6.         ECOLOGical Impact Assessment

 

6.1       Introduction

 

This section of the EIA report assesses the potential ecological impact associated with the proposed 132 kV supply circuit from Pui O via Chi Ma Wan Peninsula via sea crossing towards Cheung Chau.  Baseline ecological conditions in the Study Area have been established based on a literature review and field surveys.  Potential sources of impacts have been identified and assessed and, where appropriate, requirements for mitigation and monitoring recommended.

 

6.2       Environmental Legislation and Criteria

 

A number of international and local regulations, legislation and guidelines provide the framework for the protection of species and habitats of ecological importance.  Those related to the Project are:

 

·         Country Parks Ordinance (Cap 208);

 

·         Forests and Countryside Ordinance (Cap 96) and its subsidiary legislation, Forestry Regulations;

 

·         Wild Animals Protection Ordinance (Cap 170);

 

·         Town Planning Ordinance (Cap 131);

 

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

 

·         Technical Memorandum on Environmental Impact Assessment Process (EIA-TM) for the Environmental Impact Assessment Ordinance; and

 

·         United Nations Convention on Biodiversity (1992).

 

The Country Parks Ordinance provides for the designation and management of Country Parks and Special Areas.  Country Parks are designated for the purpose of nature conservation, countryside recreation and outdoor education.  Special Areas are created mainly for the purpose of nature conservation.

 

The Forests and Countryside Ordinance prohibits felling, cutting, burning or destroying of trees and growing plants in forests and plantations on Government land.  Related subsidiary Regulations prohibit the picking, felling or possession of listed rare and protected plant species.  The list of protected species in Hong Kong which comes under the Forestry Regulations was last amended on 11 June 1993 under the Forestry (Amendment) Regulation 1993 made under Section 3 of the Forests and Countryside Ordinance.

 

Under the Wild Animals Protection Ordinance, designated wild animals are protected from being hunted, whilst their nests and eggs are protected from destruction and removal.  All birds and most mammals are protected under this Ordinance.  The Second Schedule of the Ordinance that lists all the animals protected was last revised in June 1992.  All cetaceans are protected under this Ordinance.

 

The recently amended Town Planning Ordinance provides for the designation of coastal protection areas, Sites of Special Scientific Interest (SSSIs), Green Belt or other specified uses that promote conservation or protection of the environment, e.g. conservation areas.  The authority responsible for administering the Town Planning Ordinance is the Town Planning Board.

 

 

Chapter 10 of the HKPSG covers planning considerations relevant to conservation.  This chapter details the principles of conservation, the conservation of natural landscape and habitats, historic buildings, archaeological sites and other antiquities.  It also addresses the issue of enforcement.  The appendices list the legislation and administrative controls for conservation, other conservation related measures in Hong Kong and Government departments involved in conservation.

 

Annex 16 of the EIA-TM sets out the general approach and methodology for assessments of ecological impacts arising from a project or proposal, to allow a complete and objective identification, prediction and evaluation of the potential ecological impacts.  Annex 8 recommends the criteria that can be used for evaluating ecological impacts.

 

The Peoples' Republic of China (PRC) is a Contracting Party to the United Nations Convention on Biological Diversity of 1992.  The Convention requires signatories to make active efforts to protect and manage their biodiversity resources. The Government of the Hong Kong Special Administrative Region has stated that it will be 'committed to meeting the environmental objectives' of the Convention.

 

6.3       Terrestrial Ecology

 

6.3.1     Assessment Methodology

The establishment of the baseline terrestrial ecological profile of the Study Area (covering all areas within 500m of the proposed works area) and assessment of potential impacts are based on field surveys including habitat/vegetation and wildlife, as well as a review of the available literature.  A literature review of the terrestrial ecological conditions within the Study Area was conducted including the Ecological Study of Freshwater Wetland in Hong Kong (Dudgeon and Chan, 1996).  Consultations with local ecologists were also undertaken, where appropriate.  Habitat and ecological communities within the Study Area were mapped with reference to the Vegetation Map prepared by World Wide Fund for Nature Hong Kong (1993).

 

Broad scoping field surveys were then undertaken to supplement and field-check the data collected through the baseline/literature review process.  Areas of ecological interest that would be directly or indirectly affected by the proposed electric cable circuit were then surveyed in more detail.

 

All the field data wereere collected between October 2000 and September 2001, covering the transitional period of wet and dry seasons, as well as the wet and dry season.  The ecological surveys covered habitat/vegetation, mammals, avifauna, amphibian/reptile, invertebrates and stream fauna, as well as applicable night surveys, and the methodologies used are presented below.

 

Habitat/Vegetation

Each representative habitat type was surveyed on foot.  All plant species encountered were identified and recorded to species level, whenever possible, and the relative abundance of the plant species was also recorded.  The dominant flora and fauna of each habitat/land-use type were also identified, with subsequent further habitat and vegetation verifications undertaken.  Surveys were undertaken on 20, 22 and 27 November 2000 and 6 September 2001.  Species names and local conservation status of all native plant species & all naturalized exotic species followed Corlett et al. (2000), while the different names used in the Checklist of Hong Kong Plants (Hong Kong Herbarium, 1993) were listed in brackets as well for completeness.  Names of cultivated plants follow the Checklist of Hong Kong Plants (Hong Kong Herbarium, 1993). 

 

 

Mammals

Signs or other evidence of mammal presence were noted in the field by active searching in potential mammal habitats.  Surveys were undertaken on 28 October and 11 November 2000.

 

Avifauna

The bird surveys were undertaken in all major habitat types within the Study Area quantitatively (using the point count method) and qualitatively.  For the point count method, a total of twenty minutes was spent counting birds at each point (Figure 6.1).  All birds seen or heard within 30 m of each point count location were counted and identified to species level where possible.  All the bird species seen or heard within the Study Area were also recorded.  Signs of breeding (e.g. nests, recently fledged juveniles) and the habitat utilization of the different species were also recorded.  Surveys were undertaken on 25 October, 27 November and 20 December 2000.

 

Amphibian/Reptile

Sampling techniques involving direct observation and active searching for reptiles in potential shelter sites/hiding places and, for amphibians in potential habitats, were employed.  Surveys were undertaken on 28 October and 11 November 2000.

 

Invertebrates (Butterfly, Dragonfly and Damselfly)

The abundance of adult butterfly, dragonfly and damselfly fauna were investigated by direct observation and active searching, in all major habitat types within the Study Area.  Any butterfly, dragonfly and damselfly seen were identified and counted during the survey.  Butterfly, dragonfly and damselfly were netted where required for identification.  Identification of Odonates followed Wilson (1997) and identification of butterflies followed Walthew (1997).  The weather conditions on both days were suitable for the survey of aerial insects (sunny, warm and light wind conditions) (New, 1998).  Surveys were undertaken during the active day time of butterfly, dragonfly and damselfly (between 1000 and 1600 hrs).  Surveys were undertaken on 27 October and 1 November 2000.

 

Aquatic Fauna

Aquatic fauna were investigated through direct observation and active searching, as well as using a hand net.  The freshwater fish survey used hook and line (in main stream) and hand-nets (mainly in marshes and near estuaries).  Surveys were undertaken on 27 & 28 October and 11 November 2000.

 

Night Survey

A night survey (11 October 2000) was undertaken in the Pui O areas mainly focusing on nocturnal wildlife including mammals and amphibians. 

 

The potential ecological impacts due to the installation of 132 kV circuit were assessed following EIA-TM Annex 16 guidelines and the impacts evaluated based on the criteria in EIA-TM Annex 8.

 

6.3.2     Baseline Condition

Site of Conservation Importance

Lantau South Country Park

Lantau South Country Park encompasses a wide range of land habitats, from grassland to some of the finest forest in Hong Kong.  The Park has a long coastline, particularly in Chi Ma Wan Peninsula, supporting a wide range of fauna such as insects, reptiles and a variety of birds.  Parts of the Lantau South Country Park are located within the Study Area, but outside the Works Area (Figures 6.2 & 6.3), comprising generally tall shrubland or forest.

 

Pui O Marsh and Taro Bed

Pui O Marsh and Taro Bed were identified as important wetlands by Dudgeon and Chan (1996) and comprise part of an extensive, low-lying wetland.  The Taro Bed was reported as containing a number of rare macroinvertebrates, including Macrodiplax larvae, hydrophilid beetles and Sphaeromias sp., and several frogs (ie Polypedates megacephalus and the Marbled Pygmy Frog Microhyla pulchra).  The area is distinctive because of the presence of a resident population of water buffaloes, one of the few remaining areas where they still occur in Hong Kong.

 

Habitat/Vegetation

The field surveys identified that the Study Area is covered by a variety of habitats including forest, tall shrubland, shrubland and grassland mixture, wetland, abandoned farmland, farmland, rocky shore, sandy beach, backshore shrubland, mangrove, brackish mudflat, plantation, wasteland, village area and stream.  Wetland and village area were the dominant habitat type in the flat land area whereas the hillsides were dominated by tall shrubland and forest.  The Study Area and the locations of various habitat types are shown on Figures 6.2 and 6.3, and photographic records of representative habitat types are shown on Figure 6.4.  Species lists of flora and fauna are given in Appendix G.

 

Forest

Forest found within the Study Area included secondary and fung-shui forests.  The forests are continuous with a height ranging from 4 m to 15 m, and diameter at breast height (dbh) ranging from 10 cm to 70 cm.  The forests showed considerable variation in species composition and structure with a total of 62 species of trees and 113 plant species recorded.  Since secondary and fung-shui forests are physically continuous and showed a continuum in composition, they are regarded as a single habitat type.

 

The secondary forest is the predominant forest habitat type within the Study Area with a height ranging from 4 m to 10 m.  The plant diversity is co-dominated by Sapium discolor, Mallotus paniculatus, Microcos paniculata, and Sterculia lanceolata.  The introduced species Casuarina equisetifolia and Tristania conferta are locally abundant and apparently planted on the hillside south-east of Chi Ma Wan Road, but the native secondary woodland species still dominate. 

 

There are five patches of fung-shui forest, one close to the proposed Pui O portal, two behind Ham Tin and two behind Pui O Lo Wai Tsuen and Pui O San Wai Tsuen, found in the Study Area.  The fung-shui forest is relatively old growth with a height rainging from 6 m to 15 m and has not been disturbed for 20 to 50 years.  The plant diversity is co-dominated by Aquilaria sinensis, Bischofia javanica, Machilus chekiangensis, Ailanthus fordii, and Sterculia lanceolata. 

 

 

Eight plant species of conservation importance were found including six rare to very rare species, Ailanthus fordii, Malaisia scandens, Urceola micrantha (Parabarium micranthum), Uncaria hirsuta, Uvaria calamistrata, and Xenostegia tridentata (Merremia hastata) and two locally common but protected species in China and Guangdong (Aquilaria sinensis and Gmelina chinensis).  Although Dalbergia balansae is also listed as “rare” in Corlett et al. (2000), it has been found to be locally very abundant in a number of places in Hong Kong and was widely planted in Hong Kong, and therefore should be ranked in the “restricted” category (S. C. Ng pers. comm.).

 

Tall Shrubland

Tall shrubland is defined as woody vegetation with a modal height of 1.5 m to 4 m and is a transitional stage in ecological succession between shrubland and forest.  This habitat type is similar to shrubland in species composition but tends to be dominated by woody species and climbers.  A total of 127 plant species were recorded in this habitat within the Study Area which is dominated by Litsea rotundifolia var. oblongifolia, Rhodomyrtus tomentosa, Cratoxylum cochinchinense, Eurya nitida (E. japonica in HK Checklist) and Strophanthus divaricatus.  The floristic diversity is considered high and the structural diversity is considered moderate to high. Five plant species of conservation interest were found including one rare species, Cyclobalanopsis glauca, and four locally common but protected species in Hong Kong (Pitcher Plant Nepenthes mirabilis and Cleisostoma simondii (C. teres)), Guangdong, (Gmelina chinensis), and China (Artocarpus hypargyreus), respectively.

 

Shrubland and Grassland Mixture

Shrubland and grassland mixture is defined here as vegetation dominated by herbaceous and woody plant species with a modal height of less than 1.5 m.  This habitat is mainly found at higher altitude and in small patches behind rocky shores within the Study Area.  A total of 56 plant species were recorded in the shrubland and grassland mixture within the Study Area which is dominated by Litsea rotundifolia var. oblongifolia, Rhodomyrtus tomentosa, Dicranopteris linearis, Eulalia quadrinervis, and Ischaemum barbatum.  The co-dominance of Dicranopteris linearis suggested that the habitat had been frequently disturbed by hill fires.  Neither rare nor protected plants were recorded during the survey.  This habitat is relatively high in floristic diversity but moderate in structural diversity.

 

Wetland

Wetland refers to the waterlogged and seasonally or permanently submerged flatland.  This habitat was found between the Pui O villages and the Pui O beach including the Pui O Marsh and Taro Bed.  It is a semi-natural habitat originated from paddy fields abandoned approximately 20 years ago.  The height of the vegetation is maintained below 1 m due to the grazing effect of Water Buffalo.  There was a total of 52 species recorded in this habitat which is high compared with other wetlands in Hong Kong.  The major dominant species found in the wetland included Bacopa monnieri, Sacciolepis indica, Isachne globosa, Rotala indica, and Chrysopogon aciculatus.  This habitat is relatively high in floristic diversity but low in structural diversity.  There were four rare to very rare species recorded, Azolla imbricata, Ceratopteris thalictroides, Marsilea quadrifolia and Salvinia natans, which are mostly past paddy field weeds.  The habitat itself, however, is of high quality and rare because of its size and floristic diversity and the high abundance of the locally rare Marsilea quadrifolia and Salvinia natans, both of which are locally co-dominant at the center of the wetland.  Although Fimbristylis acuminata was listed as “rare” in Corlett et al. (2000), it is locally abundant in a number of wetland sites in Hong Kong and should be ranked in the “restricted” category (S.C. Ng, pers. comm.).

 

Abandoned Farmland

The abandoned farmland was found beside the wetland habitat between Pui O Lo Wai Tsuen/ San Wai Tsuen and the Pui O beach.  This habitat is similar to wetland in appearance but does not have permanently waterlogged soil and is rarely submerged.  Similar to the wetland habitat, the height of the vegetation is maintained below 1 m due to the grazing effect of Water Buffalo, although isolated trees or shrubs of Sapium sebiferum and Lantana camara could be found on the mud-bund.  There was a total of 47 species recorded in this habitat dominated by Chrysopogon aciculatus, Cynodon dactylon, Cyperus rotundus and Rotala indica.  This habitat is relatively moderate in floristic diversity but low in structural diversity.  Neither rare nor protected plants were recorded during the survey.

 

Farmland

There were only two small patches of active farmland found beside the wetland at Pui O in the Study Area.  Although the vegetation cover was greater than 60%, only 16 species were recorded and the species composition was dominated by introduced crop plants including Ipomoea batatas, Lactuca sativa, Clausena lansium, and Dimocarpus longan.  Both the floristic and structural diversity of the habitat was considered to be low.  Neither rare nor protected plants were recorded during the survey.

 

Rocky Shore

The vegetation cover is extremely sparse at the sea side, which is dominated by barren bedrock and boulders, whereas the back is dominated by typical backshore vegetation and is continuous to shrubland or secondary forest behind.  There was a total of 56 species recorded in this habitat dominated by Severinia buxifolia (Atalantia buxifolia), Heteropogon contortus, Sageretia thea, and Litsea rotundifolia var. oblongifolia.  This habitat is relatively moderate in floristic diversity but low in structural diversity due to the sparse vegetative cover.  One locally rare species, Rhamnus leptophyllus, was found in this habitat.  It had been confused, in the past, with R. brachypoda, a restricted species in HK.  Although Berchemia lineata and Trachelospermum jasminoides were listed as “rare” in Corlett et al. (2000), they are more abundant and should be ranked in the “restricted” category (S.C. Ng, pers. comm.).

