVNP and identify any
sources of actual or potential disturbance to birds due to operational
activities for 12 months following the completion of the construction period. |
Measures
to respond to decreases in numbers of large waterbirds using the river channels
are detailed in Table 13.154.
Action and limit levels will be determined following evaluation of the
pre-construction (baseline) data. Note that waterbird numbers refer to combined
numbers using the channels and LVNP.
Table
13.154 - Action and Limit Levels and Responses to Evidence of Disturbance to
Waterbirds using in Ng Tung, Sheung Yue and Shek Sheung Rivers
|
Action
Level |
Response |
Limit
Level |
Response |
|
Construction Phase |
|||
|
Decline in numbers of all waterbird species relative to numbers during
Baseline Monitoring such that the Action Level response is triggered. |
Investigate cause and if cause identified as related to NDAs project
instigate remedial action to remove or reduce source of disturbance. |
Decline in numbers of all waterbird species relative to numbers during
Baseline Monitoring such that the Limit Level response is triggered. |
Investigate cause and if caused identified as related to NDAs project
instigate remedial action. Review and adjust LVNP management measures to
improve conditions for affected species. |
|
Decline in numbers of any one waterbird species occurring in
significant numbers* during Baseline Monitoring such that the Action Level
response is triggered. |
Investigate cause and if cause identified as related to NDAs project
instigate remedial action to remove or reduce source of disturbance. |
Decline in numbers of any one waterbird species occurring in
significant numbers* during Baseline Monitoring such that the Limit Level
response is triggered. |
Investigate cause and if caused identified as related to NDAs project
instigate remedial action. Review and adjust LVNP management measures to
improve conditions for affected species. |
|
Operational Phase |
|||
|
Decline in numbers of all waterbird species relative to numbers during
Baseline Monitoring such that the Action Level response is triggered. |
Investigate cause and if cause identified as related to NDAs review
and adjust LVNP management measures to improve conditions for affected
species in LVNP. |
Decline in numbers of all waterbird species relative to numbers during
Baseline Monitoring such that the Limit Level response is triggered. |
Investigate cause and if cause identified as related to NDAs consider
and implement additional mitigation measures (e.g. additional screening and
screen planting, adjustments to infrastructure design). |
|
Decline in numbers of any one waterbird species occurring in
significant numbers* during Baseline Monitoring such that the Action Level
response is triggered. |
Investigate cause and if cause identified as related to NDAs review
and adjust LVNP management measures to improve conditions for affected
species. |
Decline in numbers of any one waterbird species occurring in
significant numbers* during Baseline Monitoring such that the Limit Level
response is triggered. |
Investigate cause and if cause identified as related to NDAs consider
and implement additional mitigation measures (e.g. additional screen
planting, adjustments to infrastructure design). |
* Whether numbers are significant will depend on
species and season and should be determined following the collection and
evaluation of Baseline survey data.
Monitoring of Compensatory Egretry Habitat Provision
Site clearance works at the current egretry location at Man Kam To Road should be undertaken outside the ardeid breeding
season (typically 1st March to 31st July). Irrespective
of the foregoing, egretry location should be checked for any evidence of
occupation by a qualified ecologist of the ET prior to the commencement of any
works activity within 100m of the egretry.
An Egretry Habitat Creation and Management Plan that includes the
monitoring and reporting requirements will be prepared and the measures
proposed in this plan shall be implemented as an advance works element of the
project.
The plan should detail any site preparation works, including changes to
ground levels in the proposed compensatory planting site in FLN area A1-7.
Consideration should be given as to whether the area and type of wetland and
non-wetland habitats should be adjusted, subject to ensuring that the principle
of ‘no net loss’ of wetland function is adhered to.
The plan should also include a detailed planting plan, including, but
not limited to, planting a clump of Bambusa
eutuldoides as a compensatory breeding site. Measures to protect the site
from disturbance including fencing, use of water as a barrier to inhibit
disturbance, and screen planting and bunding should be included.
The plan should also detail post-construction methods to attract
breeding ardeids including, but not limited to use of decoy models and
recordings of breeding vocalisations to attract birds, following current best
international practice.
