7. ECOLOGICAL IMPACT ASSESSMENT

7.1 Introduction

7.1.1 The Project is intended to alleviate the flooding problem in the area by converting the existing Hang Hau Tsuen stream between Deep Bay and Deep Bay Road into an engineered channel (Figures 2.1 – 2.3). This section present the assessment for ecological impacts associated with the Project.

7.2 Relevant Legislation and Guidelines

7.2.1 The HKSAR ordinances and regulations relevant to ecological assessment of this Project include the following:

· Forests and Countryside Ordinance (F&CO) (Cap. 96) and its subsidiary legislation, the Forestry Regulations;

· Town Planning Ordinance (TPO) (Cap. 131);

· Wild Animals Protection Ordinance (WAPO) (Cap. 170);

· Country Parks Ordinance (CPO) (Cap. 208) and its subsidiary legislation;

· Protection of Endangered Species of Animals and Plant Ordinance (Cap. 586); and

· Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) and the associated TM (EIAO-TM).

7.2.2 Ecological assessment will also make reference to the following guidelines and standards as well as international conventions:

· Hong Kong Planning Standards and Guidelines (HKPSG) Chapter 10, "Conservation";

· Ecological Baseline Survey For Ecological Assessment (EIAO Guidance Note No. 7/2002);

· PELB Technical Circular 1/97 / Works Branch Technical Circular 4/97, "Guidelines for Implementing the Policy on Off-site Ecological Mitigation Measures";

· Relevant wildlife protection laws in PRC;

· Convention on Wetlands of International Importance Especially as Waterfowl Habitat (the "Ramsar Convention"), which requires parties to conserve and make wise use of wetland areas, particularly those supporting waterfowl populations;

· United Nations Convention on Biological Diversity, which requires parties to regulate or manage biological resources important for the conservation of biological diversity, to promote the protection of ecosystems, natural habitats and the maintenance of viable populations of species in natural surroundings; and

· International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species.

7.3 Study Area

7.3.1 The assessment area for the purpose of this ecological impact assessment included all areas within 500 m distance from the Project area as stated in the EIA Study Brief or other project alignments as identified in the EIA, or the areas likely to be impacted by the Project.

7.4 Field Survey Scope and Methodology

7.4.1 Information gathered from literature was verified during field surveys to determine whether any significant changes from the baseline conditions might occur.

7.4.2 According to the EIA Study Brief Section 3.4.9.3 (iii), the duration of field surveys shall be at least 6 months covering the winter migratory bird season. Seven-month ecological surveys were carried out from November 2007 to May 2008 which included both winter migratory bird season and wet season. The survey programme therefore fulfilled the requirements of ecological field surveys as stipulate in the EIA Study Brief.

Habitat and Vegetation Survey

7.4.3 Habitats were mapped (as shown in Figure 7.1) based on the latest government aerial photos and field ground truthing. Representative areas of each habitat type were surveyed by ground truthing. Plant species of each habitat type encountered and their relative abundance, with special attention to rare or protected species, were recorded. Colour photographs of all habitats encountered on site and of ecological features of special importance were provided in Figure 7.2. Habitat maps of the study area were produced at the required scale using GIS software.

Terrestrial and Aquatic Fauna

7.4.4 The bird communities of terrestrial habitats in the Project and assessment areas were surveyed quantitatively using the transect count method. Bird community of coastal habitats including mangroves and inter-tidal mudflat was observed from vantage points. Locations of transects and vantage points are also shown in Figure 7.1. All birds seen or heard were identified and counted. Behaviour of breeding (e.g., presence of nests, recently fledged juveniles, birds carrying nesting materials) was recorded. Bird species observed outside sampling transects / vantage points but within the assessment area were recorded in order to produce a complete bird species list for the assessment area. Ornithological nomenclature in this report follows Carey et al. (2001).

7.4.5 Dragonflies and butterflies within the Project and assessment areas were surveyed quantitatively using the transect count method. Locations of transects are shown in Figures 7.1. Dragonfly and butterfly species observed outside sampling transects but within the assessment area were recorded in order to produce complete species lists. Nomenclature for dragonflies follows Wilson (2004); nomenclature for butterflies follows Yiu (2004).

7.4.6 Mammals and herpetofauna in the Project and assessment areas were surveyed qualitatively. Reptiles and amphibians were recorded by visual and acoustic survey and identified to species level. All sightings, tracks, and signs of mammals were recorded. As mammals and herpetofauna are generally nocturnal, a night survey was also performed in wet season. The night survey also aimed to recorded nocturnal birds such as owls and nightjars. Nomenclature used in this report for amphibians follows Chan et al. (2005), for reptiles Karsen et al. (1998) and for mammals Shek (2006).

7.4.7 Aquatic fauna were surveyed by direct observation, active searching, and hand netting in fishponds, stream courses and drainage channel covering wet and dry seasons. Aquatic fauna found were identified and recorded, with their relative abundance.

Intertidal Fauna

7.4.8 Intertidal habitats within the study area included mangroves and intertidal mudflats. Mangrove fauna were studied by active search, while mudflat fauna were studied by both active search and transect method. Two 100 m transects (i.e. Transect S and Transect N, see Figure 7.1) were established on the mudflats just offshore to the stream outlet. 0.5 m x 0.5 m quadrats were deployed starting at 10 m on the transect and at a 10 m interval (a total of 10 quadrats on each transect). Within each quadrat, the epifauna and burrows were counted, and a core of 15 cm diameter and 20 cm depth was collected inside each quadrat. Burrows were also excavated to investigate the occupying organisms.

7.5 Recognised Site of Conservation Importance

7.5.1 No recognized sites of conservation importance are found within the 500 m assessment area. Key ecological issues of the EIA were stipulated in the EIA Study Brief or identified during the course of the EIA study include the followings:

· the Coastal Protection Area (CPA) near Hang Hau Tsuen, zoned under OZP S/YL-LFS/7 - Lau Fau Shan & Tsim Bei Tsui;

· the natural stream course and meanders of Hang Hau Tsuen stream;

· the ponds, intertidal mudflats and mangrove at or near the Project area; and

· avifauna, in particular, waterbirds.

7.6 Results

Project Area

7.6.1 The Project is located at Hang Hau Tsuen of Lau Fau Shan at Northwest New Territories.

7.6.2 Within the Project area is the Hang Hau Tsuen stream channel of about 435 m in length. The stream bank was covered with grasses along the section above tidal influence and lined with pieces of mangrove stands below the high tide level. Part of an abandoned fish pond, wasteland and village houses were found beyond the stream bank. The water quality of the stream was poor, and details were described in the following paragraphs.

Results of Literature Review

7.6.3 No ecological impact assessment under EIAO or documented ecological studies were previously carried out within or adjacent to the proposed work site. The closest project is Shenzhen Western Corridor, which is more than 1 km from the current project area.