 

Sandy Beach

This habitat type is represented by the beaches at Pui O (gazetted bathing beach) and Tai Long Wan.  Such habitat is characterized by mobile sandy substratum with very sparse to no vegetation cover at the front, whereas the back is dominated by creeper and stoloniferous plants and is continuous with backshore shrubland.  There was a total of 32 species recorded in this habitat dominated by Ipomoea pes-caprae (I. brasiliensis), Vitex rotundifolia, Clerodendrum inerme, Wedelia biflora and Canavalia rosea (C. maritima).  This habitat is relatively moderate in floristic diversity but low in structural diversity.  Neither rare nor protected plants were recorded during the survey.

 

Backshore Shrubland

Backshore shrubland refer to the dense tall shrubland found behind the sandy beach at Pui O and Tai Long Wan beaches.  There were a total of 44 species recorded in this habitat dominated by Caesalpinia bonduc, Pandanus tectorius, and Casuarina equisetifolia, which were probably planted previously.  This habitat has relatively moderate to low in floristic diversity and moderate in structural diversity.  Except rare plant species, Agave vivipara, neither rare nor protected plants were recorded during the survey.  Although the rare Agave vivipara was recorded in this habitat, it is an introduced and naturalized species and, therefore, without conservation importance.

 

Mangrove

Mangrove is defined as woody vegetation dominated by salt-tolerant species found in the intertidal area.  Mangrove was found on both sides of the estuary between Ham Tin and Pui O beach.  There was a total of 28 species recorded in this habitat dominated by Excoecaria agallocha, with other mangrove species (Kandelia candel and Aegiceras corniculatum) occurring in smaller numbers.  This habitat is relatively moderate in floristic diversity and moderate to high in structural diversity as the height of vegetation is comparable to tall shrubland.  Neither rare nor protected plants were recorded during the survey.  The mangrove trees recorded were in reasonably good condition with heights ranging from 2 m to 3 m.

 

Brackish Mudflat

Brackish mudflat refers to the mudflat found on the estuary between Ham Tin Village and Pui O beach.  There was a total of 8 species recorded in this habitat which was largely dominated by Zoysia sinica and Cyperus stoloniferus.  Both the floristic and structural diversity were considered as low.  Neither rare nor protected plants were recorded during the survey.

 

Plantation

Plantation included government plantation as well as all orchards with a usual height ranging between 3 m and 6 m.  Although this habitat is under strong human influence, it has more than 80% vegetation cover composed mainly of introduced landscape/crop tree or plants.  There was a total of 30 species recorded in this habitat dominated by Acacia confusa, Celtis tetrandra ssp. sinensis (C. sinensis), Clausena lansium, Dimocarpus longan, and Litchi chinensis.  In addition some weedy or secondary forest species were recorded.  This habitat was relatively moderate in floristic diversity and high in structural diversity.  Neither rare nor protected plants were recorded during the survey.

 

Wasteland

Wasteland refers to unused area filled with mineral debris (sand, soil, and gravel) and/ or refuse.  This habitat was found beside the wetland and Ham Tin village.  The vegetation cover was more than 60% and the species composition was similar to that of village areas with a total of 32 species and dominated by weedy species including Cynodon dactylon, Mikania micrantha, Ipomoea cairica, Eupatorium catarium (Praxelis clematidea), and Sageretia thea.  This habitat is relatively moderate in floristic diversity and simple in structural diversity.

 

Village Area

Village area included all village houses, concrete roads, and buildings.  The vegetation was sparse in this habitat with more than 70% of the area covered in concrete.  There was a total of 50 species recorded in this habitat dominated by Acacia confusa, Mikania micrantha, Ipomoea cairica, Lantana camara, and Eupatorium catarium (Praxelis clematidea).  More than half of the species recorded are either exotic, introduced, or cultivated/ornamental species.  This habitat is relatively moderate in species diversity but low in structural diversity.  Neither rare nor protected plants were recorded during the survey.

 

Freshwater Stream

There are four permanent streams (always containing water), S1, S2, S3 and S4, recorded within the Study Area.  Streams S1 and S2 are mid-sized streams, while S3 and S4 are smaller.  The upper section of stream S1 is natural with large boulders on the stream bed, while the middle section has been channelized but still with a natural rocky bottom.  The lower section is partially channelized and stream sediments consisted of fine-grains with mid to large sized boulders.  The upper and middle courses were open and the riparian vegetation comprised mostly trees.  The lower course, however, was semi-open and the riparian vegetation comprised mostly grasses and shrubs.

 

The middle section of stream S2 has been channelized and re-constructed by ‘boulder blocks’.  The lower course of S2 is estuary connected to the brackish mudflat.

 

The upper and middle courses of S3 are less disturbed and shaded by trees and shrubs.  The lower course of S3, similar to S2, is estuary connected to brackish mudflat.  There were about 10 residential buildings located alongside the lower stream course, and the stream appear to be polluted to a certain degree, evidenced by the black colour substratum in the estuary.

 

S4 is a small stream with limited freshwater flow located inside forest.  The stream base sediments consisted of fine-grains with many overlying boulders.

 

Animal Wildlife

Mammals

Except three bats (two unidentified and one Japanese Pipistrelle Pipistrellus abramus), no signs of mammal existence (such as trails, burrows) were observed or noted in the Study Area during the surveys.  However, many local villagers reported the presence of Masked Palm Civet (Paguma larvata), Barking Deer (Muntiacus reevesi) and Wild Boar (Sus scrofa).  Since the Study Area has diverse habitats and lies adjacent to Lantau South Country Park, these wide-ranging animals may occasionally visit part of the Study Area that are less affected by human disturbance.

 

Avifauna

A total of 47 bird species were recorded within the Study Area during the surveys, most of the species were recorded in Pui O.  The Majority of the recorded species are common and typical in Hong Kong, such as Chinese Bulbul Pycnonotus sinensis, Common Magpie Pica pica and White Wagtail Motacilla alba. 

 

The Greater Coucal Centropus sinensis, Pacific Reef Egret Egretta sacra, Black Kite Milvus lineatus, Great Crested Grebe Podiceps cristatus and Red-billed Starling Sturnus sericeus are commonly found in Hong Kong, however, they are regarded as species of conservation concern.  Greater Coucal Centropus sinensis, Pacific Reef Egret Egretta sacra, Black Kite Milvus lineatus and Great Crested Grebe Podiceps cristatus are listed as Class II protected wildlife of national importance in China (MacKinnon and Phillipps, 2000).  Greater Coucal Centropus sinensis and Pacific Reef Egret Egretta sacra are also listed as vulnerable and rare in China Red Data Book.  Red-billed Starling Sturnus sericeus is identified as a globally threatened species (Collar et al., 1994).  No breeding activities were recorded during the survey.

 

Amphibian/Reptile

There were only four amphibian species recorded during the surveys including Günther’s Frog Rana guentheri, Paddy Frog Rana limnocharis, Three-striped Grass Frog Rana macrodactyla and Chinese Bullfrog Rana rugulosa. Most of the species were found in Pui O Marsh and Taro Bed.  Only Chinese Bullfrog Rana rugulosa is protected in China (Hua and En, 1993) and considered as uncommon, and the other species are all common and widespread in Hong Kong.  Sixty years ago the Chinese Bullfrog was considered as the most common species locally but has since become less common (Romer, 1979; Karsen et al, 1986).

 

In the case of reptiles, five common species, Changeable Lizard Calotes versicolor, Long-tailed Skink Mabuya longicaudata, Common Rat Snake Ptyas mucosus, Checkered Keelback Xenochrophis piscator and Red-eared Slider Trachemys scripta elegans were observed during the surveys.  Except the Common Rat Snake Ptyas mucosus listed as endangered species in China Red Data Book, neither rare, endangered, nor endemic species were found.

 

Invertebrates

Twenty-eight species of butterflies were reported from Pui O in surveys conducted in 1976 (Bascombe, unpubl. data).  Most were either very common or common in Hong Kong, except four uncommon species, namely Banana Skipper Erionota torus, Bush Hopper Ampittia dioscorides, Quaker Neopithecops zalmora and Hong Kong Lacewing Cethosia biblis.  The habitat uses, food plants and global distributions of these species are shown in Appendix G Table G-19.  None of the recorded butterfly species is protected in Hong Kong or China.  Five species of dragonflies have been reported from Pui O (Wilson 1997) where Neurothemis tullia was present in large numbers in Pui O Marsh.  This species is usually found in wet abandoned cultivated lands (Wilson 1995).  Of the five recorded species all are common and widespread except Tramea transmarina (Wilson 1997).  None of the recorded dragonfly species is protected in Hong Kong or in China, and none is endemic to Hong Kong (Wilson 1997).  Pui O is the site of the only known Hong Kong record of Tramea transmarina, a migratory Southeast Asian dragonfly (Wilson 1997, Dudgeon and Chan 1996).  The specimen was recorded after a typhoon in June 1991 and was, therefore, considered a potential vagrant rather than likely to be indicative of a resident population (Wilson 1997).

 

Thirty-four species of butterfly, such as Angled Castor Ariadne ariadne, Dark Veined Tiger Danaus genutia, Common Mormon Papilio polytes and Common Grass Yellow Eurema hecabe, were recorded during the surveys.  Except five uncommon species recorded, including Purple Sapphire Heliophorus epicles, Yellow Pansy Junonia hierta, Lemon Pansy Junonia lemonias, Blue Pansy Junonia orithya and Yellow Orange Tip Ixias pyrene, all the recorded species are either very common or common in Hong Kong.  None of the butterfly species recorded in the Study Area is protected in Hong Kong or China.  Lemon Pansy, Blue Pansy and Yellow Orange Tip are dependent on woodland habitats.  The high diversity of butterflies reflects the diverse and undisturbed nature of the Study Area. 

 

A total of 17 species of dragonfly were recorded within the Study Area including Wandering Glider Pantala flavescens, Neurothemis tullia and Orthetrum sabina.  All recorded species are common and widespread in Hong Kong, and none are endemic to Hong Kong (Wilson 1997) or protected in Hong Kong or China.  Several species of dragonfly including Agriocnemis femina, Anax parthenope and Orthetrum sabina were observed laying eggs in wetland and stream areas during the surveys.

 

Aquatic Fauna

Two ecological important wetland sites in Pui O, namely Pui O Marsh and Pui O Taro Bed, were identified by Dudgeon and Chan in a Hong Kong-wide study of freshwater wetlands (1996).  A very diverse aquatic invertebrates was recorded in the two sites, with leeches reported as an important part of the invertebrate fauna in the taro bed (Dudgeon and Chan 1996; Dudgeon & Chan 1994).  Rare invertebrates recorded in abandoned cultivated lands in Pui O included hydrophilid beetles (Scavenging Water Beetles) and Sphaeromias sp. (Ceratopogonidae: Biting Midges).

 

A list of fish species has been reported from the Chi Ma Wan Peninsula (notably around Shap Long) by Chong and Dudgeon (1992) included, eels Anguilla japonica and Anguilla marmorata, the brackish-water ribbon eel Pisoodonophis boro, the Rice Fish Oryzias curvinotus, the brackish-water mullet Osteomugil ophuyseni, the brackish-water glassfish Ambassis gymnocephalus, the sea perch Lateolabrax japonicus, brackish-water sillago Sillago sihama, Mangrove Snapper Lutjanus argentimaculatus, Russell’s Snapper Lutjanus russellii, tigerfish Terapon jarbua, rabbitfish Siganus fuscescens, sleepers Eleotris acanthopoma, Eleotris oxycephala, Butis butis, gobies Tridentiger trigonocephalus, Luciogobius guttatus, Bathygobius fuscus, Glossogobius biocellatus, Glossogobius giuris, Glossogobius olivaceus, Stimatogobius javanicus, Ctenogobius giurinus, and Acanthogobius flavimanus.  The torrent loach Liniparhomaloptera disparis and freshwater goby Ctenogobius duospilus were recorded from Pui O but it should be noted that Pui O was not one of the major study sites (Chong and Dudgeon, 1992).  Dudgeon and Chan (1996) also reported that Paradise Fish Macropodus opercularis were found in Pui O.

 

Seven species of freshwater aquatic invertebrates including Mitten crab Eriocheir japonicus, Palamonid shrimp Macrobrachium sp. and Buffalo Leech Poecilobdella assimilis, were recorded within the Study Area during the field surveys.  The majority of these invertebrates were crustacean, and only one species of annelid (Buffalo Leech) was recorded.  None of the species found was protected in Hong Kong.  Two species of Atyid shrimp Caridina apodosis and Caridina serrata, were recorded during the survey, which have been reported as having a limited distribution in the south China region. (Cai & Ng 1999).  In Hong Kong, there are three species of this genus reported, namely, Caridina cantonensis, C. apodosis and C. serrata, which are usually found in mountain streams with clean water.  In a recent review on the genus Caridina, samples of the genus from different regions in East Asia were examined. Caridina serrata is only recorded on Hong Kong Island and Lantau Island, and it was suggested that this endemic species should be regarded as endangered, due to its limited distribution and the degree of urbanization of Hong Kong Island.  Caridina serrata is a tiny animal with a carapace length usually shorter than 5 mm, and the body length around 2 cm.

 

Twenty species of fish including Oreochromis niloticus, Gambusia affinis, Capoeta semifasciolata and Macropodus opercularis, were recorded within the Study Area.  Since the lower courses of the freshwater streams connected to the Pui O estuary, some brackish water fish species such as Lateolabrax japonicus, Mugil cephalus, and Sparus berda were also recorded.  Except Parazacco spilurus, listed as vulnerable in China Red Data Book, neither rare, endangered, nor endemic species were recorded.  Parazacco spilurus classified as vulnerable in the China Red Data Book (Yue and Chen, 1998) due to its scientific value and restricted range on a global scale, but it is widespread and common in Hong Kong.  Macropodus opercularis and Capoeta semifasciolata are widespread and common lowland species in Hong Kong, however, the increasing disappearance of lowland wetlands and streams due to habitat destruction and pollution may affect their population in the future.

 

6.3.3     Ecological Importance

 

The ecological importance of the habitats identified has been evaluated against the criteria recommended in Annex 8 of the EIA-TM.  This evaluation is presented below.

 

Table 6-1        Ecological Value of Forest in the Study Area

 

Criteria

Forest

Naturalness

High.  Natural secondary forest to relatively old-growth fung-shui woodland that had not been disturbed for 20 to 50 yrs.

Size

The total size of this habitat is approximately 76.2 ha.

Diversity

High in terms of floristic diversity & structural diversity.  Forest with height ranging from 4 to 15m providing a wide range of microhabitat for wildlife.

Rarity

Eight species of plant with conservation importance were found including six rare to very rare species (Ailanthus fordii, Malaisia scandens, Urceola micrantha (Parabarium micranthum), Uncaria hirsuta, Uvaria calamistrata, and Xenostegia tridentata (Merremia hastata)) and two locally common but protected species in China and Guangdong (Aquilaria sinensis and Gmelina chinensis).  Although Dalbergia balansae is also listed as “rare” in Corlett et al (2000), it has been found to be locally very abundant in a number of places in Hong Kong and was widely planted in Hong Kong, and therefore should be in the “restricted” category (S. C. Ng pers. comm.).  Five uncommon butterfly species were also recorded including Purple Sapphire Heliophorus epicles, Yellow Pansy Junonia hierta, Lemon Pansy Junonia lemonias, Blue Pansy Junonia orithya and Yellow Orange Tip Ixias pyrene.

Re-creatability

The habitat characteristics are difficult to recreate.

Fragmentation

Not fragmented.

Ecological Linkage

High.  Continuous with surrounding forest and tall shrubland.

Potential value

Ecological potential is high if the forest remains undisturbed.

Nursery/Breeding Ground

Not reported, but it is likely to be utilised by localised species of birds and mammals.

Age

Ranging from approximately 30 years for secondary forest to 100 years for fung-shui forest behind villages at Pui O.

Abundance/Richness of Wildlife

The abundance and diversity of birds and butterflies recorded were moderate and high respectively.

Overall Ecological Value

High

 

 


 

Table 6-2        Ecological Value of Tall Shrubland in Study Area

 

Criteria

Tall Shrubland

Naturalness

Moderate to High.  Natural secondary tall shrubland that had not been disturbed for 10 to 20 years.

Size

The total size of this habitat is approximately 125.9 ha.

Diversity

High in terms of floristic diversity but only moderate to high in structural diversity. 127 plant species was recorded within the habitat.