In
addition, a construction phase; post-construction ‘attraction-phase’; and
operational phase (i.e. if, and when, attraction is successful) programme for
monitoring site conditions and use of the site by ardeids and any other species
of conservation significance should be specified.
Monitoring
of Measures to Minimise Impacts to the Ma Tso Lung Stream and the Siu Hang San
Tsuen Stream
Aquatic faunal monitoring should be carried out during a 12-month
pre-construction phase, the construction phase and the first 12 months of the
operational phase.
Table 13.156 - Monitoring of
Measures to Minimise Impacts to Ma Tso Lung Stream and Siu Hang San Tsuen
Streams
|
Phase |
Methodology |
|
Pre-construction (Baseline) |
Monthly quantitative replicate surveys of stream fauna using
standardised methodology at fixed points, the number of which should be
determined prior to the first monitoring event. |
|
Construction |
Monthly quantitative replicate surveys of stream fauna using
standardised methodology at the fixed points determined in the
pre-construction phase. |
|
Post-construction |
Monthly quantitative replicate surveys of stream fauna using
standardised methodology at the fixed points determined in the
pre-construction phase. |
Measures
to respond to decreases in numbers of aquatic fauna using the watercourses and
action and limit levels to trigger these measures are detailed in Table 13.157.
Monitoring in the post-construction phase should continue for 12 months or
until a time when neither the action nor limit levels are exceeded, whichever
is the later.
Table
13.157 - Action and Limit Levels and Responses to Evidence of Declines in Aquatic
Fauna
|
Action Level |
Response |
Limit Level |
Response |
|
Construction Phase |
|||
|
Reduction in taxa diversity such that Action Level response is
triggered. |
Investigate cause and if cause identified as related to Project
instigate remedial action to remove or reduce source of disturbance. |
Reduction in taxa diversity such that Limit Level response is
triggered. |
Investigate cause and if caused identified as related to Project
instigate remedial action. |
|
Operational Phase |
|||
|
Reduction in taxa diversity such that Action Level response is
triggered. |
Investigate cause and if cause identified as related to Project review
and adjust LVNP management measures to improve conditions for affected
species. |
Reduction in taxa diversity such that Limit Level response is
triggered. |
Investigate cause and if cause identified as related to Project
consider and implement additional mitigation measures. |
* Whether numbers are significant will depend on
species and season. Action and Limit Levels and Significance threshold for each
species should be determined following collection of Baseline survey data.
Monitoring of measures to minimise impacts on ecologically sensitive habitats from disturbance and pollution
In order to
monitor the effectiveness of measures to minimise impacts on ecologically
sensitive habitats from disturbance and pollution standard faunal transect
surveys should be carried out in the following areas:
-
Ma Tso Lung riparian zone and associated wetland
habitats
-
Siu Hang San Tsuen Stream
-
Areas in the western part of KTN
-
Green belt areas E1-8, D1-8 and G1-3
-
AGR zone C2-4 and C2-2 in KTN NDA
-
Fanling North Freshwater Service Reservoir
-
Areas north of Ng Tung River
-
South side of Fanling Highway in the vicinity of
Pak Shek Au
-
Areas west and east of the southern limit of the
Fanling Bypass works area
Monitoring of
measures to minimise impacts should be carried out during a 12-month
pre-construction phase, the construction phase and the first 12 months of the
operational phase.
Table
13.158 - Monitoring of Measures to Minimise Impacts on ecologically sensitive
habitats from disturbance and pollution
|
Phase |
Methodology |
|
Pre-construction (Baseline) |
Monthly quantitative surveys of non-aquatic fauna using standard route
transect counts. |
|
Construction |
Monthly quantitative surveys of non-aquatic fauna using standard route
transect counts. |
|
Post-construction |
Monthly quantitative surveys of non-aquatic fauna using standard route
transect counts. |
Measures
to respond to decreases in numbers of fauna and action and limit levels to
trigger these measures are presented in Table
13.159. Monitoring in the post-construction phase should
continue for 12 months or until a time when neither the action nor limit levels
are exceeded, whichever is the later.