7.6.4 Coastal habitats within the Study Area fell within the count site “Nim Wan to Lau Fau Shan” (NW/LFS) of Waterbird Count. The proposed Project, however, would not cause loss of mudflat. The count site NW/LFS starts from the coast near Mong Tseng village in the north to Nim Wan village in the south (Carey 2002). Birds on the coastline of about 8 km were counted from various vantage points along the Deep Bay Road. The waterbird count data was not presented by vantage points. Therefore, the distribution pattern of waterbirds along the coastline from Lau Fau Shan to Nim Wan could not be determined.

7.6.5 A total of 31 waterbird and 2 raptor species were recorded in the count site “Nim Wan to Lau Fau Shan” during Waterbird Count between April 2007 and March 2008 (data from The Hong Kong Bird Watching Society). The annual mean count of this 8 km long coastline was 148 birds. This mean abundance is not considered high when compared with that in Inner Deep Bay. Little Egret Egretta garzetta is the most abundant species.

7.6.6 Bird species which are rare or protected under regional/global legislations/conventions are considered of conservation concern. Bird species recorded from NW/LFS and of conservation concern included Black Kite Milvus lineatus, Osprey Pandion haliaetus and Black-faced Spoonbill Platalea minor. All are Class 2 Protected Animal of PRC (Zheng and Wang 1998). Black Kite and Osprey are listed in Appendix 2 of CITES (ibid.).

7.6.7 Black Kite is common and widespread in Hong Kong. This species is found in many types of habitats, including urban areas (Carey et al. 2001). Osprey is mainly found in coastal waters. Black-faced Spoonbill is mainly reported in wetland habitats in the Deep Bay area (Anon. 1999). Apart from drained fishponds and gei wais, this species also feed in mudflat (ibid.).

7.6.8 Apart from Mai Po, Black-faced Spoonbills overwintering in Hong Kong are also mainly found in mudflat near Tsim Bei Tsui (Anon. 2001). This species tends to feed on open, soft-bottomed habitats without any obstructions and avoid “enclosed” area, e.g., oyster bed (ibid.). This may be related to the foraging behaviour of this species, which swings their bills from side to side while searching for preys. Any obstacle, e.g., tiles in oyster bed, in the foraging habitats may potentially damage their bills. Mudflat within the assessment area are filled with rows of oyster shells, and therefore not considered optimal foraging habitat of Black-faced Spoonbill. During the EIA study of the Shenzhen Western Corridor, it was found that abundance of waterbirds on mudflat with oyster bed was statistical significantly lower than that on mudflat without oyster bed (Ove Arup & Partners HK Ltd. 2002).

Results of Field Surveys

Habitat and Vegetation

7.6.9 Major habitats recorded within the Study Area include woodland, plantation, grassland/shrubland, agricultural land, fishpond, stream/channel, mangrove, mudflat, oyster shell piles, built-up area/wasteland and sea (Figures 7.2 and 7.3, Table 7.1).

Table 7.1

Habitats recorded within the Assessment Area

Habitat	Area (ha)	Percentage Total
Woodland	7.48	5.8
Plantation	1.17	0.9
Grassland/Shrubland	4.02	3.1
Agricultural Land	8.33	6.4
Fish Pond	1.14	0.9
Stream/Channel	Semi-natural stream: 435 m Man-made channel (nullah): 860 m	-
Mangrove	3.26	2.5
Mudflat	18.42	14.2
Oyster Shell Piles	3.82	3.0
Built-up Area/Wasteland	62.11	48.0
Sea	19.65	15.2
Total	129.40	100

7.6.10 In total, 174 plant species were recorded (Appendix 7.1). One tree species of conservation interest, Aquilaria sinensis, were recorded outside the Project Area but within the assessment area.

7.6.11 Within the impacted area, the tree survey for the current study recorded 53 nos. of trees. 42 nos. were common pioneer native tree species including Celtis sinensis and Macaranga tanarius, while the rest are exotic landscape or fruit trees. No species recorded is protected under Cap. 96 or Cap. 586.

7.6.12 Woodland was mainly located at knolls behind Ngau Hom Tsuen, east of Sha Kong Tsuen and north of Lau Fau Shan Tsuen (Figure 7.1). These woodlands are semi-natural, young and of low to moderate diversity. It was composed of a mixture of orchard trees (e.g. Litchi chinensis and Dimocarpus longan), plantation trees (e.g. Acacia confusa and Melia azedarach), and native pioneer tree species including, Celtis sinensis, Macaranga tanarius, Litsea glutinosa, and Microcos paniculatus. The understorey was fairly dense and was composed of a variety of tree, shrub, fern and herb species including Litsea rotundifolia, Psychotria asiatica, and Mussaenda erosa.

7.6.13 A total of 80 plant species were recorded in woodland habitat. One tree species of conservation interest, Aquilaria sinensis, was recorded at the foothill near Ngau Hom Tsuen on the fringe of the Study Area. It is protected under Protection of Endangered Species of Animals and Plant Ordinance. It is a Category II nationally protected tree species in China and listed as vulnerable in the China Plant Red Data Book, but it is quite common in Hong Kong.

7.6.14 Plantation was mainly recorded along road sides, in villages and in amenity area, most of which were scattered or in rows and classified as urbanised/disturbed and only plantation formed contiguous patches were mapped. It was mainly composed of exotic landscaping species. The plant diversity was low with no plant species of conservation concern recorded in this habitat.

7.6.15 Grassland/shrubland were recorded on the hillsides probably maintained by frequent hillfires from grave sites. Major species recorded included Dicranopteris pedata, Neyraudia reynaudiana, Bidens pilosa, and Miscanthus sinensis. Trees and shrubs also established at areas less impacted by fire and included Macaranga tanarius, Mallotus paniculatus, Rhus chinensis and Rhodomyrtus tomentosa. A total of 44 plant species was recorded within the grassland/shrubland habitat. No species of conservation interest was recorded.

7.6.16 Agricultural land was mainly composed of croplands and orchards. Most of the croplands were abandoned and dominated by grasses and weeds, while a few pockets were actively farmed and mainly grown with vegetables. Orchards dominated by Dimocarpus longan and Litchi sinensis; some of which appeared to be actively managed. A total of 41 plant species were recorded. No species of conservation interest was recorded in this habitat.

7.6.17 Four fishponds were recorded within the assessment area, all appeared to be abandoned. Grassy and weedy vegetation were recorded on the pond bunds. Pond bunds supported a few mangrove and mangrove associated species (e.g., Acanthus ilicifolius, Kandelia obovata).