Rarity

Five species of plant with conservation interest were found including one rare species (Cyclobalanopsis glauca) and four locally common but protected species in Hong Kong, (Nepenthes mirabilis, Cleisostoma simondii (C. teres)), Guangdong (Gmelina chinensis), and China (Artocarpus hypargyreus), respectively.  Common Rat Snake Ptyas mucosus and Black Kite Milvus lineatus were recorded near Shap Long Kau Tsuen and Tai Long Wan respectively.

Re-creatability

Moderate.

Fragmentation

Not fragmented.

Ecological Linkage

High. Continuous with surrounding forest and shrubland & grassland mixture.

Potential value

High.  Have the potential to accumulate native plant and animal species.

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found during the survey on literature review.

Age

Approximately 20 years.

Abundance/Richness of Wildlife

The abundance and richness of birds recorded were moderate.

Overall Ecological Value

Moderate

 

 

Table 6-3        Ecological Value of Shrubland and Grassland Mixture in Study Area

 

Criteria

Shrubland and Grassland Mixture

Naturalness

Moderate to Low.  Natural shrubland regenerated after hill fires 3 to 7 years ago.

Size

The total size of this habitat is approximately 29.2 ha.

Diversity

High in terms of floristic diversity but only moderate in structural diversity.  56 plant species was recorded within the habitat.

Rarity

Neither rare nor protected species were recorded during the survey.

Re-creatability

Readily re-creatable.

Fragmentation

Moderate.

Ecological Linkage

High. Continuous with surrounding forest and tall shrubland.

Potential value

Moderate.  Have the potential to accumulate native plant and animal species.

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found during the survey or literature review.

Age

More than 20 years.

Abundance/Richness of Wildlife

The abundance and richness of all wildlife recorded were low.

Overall Ecological Value

Low

 

 

Table 6-4        Ecological Value of Wetland in the Study Area

 

Criteria

Wetland

Naturalness

Moderate.  Semi-natural habitat formed from paddy field abandoned about 20 years ago.

Size

The total size of this habitat is approximately 14.7 ha.

Diversity

High in terms of floristic diversity but low in structural diversity.  52 plant species was recorded which is high compare to other wetland in Hong Kong.

Rarity

Four rare species to very rare species were found (Azolla imbricata, Ceratopteris thalictroides, Marsilea quadrifolia, and Salvinia natans), although they are mostly past paddy field weeds. The habitat itself, however, is of high quality and rare because of its size and species diversity and the high abundance of the locally rare Marsilea quadrifolia and Salvinia natans, both of which are locally co-dominant at the center of the wetland.  Although Fimbristylis acuminata was listed as “rare” in Corlett et al. (2000), it is locally abundant in a number of wetland sites in Hong Kong and should be in “restricted” category (S.C. Ng, pers. comm.).  Two bird species of conservation concern including Greater Coucal Centropus sinensis and Red-billed Starling Sturnus sericeus were recorded in the wetland habitat.  Uncommon Chinese Bullfrog Rana rugulosa was also recorded beside Stream S2 middle course.

Re-creatability

The habitat characteristics are difficult to recreate.

Fragmentation

The habitat is less fragmented.

Ecological Linkage

High.  Continuous with nearby brackish mudflat and wetland.

Potential value

Low.

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found during the survey or literature review.

Age

Approximately 30 years.

Abundance/Richness of Wildlife

The abundance and richness of all wildlife recorded were high.

Overall Ecological Value

High

 

 

Table 6-5        Ecological Value of Abandoned Farmland and Farmland in Study Area

 

Criteria

Abandoned Farmland

Farmland

Naturalness

Moderate.  Semi-natural habitat formed from paddy field abandoned about 20 years ago.

Low.  Completely human dominated habitat with some weedy species.

Size

The total size of this habitat is approximately 4.5 ha.

The total size of this habitat is approximately 1.7 ha.

Diversity

Moderate in terms of floristic diversity but low in structural diversity.  52 plant species was recorded which is high compare to other wetland in Hong Kong.

Low in terms of floristic diversity and structural diversity.  16 plant species was recorded.

Rarity

Neither rare nor protected species were recorded during the survey.

Neither rare nor protected species were recorded during the survey.

Re-creatability

Readily re-creatable.

Readily re-creatable.

Fragmentation

Highly fragmented.

Highly fragmented.

Ecological Linkage

High.  Continuous with nearby wetland.

Low.

Potential value

Moderate.  May convert to wetland if undisturbed.

Low.

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found during the survey or literature review.

No records of significant nursery or breeding grounds were found during the survey or literature review.

Age

Approximately 30 years.

Approximately 10 years.

Abundance/Richness of Wildlife

The abundance and richness of all wildlife recorded were low.

The abundance and richness of all wildlife recorded were low.

Overall Ecological Value

Moderate

Low

 

 

Table 6-6         Ecological Value of Terrestrial Habitats in Rocky Shore and Sandy Beach in Study Area

 

Criteria

Rocky Shore

Sandy Beach

Naturalness

Moderate. Natural habitat that had not been disturbed for 5 to 10 years.

Moderate.  Natural habitat that had not been disturbed for approximately 5 to 10 years.

Size

The total size of this habitat is approximately 4.4 ha.

The total size of this habitat is approximately 4.7 ha.

Diversity

Moderate in terms of floristic diversity but low in structural diversity because of sparse vegetation.  56 plant species was recorded within the habitat.

Moderate in terms of floristic diversity but low in structural diversity.  32 plant species was recorded within the habitat.

Rarity

One locally rare species, Rhamnus leptophyllus, was found in this habitat.  It had been confused, in the past, with R. brachypoda, a restricted species in HK. 

Pacific Reef Egret Egretta sacra was recorded in the Pui O beach during the survey.

Re-creatability

Moderate to High in terms of vegetative re-creatability.

Moderate to High in terms of vegetative re-creatability.

Fragmentation

Moderate.

Moderate

Ecological Linkage

Low.  Continuous with surrounding tall shrubland.

Moderate.  Continuous with surrounding backshore shrubland.

Potential value

Moderate

Moderate

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found during the survey or literature review.

No records of significant nursery or breeding grounds were found during the survey or literature review.

Age

More than 20 years

More than 20 years.

Abundance/Richness of Wildlife

The abundance and richness of all wildlife recorded was low.

The abundance and richness of all wildlife recorded was low.

Overall Ecological Value

Low

Low

 

 

Table 6-7        Ecological Value of Backshore Shrubland and Mangrove in Study Area

 

Criteria

Backshore Shrubland

Mangrove

Naturalness

Moderate to low, because of high abundance of introduced tree species.

High.  Natural habitat that had not been disturbed for more than 20 years.

Size

The total size of this habitat is approximately 3.5 ha.

The total size of this habitat is approximately 1 ha.

Diversity

Moderate to low in terms of floristic diversity and moderate in structural diversity.  Only 24  plant species were recorded.

Moderate in terms of floristic diversity and moderate to high in structural diversity as the height of vegetation is comparable to tall shrubland.  28 species were recorded, which is moderate compared to other mangroves in HK.

Rarity

Neither rare nor protected species were recorded during the survey.  Although one rare plant species (Agave vivipara) was recorded in the study, it is an introduced and naturalized species and so is of no conservation importance. 

Neither rare nor protected species were recorded during the survey.

Re-creatability

Readily re-creatable.

The habitat is difficult to recreate.

Fragmentation

Moderate

Moderate

Ecological Linkage

Moderate.  Continuous with nearby sandy shore and wetland.

Moderate.  Continuous with nearby brackish mudflat and wetland.

Potential value

Moderate

Moderate

Nursery/Breeding Ground

No record of significant nursery or breeding grounds were found during the survey or literature review.

No record of significant nursery or breeding grounds were found during the survey or literature review.

Age

More than 20 years.

More than 20 years.

Abundance/Richness of Wildlife

The abundance and richness of all wildlife recorded were low.

The abundance and richness of birds recorded were moderate.

Overall Ecological Value

Low

High

 

 

Table 6-8        Ecological Value of Brackish Mudflat and Plantation in Study Area

 

Criteria

Brackish Mudflat

Plantation

Naturalness

High.  Natural habitat.

Low to moderate.  Completely human dominated habitat with some weeds and secondary woodland species.

Size

The total size of this habitat is approximately 4.2ha.

The total size of this habitat is approximately 8.7ha.

Diversity

Low in terms of floristic diversity and structural diversity.  8 plant  species was recorded.

Moderate in terms of floristic diversity and high in structural diversity, as trees 3 to 6 m tall provide high habitat heterogeneity.  30 plant species was recorded.

Rarity

No species of conservation importance were found in this habitat.

No species of conservation importance were found in this habitat.

Re-creatability

The habitat characteristics are difficult to recreate.

Readily re-creatable.

Fragmentation

Less fragmented.

Heavily fragmented.

Ecological Linkage

High.  Continuous with nearby brackish marsh and wetland.

Not functionally linked with any important habitat.

Potential value

Ecological potential is low

Ecological potential is low.

Nursery/Breeding Ground

No record of significant nursery or breeding grounds were found during the survey or literature review.

No record of significant nursery or breeding grounds was found in the survey or literature review.

Age

More than 20 years.

Approximately 30 years.

Abundance/Richness of Wildlife

The abundance and richness of birds recorded were moderate.

The abundance and richness of wildlife recorded were low.

Overall Ecological Value

High

Low

 

 

Table 6-9        Ecological Value of Wasteland and Village Area in Study Area

 

Criteria

Wasteland

Village Area

Naturalness

Low.  Heavily disturbed and disrupted by past and current human activities.

Low.  Heavily disrupted and disturbed by human activities.

Size

The total size of this habitat is approximately 9.5 ha.

The total size of this habitat is approximately 96.7 ha.

Diversity

Moderate in terms of floristic diversity but low in structural diversity.  31 species was recorded.

Moderate in terms of floristic diversity but low in structural diversity.  50 plant species was recorded but more than half of them are either exotic, introduced, or cultivated/ornamental species.

Rarity

Japanese Pipistrelle Pipistrellus abramus was recorded near Ham Tin during the survey.

Neither rare nor protected species were recorded during the survey.

Re-creatability

Readily re-creatable.

Readily re-creatable.

Fragmentation

Heavily fragmented.

Heavily fragmented.

Ecological Linkage

Not functionally linked with any important habitat.

Not functionally linked with any important habitat.

Potential value

Ecological potential is low.

Ecological potential is low.

Nursery/Breeding Ground

No record of significant nursery or breeding grounds was found in the survey or literature review.

No record of significant nursery or breeding grounds was found in the survey or literature review.

Age

No information and considered irrelevant.

No information and considered irrelevant.

Abundance/Richness of Wildlife

The abundance and richness of wildlife recorded were low.

The abundance and richness of wildlife recorded were low.

Overall Ecological Value

Low

Low

 

 

Table 6-10       Ecological Value of Stream Habitats in Study Area

 

Criteria

Stream

Naturalness

The S4, upper course of S1 and S3 and lower course of S2 remain natural, while the remaining sections are disturbed to a certain extent.

Size

The length of S1, S2, S3 and S4 are approximately 0.8 km, 0.9 km, 50 m and 200 m  respectively.

Diversity

The wildlife observed in stream habitat was moderate to high in diversity.

Rarity

Vulnerable freshwater fish Parazacco spilurus (listed in China Red Data Book) and rare Atyid shrimp Caridina serrata were found in S1 and S4 respectively.

Re-creatability

The stream habitats may be re-created but colonisation by stream fauna is not guaranteed.

Fragmentation

Not applicable.

Ecological Linkage

High.  Functionally linked to wetland, particularly Pui O Marsh and Taro Bed.

Potential value

The potential value is moderate to low.

Nursery/Breeding Ground

No records of significant nursery or breeding grounds were found.

Age

Not applicable.

Abundance/Richness of Wildlife

The aquatic faunal abundance and richness recorded were high.

Overall Ecological Value

Moderate

 

 

Based on the ecological conditions presented in the above sections, it is considered that the forest, brackish mudflat, wetland and mangrove have high ecological value.  The abandoned farmland, tall shrubland, stream (S1 to S4) are regarded to have moderate ecological value, while the other terrestrial habitats are common and typical habitats in Hong Kong and most of the species identified are common and widespread and therefore considered to be of low ecological value.

 

The list and evaluation of the floral and faunal species of ecological interest recorded within the Study Area (Figures 6.5 - 6.8), according to the EIA-TM, are given in Tables 6.11 and 6.12 below:

 

Table 6-11       Evaluation of Floral Species of Ecological Interest Recorded within the Study Area

 

Species

Growth Form

Location

Protection Status

Distribution

Rarity

Ailanthus fordii

Tree

Forest

Protected in HK

Ma On Shan, Tai Om, Cheung Sha, Victoria Peak and Lai Chi Wo

Rare

Aquilaria sinensis (Incense Tree)

Tree

Forest

Class III national protection (Wu et al. 1988), Listed as “Vulnerable” in the “China Plant Red Data Book” (Fu et al. ).

Widespread in Hong Kong

Common

Artocarpus hypargyreus

Tree

Tall shrubland

Class III national protection (Wu et al. 1988), Listed as “Vulnerable” in the “China Plant Red Data Book” (Fu et al. 1992).

Widespread in Hong Kong.

Common

Azolla imbricata (Water Fern)

Giant herb

Wetland

Past paddy field weed, no protection status.

Tai Po, Sha Tau Kok and Tan Chuk Hang

Rare

Ceratopteris thalictroides (Water Fern)

Herb

Wetland

Past paddy field weed, no protection status.

Sam A Tsuen, Li Chi Chong, Kam Tin, Po Toi Island and Ping Chau (Mirs Bay)

Rare

Cleisostoma simondii (C. williamsonii, C. teres, Sarcanthus teretifolius)

Epiphyte

Tall shrubland

Protected in HK (Forestry Regulations of the Forest and Countryside Ordinance).

Widespread in Hong Kong.

Very common

Cyclobalanopsis glauca

Tree

Tall shrubland

No protection status.

Pok Fu Lam, Tai Tam, D’Aguilar Peninsula, Ma On Shan, Kai Kung Shan, Sham Wat.

Rare

Gmelina chinensis

Tree

Forest and tall shrubland

Protected in Guangdong (Wu et al. 1988).

Widespread in Hong Kong.

Common

Malaisia scandens

Climber

Forest

No protection status.

Tong Fuk, Tai O, Soko Islands.

Rare

Marsilea quadrifolia (Four-leaf Fern)

Herb

Wetland

Past paddy field weed, no protection status.

Not known to be found in other locality recently.

Very rare

Nepenthes mirabilis (Pitcher Plant)

Herb

Tall shrubland

Protected in HK. (Forestry Regulations of the Forest and Countryside Ordinance).

North Lantau and northwest New Territories.

Common

Rhamnus leptophylla

Shrub

Rocky shore

Previously confused with R. brachypodus, no protection status

Unknown.

Rare

Salvinia natans

Giant herb

Wetland

Past paddy field weed, no protection status

Hang Ha Po (Lam Tsuen).

Rare

Uncaria hirsuta

Climber

Forest

No protection status.

Ma On Shan & vicinity, San Tau (Lantau).

Rare

Uvaria calamistrata

Climber

Forest

No protection status.

Sunset Peak, Sham Wat, San Tau, Pak Mong and Nam Fung Road SSSI.

Rare

Urceola micrantha (Parabarium micranthum, Ecdysanthera micrantha)

Climber

Forest

No protection status.

Mt Nicholson and Nam Fung Road fung shui wood.

Rare

Xenostegia tridentata (Merremia hastata)

Climber

Forest

No protection status.

Specimen collected from Soko Island, Pok Toi & Tuen Mun.

Very rare

 

 

Table 6-12       Evaluation of Faunal Species of Ecological Interest Recorded within the Study Area

 

Species

Common Name

Location

Protection Status

Distribution

Rarity in HK

Unidentified bat

 

Near brackish mudflat

All bats are protected

Unknown

Unknown

Pipistrellus abramus

Japanese Pipistrelle

Wasteland near Ham Tin

All bats are protected

Widespread in Hong Kong

Common

Centropus sinensis

Greater Coucal

Wetland at Pui O

All birds are protected, Class 2 protected wildlife of national importance in China and vulnerable in China Red Data Book

Widespread in Hong Kong

Common

Egretta sacra

Pacific Reef Egret

Pui O beach

All birds are protected, Class 2 protected wildlife of national importance in China and rare in China Red Data Book

Hong Kong’s coastal areas

Common

Milvus lineatus

Black Kite

Flying over Pui O and Tai Long Wan tall shrubland

All birds are protected, Class 2 protected wildlife of national importance in China

Widespread in Hong Kong

Very common

Podiceps cristatus

Great Crested Grebe

Coastal water outside estuary mouth.