Table
13.159 - Action and Limit Levels and Responses to Evidence of Declines in
Aquatic Fauna
|
Action Level |
Response |
Limit Level |
Response |
|
Construction Phase |
|||
|
Reduction in species diversity such that Action Level response is
triggered. |
Investigate cause and if cause identified as related to Project
instigate remedial action to remove or reduce source of disturbance. |
Reduction in taxa diversity such that Limit Level response is
triggered. |
Investigate cause and if caused identified as related to Project
instigate remedial action. |
|
Operational Phase |
|||
|
Reduction in species such that Action Level response is triggered. |
Investigate cause and if cause identified as related to Project review
and adjust LVNP management measures to improve conditions for affected
species. |
Reduction in taxa diversity response is triggered. |
Investigate cause and if cause identified as related to Project
consider and implement additional mitigation measures. |
* Whether numbers are significant will depend on
species and season. Action and Limit levels Significance threshold for each
species should be determined following collection of Baseline survey data.
An ecological impact assessment has been conducted to address the potential ecological impacts arising from the development of the NDAs.
The area of highest ecological value in the Study Area is Long Valley which is a site of ecological significance in a Hong Kong context due to its being the largest remaining contiguous area managed for the production of wet agricultural crops. These, in combination with the other habitats in the Long Valley area, support a diverse fauna, of which the bird community, especially the freshwater-associated wetland bird community, is of high significance.
The Ma Tso Lung Stream, its tributaries and the riparian zone of these streams is also of ecological importance. While it is disturbed in several places by developed areas, and includes some partially channelised sections in the north of the Study Area, much of the stream is largely natural. A number of species of conservation importance have been found in or near the stream, of these Three-banded Box Terrapin, which is listed as being Critically Endangered globally is of greatest significance.
Other habitats and sites of particular ecological interest include the channel of the Ng Tung, Sheung Yue and Shek Sheung Rivers, fung shui woodland at Ho Sheung Heung, young secondary woodland and older plantations and some other streams.
Alternatives to safeguard the conservation value of Long Valley were considered and it is proposed to designate the area of highest ecological value (37.17ha), the largely wetland area south and east of the Sheung Yue River and south and west of the Shek Sheung River, as LVNP, zoned as Other Uses (OU) Nature Park (area C1-9 in KTN).
The proposed Long Valley Nature Park will safeguard the ecological value of this freshwater wetland area, which is unique in a Hong Kong context. Active conservation management of the LVNP will also provide the opportunity to enhance its ecological value, both to mitigate for loss of wetland habitats and other impacts on wetland fauna, and to increase its value for wildlife.
It is proposed to retain the agricultural (AGR) zonings of the area west and north of the Ng Tung and Sheung Yue Rivers and east of Ho Sheung Heung (C2-2), and the area south and east of area C1-9 and east of Yin Kong (C1-6). To strengthen the planning control over the AGR zone to reflect the importance of this area being on the flight path of the birds and a buffer zone for the LVNP, stringent planning control will be exercised and such intention will be stated in an Explanatory Statement of the relevant Layout Plan.
Alternatives to avoid potential impacts to Man Kam To Road Egretry were considered, but were found to be impractical due to engineering constraints and requirements; mitigation measures to compensate for this loss are therefore proposed;
Alternatives to avoid potential impacts to the Ma Tso Lung Stream and marsh and its riparian corridor and fauna of conservation significance were considered, and the stream and its tributaries and their riparian corridors south of the point where it will be crossed by the LMC Loop Eastern Connection Road will be included in a Green Belt zone (KTN area H1-1) where there is a presumption against development. Where the construction of the LMC Loop Eastern Connection Road will result in unavoidable impact to a downstream section of the stream in the north of the Project Area, alternatives to minimise impacts were considered. Avoidance of direct impacts by placing the road on viaduct were evaluated as being greater than impacts of diverting a section of the stream and minimising and compensating for such impacts.