7.6.18 Mangrove lies mainly on intertidal mudflats, while small stands were also found along stream bank section subject to tidal influence. The mangrove stands were dominated by Kandelia obovata, while other mangrove and mangrove associated species including Acanthus ilicifolius, Acrostichum aureum and Derris trifoliata were also recorded. The exotic and invasive mangrove species Sonneratia caseolaris was observed among the Kandelia stands. Although not abundant, their growth was fairly robust. Oyster shell piles were very common on the mudflats. Except mangroves stands which colonised the fringe of some piles, oyster shell piles are void of vegetation.

7.6.19 The upstream concrete section (open nullahs) and lower semi-natural section of Hang Hau Tsuen stream were within the Assessment Area. The open nullahs (San Hing Tsuen Channel and Fung Kong Tsuen Channel) to the east of Deep Bay Road were void of vegetation, with exception of a few stands of water hyacinth (Eichhornia crassipes) on water surface. To the west of Deep Bay Road, grasses, herbs, weeds and common tree species were recorded beyond the tidal influence along the stream bank, including Microstegium ciliatum and Mikania micrantha. About one-third of this stream section is under tidal influence. Narrow strips of mangrove stands dominated by Acanthus ilicifolius and Derris trifoliata colonised the stream banks, the extent of which is limited by the village houses established along both banks. The whole section of Hang Hau Tsuen Stream to the west of Deep Bay Road lies inside the Project Area.

7.6.20 Villages, container storage area, vehicular access road and footpaths and construction sites constituted the built-up area and wasteland. Except roadside trees and landscape plantings, most of the surface was concrete or void of vegetation. This area has little ecological value.

Terrestrial Fauna

7.6.21 Most of the assessment area is urbanized/disturbed area which is subjected to very high human disturbance level, with very little vegetation and of very low value as habitat of terrestrial fauna. Apart from mudflat, the other habitats within the assessment area are fragmented and small in size. Fauna in the assessment area are mostly disturbance tolerant.

7.6.22 There are rows of oyster shell piles on the mudflat near the shore within the assessment area. These dumps occupied some potential foraging habitats of waterbirds. This factor, together with high human disturbance, reduced the value of mudflat near the shore as foraging habitats of waterbirds within the assessment area.

7.6.23 A total of 46 species of birds were recorded within the assessment area during quantitative surveys (Appendix 7.2). The bird species (e.g., Crested Myna Acridotheres cristatellus, Chinese Pond Heron Ardeola bacchus) are typical of urban areas and disturbed coastal areas. Large Hawk Cuckoo Hierococcyx sparverioides and House Swift Apus nipalensis were recorded between transects. Both are common and widespread in Hong Kong.

7.6.24 Species richness of avifauna was low in all types of habitats within the assessment area. Bird abundance was low to moderate in urbanised/disturbed area, coastal habitats (mangroves and mudflat) and abandoned agriculture, and low in other types of habitats.

7.6.25 The four fishponds within the assessment area appeared to be abandoned. The trash shrimps and fishes trapped in shallow waters and attracting many waterbirds in active fishponds during drain-down for harvesting of commercial fishes (Young and Chan 1997), were not available in these four ponds. These four ponds were not drained throughout the study period. In addition, these ponds are surrounded by urbanised/disturbed areas, which are of very high human disturbance. The ecological value of the fishponds within the assessment area as foraging habitats of waterbirds is limited.

7.6.26 The upstream section of the Hang Hau Tsuen stream within the assessment area is channelised and of very poor water quality and highly reduced habitat complexity. This section is hence of minimal ecological value. The lower section of Hang Hau Tsuen stream is narrow, semi-natural with no real riparian zone and surrounded by urbanised/disturbed area (e.g., container storage area). The ecological value of this section of stream within the assessment area as foraging habitats is limited.

7.6.27 Nests of Barn Swallow Hirundo rustica were found in urbanised/disturbed areas within the assessment area. This species builds their nests in the eaves of buildings. Individuals of Crested Myna Acridotheres cristatellus, Black-necked Starling Sturnus nigricollis, Black-billed Magpie Pica pica and Eurasian Tree Sparrow Passer montanus were observed carrying nesting materials in urbanised/disturbed areas within the assessment area. All these species are common and widespread in Hong Kong.

7.6.28 Bird species of conservation concern included Black Kite and Greater Coucal Centropus sinensis. Both are common and widespread in Hong Kong, and are found in many types of habitats. Black Kite even occurs in urban areas. Both Black Kite and Greater Coucal are Class 2 Protected Animal of PRC (Zheng and Wang 1998). The former is also listed in Appendix 2 of CITES (ibid.).

7.6.29 A total of 21 species of butterfly were recorded in the assessment area (Appendix 7.3). All are common and widespread (e.g., Common Grass Yellow Eurema hecabe) in Hong Kong (Yiu 2004). Three additional species were recorded between transects. These were Forest Hopper Astictopterus jama, Oriental Straight Swift Parnara bada and Ceylon Blue Tiger Ideopsis similis. All are common in Hong Kong (ibid.). Both species richness and abundance of butterfly were low in all types of habitats within the Study Area.

7.6.30 A total of 12 species of dragonfly were recorded in the assessment area (Appendix 7.4). All are common and widespread (e.g., Wandering Glider Pantala flavescens) in Hong Kong (Wilson 2004). Species richness was very low in urbanised/disturbed area, coastal habitats (mangroves and mudflat), woodland, plantation and grassland, and low in other types of habitats within the assessment area. Abundance of dragonfly were very low in urbanised/disturbed area, coastal habitats (mangroves and mudflat), woodland, plantation and grassland, and low in fishponds and stream, and low to moderate in abandoned agricultures within the assessment area.

7.6.31 There are few aquatic habitats within the assessment area. The Hang Hau Tsuen stream within the assessment area is of poor water quality and the water is brackish. Hence this stream is not optimal habitats of dragonfly nymphs. The presence of fishes in fishponds also reduced their value as dragonfly breeding habitats. These factors also contributed to the low diversity of amphibian in the assessment area as the larval stage of amphibian is aquatic.

7.6.32 A total of 4 species of amphibian were recorded within the assessment area during quantitative surveys (Appendix 7.5). Both are common and widespread (e.g., Asian Common Toad Bufo melanostictus) in Hong Kong (Chan et al. 2005).

7.6.33 A total of 4 species of reptiles were recorded within the assessment area (Appendix 7.5). All are common and widespread in Hong Kong. All are common and widespread (e.g., Long-tailed Skink Mabuya longicaudata) in Hong Kong (Karsen et al. 1998).

7.6.34 Non-flying mammal found within the assessment area during the field surveys included Greater Bandicoot Rat Bandicota indica and Roof Rat Rattus rattus (Appendix 7.5). Both are common in Hong Kong (Shek 2006). The use of habitats within the assessment area by non-flying mammal is considered limited due to high level of human disturbance and presence of dogs and cats.

7.6.35 Japanese Pipistrelle Pipistrellus abramus were recorded from all types of habitats except grassland within the assessment area (Appendix 7.5). This is the commonest bat species in Hong Kong. All bats are protected under WAPO.