All birds are protected, Class 2 protected wildlife of national importance in China

Deep Bay

Uncommon

Sturnus sericeus

Red-billed Starling

Wetland at Pui O

All birds are protected, globally threatened species

Deep Bay, Tai O and Long Valley

Common, but localised

Rana rugulosa

Chinese Bullfrog

Pui O Taro Bed and wasteland beside football pitch at Pui O

Class 2 protected wildlife of national importance in China

Sham Wat, Shui Hau, Mui Wo, Long Valley and New Territories

Uncommon

Ptyas mucosus

Common Rat Snake

Tall shrubland near Shap Long Kau Tsuen

Listed as endangered in China Red Data Book.

Widespread in Hong Kong, including Keung Fhan, Tong Fuk and Mui Wo

Common

Parazacco spilurus

Predaceous chub

Stream S1 (upper course)

Listed as vulnerable in China Red Data Book

Tung Chung, Wang Tong and Sha Lo Wan

Common

Heliophorus epicles

Purple Sapphire

Forest near Ham Tin

No protection status

Central to southeast Asia

Uncommon

Junonia hierta

Yellow Pansy

Forest near Ham Tin

No protection status

Central to southeast Asia

Uncommon

Junonia lemonias

Lemon Pansy

Forest near Ham Tin

No protection status

Central to southeast Asia

Uncommon

Junonia orithya

Blue Pansy

Forest near Ham Tin

No protection status

Central to southeast Asia

Uncommon

Ixias pyrene

Yellow Orange Tip

Forest near Ham Tin

No protection status

Central to southeast Asia

Uncommon

Caridina serrata

Atyid shrimp

Stream S4

No protection status

Hong Kong Island and Lantau only

Endemic, Very rare

 

 

6.3.4     Impact Assessment

Potential Sources of Impact

The proposed 132 kV circuit alignment includes five sections, Pui O Substation to Pui O Beach (Pui O portal) using underground cable, Pui O Beach to Tai Long Wan east (Tai Long Wan portal) using cable tunnel, Tai Long Wan east to Cheung Chau Sai Tai Road using submarine cable, Cheung Chau Sai Tai Road to Cheung Chau South Station using underground cable and Cheung Chau South Station to Cheung Chau North Substation using underground cable.  The sections using underground cable will be buried underneath footpaths and/or roads, and the ground surface will be reinstated afterwards.  Impacts due to habitat fragmentation and isolation therefore would not be expected.  Direct habitat/ area loss would not be expected in the Pui O Marsh and Taro Bed, the listed ecological sensitive receivers.

 

The potential impact associated with the project will be:

 

Construction Phase

·       direct habitat loss of tall shrubland, particularly within South Lantau Country Park, as a result of construction of tunnel portal for the 132 kV circuit installation and the related temporary work sites such as construction of platform, temporary access road and slope work (Figures 6.9 & 6.10);

·       direct loss of protected epiphyte Cleisostoma simondii located at the Pui O portal (size of the epiphyte patch is less than 50cm x 50 cm);

·       indirect impact to the lower courses of streams in the vicinity of the proposed 132 kV circuit due to construction runoff;

·       indirect impact to the surrounding habitats and associated wildlife, particularly the identified rare/ protected species, because of increased human activities/ disturbance such as storage or dumping of construction material, or hill fire.

 

Operational Phase

·       indirect impact due to increased human activities for the maintenance of the electric cable.

 

Impact Evaluation

Potential impacts on terrestrial ecology evaluated according to Table 1 of Annex 8 of the EIA-TM are given below:

 

Table 6-13      Overall Impact Evaluation for Tall Shrubland

 

Evaluation Criteria

Tall Shrubland

Habitat quality

The habitat quality of tall shrubland is moderate.

Species

There may be potential direct or indirect impact to the wildlife inhabiting the areas.  The protected but common epiphyte Cleisostoma simondii located at the Pui O portal will be affected.  The patch of epiphyte is small (50x50cm) and its loss is not considered to be significant.

Size/Abundance

Approximately 0.15 ha of tall shrubland at Pui O portal (750 m2) and Tai Long Wan portal (700 m2) will be lost.

Duration

The impact will persist during the construction and operational phases.

Reversibility

The impact of direct habitat loss is irreversible. 

Magnitude

The scale of the habitat loss is small in the context of the surrounding similar habitats.

Overall Impact Conclusion

Low to Moderate

 

 

Table 6-14      Overall Impact Evaluation for South Lantau Country Park

 

Evaluation Criteria

South Lantau Country Park

Habitat quality

The habitat being affected is tall shrubland with moderate quality.

Species

There may be potential direct or indirect impact to the wildlife inhabiting the areas.  Neither rare nor protected species will be affected.

Size/Abundance

Approximately 0.125 ha (tall shrubland), 500 750 m2 at Pui O portal and 700 m2 at Tai Long Wan portal will be affected.  The affected areas have been included in Table 6-13.

Duration

The impact will persist during the construction and operational phases.

Reversibility

The impact of direct habitat loss is irreversible. 

Magnitude

The scale of the habitat loss is small in the context of the surrounding similar habitats.

Overall Impact Conclusion

Low to Moderate

 

 

Table 6-15       Overall Impact Evaluation for Village Area

 

Evaluation Criteria

Village Area

Habitat quality

The habitat quality of the village area is low.

Species

The potential exists for direct or indirect impacts to the wildlife inhabiting the areas.  However, neither rare nor protected species will be affected.

Size/Abundance

Approximately 250 m2 will be lost.

Duration

The impact will persist during the construction and operational phases.

Reversibility

The impact of direct habitat loss is irreversible. 

Magnitude

The scale of the habitat loss is small in the context of the surrounding similar habitats.

Overall Impact Conclusion

Low

 

 

In conclusion, with the exception of the low to moderate impact to the loss of tall shrubland located inside South Lantau Country Park, as well as a small patch of protected but common species Cleisostoma simondii, the ecological direct impact due to the construction and operation of the 132 kV cable circuits is expected to be low.  The loss of the small patch of common but protected epiphyte plant Cleisostoma simondii, is not considered a significant impact and does not require mitigation as the species is common and the success of transplanting is considered questionable.  Only a small area (approximately 0.125 ha) of South Lantau Country Park will be affected due to the construction of tunnel portals (Pui O and Tai Long Wan) and the impacts are not expected to be unacceptable.  No direct impacts on the Pui O Marsh and Taro Bed, the listed ecological sensitive receivers, will be expected.

 

In general, the proposed 132kV cable circuits will be located underneath the existing roads and footpaths.  The construction activities are not expected to cause disturbance to the habitats utilised by wildlife (including the species of ecological interest).  Consequently, the direct impacts will be of low severity.

 

The potential indirect impacts (mainly noise disturbance) to the surrounding habitats and associated wildlife, particularly the species of ecological interest, due to the construction activities would not expected to be high owing to the temporary nature and small scale of the construction work given that regular checks on good construction practice will be conducted.  Given good construction practice, silty runoff could be controlled and limited impacts would be expected.  No impacts during the operational phase are expected.

 

6.3.5     Mitigation Measures

The following mitigation measures to minimise disturbance due to the project are recommended below.

           

·         Prevent stream sedimentation during construction, particularly tunnel construction, by erection of sediment barriers and operation of stilling ponds in streams which could be potentially affected.

·         Erect fences along the boundary of construction sites before the commencement of works to prevent tipping, vehicle movements, and encroachment of personnel into adjacent areas, particularly streams S1 to S4, forest beside the Pui O portal, Pui O Marsh and Pui O Taro Bed.

·         Regularly check the work site boundaries to ensure that they are not exceeded and that no damage occurs to surrounding areas.

·         Treat any damage that may occur to individual major trees in the adjacent area with surgery.

·         Reinstate temporary work sites/disturbed areas immediately after completion of the construction by on-site tree/shrub planting.  Tree/shrub species used should take reference from those in the surrounding area.

·         Prohibit and prevent open fires within the site boundary during construction and provide temporary fire fighting equipment in the work areas, particularly close to forest areas.

 

6.3.6     Residual Impact

There will be a loss of 0.15 ha of tall shrubland (with moderate ecological value), mainly located within South Lantau Country Park (0.12 ha), due to the construction of tunnel portals (Pui O and Tai Long Wan).  The loss of part of the tall shrubland will be mitigated through scrub compensatory planting.  The actual loss (tall shrubland and areas within South Lantau Country Park) will be considered as a residual impact, however, its loss would be compensated through site shrub planting.  With implementation of the above mentioned mitigation measures, no adverse residual impact is expected. 

 

6.3.7     Environmental Monitoring & Audit

The implementation of the terrestrial ecological mitigation measures stated in Section 6.3.5 should be checked as part of the environmental monitoring and audit procedures during the construction period as presented in the separate Environmental Monitoring and Audit Manual.

 

6.3.8     Conclusion

Altogether 15 habitat types were found in the Study Area, including forest, tall shrubland, shrubland-grassland mixture, wetland, abandoned farmland, farmland, rocky shore, sandy shore, backshore shrubland, mangrove, brackish mudflat, plantation, wasteland, village area and stream.  Based on the ecological conditions presented in the above sections, it is considered that the forest, wetland and mangrove have high ecological value.  The brackish mudflat, abandoned farmland, tall shrubland, stream (S1 to S4) are regarded as having moderate ecological value, while the other terrestrial habitats are common and typical habitats in Hong Kong and most of the species identified are common and widespread and therefore considered to be of low ecological value.

 

The proposed 132 kV circuits will mainly be located on existing road/ footpaths.  The impacts due to the construction and operation of the underground cable are considered to be low, and no adverse residual impact is expected.  The most sensitive issue is the direct habitat loss (0.125 ha of tall shrubland) within the South Lantau Country Park, in which no unacceptable residual impact will be expected.  Mitigation measures in the form of good construction practice and scrub compensatory planting are recommended to minimise potential disturbance to the surrounding environment. 

 

6.4       Marine Ecology

 

6.4.1     Assessment Methodology

The marine ecological impact assessment was performed using relevant information from the literature and field surveys.  All coastal habitats were examined within the Study Area (covering any area within 500m of the proposed work area), including intertidal and subtidal.  Areas of ecological interest that would be directly or indirectly affected by the proposed electric cable circuit including intertidal natural rocky shore, intertidal sandy shore (natural and modified), intertidal mudflat and mangrove were surveyed in more detail.  All the intertidal ecological surveys were undertaken between October and December 2000, and a dive survey focusing on the subtidal hard bottom at Chi Ma Wan Peninsula was undertaken in November 2000.

 

The specific methodologies of surveys of different habitats of ecological interest are presented below:

 

Dive Surveys at Chi Ma Wan

Reconnaissance Survey (Qualitative)

The main objective of this work was to identify marine ecological assemblages of high ecological value or conservation interest within the survey areas.  To fulfil this objective, dive surveys to search for corals and marine fauna of conservation importance were conducted along the proposed cable alignment.  A reconnaissance survey along the shore of the cable landing location was conducted to identify any areas that support assemblages of corals (Octocorals and/or hard corals). 

 

During the qualitative survey the positions and depth of any areas that support coral assemblages were recorded so that they could be surveyed quantitatively.

 

Quantitative Dive Survey

A quantitative dive survey was undertaken at each of the proposed cable landing points (Figure 6.11).  Identification of the location of highest coral coverage along the Chi Ma Wan sub-tidal shore was based on the results of the reconnaissance survey.  At each location five 10 m transects running parallel to the shore and one 100 m perpendicular transect along the proposed cable alignment were surveyed.  The ten metre quantitative video transects were undertaken to ascertain the percentage cover, colony density, species richness and diversity of corals at that location.  Categories of benthic attributes used in the surveys are presented in Table 6.16.  The outer seabed areas associated with each cable route were also investigated by the use of 100 m perpendicular transect.  The 100 m transects were run perpendicular to the shore to a distance deemed within safe limits for divers given the high level of shipping traffic between Cheung Chau and Chi Ma Wan.

 

Photographs of representative coral species located in the surveyed areas were taken using an underwater camera.  Video transects were recorded at each of the survey sites.  Each transect was filmed at approximately 40cm above the substrate and at a constant speed in compliance with standard protocols for coral surveys (no more than 10 metres per minute).  The video transects recorded a 40 cm swath of seabed.  The video camera was held perpendicular to the substrate to minimise parallax error and to keep the substrate in focus.

 

The quantitative surveys were conducted along each 10m transect at a depth range between -1m to -7m PD dependent on where corals were observed to be most abundant during the qualitative survey.  Information was recorded during the surveys concerning the physical nature of the site.  This information consisted of observations regarding the degree of exposure of the site to wave action, the nature of the substrate type and the topographic profile of the site.  Data on colony abundance of hard corals and octocorals (soft corals and gorgonians) was extracted from the video transects.  Counts of colony abundance of hard and soft corals were made for each site.  Wherever possible, hard corals were identified to species level by coral specialists using regional texts.

 

Table 6-16       Categories Used in the Quantitative Surveys – Benthic Attributes

 

Ecological

Substratum

Hard coral

Bedrock

Dead standing coral

Boulders

Soft coral (including gorgonians)

Sediment – sand and/or mud

Anemone beds

Rubble – dead coral fragments/shell

Other benthos: sponges, zoanthids, ascidians and bryozoans

Cobbles

Macro-algae

 

 

 

Intertidal Natural Rocky Shore

Intertidal natural rocky shore surveys were undertaken at three locations on the Chi Ma Wan Peninsula to characterise the assemblages present in the intertidal region.  Rocky shore organisms originated in purely marine habitats and have evolved and adapted to live on intertidal shores.  The extent of their adaptations to this habitat will dictate where they are found on the shore.  The more adapted a species is to terrestrial conditions the higher it will be found on the shore, causing zonation patterns.  The survey design involved sampling throughout all of the intertidal zones so that the vertical range of all species was represented.  At each site three 10 m wide horizontal (belt) transects were set up along the shore (no less than 50 m apart) and surveyed at three heights up the shore at 50 cm intervals perpendicular to the waterline starting at 1.5 m above Chart Datum.  On each transect, 6 quadrats (50 x 50 cm) were placed randomly to assess the abundance and distribution of flora and fauna.  All animals found in each quadrat were identified and recorded to species level so that density m-2 could be determined.  Sessile organisms such as barnacles, oysters and algae in each quadrat were not counted but estimated as percentage cover on the rock surface.

 

Intertidal Sandy Shore

On the intertidal natural sandy shore near Stream S3 at Pui O (Figure 6.12), five line transects were deployed from the low tide mark up to the high tide mark and the presence of organisms was noted.  No ecological survey was undertaken on the modified sandy shore (Pui O Gazetted Bathing Beach), but additional five line transects were deployed beside the beach near the interdial mudflat for reference.  At five equidistant points chosen along each of the transects, a 50 x 50 x 50 cm core was taken and all macrofauna visible to the naked eye within the core were identified and recorded.

 

Intertidal Mudflat and Mangrove

The intertidal mudflat at Pui O was surveyed at three tidal-levels, low, mid and high.  At each tidal level, 5 quadrats (25 x 25 cm) were placed randomly to assess the abundance and distribution of flora and fauna.  All animals found in each quadrat were identified and recorded to species level so that density m-2 could be determined.  Since all the recorded mangrove were found on the intertidal mudflat, the mangrove was surveyed as a part of the intertidal mudflat on the high tidal-level.  The vegetative community of the mangrove has been fully discussed in Section 6.3.2.

 

6.4.2     Baseline Conditions

The marine ecological habitats in the Study Area are mainly categorised into natural intertidal rocky shore, intertidal sandy shore (natural and modified), artificial seawall, intertidal mudflat, mangrove and subtidal habitats.  The coastal habitats are presented on Figure 6.12.  Intertidal field surveys were undertaken in December 2000 and the locations where field surveys were conducted are shown on Figure 6.13. 