Options to find an appropriate balance between the width of buffer which could be provided post-diversion, and the length of stream to be diverted were then considered; and it was resolved that the optimum solution, given the site constraints, is for a section of 130m of Ma Tso Lung Stream to be diverted and reinstated, with a minimum buffer width of 15m from the road to be maintained, following diversion, on the west side of the stream. On the east side a buffer width of up to 30m would be maintained from any development under the Project (such that at no point will the combined width of the buffer on both sides of the stream be less than 45m). The stream section to be diverted will be reinstated with natural materials and marsh vegetation will be established alongside the stream, Tree and shrub planting will be undertaken on each side of this up to the edges of the buffer zone. Once this vegetation has become established it is considered that the ecological value of the riparian corridor as a movement corridor for target fauna species of conservation significance will be fully mitigated, if not increased. In addition, in order to maintain connectivity for fauna moving in a direction perpendicular to the riparian corridor (and the LMC Loop Eastern Connection Road) a faunal underpass will be formed beneath the road. This, together with similar underpasses to be provided to the north of the project boundary under the LMC Loop project, will mitigate for cumulative fragmentation impacts of the two projects.
Finally, in order to minimise mortality impacts on fauna, construction stage barriers are proposed to prevent fauna from entering any project works area and a permanent barrier is proposed to minimise mortality impacts on fauna, in particularly the critically endangered Three-banded Box Terrapin,
Impacts of the Project
Construction and operation of the Project will result in a range of ecological impacts some of which, if unmitigated, are predicted to cause ecological impact of significance. The key habitat losses and indirect impacts are as follows:
Direct Impacts
Direct impacts of the Project will not result in the direct loss of areas of habitat that are of high importance, either in terms of function or area, in the context of the Study Area and the northern New Territories. However, the combined loss of wetland habitats of ecological value, including wet agricultural land, pond, mitigation wetland and seasonally wet grassland is 8.70ha. Most of the areas which will be lost are fragmented and somewhat disturbed, and of limited ecological function, but the loss of wetland area, in aggregate, is of significance.
Indirect Impacts
· Disturbance impact on Long Valley;
· Indirect impact including disturbance, hydrological impact, potential pollution impact and fragmentation impact on Ma Tso Lung Stream and riparian corridor;
· Disturbance impact on Sheung Yue, Ng Tung and Shek Sheung Rivers and on wetland-dependent fauna using the rivers, in particular impacts on large waterbirds foraging in the Sheung Yue River and using the flight-line linking Long Valley along the Ng Tung River to Hoo Hok Wai;
· Disturbance impact on Ho Sheung Heung fung shui and secondary woods.
Key Mitigation Measures
Mitigation measures comprise the following:
· Designation of 37.17ha of Long Valley (LVNP) as Other Uses (Nature Park) in the revised RODP;
·
Habitat
enhancement measures to be implemented in LVNP to compensate for loss of
wetland habitats and ecological function of loss of dry agricultural land;
·
A
series of measures to mitigate for disturbance impacts on Long Valley,
including planning control, installation of 2m high fences around works areas;
restrictions on work during the ardeid breeding season on flight-lines;
·
Preservation and provision of screen planting and
optimize building setback along main river channels;
·
Phasing of works along main river channels and near
Egretries;
·
Provision of alternative egretry roosting site;
·
A
series of measures to protect the Ma Tso Lung Stream riparian corridor
including designation of a no-building buffer zone, minimisation of stream
diversion, restoration of the stream to natural conditions following diversion,
restoration and enhancement of vegetation in the riparian corridor, LMC Loop
Eastern Connection Road to cross the stream on viaduct, a permanent barrier on
the at-grade section of the LMC Loop Eastern Connection Road to prevent terrestrial
fauna mortality and a faunal underpass to mitigate for fragmentation impacts;
·
Compensation
for loss of secondary woodland and higher value plantation by provision of
compensatory woodland habitats, and native tree and shrub planting;
·
Pollution
control in works areas of ecological significance, and in or adjacent to
watercourses;
·
Installation
of 2m high fences around works areas adjacent to habitats/areas of ecological
importance.
After implementation of mitigation measures, no significant adverse residual ecological impacts are predicted. While mitigation measures to reduce disturbance impacts on waterbirds using the main river channels are proposed, disturbance impacts to the more sensitive species on the Sheung Yue and Ng Tung River channels will be mitigated in full by provision and management of compensatory wetland habitat within Long Valley.
Construction phase impacts of Low severity are predicted on some wooded habitats and areas on some species using these habitats and operation phase disturbance impacts of Low severity on Ho Sheung Heung fung shui woodland and secondary woodland. However, the compensatory woodland habitat to be provided will generate a net ecological benefit to the Study Area once established.
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