Aquatic Fauna

7.6.36 Two types of freshwater habitats occurred within the assessment area, i.e. the four abandoned fishponds and the Hang Hau Tsuen stream. Fishponds are man-made habitats and isolated from other natural water bodies. Aquatic fauna in fishponds are usually cultivated species or naturalized exotic species, and thus not considered of conservation importance. During the field surveys, only individuals of Tilapia of low abundance were sighted in the abandoned fishponds.

7.6.37 Hang Hau Tsuen stream is located to the west (seaward side) of Deep Bay Road and flows through the southern part of the village. The upstream flow originates from the concrete drainage channels of San Hing Tsuen Channel and Fung Kong Tsuen Channel to the east of Deep Bay Road. It is believed that the existing stream course is only the remnant of the original stream which alignment is untraceable now. Based upon various versions of government countryside series maps, the concrete drainage channel was constructed in the mid to late 1990’s. The concrete drainage channels drain a vast area between Lau Fau Shan Road and Deep Bay, of which the majority are open storages, and discharges into Hang Hau Tsuen stream. Based upon observation on site, the quality of the channel water is very turbid and apparently not good. No aquatic fauna was observed inside the concrete drainage channels during field survey.

7.6.38 After entering Hang Hau Tsuen stream, the quality of the flow was seriously further deteriorated by the discharges from village houses along the stream course. The majority of the stream course bottom was also occupied by rubbish and waste. From the odour and colour of the water and other signs, it is believed that the substratum and the water are in anoxic conditions. The lower part of the stream course is under some tidal influence (probably during spring high tide), and some mangroves invade into the stream course. No freshwater aquatic life was recorded in the entire stream course during field survey, but during flooding tide some marine and estuarine species such as mangrove mud crabs and mullets which follow the incoming seawater were observed inside the lower section of the stream course. But they were also of low abundance. Some intertidal fauna (e.g. Uca arcuata) were however found at the stream outlet and would be covered in the sections on intertidal fauna below.

Intertidal Fauna

7.6.39 Intertidal habitats within the assessment area include intertidal mudflats and mangroves. Results of line transect are summarised in Appendix 7.6.

7.6.40 The majority of the intertidal zones at Outer Deep Bay are intertidal mudflats, including the intertidal zone within the assessment area. The mudflats might extend seaward from the coastline for up to 1 km during low tide, or even a longer distance. Although there are harvested oyster shells piling up on the shore, no oyster rafts were observed within 500 m distance from the Project boundary while the nearest oyster beds are located over 300 m from the Project boundary (see Figure 8.2). There were abundant fauna on the mudflats just offshore to Hang Hau Tsuen, including mudskippers (Periophthalmus cantonensis near mangrove stands and Boleophthalmus pectinirostris on more open mudflats), crabs (including Uca lactea, Metaplex elegans, Illoplex formosensis and Macrophthalmus latereillei), and snails (mainly Cerithidea djadjariensis). Numerous burrows scattered on the mudflats, mostly occupied by the crab species mentioned above, with the Metaplex and Macrophthalmus occupying the larger burrows (usually larger than 1 cm in diameter, and up to 2 cm) and Illoplex occupying the smaller burrows (usually smaller than 1 cm in diameter). There were also some burrows with narrow and cryptic openings occupied by mudskippers Boleophthalmus pectinirostris. Abundant polychaetes were revealed when the mud was excavated.

7.6.41 Along the transects, the fauna species compositions changed as the distances from shore increased. Species with higher association with mangroves (such as Illoplex formosensis and Cerithidea djadjariensis) concentrated in areas closer to the shore, while other typical mudflat fauna (such as mudskippers) were more abundant in farther part.

7.6.42 The core samples were processed with sieves of 0.5 mm mesh size and preserved for identification and counting. The results of the core samples are shown in Appendix 7.6. A total of five species on infauna was found in the core samples, including two species of polychaetes, one species of amphipods and two species of crabs. All species found are common mudflat species and with no special conservation importance. The abundance of infauna was higher in cores nearer to the shore. This distribution pattern might be a result of the nutrient input from the polluted stream flow, as the abundance of some infauna species such as polychaetes would be promoted by nutrient level.

7.6.43 The results of the quadrats showed a similar distribution pattern with higher number of crab burrows and snails near the shore. No prominent crab burrows and snails were observed over 50 m from the shore. It, however, should be noted that mudskippers Boleophthalmus pectinirostris were observed on the more open area of the mudflat, including the far end of the transects, but their cryptic burrows were not covered by any of the quadrats.

7.6.44 Horseshoe crab was not recorded during the field surveys, but the mudflats in Hang Hau Tsuen provide a habitat for their juveniles. During a recent horseshoe crab study (Shin et al. 2007), juveniles were recorded along Deep Bay coastlines both to the north (e.g. Tsim Bei Tsui) and to the south (e.g. Pak Nai) of Hang Hau Tsuen.

7.6.45 Established mangroves colonised the higher levels of the mudflats. Mangrove stands were dominated by Kandelia obovata.

7.6.46 The observed fauna abundance inside the mangroves were lower than that on the mudflats. Species recorded included snails Neritina violacea, Nerita chamaeleon, Littoraria ardouiniana, bivalves Gelonia erosa, crabs Perisesarma bidens and Metaplex elegans.

7.6.47 Some mangrove plants also invaded into the stream channel and lied along stream banks, where more Acanthus ilicifolius could be found. Mangrove mud crab Scylla paramamosain was occasionally sighted inside this channel during flooding tide, together with Mullets Mugil cephalus, both of low abundance. No other macro mangrove fauna were observed among these mangrove plants during the survey period between November 2007 to May 2008. In a supplementary site visit in July 2008, however, some individuals of sesarmine crabs including Parasesarma plicata, Perisesarma bidens, and Chasmagnathus convexus as well as Uca arcuata were observed among the mangroves. All of these crabs were common in mangrove habitats in Hong Kong.

7.6.48 At the stream outlet, there were several patches of small-sized sand dunes near a footbridge. Abundant individuals of Uca arcuata were found on the sand. This is a common Uca species in Hong Kong.

7.7 Evaluation of Habitats and Species

7.7.1 The ecological importance of the habitats within the assessment area was evaluated in accordance with the criteria stipulated in Annex 8 of EIAO-TM.