 

Soft Bottom Benthos

 

A study of benthic assemblages throughout Hong Kong was undertaken by Shin & Thompson (1982).  The study concluded that the western waters of Hong Kong supports assemblages that are polychaete dominated (82.5 %).  Species diversity at locations near the Study Area was ranked intermediate (34.4 m-2) when compared with other areas in Hong Kong (values ranging from 32.4 to 38.4 m-2).  The mean number of individuals was 107.1 m-2 which is higher than the average for Hong Kong (101.4 m-2) and the mean biomass for the area was 23.9 g m-2, which is low compared to the overall mean biomass for Hong Kong at 35.2 g m-2. 

 

In March 2000 surveys were conducted of the infauna present in and around the South Cheung Chau Open Sea Disposal Ground (ERM 2000a).  Some of the sampling stations were close to Shek Kwu Chau just south of the Study Area.  The surveys recorded fine grain sediments that supported low abundance (405 m-2), and biomass (27.3 gm-2) of infaunal assemblages that were dominated by polychaete worms, corophiid amphipods and pinnotherid crabs.  Although the infauna were regarded as undisturbed the sediments supported relatively low ecological value assemblages compared with other sites in Hong Kong.  It is expected that the assemblages between Chi Ma Wan and Cheung Chau will be similar in composition and hence ecological value.

 

Subtidal Hard-Bottom Habitats

Apart from its southern and eastern shores, where the shallow subtidal area is initially rocky and coral-encrusted, the seabed of Hong Kong is soft and comprises a mixture of sand and mud which varies in detailed composition from place to place and under differing degrees of current scour (Morton et al. 1995).  In northwestern areas, as shown in the Study Area, under the influence of the Pearl River large quantities of silt are deposited regularly.  The subtidal hard-bottom habitats are mainly found in the Study Area fringing exposed coasts (ie Chi Ma Wan Peninsula).  The benthic assemblages are a continuum of those found in the lower shore of the littoral zone.

 

The general physical and biological description, seabed composition, and percentage composition of identified benthos including hard and soft corals of the three proposed cable landing locations (Figures 6.14 to 6.16) are provided below:

 

Location A

Location A has a narrow (<10 m) subtidal nearshore boulder seabed to a depth of -4 m C.D.  The boulders were of a large size 2-3 m diameter with wide vertical and horizontal surfaces and all had silt coverage.  The seabed gently shelved to a depth of -6 m C.D. and consisted of scattered large boulders with sand patches, once out from the nearshore area at a distance of 30 m the seabed was flat, barren and composed of fine sand/mud sediment.

 

The hard substratum was dominated by large boulders encrusted with encrusting and ball sponges (Halichondria spp., Callyspongia sp. and Tethya sp.), the common brown/orange bryozoan (Order: Cheilostomata, Genus: Schizoporellidae), the green-lipped mussel (Perna viridis), dead barnacles (Balanus spp.) and rock oysters (Saccostrea sp.).  Large quantities of sea urchins (Anthocidaris crassispina and Temnopleurus reevesi) and pink sea cucumbers Colochirus crassus were also recorded. General observations of the nearshore area revealed a few isolated colonies of soft and ahermatypic corals including white whip corals (Euplexaura sp., majority were <3 cm tall), soft coral Dendronephthya sp. and ahermatypic coral Tubastrea sp.  Small, scattered and encrusting colonies of the hard corals Psammocora superficialis  and Cyphastrea serailia were also recorded during the reconnaissance survey (Table 6-17).  

 

The subtidal habitat was heterogeneous with large sand and boulders patches as reflected by the large standard error in percentage composition The abundance of hard coral (Psammocora superficialis  and Cyphastrea serailia) recorded was extremely low in the nearshore at 3.25 ± 6.5 %.  A white whip gorgonian (Euplexaura sp.) and one orange whip gorgonian Euplexaura sp. were also recorded during the quantitative survey (Table 6-18).

 

 

Table 6-17      Percentage Composition of Substratum and Associated Benthos Recorded along Transects at Location A, B and C

 

 

Location A

Location B

Location C

 

Mean (%)

SE

Mean (%)

SE

Mean (%)

SE

Hard coral

3.25

6.50

1.47

2.93

0.40

0.80

Boulders/bedrock

56.82

33.69

88.13

10.72

74.00

9.05

Sand

32.33

36.91

7.33

8.26

17.47

5.47

Mussel Perna viridis

0.27

0.33

1.47

2.93

7.20

6.13

Sponge

4.53

7.23

0.53

0.78

0.53

0.78

Bryozoan

2.80

4.05

0.93

0.53

0.40

0.33

Algae

-

-

0.13

0.27

-

-

 

 

Table 6-18      Species of Hard and Soft Corals Recorded during Qualitative Survey within the Three Locations A, B and C at Chi Ma Wan Peninsula

 

 

Location A

Location B

Location C

Hard Coral

 

 

 

Psammocora superficialis

ü

ü

 

Cyphastrea serailia

ü

 

ü

Porites lobata

 

ü

ü

Goniopora stutchburyi

 

ü

 

Oulastrea crispata

 

ü

 

Soft Coral

 

 

 

Dendronephthya sp

ü

 

 

Euplexaura spp.

ü

ü

ü

 

 

The offshore seabed consisted of large boulders and sand patches shelving gently to a depth of 8.5 m where the seabed was barren and composed of fine sand/mud sediment.  Boulders were covered in a layer of sediment and dead encrusting barnacles (Balanus spp.).  There were several colonies of the ahermatyic coral Tubastrea sp. and one colony of the soft coral Dendronephthya sp. (white body with red spicules).  Ten individuals of the white whip coral (Euplexaura sp.) were recorded and four orange whip corals (Euplexaura sp.).  There were also several juvenile Euplexaura spp. noted.  All gorgonians were isolated colonies and not abundant.  Location A recorded the highest number of gorgonians for the three locations.

 

Location B

Similar to Location A there was a relatively narrow band of hard substratum (large boulders) gently shelving to a barren sand seabed.  The hard substratum had high sediment deposit and was dominated by large boulders encrusted with sponges (Halichondria spp., Callyspongia sp. and Tethya sp.), bryozoans, Perna viridis, dead large barnacle shells (Balanus spp.) and live rock oysters (Saccostrea sp.).

 

Extremely low percentage cover (1.47 ± 2.93 %) of hard coral, consisting of scattered, encrusting colonies of Porites lobata, Psammocora superficialis and Goniopora stutchburyi, was recorded during the quantitative survey (Tables 6.17 & 6.18).  The whip coral Euplexaura sp. and hard coral Oulastrea crispata were also recorded from this location.

 

The perpendicular transect survey indicated the seabed was composed of large boulders and sand patches, whereas the boulder surfaces were heavily encrusted with dead barnacles (Balanus spp.) and high sediment deposit.  The benthos recorded along the perpendicular transect included Perna viridis, encrusting sponges Halichondria sp., knobbly sponges Callyspongia spp., ball sponge Tethya sp., bryozoans, rock oysters Saccostrea sp. and short-spined sea urchins Anthocidaris crassispina.  A colony of whip coral Euplexaura sp. as well as several discarded gill nets were also recorded during the survey.

 

Location C

Location C was the most northerly site surveyed at Chi Ma Wan Peninsula.  Similar to Location A and B there was an extremely narrow band of hard substratum (medium-sized boulders) gently shelving to a barren sand seabed.  A relatively low species diversity and abundance of benthos were recorded in Location C.

 

The surfaces of the boulders were dominated by Perna viridis and barnacles.  The hard coral coverage was the lowest recorded among the three locations (0.40 ± 0.80 %), with only Porites lobata and Cyphastrea serailia recorded (Tables 6.17 & 6.18).  One individual of whip coral Euplexaura sp. was recorded during the survey.

 

No soft corals were observed along the perpendicular transect during the survey.  Other organisms recorded included black short-spined Anthocidaris crassispina and decorator urchins Temnopleura reevesi.

 

A narrow band of large-medium sized boulders dominated the nearshore subtidal areas of the three proposed cable landing locations at Chi Ma Wan Peninsula.  A high sediment deposit was observed on all hard substrate surfaces and the existing benthos dominated by encrusting organisms such as barnacles (dead), rock oysters, sponges and bryozoans.  Hard and soft coral coverage was extremely low with scattered distribution.  Location A possessed the highest number of soft corals and percentage cover of hard corals although the mean value was less than 4 %.

 

In 1999 dive surveys were conducted around Penny’s Bay, Pa Tau Kwu and Sze Pak Wan as part of the Theme Park EIA (ERM 2000b).  The coral community at Penny’s Bay was composed of a shallow, thin veneer of common faviid coral species.  Twelve hard coral species were recorded and percent live coral cover was generally low (9%), however, the inner part of Penny’s Bay appeared to still support a relatively healthy, simple coral community.  When compared to other sites in Hong Kong, especially those in the western harbour area, the assemblages were composed of a high number of coral colonies with a medium to high percentage cover and classified as of high ecological value.  In comparison to areas of conservation value in the eastern waters of Hong Kong, such as South Ninepin Island or Ping Chau, the assemblages were of lower diversity and abundance.  Surveys conducted by AFCD in the western waters of Hong Kong have reported the hard coral species recorded along the Chi Ma Wan coastline from a number of other locations, including Peng Chau, Kau Yi Chau, Siu Kau Yi Chau, Chau Kung To, Tai Lei and Silver Island.  The findings of the AFCD surveys emphasise the widespread nature of the corals recorded in the present study.

 

The results of the present survey at Chi Ma Wan recorded soft and hard coral assemblages of lower abundance and diversity than those at Penny’s Bay and consequently are assigned a lower ecological value. 

 

Natural Intertidal Rocky Shore

Rocky shore organisms originated in purely marine habitats and have evolved and adapted to live on intertidal shores.  The extent of their adaptations to this habitat will dictate where they are found on the shore.  The more adapted the species is to terrestrial conditions, the higher it will be found.  This causes zonation patterns.  Their recruitment period and the primary productivity of the shore will affect the abundance of intertidal organisms.  Typical exposed rocky shore communities consist of periwinkles, barnacles and limpets.  Encrusting algae are common in the low intertidal zone. 

 

 

In total, 15 species of animals and 3 species of macroalgae were recorded on the rocky shores within the Study Area.  Animals recorded on the shores at the surveyed sites were largely molluscs.  The most abundant were herbivorous molluscs, including the limpets (Notoacmaea schrenkii, Patelloida saccharina and Cellana toreuma) on the mid (2.0 m above Chart Datum) and low (1.5 m above CD) shore, and the periwinkles (Nodilittorina radiata, N. vidua and N. trochoides) on the high (2.5 m above CD) and mid shore.  The predatory gastropod Thais clavigera (the common dogwhelk) was also recorded in the low shore region.  Sessile filter-feeding barnacles such as the acorn barnacle (Tetraclita squamosa) were also common on the shores (Table 6-19).  Macroalgae (Hildenbrandia occidentalis, Ulva fasciata and Corallina sp.) and Bivalves such as the mussels (Septifer virgatus) and the rock oyster (Saccostrea cucullata) were also seen on the shores but in low abundances. 

 

Table 6-19       Density (m-2) of Intertidal Fauna and Percentage Cover (%) of Sessile Fauna and Flora Recorded at South-east of Chi Ma Wan Peninsula

 

Species

Location A

Location B

Location C

Snail

 

 

 

Nodilittorina radiata

181.78

107.11

80.00

Nodilittorina vidua

97.56

28.22

22.89

Nodilittorina trochoides

4.89

0

0

Thais clavigera

0.44

0.44

2.44

Monodonta labio

0

0.22

0

Limpet

 

 

 

Cellana grata

0.67

1.33

0.89

Cellana toreuma

6.22

3.11

4.89

Notoacmaea shrenkii

20.89

16.22

18.44

Patelloida saccharina

7.33

19.33

16.22

Siphonaria japonica

0

0

1.11

Chiton

 

 

 

Acanthopleura japonica

0.22

2.67

8.67

Barnacle (% cover)

 

 

 

Tetraclita squamosa

13.2

19.4

20.2

Capitulum mitella

0.3

0.8

3.2

Bivalve (%cover)

 

 

 

Septifer virgatus

0

0.4

6.4

Saccostrea cucullata

0.7

2.1

0.1

Macroalgae (%cover)

 

 

 

Hildenbrandia occidentalis

4.3

1.6

0

Ulva fasciata

0

0

0.1

Corallina sp.

1.0

1.7

0

 

Natural Intertidal Sandy Shores

 

In the lee of headlands or within shallow bays, wave action is reduced and there is an accumulation of sand and detrital material.  Exposed sandy beaches are relatively unstable environments and the fauna is sparse.  However, with increasing shelter substrate stability allows for the development of a rich community of burrowing animals.  Where a river or stream discharges to a sandy shore, forming an estuary, a greater percentage of very small particles are found, due to the deposition of terrigenous material eroded by the river.  Such shores retain water more readily and the beach comprises black, organic-rich or compacted mud.  Typical sandy shore communities consist of numerous species of burrowing crabs, potamid gastropods (e.g. Batillaria multiformis), bivalves and worms.

 

The Study Area contains several small sandy shore areas which are illustrated on the habitat map presented on Figure 6.12.  Only one organism, the bivalve Fulvia mutica, was recorded in the sandy shore close to the proposed portal area at Pui O during the survey.

 

Modified Sandy Shore (Gazetted Beach)

Pui O Beach is the only gazetted beach found within the Study Area.  It was the beach of water quality categorised as "Good" under EPD's Beach Water Quality Monitoring Programme (EPD, 1999).  Beaches that have been developed for recreational use (such as that at Pui O) appear almost devoid of life (Morton et al 1996).  The exception to this are wave exposed beaches in the surf where unique assemblages of surf clams, mole crabs and hermit crabs are present.  No beaches of this type are found in the Study Area. 

 

Artificial Seawall

The majority of the coastal areas on Cheung Chau have been reclaimed and lined with vertical artificial seawalls.  Few surveys have been conducted on the colonization of organisms on artificial seawalls in Hong Kong, however, fouling organisms have been anecdotally recorded as common on artificial seawalls, wharf files and other marine structures (Morton & Morton 1983; Huang et al. 1992; Binnie 1996, 1997).  Various species of algae, coelenterates, ascidians, bryozoans, sponges, crustaceans, molluscs and polychaetes are also commonly observed on these artificial structures.  Therefore, it can be presumed that species commonly found on these surfaces in Hong Kong waters will be found on the artificial seawalls within the Study Area.

 

Intertidal Mudflat and Mangrove

Mudflats are usually found where a river or stream discharges freshwater into a bay, and the eroded soil carried by streams is deposited as mud or silt.  In general, the upper part of a mudflat develops into mangrove in tropical areas.  The fauna of soft mud flats consists of mudskippers, grapsid and sesarmid crabs and a few browsing ceriths on the surface with burrowing bivalves and worms as the infauna (Morton & Morton 1983).

 

The substrata of the mudflat at Pui O is composed of mud and sand.  Findings of the surveys for this Study indicated that the mud flat fauna was dominated by the snails, including the cerithid (Cerithidea djadjariensis), the neritid (Clithon oualaniensis) and the nassarid (Nassarius festivus).  Fiddler crabs (Uca spp.) and potamid (Batillaria multiformis) were also common on the mud flat (Table 6-20).  The mudflat (approximately 4.2 ha) is likely to be less disturbed with good conditions.  The ecological value of the habitat is regarded as high based on the results obtained from the site survey.

 

 

Table 6-20      Density (m-2) of Intertidal Fauna Recorded on Mudflat at Pui O

 

Species

High Tidal Level

(incl. mangrove)

Mid Tidal Level

Low Tidal Level

Molluscs

 

 

 

Batillaria multiformis

0

3.2

9.6

Cerithidea djadjariensis

0

275.2

89.6

Cerithidea microptera

9.6

0

0

Clithon spp.

0

0

265.6

Terebralia sulcata

6.4

0

0

Nassarius festivus

0

25.6

150.4

Crustacean

 

 

 

Uca chlorophthalmus crassipes

25.6

0

0

Uca lactea

0

22.4

0

Pseudosesarma patshuni

3.2

0

0

Hermit crab

0

0

6.4

 

Mangroves are regarded as of ecological importance as they provide food, shelter and breeding grounds for various pelagic and coastal fisheries and birds (Tam & Wong 1997).  The EIA-TM (Annex 8) indicates that established mangrove stands of any size should be regarded as important habitat types and, therefore, require ecological impacts assessments to be performed.  In Hong Kong, the number and area of mangrove habitats in Hong Kong has been greatly reduced in the past due to reclamation and infrastructure development over the past decades (Tam & Wong 1997).