Table 7.2

Evaluation of Woodland Habitat within the Assessment Area

Criteria	Description
Naturalness	Semi-natural habitat
Size	7.48 ha
Diversity	Moderate plant diversity, low bird and butterfly diversity, very low dragonfly diversity.
Rarity	No rare terrestrial flora or fauna recorded. One locally common but protected tree species, Aquilaria sinensis, was recorded.
Re-creatability	Difficult to recreate and takes time to mature
Fragmentation	Isolated patch on hillslopes
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	High with protection
Nursery/breeding ground	No significant record, but can provide breeding habitats for birds, reptiles and butterflies
Age	Young
Abundance/richness of wildlife	Low bird and butterfly abundance, very low dragonfly abundance
Overall ecological value	Moderate

Table 7.3

Evaluation of Plantation Habitat within the Assessment Area

Criteria	Description
Naturalness	Man-made
Size	1.17 ha
Diversity	Low plant diversity, low bird and butterfly diversity, very low dragonfly diversity.
Rarity	No rare species recorded
Re-creatability	Easy to recreate
Fragmentation	Formed isolated pockets near village houses and along roads
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	Moderate with active management including thinning and interplant with native species
Nursery/breeding ground	No significant record. Value as breeding habitat for terrestrial fauna is low due to sparse canopy and made up of exotic tree species.
Age	Young
Abundance/richness of wildlife	Low bird and butterfly abundance, very low dragonfly abundance
Overall ecological value	Low

Table 7.4

Evaluation of Grassland/Shrubland Habitat within the Assessment Area

Criteria	Description
Naturalness	Natural but frequently disturbed by fire
Size	4.02 ha
Diversity	Low flora diversity, low bird and butterfly diversity, very low dragonfly diversity.
Rarity	No rare species recorded
Re-creatability	Maintained by hillfire
Fragmentation	Continuous stands on hillsides
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	Low due to presence of grave sites
Nursery/breeding ground	No significant record. Value as breeding habitat for terrestrial fauna is low due to high level of disturbance and low vegetation cover
Age	N/A
Abundance/richness of wildlife	Low bird and butterfly abundance, very low dragonfly abundance
Overall ecological value	Low

Table 7.5

Evaluation of Agricultural Land within the Assessment Area

Criteria	Description
Naturalness	Man-made
Size	8.33 ha
Diversity	Low flora and fauna diversity
Rarity	No rare species recorded
Re-creatability	Easy to recreate
Fragmentation	Patches on hillsides or near villages
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	Low
Nursery/breeding ground	No significant record. Value as breeding habitat for terrestrial fauna is low due to high level of disturbance and low vegetation cover
Age	N/A
Abundance/richness of wildlife	Low bird and butterfly abundance, low to moderate dragonfly abundance
Overall ecological value	Low

Table 7.6

Evaluation of Ponds within the Assessment Area

Criteria	Description
Naturalness	Man-made abandoned fishponds
Size	1.14 ha
Diversity	Low flora and fauna diversity
Rarity	No rare species recorded
Re-creatability	Easy to recreate
Fragmentation	Isolated from the fishpond area in Inner Deep Bay, also separated from other fishponds in outer Deep Bay coast.
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	Low
Nursery/breeding ground	No significant record. Value as breeding habitat for terrestrial fauna is low due to high level of disturbance and low vegetation cover
Age	N/A
Abundance/richness of wildlife	Low fauna abundance
Overall ecological value	Low

Table 7.7

Evaluation of Mangrove within the Assessment Area

Criteria	Description
Naturalness	Natural
Size	3.26 ha
Diversity	Low flora diversity, low bird and butterfly diversity, very low dragonfly diversity, low to moderate mangrove fauna diversity.
Rarity	No rare mangrove faunal species was recorded
Re-creatability	Easy to recreate
Fragmentation	Mostly formed large stands, patchy along stream
Ecological linkage	Linked to intertidal mudflats
Potential value	High
Nursery/breeding ground	No significant record, but can provide breeding habitats for birds
Age	N/A
Abundance/richness of wildlife	Very low dragonfly abundance, low butterfly abundance, low to moderate bird abundance, low to moderate mangrove fauna abundance
Overall ecological value	Moderate to high

Table 7.8

Evaluation of Stream/Channel within the Assessment Area

Criteria	Description
Naturalness	Man-made (concrete drainage channel and box culvert), or semi-natural (stream remnant)
Size	435m stream remnant and 860m of man-made channel (nullah)
Diversity	Low flora and fauna diversity
Rarity	No freshwater aquatic species, but with some common estuarine fauna such as crabs and mullets. No rare species recorded
Re-creatability	Nullah: easy to recreate; natural tributaries: difficult to recreate
Fragmentation	N/A
Ecological linkage	Isolated from the sea by concrete walls and nullah, no significant linkage was observed.
Potential value	Low
Nursery/breeding ground	No significant record. Limited value as breeding habitat for dragonfly and amphibian
Age	N/A
Abundance/richness of wildlife	No freshwater aquatic species recorded. Low fauna (including estuarine and mangrove fauna) abundance
Overall ecological value	Low

Table 7.9

Evaluation of Built-up/Wasteland Habitats within the Assessment Area

Criteria	Description
Naturalness	Man made habitat
Size	62.11 ha
Diversity	Low bird and butterfly diversity, very low dragonfly diversity.
Rarity	No rare species recorded
Re-creatability	Easy to recreate
Fragmentation	None
Ecological linkage	Not functionally linked to habitats of conservation importance
Potential value	Low
Nursery/breeding ground	No significant record. There were breeding records of disturbance tolerant bird species.
Age	N/A
Abundance/richness of wildlife	Low bird and butterfly abundance, very low dragonfly
Overall ecological value	Low

Table 7.10

Evaluation of Mudflats within the Assessment Area

Criteria	Description
Naturalness	Natural
Size	18.42 ha*
Diversity	Moderate mudflat fauna diversity.
Rarity	No rare faunal species was recorded
Re-creatability	Re-creatability subject to the local hydrological regime.
Fragmentation	Not fragmented.
Ecological linkage	No special linkage observed
Potential value	Moderate
Nursery/breeding ground	No significant record, but can provide nursery habitats for horseshoe crabs
Age	N/A
Abundance/richness of wildlife	Moderate mangrove fauna abundance
Overall ecological value	Moderate

*extent estimated based on 2007 government aerial photos. Extend varied due to tide level and could be larger during low tide.

7.7.2 In accordance with Table 3, Annex 8 of the EIAO-TM, the ecological value of species was assessed in terms of protection status (e.g. fauna protected under WAPO (except birds), and flora and fauna protected under regional/global legislations/conventions), species distribution (e.g. endemic), and rarity (e.g. rare or restricted). The list and evaluation of the flora and faunal species of conservation concern recorded within the assessment area, according to the EIAO-TM, are given in Tables 7.11 and 7.12.