 

Mangrove refers to habitats with woody vegetation dominated by salt-tolerant species found on inter-tidal areas.  Three patches of mangrove (with total 1 ha) were found at Pui O.  Major mangrove species found in the Study Area included Excoecaria agallocha, Kandelia candel and Aegiceras corniculatum, for details of the floristic and structural diversity of the mangrove refer to Section 6.3.2.

 

 

Marine Mammals

 

The review below is based on stranding records collected in Hong Kong since 1973 (Parsons et al. 1995), and detailed studies conducted on the ecology of Hong Kong's small cetaceans since 1994 (Jefferson 1997; Jefferson and Leatherwood 1997; Parsons 1997; Jefferson 1998; Parsons 1998; Jefferson and Braulik 1999; Hung 2000; Jefferson 2000).  The Indo-Pacific Humpback Dolphin, Sousa chinensis, and the Finless Porpoise, Neophocaena phocaenoides, are the only species of marine mammal regularly sighted in Hong Kong waters.

 

Indo-Pacific Humpback Dolphin (Sousa chinensis)

 

Humpback dolphins (also known locally as Chinese white dolphins) are found in all the waters surrounding Lantau Island (Parsons et al. 1995; Jefferson 2000), whilst the area to the north of Lantau appears to be by far the most important habitat in Hong Kong.  North Lantau is heavily used in all seasons, and the western portion of the North Lantau area has high densities of dolphins throughout the year (Jefferson 1998, 2000).  North Lantau is the only place in Hong Kong where dolphins are seen year round.  Pods of dolphins are most frequently sighted in the western part of these waters around the Sha Chau and Lung Kwu Chau Marine Park and the Chek Lap Kok platform.

 

The South Lantau and East Lantau areas are used much less extensively and only appear to be important seasonally.  The waters to the south of Penny's Bay and east of the Pa Tau Kwu and Fa Peng shores showed a seasonal pattern in sightings of the dolphin (Jefferson 1997).  Dolphins do not normally appear to use the area in spring or early summer and they were largely observed during autumn and winter months.  However, their abundance and density recorded in the area were very low when compared to North Lantau (the highest East Lantau sighting rate was only 15% of the yearly average for North Lantau). 

 

South Lantau (mainly the western portion around Fan Lau and the Sokos Islands) is used by dolphins primarily in the summer and autumn seasons, when there are estimated to be 20 and 17 dolphins present, respectively (only about 3 dolphins are estimated to be present in winter, and none in spring - Jefferson 2000). 

 

Individual movements and ranging patterns of dolphins have recently been investigated (Hung 2000).  It was found that, while most dolphins apparently do not use the East Lantau area, some individuals that occur primarily in North Lantau use the East Lantau area as part of their range.  At least one individual that used to occur primarily in East Lantau (EL07) may have shifted its home range to the North Lantau area (Hung 2000).  As the waters within and in proximity of the Study Area show few sightings of dolphins (Figure 6.12), the area does not appear to be highly utilised by dolphins.  Therefore, it is unlikely that this area contains critical Sousa chinensis habitat.

 

Finless Porpoise (Neophocaena phocaenoides)

 

Finless porpoises occur in the waters to the south and east of Lantau Island (Parsons et al. 1995; Jefferson and Braulik 1999).  The entire South Lantau area is used seasonally by finless porpoises in winter and spring, when there are estimated to be 10 and 25 porpoises present, respectively (Jefferson and Braulik 1999).  Interestingly, these are the seasons when humpback dolphins are not present in the area.  Both strandings and sightings indicate that East Lantau is used by finless porpoises (Parsons et al. 1995; Jefferson and Braulik 1999).  No sightings of Finless Porpoise have been recorded within the Study Area and only a few sightings were observed in the vicinity of the Study Area (Figure 6.12).  The marine waters are thus unlikely to contain critical habitats for Neophocaena phocaenoides. 

 

 

6.4.3     Evaluation Criteria

According to the EIA-TM Annex 8 the ecological value/importance of a habitat can be evaluated using the following criteria:

 

·         Naturalness;

·         Size;

·         Diversity;

·         Rarity;

·         Re-creatability;

·         Ecological Linkage;

·         Potential value;

·         Nursery Ground;

·         Age; and,

·         Abundance.

 

Subtidal Soft-Bottom Habitats

The criteria listed above have been applied to the information gathered or reviewed on the marine ecology of the subtidal soft bottom benthic habitats within the Study Area in order to determine their ecological value.  The application of these criteria has led the habitat to be classified as of low ecological value (Table 6-21).

 

Table 6-21       Ecological Value of the Subtidal Soft Benthos Assemblages within the Study Area

 

Criteria

Subtidal Soft Benthos

Naturalness

The habitat between Chi Ma Wan Peninsula and Cheung Chau (ie of the Adamasta Channel) where the submarine cables will be laid is a navigation channel and is, therefore, subject to propeller scour disturbance. 

Size

The submarine cable laying works will involve the loss of 0.5 hectares of soft bottom subtidal habitats along the submarine cable alignment. 

Diversity

The assemblages are of similar diversity when compared to other areas of Hong Kong.

Rarity

No organisms were found that are considered as rare.

Re-creatability

The habitat cannot be re-created on site.

Ecological Linkage

The surrounding environment contains many other areas of soft substrate.

Potential Value

It is unlikely that the site can develop conservation interest.

Nursery Area

None identified in the review.

Age

The fauna appear to be typical of those present in Hong Kong's soft benthos.  The sediments in the habitat are constantly accreting and eroding and the fauna present there are typically short lived (less than 2 years).

Abundance

Abundances appear to be similar when compared to other areas of Hong Kong.

SUMMARY

The sediments support average diversity and abundance of benthic organisms that are typical of Hong Kong's benthos. 

Ecological Value - Low.

Note:       n/a:          Not Applicable

 

 

Subtidal Hard-Bottom Habitats

The criteria listed above have been applied to the information gathered or reviewed on the marine ecology of the subtidal hard-bottom benthic habitat within the Study Area.  The habitat has been classified as of low ecological value (Table 6-22). 

 

Table 6-22       Ecological Value of the Subtidal Hard-Bottom Habitat within the Study Area

 

Criteria

Subtidal Hard-Bottom Habitat

Naturalness

There is evidence at the site of indirect impacts to the assemblages through poor water quality and deposited sediments.

Size

The assemblages extend along the entire length of the natural rocky coast of Chi Ma Wan Peninsula (approx. 10 km), but are found along a narrow band at depths of 3 - 4 m below chart datum.

Diversity

A total of five species of hard corals and two species of soft corals were recorded within the Study Area, which represents a relatively low diversity. 

Rarity

All of the species of corals are commonly recorded on rocky coasts in the western and eastern waters of Hong Kong.

Re-creatability

The habitat can be recreated through the deployment of artificial reefs.

Ecological Linkage

It is suspected that the surrounding environment contains similar subtidal habitats.

Potential Value

It is unlikely that the site can develop conservation interest.

Nursery Area

None identified during the literature review or field surveys.

Age

The subtidal fauna is generally short lived apart from the isolated colonies of hard corals which are slow growing and long lived.  

Abundance

Abundances of hard and soft corals appear to be of low abundance when compared to the western as well as the eastern waters of Hong Kong.

SUMMARY

The subtidal fauna appears to be of low diversity and abundance with few colonies of hard and soft corals present. 

Ecological Value - Low.

Note:       n/a:          Not Applicable

 

 

Intertidal Habitats

The criteria listed above have been applied to the information gathered or reviewed on the marine ecology of the intertidal habitats within the Study Area in order to determine their ecological value.  The application of these criteria has led the intertidal mudflat and mangrove to be classified as high, intertidal rocky shores as medium, whereas, the intertidal sandy shores and artificial seawall have been classified as of low ecological value (Tables 6.23 to 6.25).

 

Table 6-23       Ecological Value of Intertidal Mudflat and Mangrove Within the Study Area

 

Criteria

Intertidal Mudflat

Mangrove

Naturalness

The habitat is relatively undisturbed by human impact.

The mangrove is relatively undisturbed by human impact.

Size

The total size of the intertidal mudflat is approximately 4.2 ha.

The total size of the mangrove is approximately 1 ha.

Diversity

The intertidal communities are typical of mudflat in Hong Kong.

The intertidal communities are typical of mangrove in Hong Kong.

Rarity

No species recorded are considered rare.

No species recorded are considered rare.

Re-creatability

The habitat can be re-created.

The habitat can be re-created.

Ecological Linkage

The surrounding environment contains few similar intertidal habitats.

The surrounding environment contains few similar intertidal habitats.

Potential Value

The site can develop conservation interest.

The site can develop conservation interest.

Nursery Area

Mudflats are reported to be nursery habitats for many species.

Mangroves are reported to be nursery habitats for many species.

Age

n/a for these assemblages as the life cycle of the fauna is very short.

Unknown.  The mangroves trees were mature and in good condition.

Abundance

Assemblages showed moderate abundance and appear to be typical of other intertidal mudflats in Hong Kong.

Assemblages showed moderate abundance and  appear to be typical of other mangroves in Hong Kong.

SUMMARY

The intertidal mudflat supported assemblages similar to other mudflats in Hong Kong. The habitat appears to have suffered little human disturbance.

Ecological Value - High.

The mangrove supported assemblages similar to other mangroves in Hong Kong.  The habitat appears to have suffered little human disturbance.

Ecological Value - High.

Note:       n/a:          Not Applicable

 

 

Table 6-24       Ecological Value of Rocky Shore and Sandy Shore Within the Study Area

 

Criteria

Rocky Shore

Sandy Shore

Naturalness

The habitat is undisturbed by human impact due to the steep rocky terrain of much of the intertidal zone and remoteness of the shore.

The sandy shore at Tai Long is relatively undisturbed by human impact due to its remoteness. 

The sandy shore at the Pui O Portal is relatively undisturbed due to its remoteness.

The sandy beach at Pui O is highly disturbed by human impacts through development for recreation as a gazetted beach.

Size

The area covers almost the entire length of Chi Ma Wan Peninsula (approx. 10 km).

The shore at Tai Long is approx. 500 m.

The shore at the Pui O Portal is approx. 200 m.

The Pui O Beach is approx. 900 m. 

Diversity

The intertidal communities are typical of exposed rocky shores in Hong Kong.

Field surveys show that the sandy shore at the Pui O Portal are of low species diversity.  The shore at Tai Long Wan is likely to support assemblages of similar diversity.

Assemblages at the Pui O gazetted beach are thought to be of low diversity as it is a highly disturbed habitat.

Rarity

No species recorded are considered rare.

No species recorded are considered rare.

Re-creatability

The habitat can be re-created.

The habitat can be re-created.

Ecological Linkage

The surrounding environment contains similar intertidal habitats.

The surrounding environment contains few other similar intertidal habitats.

Potential Value

Unlikely that the site can develop conservation interest.

Unlikely that the site can develop conservation interest.

Nursery Area

None identified during the literature review or field surveys.

None identified during the literature review or field surveys.

Age

n/a for these assemblages as the life cycle of the fauna and flora is very short.

n/a for these assemblages as the life cycle of the fauna is very short.

Abundance

Assemblages were of moderate abundance and appear to be typical of other exposed shores in Hong Kong.

Assemblages at the Pui O Portal were of low faunal abundance.  This finding is typical of semi-exposed sandy beaches in Hong Kong.  The shore at Tai Long Wan is likely to support assemblages of similar abundance.

Reviewed literature indicates that gazetted beaches that are frequently used for recreational purposes supporting low abundance of organisms. 

SUMMARY

The fauna of the intertidal region appears to be typical of exposed shores in Hong Kong.  The sites appear to have suffered little human disturbance.

Ecological Value - Medium.

The sandy shores at Tai Long Wan and the Pui O Portal support assemblages of low diversity and abundance and are typical of other semi-exposed beaches in Hong Kong. 

Literature reviews indicate that the gazetted beach at Pui O is likely to support low faunal diversity and depauperate assemblages typical of other recreational beaches in Hong Kong.

Ecological Value - Low.

Note:       n/a:          Not Applicable

 

 

Table 6-25       Ecological Value of the Artificial Seawalls in the Study Area

 

Criteria

Artificial Seawalls

Naturalness

The habitat is disturbed by human impacts through stormwater discharges and development of residential & industrial areas.

Size

The Cheung Chau artificial seawall is approximately 1.2 km long, the majority of which is vertical.

Diversity

Reviewed literature indicates that sloping artificial seawalls support similar assemblages to natural intertidal shores.  Vertical seawalls, however, support lower diversity than natural shores.  Corals have been reported colonising the subtidal sections of sloping artificial seawalls in North Lantau.

Rarity

No rare species were reported in the literature reviewed.

Re-creatability

The habitat can be re-created.

Ecological Linkage

The surrounding coastlines are composed of a mixture of natural and artificial intertidal shores.

Potential Value

The site can develop conservation interest if over time and under favourable conditions it becomes colonised by hard or soft corals.

Nursery Area

None identified during the literature review.

Age

The seawalls were constructed more than 10 years ago.

Abundance

Reviewed literature indicates that artificial seawalls support similar assemblages to natural intertidal shores.  Corals have been reported colonising the subtidal sections of sloping artificial seawalls (e.g. tetrapods, dolosse blocks or rubble mound) where water quality is good.

SUMMARY

The fauna of the intertidal region of the artificial seawalls are reported to support similar diversity and abundance of intertidal organisms as natural seawalls.  Subtidal portions of sloping seawalls can also support coral growth, however, this depends on the age of the seawall and environmental conditions of the area.  The Cheung Chau seawalls are largely vertical and as such do not support communities of more than low ecological value.  The breakwaters of the Cheung Chau Typhoon Shelter are unlikely to support assemblages that are of more than low ecological value as the waters in the typhoon shelter are generally subject to pollution due to vessels, storm-drains and surface-runoff.

Ecological Value - Low.

 

 

Marine Waters within the Study Area

The same assessment criteria have been applied to the marine waters within the Study Area with regard to the usage of the area by protected species of marine mammals.  This habitat has been classified as of low ecological value depending largely on the use of the area by protected species of marine mammals (Table 6-26).

 

Table 6-26       Ecological Value of the Marine Waters within the Study Area

 

Criteria

Marine Waters between Chi Ma Wan Peninsula and Cheung Chau

Marine Waters off Pui O

Naturalness

Disturbed as a result of fishing activities and in close proximity to some of the busiest shipping lanes in Hong Kong.

Disturbed as a result of recreation activities at the Pui O gazetted beach.

Rarity

No dolphins or porpoises have been recorded in the immediate area.

No dolphins or porpoises have been recorded in the immediate area.

Re-creatability

n/a

n/a

Ecological Linkage

Preferred marine mammal habitat occurs to the north and west of Lantau.

Preferred marine mammal habitat occurs to the north and west of Lantau.

Potential Value

Limited value due to heavy navigational use of the area.

Limited value due to heavy recreational activities in the area.

Nursery Area

No nursery areas were identified in the review of baseline conditions.

No nursery areas were identified in the review of baseline conditions.

Abundance

Marine mammals have not been recorded within the immediate area.

Marine mammals have not been recorded within the immediate area.

SUMMARY

No marine mammals have been sighted in the immediate area.

Ecological Value - Low for both species.

No marine mammals have been sighted in the immediate area.

Ecological Value - Low for both species.

 

6.4.4     Impact Assessment

Sensitive receivers for marine ecological impact assessment are identified to assess the potential impacts to resources outside the reclamation areastemporary working platform as a result of perturbations to water quality, during both the construction and operation phases.  Information presented in the review of literature and in the results of the field surveys has indicated that the Study Area contains the following marine ecology sensitive receivers:

 

·                     High ecological value mangrove habitat at Pui O.

·                     High ecological value intertidal mudflat assemblages at Pui O. 

·                     Medium ecological value intertidal rocky shores at Tai Long Wan Landfall.