Table 7.11

Evaluation of Floral Species of Conservation Importance within the Assessment Area

Common name	Scientific name	Locations	Protection status	Distribution	Rarity	Relevance to Project
Incense Tree	Aquilaria sinensis	Woodland at the foothills near Ngau Hom Tsuen but outside the impacted area	Protected under Protection of Endangered Species of Animals and Plant Ordinance, CITES Appendix II, Category II nationally protected species in China and is listed as vulnerable in the China Plant Red Data Book and by IUCN.	Lowland forests and fung shui woods	Locally common	Located 480 m away from Project Area and will not be affected by the Project

Table 7.12

Evaluation of Faunal Species of Conservation Importance within the Assessment Area

Common name	Locations	Protection status	Distribution	Rarity	Relevance to Project
Japanese Pipistrelle	All types of habitats except grassland	WAPO	Widely distributed in Hong Kong	Common in Hong Kong	No. Habitat affected is not considered important to this species due to limited size
Black Kite	Coastal areas	WAPO; Class 2 Protected Animal of PRC; Appendix 2 of CITES	Widely distributed in Hong Kong	Common in Hong Kong	No. Habitat affected is not considered important to this species due to limited size and high level of disturbance
Greater Coucal	Fishpond	WAPO; Class 2 Protected Animal of PRC	Widely distributed in Hong Kong	Common in Hong Kong	No. Habitat affected is not considered important to this species due to limited size and high level of disturbance
Horseshoe crab	Deep Bay mudflat	N/A	Western New Territories and Lantau	Uncommon in Hong Kong	Limited as no mudflat will be impacted.

7.8 Impact Identification and Evaluation

7.8.1 The potential terrestrial and aquatic ecological impacts arising from the construction works of the preferred option, including loss of habitats, removal of vegetation, and disturbance to animals were quantitatively assessed in accordance with Annexes 8 and 16 of the EIAO-TM.

7.8.2 The proposed project works comprise:

(i) training of Hang Hau Tsuen stream including construction of a drainage channel of 370 m in length connecting the downstream ends of Fung Kong Tsuen Channel and San Hing Tsuen Channel to Deep Bay;

(ii) construction of a 25 m long triple-cell box culvert of 5.5 m (w) x 3 m (H) beneath the Deep Bay Road and 4 nos. of footbridges across the channel;

(iii) provision of an access road of 3.5 m in width with passing bays along the northern bank of the channel, a maintenance access of 3.5 m in width within the southern portion of the channel and footpaths of 2 m in width on both sides of the channel;

(iv) construction of bypass drain of 220 m in length directing additional runoff during wet season from the proposed channel to the channel outfall and other various ancillary drainage facilities; and

(v) provision of a viewing point, car park and amenity area near the channel outfall.

Construction Phase Impacts

Site Formation

7.8.3 The direct ecological impact during construction would be loss of habitats. All area within the site boundary, except the lower stream section with bypass channel, will be lost (Figure 7.3). The proposed Project would cause permanent loss of 260 m of stream and 40 m of nullah, 0.13 ha of an abandoned fishpond, 0.02 ha of plantation, 0.49 ha of grassland/shrubland (grassy bank), 0.07 ha of mangrove, and 1.12 ha of built-up area/wasteland. (Table 7.13). The plant species of ecological interest, Aquilaria sinensis was found in woodland outside the site boundary and will not be affected.

7.8.4 There will no direct ecological impacts to the mudflat habitats as well as the mangroves on mudflats. With the construction of bypass channel on the tidal section, most mangrove patches along the lower stream bank will be preserved. Within the Coastal Protection Area, part of an abandoned fishpond and wasteland will be affected.

7.8.5 The habitats to be affected are either of limited size (mangrove) and/or of low ecological values (e.g. plantation, grassland/shrubland, fishpond, stream, built-up area/wasteland). According to the tree assessment, a total of 27 trees will be retained, 16 trees will be fell, and 10 will be transplanted. The trees to be fell are composed of amenity and fruit tree and common native pioneer trees. Loss of plantation and associated trees will be mitigated by compensatory landscape tree planting, the details are included in Chapter 9 – Landscape and Visual Impact Assessment.

7.8.6 The total size of mangrove within the channel is about 0.15 ha, 0.07 ha of which is to be lost, while 0.08 ha is to be retained. Most of the mangrove patches along the northern side of the lower section of the stream will be preserved by retaining of the lower portion of the stream channel, although minor loss on the southern side is inevitable due to construction of footpath, bridges and maintenance access. The mangroves along the southern bank need to be removed because apart from providing space for the maintenance access, the channel bed will need to be slightly level down to form the new natural stream course and in order to meet the required hydraulic capacity. Mangrove species loss include mainly Acanthus ilicifolius and a few individual of Kandelia obovata, both are very common species in local mangrove stands. The loss constitutes to 0.06% of the mangrove recorded within the assessment area, and is negligible compared to the mangroves recorded in Deep Bay. Therefore loss of mangrove caused by the project is considered minor.

7.8.7 The area of terrestrial habitat to be lost is small. Due to the disturbed nature, these habitats are of low ecological value as habitats of terrestrial fauna. There is no loss of optimal habitat of the fauna of conservation concern listed in Table 7.12. The impact to these species is ranked as minor.

7.8.8 The stream course affected is in poor conditions for aquatic life and currently is not likely to be colonised by freshwater fauna. The loss or disturbance of this habitat would not have impacts on freshwater fauna. Intertidal fauna Uca arcuata colonising the sand dunes near the outlet and estuarine fauna such as mullets and mangrove mud crabs might be impacted by the works. These fauna species are common in Deep Bay and are not of special conservation importance. Alternative habitats are also available in the vicinity along the Deep Bay coastline if the outlet is disturbed by the works. This impact is thus negligible.

7.8.9 During construction, the water bodies could be adversely impacted through silt-laden site runoff, disturbance of stream sediment during excavation, concreting works, runoff from workshops & depot and increased sewage and wastewater resulting from the additional workforce on site. These impacts can be readily mitigated through the construction of a suitable drainage system with silt traps, good site management practices, careful working practices when excavating sediments and proper sewage collection and disposal system (Section 5.12.12). Therefore the impact is antipcated to be insignificant.

7.8.10 The fishponds are artificial habitats and the aquatic life inside was mainly exotic Tilapia and probably also other cultured fish species which are not native. The ecological value of fishponds in terms of aquatic life is low. Therefore impacts of loss of fishpond to aquatic fauna is low.

7.8.11 Due to limited in size, disturbed nature and low ecological value of all the habitat types to be lost, the overall ecological impacts are ranked as minor. Other than compensatory landscape tree planting for loss of trees and standard site practices, no other mitigation measures are required.

Table 7.13

Estimated Habitat Loss

Habitat	Size of Loss (ha)
Plantation	0.02
Mangrove	0.07
Grassland / Shrubland	0.49
Stream / Channel	Stream: 260 m ; Nullah 40 m
Fish Pond	0.13
Built-up Area/Wasteland	1.12

Construction Disturbance

7.8.12 Noise and visual disturbance may occur during site formation and construction, potentially affecting the distribution and behaviour of fauna of the adjacent habitats. The construction work will only affect urbanized/disturbed habitats and associated fauna, which are of low ecological importance. In addition, the construction phase will be short term. The impact of dust, noise and visual disturbance arising from construction works will be localised. Fauna inhabiting the areas adjacent to the work area are habituated to high level of disturbance. Therefore the uses of these areas by wildlife during construction phase will not be significantly affected.

7.8.13 The potential impact from construction disturbance to these fauna is therefore anticipated to be minimal.

Operation Phase Impacts

7.8.14 Due to the nature of the Project, besides the permanent habitat losses which have been addressed in the above sections, the operation impact on ecology is considered minimal. In contrast, the Project would improve the conditions of the stream channel by removal of trashes inside during construction, and prevention of the accumulation of organic pollutants during operation. This might help the stream fauna to re-colonise Hang Hau Tsuen stream during operation phase.

7.8.15 With the proposed design of using rip-rap and original stream bed materials lining which mimics the current stream condition, sediment will be allowed to accumulate on the channel bed which will reduce sudden discharge of sediment downstream during storm flow. By raising the bank level and widening of the stream, water flowrate will not increase significantly. Furthermore, the retained mangroves and stream bed from parts of the midstream to the downstream sections would have similar effect in retaining the sediment as in the current condition. The proposed channel will therefore have negligible effect on sediment deposition pattern. The sediment deposition pattern will remain the same as in current situation which is predominantly controlled by the tidal action of Deep Bay (see Section 5.8.7). Therefore, the intertidal habitats including mudflats and mangroves would not be affected by changes of flow volume and the consequential changes in water quality parameters such as salinity. No impacts on the intertidal habitats are anticipated. The waterbirds utilising the mudflat will therefore not be affected.

7.8.16 Provision of car parking spaces and viewing point near the channel outfall aims to improve the amenity values for the site. The existing human disturbance level is high due to the presence of villagers, and value of mudflat is degraded by oyster shell piles for waterbirds (see Section 7.6.22). In addition, the number of visitors is expected to be small. Therefore, the potential disturbance impacts during operation from the viewing point and car park is expected to be minimal.

7.8.17 Maintenance would be necessary for the proposed channel to remove excessive sediment, vegetation, rubbish, debris and obstructions in order to maintain its hydraulic performance and structural integrity. Siltation will generally be allowed to accumulate and removal of excess silt would be carried out at locations where it would impede water flow. Little maintenance will be necessary for the natural stream bed section of the channel. However, a maintenance access will be provided along the southern portion of the channel to allow maintenance personnel to access and maintain the channel bank and box culvert (footbridge). The alignment of the maintenance access has been selected to minimize disturbance to existing mangroves lying along the northern bank. Given the small scale maintenance works that may be required, the maintenance works are not expected to create adverse ecological impact.

Table 7.14

Summary of Ecological Impacts and Mitigation Measures

Activity	Source	Receiver	Nature of Impacts						Severity	Mitigation Required
			Habitat quality	Species affected	Size-abundance	Duration	Reversibility	Magnitude
Site formation	Site preparation	Terrestrial habitat and associated flora and fauna	All are of low ecological importance	Fauna and flora species recorded in the project area	260 m of stream and 40 m of nullah, 0.13 ha of an abandoned fishpond, 0.02 ha of plantation, 0.49 ha of grassland / shrubland (grassy bank), 0.07 ha of mangrove, and 1.12 ha of built-up area / wasteland.	Long term and permanent	Irreversible	Low	Minor	Yes, compensatory landscape tree planting and mangrove planting
Noise, dust and visual disturbance	Works equipment and human activities	Faunal species on adjacent habitats	Terrestrial habitats affected are of low ecological importance	Disturbance sensitive fauna	Terrestrial habitats affected confined to areas adjacent to work areas.	Temporary	Reversible	Low	Minor	Yes, good site practice

7.9 Impact Avoidance and Mitigation Measures

7.9.1 The aims of the ecological impact assessment are to protect, maintain or rehabilitate the natural environment, in particular, recognised sites of conservation importance and other ecological sensitive areas. The above assessment has identified and quantified the potential ecological impacts associated with the Project. Measures to avoid, minimize and mitigate impacts are discussed in this section.

Impact Avoidance

7.9.2 The layout of the preferred option had avoided the mangroves at the lower reach of the Hang Hau Tsuen stream.

7.9.3 Good site practices and precautionary measures should be implemented to avoid encroachment onto the nearby natural habitats, minimise disturbance to wildlife, and ensure good water quality. Examples of water quality mitigation measures are detailed in Section 5.7 of the EIA report. Other precautionary measures include:

· Temporary fencing should be erected along the portion of the mangroves proposed to be retained to form protection zones to restrict access by construction workers or equipment or works. Unnecessary felling of the mangroves within these protection zones is prohibited. Signage should be provided at conspicuous location to warn workers from entering and disturbing these zones.

· All workers should be regularly briefed to avoid disturbing the flora and fauna near the works area.

· Surface run-off and wastewater from construction sites should be discharged into water bodies via adequately designed silt removal facilities such as sand traps, silt traps and sediment basins.

· Open stockpiles susceptible to erosion should be covered with tarpaulin or similar fabric and provided with containment such as bunds, sand bag barriers or equivalent measures, especially during the wet season (April – September) or when heavy rainstorm is predicted.

· Excavation works within the existing stream section should be programmed to be carried out during periods of low flow (dry season from 1st October to 31st March) as far as practicable to minimise impacts on downstream water quality and sensitive receivers. The excavation area should be limited to section of half width of the stream in order to maintain continuous water flow within the stream during the construction phase.

· Sewage arising from construction workers on site should be collected in a suitable storage facility, such as portable chemical toilets and disposed via licensed contractors.

Impact Minimisation

7.9.4 The site boundary of the Project has been limited to high disturbed area including built-up area and wasteland. Although of low ecological value, only section of the abandoned fish pond within the site boundary will be resumed, while the remaining portion of the pond will be preserved. The loss of mangrove has also been minimised as much as possible, while maintaining the necessary flood conveyance capacity and channel design.

Impact Mitigation

7.9.5 The impact during both construction and operation phases are anticipated to be minimal. However, compensatory landscape tree planting and compensatory mangrove planting and good site practices are recommended to mitigate the impacts.

7.9.6 The channel layout has been designed to retain as much trees as possible. To mitigate the loss of 16 trees, 114 nos. of new trees in heavy standard size will be planted within the site. The proposed trees consisting mostly of native species will include Celtis sinensis, Cinnamomum parthenoxylon, Ficus microcarpa, Hibiscus tiliaceus and Cassia siamea. The total aggregated girth size of compensatory trees of 8.55 m is more than the felled 3.59 m. Therefore, loss of tree will be compensated with a ratio of more than 1:1 in terms of numbers and aggregated girth size.