 

It is considered important to the environmental acceptability of the Project that construction and operational activities of the proposed cable installation do not unacceptably impact these sensitive receivers.

 

Potential Sources of Impact

Impacts to marine ecological resources arising from the construction works may be divided into those due to direct disturbances to that habitat and those due to perturbations to key water quality parameters.

 

Construction Phase

            Direct Impacts

            Direct impacts to marine ecological resources include habitat loss due to the laying of the submarine cable circuit in the Adamasta Channel between Chi Ma Wan Peninsula and Cheung Chau, and the reclamation workstemporary working platform at the Pui O Portal. 

            The submarine cables will be covered by concrete slabs of approximate dimensions 2m(W)x3m(L)x0.3m(D) as protection against maintenance dredgers. They will be placed on the seabed by barge and crane or diver. The concrete slabs will gradually be affected by natural sedimentation patterns in the area and covered, thereby re-establishing the base stratum. It takes about 3 months to complete the installation of protective concrete slabs.

 

            Subtidal Soft Benthos:  The submarine cables are proposed to be laid by “direct burying method” below the existing seabed to a depth of not less than 3 m deep with 200 mm thick concrete slab directly laid on the seabed along the cable alignment.  The soft bottom seabed surface along the cable alignment will be replaced by hard concrete slab. 

            Findings from a review of the literature indicate that the benthic assemblage in areas where the cables will be laid are dominated by polychaetes and similar to elsewhere in Hong Kong in terms of species composition and abundance.  All the species recorded occur frequently in Hong Kong and no rare species were observed.  As a result, the assemblages were regarded as of low ecological value.

            As the proposed cable laying works will result in the temporarypermanent loss of 0.5 hectares of subtidal soft benthic habitats, which are of low ecological value, the severity of the impact is not anticipated to be unacceptable.

Artificial Seawalls (Breakwater):  The proposed submarine cables will pass through the existing breakwater of the Cheung Chau Typhoon Shelter.  Armour rock of the breakwater will be temporarily removed for laying the proposed submarine cables.  The submarine cables will be laid on precast concrete trough and protected with concrete prior to backfill with armour rock to the original status.  As breakwaters are artificial habitats and support assemblages of low ecological value, and they will be backfilled with armour rock to the original status once the cable laying works are complete, no adverse direct impacts to the artificial habitat are likely to occur.  

 

Subtidal Hard Bottom Habitats:  For the landfall at Tai Long Wan a concrete cable trough will be used for installing the shore end segment of the proposed submarine cables.  Protective cover may be required for protecting the submarine cables when located at shallow water at Tai Long Wan.  Field surveys indicate that the subtidal hard bottom habitats support assemblages of low diversity and abundance with few colonies of hard and soft corals present.  As the cable will be installed by means of cable trough, which is small in diameter (approx. 0.3 m), it is anticipated that the direct impacts to the low ecological value subtidal hard bottom habitats are unlikely to be severe. 

 

Intertidal Habitats:  Field surveys undertaken at the rocky shores at the Tai Long Wan landfall site show that the habitats support intertidal communities that are typical of exposed rocky shores in Hong Kong and are considered as of medium ecological value.  The proposed cable landing works at the Tai Long Wan landfall will only affect a small area of the habitat which is unlikely to represent an unacceptable ecological impact.  Over time it is expected that rocky shore organisms will colonise the concrete covered cable trough and similar communities will be re-established.

 

The proposed reclamation works temporary working platform at the Pui O Portal will result in the temporary loss of 0.01855 ha intertidal sandy shore habitats.  The sandy shore survey conducted at the proposed Portal site indicates that the habitat supports assemblages that are of low diversity and abundance and is considered to be of low ecological value.  As the area to be directly affected by the formaproposed reclamation works temporary construction of thea temporary working platform, which will be reinstated upon completion of excavation of the tunnel is of low ecological value and is small in size (0.018 ha ha), the impact is considered as acceptable.  No direct loss of habitat will occur at the high ecological value mangrove or mudflat at Pui O.

 

Indirect Impacts

 

            Indirect impacts to marine ecological resources during the construction phase include sediment release associated with the proposed cable laying activities in the seabed area in the Adamasta Channel between Chi Ma Wan Peninsula and Cheung Chau, and the reclamation workstemporary working platform at the Pui O Portal, as well as impacts through high and low frequency underwater noise and increases in vessel traffic associated with the construction works.  Potential impacts to water quality from sediment release are listed below:

·         increased concentrations of suspended solids (SS);

·         a resulting decrease in DO concentrations; and,

·         an increase in nutrient concentrations in the water column.

 

Suspended Solids (SS)

 

Subtidal Soft Benthos: Sessile organisms within the benthos will be susceptible to the effects of increased sediment loads.  Effects can be lethal or sublethal (e.g. reduction in reproductive potential due to stress incurred by constantly having to flush out the depositing material).  The effects of sedimentation on organisms will also depend on other factors, such as an organism's tolerance, growth orientation of sessile organisms and water movement.  Infaunal benthic assemblages in Hong Kong are located in soft muds and sands which are frequently disturbed by storms, seabed currents and constant trawling activity which reworks the sediments creating high suspended sediments loads in the water column.  Benthic invertebrates are, therefore, unlikely to be adversely affected by the proposed reclamation activities formation of thea temporary working platform at the Pui O Portal and the submarine cable laying works in the Adamasta Channel.

 

The water quality assessment undertaken for the proposed Project indicates that the potential water impacts associated with the proposed construction activities are anticipated to be acceptable as indicated by predicted compliance with the applicable WQOs.  Impacts to benthic assemblages immediately outside of the reclamationtemporary working platform site and the cable laying area are expected to occur temporarily and be confined to small areas.  Based on the assumption that eventually these affected areas will be recolonisied by fauna typical of the area, then the temporary indirect disturbance to this low ecological value assemblage is deemed acceptable.

 

 

Subtidal Hard Surface Habitats:  Soft corals, gorgonians, hard corals and anemones may be injured by both high suspended sediment concentrations and high deposition rates.  Damage (sublethal effects) or mortality (lethal effects) can result from a reduction in light penetration which kills the photosynthesizing symbiotic algae associated with the hard corals, and also from the deposition of sediment onto the corals surface which physically blocks the respiratory and feeding apparatus.  An assessment of the effects of sand dredging at West Po Toi (ERM 2001) assumed that prolonged turbidity and a sustained sedimentation rate of 10 mg cm-2 day-1 (= 0.1 kg m-2 day-1) was damaging to corals.  Negative impacts to corals may also arise from increased SS in the water column.  As water quality perturbations resulting from the proposed Project works are predicted to be minor and compliant with the WQO it is not anticipated that sediment deposition rates will exceed 0.1 kg m-2 day-1 along the coast at Tai Long Wan.

 

Intertidal Habitats:  Intertidal habitats within the Study Area which may be affected by the cable laying and reclamation activities and formation of the temporary working platform include the high ecological value mangrove and intertidal mudflat at Pui O, the medium ecological value intertidal rocky shore habitat, and the low ecological value sandy shore at Tai Long Wan and gazetted beach at Pui O.  Water quality assessment results predict that unacceptable elevations of SS concentrations are unlikely to occur.  Consequently, unacceptable impacts to these intertidal habitats are thus not anticipated. 

 

Marine Mammals:  Mobile animals such as marine mammals have the ability to avoid areas where SS levels have increased, thus avoiding any impacts.  Impacts can occur to these mammals as an indirect result of increased SS levels.  The cable laying activities and the reclamation workstemporary working platform associated with the Project may cause perturbations to water quality which have the potential to impact the fisheries resources of the South-east Lantau area.  The Indo-Pacific Humpbacked Dolphin, Sousa chinensis, in Hong Kong waters feed primarily on fish.  The dolphins are often seen associated with pair trawlers which are likely to provide them with increased feeding opportunities; this appears to be confirmed by the limited data available from stomach contents analyses.  By examining the stomachs of 12 stranded dolphins, Jefferson (1998) found that, with the exception of one individual’s stomach content, which contained some squid remains, only fish had been consumed.  At least twenty species of fish belonging to 13 families were found in the stomach of these stranded dolphins. The most abundant families were anchovies - Engraulidae, croakers - Sciaenidae, and sardines - Clupeidae accounting for more than 81% of all fish in the stomachs of the stranded dolphins.

 

The Finless Porpoise, Neophocaena phocaenoides, is thought to be an opportunistic feeder with known prey including crustaceans (shrimps and prawns), cephalopods (squid and octopus) and small pelagic fish of low commercial value (anchovies, croakers and sardines).  They are thus likely to be affected by any significant changes in key water quality parameters arising from the project works.  A deterioration in water quality is likely to cause these mobile fish to move out of the area thus interfering with the dolphin and porpoises normal feeding patterns. 

 

The water quality assessment undertaken for the Project indicates that the construction activities are unlikely to adversely affect the marine water quality within and in the vicinity of the Study Area.  In addition, the marine areas within and in the vicinity of the Study Area show few sightings of marine mammals and therefore the areas are not a critical habitat for the animals.  It is thus expected that unacceptable impacts to the marine mammals arising from elevated SS levels will not occur.

 

            Dissolved Oxygen

 

The relationships between SS and DO are complex, with increased SS in the water column combining with a number of other effects to reduce DO concentrations in the water column.  Elevated SS (and turbidity) reduces light penetration, lowers the rate of photosynthesis by phytoplankton (primary productivity) and thus lowers the rate of oxygen production in the water column. This has a particularly adverse effect on the eggs and larvae of fish, as at these stages of development, high levels of oxygen in the water are required for growth due to their high metabolic rate.  Although respiratory responses and tolerance of hypoxia were studied in two marine fish (Wu & Woo 1984), it is not possible to set critical thresholds for this parameter for other marine organisms due to lack of tolerance data for species in Hong Kong.  DO depletions are most likely to affect sessile organisms as they cannot move away from areas where DO is low (unlike mobile species such as fish). 

 

As the scale of reclamation temporary working platform is very small (0.055 ha180m2) and the methodology used for cable laying are unlikely to severely affect water quality, impacts resulting from depletions of DO as a result of the construction activities associated with the proposed Project are unlikely to be severe.  It is thus expected that unacceptable impacts to the marine ecological resources present in the vicinity of the reclamation temporary working platform and the cable laying operations arising from very small depletions in DO levels will not occur.

 

Nutrients

 

High levels of nutrients (total inorganic nitrogen - TIN and ammonia) in seawater can cause rapid increases in phytoplankton often to the point where an algal bloom occurs.  An intense bloom of algae can lead to sharp increases in DO levels in surface water.  However, at night and when these algae die there is usually a sharp decrease in the levels of dissolved oxygen in the water as dead algae fall through the water column and decompose on the bottom.  Anoxic conditions may result if DO concentrations are already low or are not replenished.  This may result in mortality to marine organisms due to oxygen deprivation. 

 

Significant increases in nutrients in the vicinity of the construction works areas are unlikely to occur and unacceptable impacts to sensitive marine ecological habitats (mangrove and intertidal mudflat at Pui O) as a result of nutrient increase are therefore not expected.  Due to the small-scale of reclamationtemporary working platform and the transient and localised impacts resulting from the cable laying activities, it is expected that unacceptable impacts to the marine ecological habitats and populations present in the vicinity of the works areas arising from very small elevations in nutrient levels will not occur.

 

High and Low Frequency Noise

 

As cetaceans are protected under the Wild Animals Protection Ordinance (Cap 170), 1980 any lethal and sublethal impacts due to underwater noise on marine mammals will be deemed unacceptable.  Cetaceans are animals that rely heavily on acoustic information to communicate and to explore their environment.  Therefore, any significant noise that disrupts communication or echolocation channels would be potentially harmful. 

 

Studies have shown that because of the efficient transfer of sound in water, dolphins can detect noises associated with vessels similar to dredgers at distances up to approximately 5 km (Richardson et al. 1995).  Noise disturbance interferes with communication and echolocation pulses, which are used for navigation and feeding, leading to behavioural changes.  There is evidence suggesting that some cetacean species will minimise their use of areas affected by underwater noise.

 

Most dolphins can hear within the range of 1 - 150 kHz though the peak for a variety of species is between 8 - 90 kHz (Richardson et al. 1995).  Dredging and large vessel traffic generally results in mostly low frequency noise typically in the range of 0.02 - 1 kHz which are below the peak range of 8 - 90 kHz reported for dolphins and therefore, would not likely cause problems.   As the marine waters in the vicinity of the proposed works areas do not contain critical habitats for marine mammals, it is thus anticipated that adverse underwater noise impacts will not occur.

  

            Vessel Traffic

 

Increases in marine traffic may disturb normal cetacean movement patterns through potential collision with vessels, increased turbidity generated by propellers and submerged equipment. Additionally, vessel passes and noise can cause behavioural disturbance to these animals.  This could affect both species.  However, significant increases in vessel traffic as a result of the construction activities associated with the Project are unlikely and the habitat in the vicinity of the works areas is not a critical habitat for marine mammals.  It is thus anticipated that unacceptable impacts to marine mammals as a result of the slight increase in vessel traffic will not occur. 

 

            Assessment of Environmental Impacts - Construction

 

The following section discusses and evaluates the impacts to marine ecological habitats within the Study Area in the Adamasta Channel between Chi Ma Wan Peninsula and Cheung Chau and at Pui O.  From the information presented above the marine ecological impact associated with the construction of the Project has been evaluated in accordance with the EIA-TM Annex 8 Table 1 as follows:

 

·         Habitat Quality:  The reclamation workstemporary working platform at Pui O will result in the temporary loss of 0.055 ha180m2 of intertidal sandy shore.  The cable laying works to be undertaken in the Adamasta Channel will result in the permanent temporarypermanent loss of 0.5 ha of soft bottom benthic habitat.  Although the sandy shore and soft bottom habitat within the works areas will be permanentlypermanently lost, these habitats are of low ecological value.  High ecological value habitats (mangrove and intertidal mudflat at Pui O) in the vicinity of the temporary working platformreclamation site are not predicted to be affected by the construction activities.  The marine areas within the Study Area are not critical habitats for the Finless Porpoise and Indo-Pacific Humpbacked Dolphin and, therefore, the marine mammals are unlikely to be affected by the proposed construction activities associated with the Project.

 

·         Species:  No organisms of ecological interest were recorded during the field surveys or reported from the literature apart from the few colonies of the hard coral species which were recorded in low abundance but are commonly found in eastern and western waters of Hong Kongfrom the subtidal hard surface bottom near Tai Long Wan. 

 

·         Size:  The low ecological value intertidal assemblages within the 0.055 ha 180m2 temporary working platform reclamation site at Pui O and the subtidal soft benthic organisms within the 0.5 ha along the cable alignment in the Adamasta Channel will be directly lost but will be re-established.  As will small areas (2 linear m) of rocky intertidal and subtidal habitat at the cable landing points.  Areas outside the work sites will experience short term impacts due to water quality perturbations as a result of the reclamation and submarine cable laying activities.

 

·         Duration:  Increases in SS levels in the vicinity of sensitive receivers are expected to be low and temporary, and due to constraints on reclamation and submarine cable laying operations, within environmentally acceptable limits (as defined by the WQO's).  Impacts to benthic and intertidal assemblages in the submarine cable laying areas in the Adamasta Channel will be permanenttemporary.  Impacts to the intertidal assemblages at the Pui O temporary reclamation site working platform will occur during construction but once the reclamation works area has been removed the assemblages are expected to recolonise the area.

 

·         Reversibility:  Impacts to subtidal and intertidal assemblages within the reclamation temporary working platformarea and submarine cable laying sites are irreversible, whereas impacts to assemblages outside of these works areas are expected to be transient and recolonization should occur.

 

·         Magnitude:  The impacts to the ecologically sensitive habitats outside of the works areas defined in this review will be of low magnitude during construction of the Project.  Impacts to assemblages within the reclamation temporary working platformarea and submarine cable laying sites are of low severity due to the small size of the areas affected and the low ecological value of the habitat lost.

 

            Operation Phase

 

            Operational impacts to marine ecological resources may occur through the following:

 

Hydrodynamic Regime

 

Impacts to marine ecological resources could potentially occur if the shape of the reclamation causes a change on the hydrodynamic regime of the Pui O coastline.  Impacts of this nature could potentially lead to increased seabed current speeds which may cause seabed scour thus impacting subtidal assemblages, or conversely the current speeds may drop affecting flushing and water exchange of an area.  Inadequate flushing could lead to reduction in dissolved oxygen (DO) an increase in nutrients and consequent impacts to marine ecological resources (DO and nutrient impacts are discussed above).