7.9.7 To mitigate the loss of 0.07 ha of mangrove patches, a total of 0.07 ha, mainly of newly formed surface at the northern part of the downstream section of the channel is identified for compensatory mangrove planting (Figure 7.3). Therefore, loss of mangrove will be compensated with a ratio of 1:1. Upon completion of construction, the mangrove compensation area will be filled with mud of at least 60 cm in depth to be collected from suitable stream bed material excavated during construction, the abandoned fish pond, or mudflat outside the project area. The final level of the planted area should be about 1-2 mCD. Mangrove species to be planted will include Kandelia obovata at about 1-1.5 mCD and Acanthus ilicifolius at about 1.5-2 mCD, the major species found at the site. Mangrove seedlings of at least 60 cm in height purchased at Futian or Mai Po Nature Reserve should be planted at 1 m spacing. Upon completion of planting, monitoring for survival and growth should be conducted for two years during the operation phase. The monitoring of the compensatory mangrove will be implemented by the project proponent. It is anticipated that both the retained and the compensated mangrove in the mangrove zone (Figure 2.7; Figure 7.3) would need no maintenance in the long run.

7.9.8 Before commencement of the works, the Contractor should submit details of the mitigation measures to be implemented during construction stage as part of their working method statement to the Engineer for approval. This should also include the details of the mangrove planting. This should be reviewed by the Environmental Team Leader and verified by the Independent Environmental Checker.

7.9.9 During operation phase, management and maintenance of the channel bed should be limited to the minimum required to prevent flooding and ensure safety. The channel should be permitted to find (and adjust) its own low flow channel and natural changes in the deposition of silt, sand, rock should be tolerated except where a specific flooding or safety issue is identified. Environmental considerations for maintenance of the proposed channel (see Section 5.9) should be adopted.

7.9.10 Vegetation management within the channel should be restricted to removing of obstructions and preventing tree establishment, while the presence of vegetation should be tolerated as much as possible. If clearance of vegetation is required to prevent obstruction of water flow, where specific flooding or safety issues have been identified, this should be undertaken during the dry season. Expert advice from AFCD should be sought in case of doubt.

7.9.11 To further mitigate stream loss, a layer of approximately 100 mm thick original river bed material will be added on top of the rip-rap bedding of the dry weather flow channel to recreate a natural stream environment. This would allow recolonization of benthic communities and re-establishment of vegetation within the channel.

7.10 Residual Ecological Impacts

7.10.1 Net loss of habitats including fishpond and stream channel would constitute the residual ecological impacts. Due to the small extent of loss and/or the low ecological value of the habitat, the residual impact is considered acceptable.

7.11 Ecological Monitoring and Audit

7.11.1 No specific ecological monitoring is required during construction phase.

7.11.2 The weekly site audit undertaken by the Environmental Team should include checking the retained mangroves are properly fenced off and are not adversely affected by construction works.

7.11.3 Ecological monitoring programme is proposed during operational phase to ensure the survival and growth of the compensatory mangrove planting. Quadrats should be employed at each planting area. Individuals within each quadrats should be recorded by species, and their height measured and health condition recorded. Monitoring should be carried out by a suitable qualified ecologist employed by the project proponent once every quarter for two years after completion of the mangrove planting. Should the overall survival rate of each mangrove species be lower than 75%, replanting should be implemented by the Contractor under the landscape establishment works contract.

7.11.4 The compensatory landscape tree planting should be maintained and monitored under the landscape establishment works contract to ensure the survival and successfulness of the mitigation measure.

7.11.5 The monitoring requirement is broadly presented in Chapter 10 of this Report. Details of the ecological monitoring and audit will be presented in the separate EM&A Manual.

7.12 Summary

7.12.1 The Project has avoided and minimised much of the environmental and ecological impacts by adopting the preferred option. The habitats to be lost would be small in size and not of high ecological value (260 m of stream and 40 m of nullah, 0.13 ha of an abandoned fishpond, 0.02 ha of plantation, 0.49 ha of grassland/shrubland (grassy bank), 0.07 ha of mangrove, and 1.12 ha of built-up area/wasteland). Compensatory landscape tree planting consisting mostly of native species and compensatory mangrove planting will be provided to mitigate the loss, and the residual impact is considered acceptable. Ecological monitoring is proposed to monitor the survival and growth of the mangrove planting during operation phase.

7.13 References

Anon. 1999. Conservation Management of the critically endangered Black-faced Spoonbills (Platalea minor) in the Mai Po and Inner Deep Bay Ramsar Site. Unpublished report by WWFHK to the Agriculture, Fisheries and Conservation Department, Hong Kong Special Administrative Region Government.

Anon. 2001. Preparation of a conservation plan for the Black-faced Spoonbill (Platalea minor) in Hong Kong. Tech. Report 2 – Additional Works. Unpublished report by WWFHK to the Agriculture, Fisheries and Conservation Department, Hong Kong Special Administrative Region Government.

Carey, G.J., Chalmers, M.L., Diskin, D.A., Kennerley, P.R., Leader, P.J., Leven, M.R., Lewthwaite, R. W., Melville, D.S., Turnbull, M. and Young, L. 2001. The Avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.

Carey, G.J. 2002. Waterbird Count Handbook: A Guide for Participants in Waterbird Counts in Hong Kong. Hong Kong Bird Watching Society. Hong Kong.

Chan, K.F., Cheung, K.S., Ho, C.Y., Lam F.N. and Tang, W.S. 2005. A Field Guide to the Amphibians of Hong Kong. Agriculture, Fisheries & Conservation Department, Government of Hong Kong Special Administrative Region.

Karsen, S., Lau, M.W.N & Bogadek, A. 1998. Hong Kong Amphibians and Reptiles. Provisional Urban Council, Hong Kong.

Ove Arup & Partners HK Ltd. 2002. Shenzhen Western Corridor: Investigation and Planning – Environmental Impact Assessment. Highways Department, Government of Hong Kong Special Administrative Region. (AEIAR-067/2002)

Shek, C.T. 2006. A Field Guide to the Terrestrial Mammals of Hong Kong. Agriculture, Fisheries and Conservation Department, Hong Kong.

Shin, P., S.G. Cheung, R. Kong, H. Chiu 2007. ECF Project 12/2003 Conservation of Horseshoe Crabs in Hong Kong. Revised Final Report submitted to ECF.

Wilson, K.D.P. 2004. Field Guide to the Dragonflies of Hong Kong. Agriculture, Fisheries and Conservation Department, Hong Kong.

Yiu, V. 2004. Field Guide to Butterfly Watching in Hong Kong. Hong Kong Lepidopterist’s Society, Hong Kong.

Young, L. & Chan, G. 1997. The significance of drained fish ponds for wintering waterbirds at the Mai Po Marshes, Hong Kong. Ibis139: 694-698.

Zheng, G.M. and Wang, Q. S. 1998. China Red Data Book of Endangered Animals: Aves. Science Press, Beijing.