 

Given the shape and small size (1800.055 ham2) of the reclamation working platform at Pui O (Figure 6.9) and the fact it is a temporary facility, it is anticipated that impacts to tidal current speeds and directions will be minimalregligablenegligible. Mitigation measures for the temporary changes to the hydrodynamic regime are, therefore, not considered to be necessary.

 

Vessel Traffic

 

Increases in marine traffic may disturb normal cetacean movement patterns through potential collision with vessels, increased turbidity generated by propellers and submerged equipment. Additionally, vessel passes and noise can cause behavioural disturbance to these animals.  This could affect both species.  However, significant increase in vessel traffic during the operation phase is not expected as vessels for maintenance and repair are unlikely to be frequent.  In addition, the marine area where the submarine cables will be laid is not a critical habitat for marine mammals.  Therefore, it is anticipated that unacceptable operational impacts to marine mammals as a result of increased traffic will not occur.

 

            Assessment of Environmental Impacts - Operation

           

The following section discusses and evaluates the potential impacts to marine ecological habitats as a result of the operation of the cable circuit in accordance with the EIA-TM Annex 8 Table 1 as follows:

 

·         Habitat Quality:  Operation of the proposed submarine cable circuit is not anticipated to affect any ecologically sensitive habitats.

 

·         Species:  No organisms of ecological interest recorded during the field surveys or reported from the literature that could potentially be impacted by operation of the submarine cable circuit.

 

·         Size:  The reclamationtemporary working platform at Pui O is not expected to affect the hydrodynamic regime of the immediate vicinity of the reclamationtemporary working platform site. The impacts are anticipated to be minimal and environmentally acceptable.

 

·         Duration:  Vessels for maintenance and repair will operate where necessary but their activities are not expected to be frequent.

 

·         Reversibility:  No irreversible impacts from the operation of the submarine cable circuit are predicted to occur.

 

·         Magnitude:  Impacts to ecologically sensitive habitats in the vicinity of the cable circuit are not predicted to occur during the operation phase.

 

6.4.5          Mitigation Measures

 

            Construction Phase

           

The above assessment indicates that during construction works the potential impacts to marine ecological assemblages are environmentally acceptable and no marine ecology specific mitigation measures are required.  Constraints on controlling impacts to water quality to within acceptable levels during construction are expected to also control impacts to marine ecology.  In accordance with the guidelines in the EIA-TM on marine ecology impact assessment the general policy for mitigating impacts to marine ecological resources, in order of priority, are:

 

·         Avoidance:  Potential impacts should be avoided to the maximum extent practicable by adopting suitable alternatives;

 

·         Minimisation:  Unavoidable impacts should be minimised by taking appropriate and practicable measures such as constraints on intensity of works operations or timing of works operations; and

 

·         Compensation:  The loss of important species and habitats may be provided for elsewhere as compensation.  Enhancement and other conservation measures should always be considered whenever possible.

 

The previous discussion has indicated that the following habitats within the Study Area will be lost:

 

·         Low Ecological Value - 0.018 ha0.055 ha  of intertidal shore at Pui O as a result of provision of of reclamation forming the temporary working platform, andalbeit temporarily asbut this will be reinstated following completion of excavation of the tunnel;

 

·         Low Ecological Value - 0.5 ha of subtidal soft bottom benthos as a result of submarine cable layingproviding the concrete indication layer over the cable.  This will be re-established by natural sedimentation over time;

 

·         Medium Ecological Value - small narrow areas (2 linear m) of rocky shores as a result of cable landing works.

 

The habitats to be lost due to the construction activities associated with the proposed Project are small in area and of low or medium ecological value.  Given that constraints on controlling impacts to water quality to within acceptable levels during construction can control impacts on marine ecology, no mitigation measures for marine ecological resources are required.  It is expected that over time rocky shore organisms will colonise the concrete covered cable trough and similar communities will be re-established.

 

            Operation Phase

               

Impacts to marine ecological resources during operation of the electric cable circuit are not predicted to occur.  Hence no marine ecology specific mitigation measures are required during Project operation.

 

6.4.6     Residual Impact

           

Taking into consideration the ecological value of the habitats discussed in the previous sections and the resultant mitigation requirements, residual impacts have been determined.

 

The residual impacts occurring as a result of the proposed Project are as follows:

 

·         The temporary loss of 0.055 ha 180m2 natural intertidal sandy shore within the Pui O reclamation temporary worksing platform site.  The residual impact is considered to be acceptable as the area of habitat lost is small and the sandy shore is of low ecological value and the effects temporary.

 

·         The loss of 0.05 ha of the subtidal soft bottom assemblages along the submarine cable alignment in Adamasta Channel.  The residual impact is not considered to be unacceptable as the habitat is of low ecological value.

 

·         The loss of small areas (2 linear m) of rocky shore at the landing points.  The residual impact is not considered to be unacceptable as the area of habitat lost is small and the intertidal portion is of moderate ecological value while the subtidal portion is of low ecological value.  Recolonisation of the concrete cable troughs by intertidal and subtidal organisms may also occur over time.

 

6.4.7     Environmental Monitoring & Audit

 

Mitigation measures to control impacts  to water quality to within acceptable levels during construction are expected to also control impacts on marine ecology.  No unacceptable impacts are expected to occur during the operation phase of the Project.  Hence, monitoring and auditing of marine ecological resources during the construction and operation of the Project is deemed not necessary.

 

6.4.8     Conclusion

           

Literature reviews of existing information supplemented with the results of recently undertaken field surveys on marine ecological resources indicate that the intertidal rocky shores within the Study Area are of medium ecological value whereas for the sandy habitats, low ecological value was assigned.  Soft bottom subtidal habitats identified in the review were regarded as of low ecological value.  A few isolated colonies of hard and soft corals were recorded on the subtidal hard surface habitats and were considered as of low ecological value.  The waters near the proposed reclamationtemporary working platform and submarine cable laying sites do not appear to be highly utilised by marine mammals and it is considered that this area does not contain critical habitat for the Indo-pacific Hump-backed dolphins and Finless Porpoises.

 

Potential impacts to marine ecological resources from the proposed construction works may arise either indirectly, e.g. through perturbations of the surrounding water quality, or directly as a result of habitat loss.  A temporary loss of 180m2 total of 0.055 ha intertidal sandy shore habitat, small areas of rocky shore and a permanent loss of 0.5 ha of subtidal soft bottom assemblages will be permanently lost as a resulted of from the construction activities associated with the Project.  However, the assemblages to be lost are of low-medium ecological value and given the small area to be directly affected, the impacts are unlikely to be severe.  Indirect impacts during the construction process, such as an increase in SS levels and decrease in DO in the water column may impact intertidal and subtidal filter feeders and other marine organisms.  However, the effects are not expected to be severe and no unacceptable impacts are predicted to occur.

 

Operational impacts to marine ecological resources are not predicted to occur through disturbances to water quality due to changes in the hydrodynamic regime of the area or an increase in marine traffic for cable maintenance and repair. 

           


References

 

Ades, G. W. J. 1999. The species composition, distribution and population size of Hong Kong bats. Memoirs of the Hong Kong Natural History Society 22:183-209.

 

Binnie Consultants Limited (1996) Fill management Study - Phase IV Investigation and Development of Marine Borrow Areas: Coral Growth at High Island Dam.  Report submitted to CED GEO, July 1996.

 

Binnie Consultants Limited (1997) Chek Lap Kok Qualitative Survey.  Final report to CED GEO, December 1997.

 

Cai, Y. and N.K. Ng  1999. A revision of the Caridina serrata species group, with descriptions of five new species (Crustacea: Decapoda: Caridea: Atyidae). Journal of Natural History, Vol. 33, 1603-1638.

 

Carey, G.J. and Young, L.  1999.  The Importance to waterfowl of the Mai Po Marshes and Inner Deep Bay Ramsar Site.  The Hong Kong Bird Report 1997.

 

Chou, I.  1996.  Monographia Rhopalocerorum Sinensium.  Henan Scientific and Technological Publishing House.

 

Chong, D. H. and Dudgeon, D. 1992. Hong Kong stream fishes: An annotated checklist with remarks on conservation status. Memoirs of the Hong Kong Natural History Society 19:79-112.

 

Collar, N.J., Crosby, M.J. and Stattersfield, A.J.  1994.  Birds to Watch 2. The World List of Threatened Birds. BirdLife International, Cambridge.

 

Corlett, R.T., Xing, F., Ng, S.C. and Chau, L.K.C. and Wong, M.Y. (2000).  Hong Kong Vascular Plants: Distribution and Status.   Memoirs of the Hong Kong Natural History Societ. 23: 1-4.

 

Dudgeon, D.  1999.  Tropical Asian StreamsZoobenthos, Ecology and Conservation.  Hong Kong University Press, Hong Kong.

 

Dudgeon, D. and Chan, W. C. E. 1996. Ecological Study of Freshwater Wetland Habitats in Hong Kong. Unpublished report for the Agriculture and Fisheries Department, Hong Kong Government.

 

Dudgeon, D. and R. Corlett 1994. Hills and Streams: An Ecology of Hong Kong. Hong Kong University Press, Hong Kong. 

 

ERM (2000a) Ecological Monitoring for Uncontaminated Mud Disposal.  Final Initial Survey Report, October 2000.

 

ERM (2000b) Construction of an International Theme Park in Penny’s Bay of North Lantau.  Final EIA Report, February 2000.

 

ERM (2001) Focussed Cumulative Water Quality Impacts of Sand Dredging at the West Po Toi Marine Borrow Area.  Final Assessment Report, July 2001.

 

Fu, L.K. and Jin, J.M. etal, Eds. 1992.  China Plant Red Data Book – Rare and Endangered Plants.  Vol.1.  Science Press, Beijing, China.

 

Goodyer, N. J. 1992. Notes on the land mammals of Hong Kong. Memoirs of the Hong Kong Natural History Society 19:71-78.


Hong Kong Herbarium.  1993, Checklist of Hong Kong plants.  Agriculture and Fisheries Department Bulletin No.1.  Hong Kong SAR Government, Hong, Kong, China.

 

Hua, H. L. and J. W. Yin.  1993.  Protected Animals in China.  Shanghai Scientific and Technological Education Publishing House.

 

Huang, Z.G., Yan, S.K., Lin, S. and Zheng, D.Q. (1992)  Biofouling communities on pier pilings in Mirs Bay.  In The Marine Flora and Fauna of Hong Kong and Southern China III (ed B Morton).  Proceedings of the Fourth International Marine Biological Workshop:  The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong 1989, p 529-543.  Hong Kong: Hong Kong University Press.

 

Hung, S.K. (2000)  Ranging patterns of Indo-Pacific hump-backed dolphins (Sousa chinensis) in the Pearl River estuary, PRC. M.Sc thesis, University of San Diego.

 

Jefferson, T.A. (1997)  Dolphins (Sousa chinensis) in East Lantau waters of Hong Kong: Assessment of potential effects of Lantau Port Development.  Report submitted to the Civil Engineering Department, Hong Kong Government, 44+ pp.

 

Jefferson, T.A. (1998)  Population biology of the Indo-Pacific hump-backed dolphin (Sousa chinensis Osbeck, 1765) in Hong Kong waters: final report.  Unpublished  report submitted to the Hong Kong Agriculture and Fisheries Department.

 

Jefferson, T.A.  (2000).  Population biology of the Indo-Pacific hump-backed dolphin in Hong Kong waters.  Wildlife Monographs, Vol 144, page 1-65.

 

Jefferson, T.A. and Braulik, G.T.  (1999)  Preliminary report on the ecology of the   finless porpoise in Hong Kong waters.  IBI Reports 9: 41-54.

 

Jefferson, T.A. and Leatherwood, S. (1997)  Distribution and abundance of Indo-Pacific hump-backed dolphins (Sousa chinensis Osbeck, 1765) in Hong Kong waters.  Asian Marine Biology 14: 93-110.

 

Karsen, S. J., Lau, M. W. N. and Bogadek, A. 1998. Hong Kong Amphibians and Reptiles. 2d ed. Hong Kong: Provisional Urban Council.

 

Lau, M. W. N. and Dudgeon, D. 1999. Composition and distribution of Hong Kong Amphibian fauna. Memoirs of the Hong Kong Natural History Society 22:1-79.

 

MacKinnon, J. and Phillipps K. (2000).  A Field Guide to the Birds of China.  Oxford University Press.

 

Morton, B. and Morton, J. 1983. The Sea Shore Ecology of Hong Kong. Hong Kong University Press, Hong Kong.

 

Morton et al (1995).  The Benthic Marine Ecology of Hong Kong: A Dwindling Heritage?  In: A Review of Coastal Infrastructure Development in Hong Kong, Proceedings of the Symposium on Hydraulics of Hong Kong Waters held on 28-29 November 1995.

Mouchel Asia Ltd (1998) Strategic Sewage Disposal Scheme Stage 1.  Baseline Monitoring and Performance Verification, Draft Final Report to EPD.

 

New, T. R.  1998.  Invertebrate Surveys for Conservation.  Oxford University Press, Oxford.

 

Parsons, E.C.M. (1997)  Hong Kong's Cetaceans: the Biology, Ecology and Behaviour of  Sousa chinensis and Neophocaena phocaenoides.  Ph.D. thesis, University of Hong Kong.

 

 

Parsons, E.C.M. (1998)  The behaviour of Hong Kong's resident cetaceans: the Indo - Pacific hump-backed dolphin and the finless porpoise.  Aquatic Mammals 24: 91 - 110.

 

Parsons, E.C.M. and Jefferson, T.A.  In press.  Post-mortem investigations on stranded dolphins and porpoises from Hong Kong waters.  Journal of Wildlife Diseases 36.

 

Parsons, E.C.M., Felley, M.L. and Porter, L.J. (1995)  An annotated checklist of cetaceans recorded from Hong Kong's territorial waters.  Asian Marine Biology 12: 79-100.

 

Reels, G. 1996. Large mammal distributions in Hong Kong. Porcupine! 15:36-38.

 

Richardson et al (1995)  Marine Mammals and Noise.  Academic Press.

 

Romer, J.D.  1979.  Annotated checklist with keys to the adult amphibians of Hong Kong.  Memoirs of the Hong Kong Natural History Society 15: 1-14.

 

Shin, P.K.S. and Thompson, G.B. (1982)  Spatial Distribution of the Infaunal Benthos of Hong Kong.  Marine Ecology Progress Series. Vol 10: 37-47

 

Tam, N.F.Y. and Y.S. Wong 1997. Ecological Study on Mangrove Stands in Hong Kong. A report submitted to Agriculture and Fisheries Department, HKSAR.

 

Walthew, G.  1997.  The status and flight periods of Hong Kong butterflies.  Porcupine! No. 16: 34-37.

 

Wilson, K. D. P.  1995.  Hong Kong Dragonflies.  Urban Council, Hong Kong.

 

Wilson, K. D. P.  1997.  An annotated checklist of the Hong Kong dragonflies with recommendations for their conservation.  Memoirs of the Hong Kong Natural History Society No. 21: 1-68.

 

Wu, D., Hu, C., Hu, Q., Li, Z., and Xing, F.  (1988).   Illustrations of rare and endangered plants in Guangdong Province.  China Environmental Science Press.  ISBN 7-80010-201-3/x149

 

Wu, R.S.S. and Woo, N.Y.S. (1984).  Respiratory Responses and Tolerance to Hypoxia in Two Marine Teleosts, Epinephelus akaara (Temminck & Schlegel) and Mylio macrocephalus (Basilewsky).  Hydrobiologia 119: 209-217.

 

Wu, X. F.  1988.  Butterflies of the Ling-nan Oasis.  Academic Periodical Press, Beijing.

 

Yue, P and Chen, Y. comps. 1998. China Red Data Book of Endangered Animals –Pisces. ed. S. Wang. Beijing: Science Press.

 

Zhao, E. comp. 1998. China Red Data Book of Endangered Animals – Amphibia and Reptilia. ed. S. Wang. Beijing: Science Press.