8. ECOLOGICAL IMPACT ASSESSMENT

8.1 Relevant Legislation, Guidelines and International Conventions

8.1.1 Government legislation and guidelines relevant to the consideration of terrestrial and aquatic ecology under this study include the following:

8.1.2 The assessment was conducted in accordance with the guidelines provided in the TMEIAP, particularly Annexes 8 and 16.

8.1.3 This study also took note of the following Guidelines:

8.1.4 International agreements relevant to this Study include:

8.2 Assessment Methodology

8.2.1 A literature review of the terrestrial ecological conditions within the Study Area was conducted. The review included Government and private sector reports, as well as unpublished information, including the following:

8.2.2 Due to the tight programme schedule, ecological surveys at Tai O and Ngong Ping were carried out under the PPFS for the study entitled "Outlying Islands Sewerage Master Plan Stage 2 Review" (namely the "PPFS surveys") to document presence and abundance of terrestrial, freshwater aquatic, and marine/coastal biota. Those surveys covered the Study Area of the current project, covering the period from July 2001 through mid January 2002, thereby covering the wet and early dry seasons. Results of these surveys were reviewed and used for impact assessment of the current project.

8.2.3 According to the study brief, ecological surveys should cover at least nine months and cover the wet and dry seasons. The PPFS surveys covered six months of wet and early dry seasons. Three more months of surveys (from mid-January to mid-April 2002) would be required to fulfil the requirement of the study brief. The same field survey methods specified for the PPFS surveys were employed during the mid-January to mid-April 2002 survey period. Survey results from mid-January to mid-April 2002 were not included and assessed in the Draft Final EIA Report due to the schedule of issuing. Survey results from mid-January to mid-April 2002 were included and assessed in the Final EIA Report. The sampling locations are shown in Drawing No. 23400/EN/062 while the survey schedule is shown inAppendix 8A. The proposed survey methodologies are summarised in the following paragraphs.

Terrestrial Ecological Surveys

8.2.4 Terrestrial ecological surveys were carried out from July 2001 to mid-April 2002, covering both dry and wet seasons, extending some 500m either side of proposed alignment and facilities, in accordance with the EIA Study Brief ESB-074/2001. Results of field surveys performed up to the end of March 2002 were incorporated in this report for impact assessment, while the results of remaining surveys performed in April 2002 (herpetofauna, invertebrates, night surveys, egretry count) are attached in Appendix 8P as supplementary information. Terrestrial Ecological Surveys include:

Habitat and vegetation survey

8.2.5 Habitat maps and the plant species list of the Study Area obtained from the on-going surveys were updated based on ground truthing. Surveys were undertaken on 31 July, 6 and 8 August, 19 October 2001, and 16 January, 25 February, 8 and 20 March 2002. Each representative habitat type was surveyed on foot. Plant species of each habitat type encountered and their relative abundance, with special attention to rare or protected species, were recorded. Photographs of each habitat type were taken. Nomenclature of plant species and their conservation status follows Xing et al. (2000). Habitat maps were digitised using ArcView GIS software.

Mammal survey

8.2.6 The survey area was searched for evidence of mammal activity, in the form of scats, burrows, footprints and other traces. These were plotted onto the habitat plans and investigated in further detail where required. Burrows were examined closely to determine whether they were in current use. Identification of mammal nomenclature follows Reels (1996) and Wilson and Reeder (1992). Surveys were undertaken during the wet seasons on 26 August, 26 and 28 September 2001 and dry seasons on 21 and 25 January, 7 February and 22 March 2002.

Bird survey

8.2.7 The bird surveys were undertaken in all major habitat types using quantitative methods (point counts) and qualitative methods. For the point count method, a total of twenty minutes were spent counting birds at each point. All birds seen or heard within 30 m of each point count location were counted and identified to species where possible. Ornithological nomenclature followed Viney et al. (1996). All bird species seen or heard outside sampling points but within the Study Area were also recorded. Evidence of breeding such as nests, recently fledged juveniles and habitat utilization was recorded. Surveys were undertaken during the wet season on 19, 25 August and 9 September 2001, and during the dry season on 25 November, 1 and 3 December 2001, 19 February, 13 and 22 March 2002.

8.2.8 Due to the tight programme schedule, the combined nine-month ecological surveys (PPFS ecological surveys and the proposed late dry season ecological surveys) from July 2001 to mid-April 2002 will not cover the entire spring bird migration season which are April and May, and breeding season of egrets and herons (April to June). To cover this data gap literature including "Hong Kong Breeding Bird Survey" and "Egretry Counts in Hong Kong" by the Hong Kong Bird Watching Society were reviewed for further information.

Amphibian and reptiles survey

8.2.9 Reptiles and amphibians were recorded by direct observation and active searching in potential concealed locations such as in leaf litter, under stones and logs. Dip-netting was used to survey tadpoles in aquatic habitats such as streams, pools and marshes. Auditory detection of species-specific advertisement calls was used to survey frogs and toads, particularly Romer’s Tree Frog. Surveys were undertaken in the wet season on 26 August, 26 and 28 September 2001 and dry season on 28 February, 7 and 22 March 2002.

Insects (dragonflies, damselflies and butterflies) survey

8.2.10 Dragonflies and damselflies (Odonata) and butterflies (Lepidoptera) were selected as indicator groups, to provide a general assessment of the diversity of invertebrate life associated with the habitats along the survey area.

8.2.11 The abundance of adult butterfly, dragonfly and damselfly fauna was investigated quantitatively (using the point count method) and qualitatively (direct observation/active searching) in all major habitat types within the Study Area. Any butterfly, dragonfly and damselfly seen within 20 m from the points was identified and counted. A total of five minutes was spent counting butterflies, dragonflies and damselflies at each point. Identification of Odonates follows Wilson (1997) and identification of butterflies follows Walthew (1997). Surveys of butterfly, dragonfly and damselfly were undertaken in the wet season on 31 July, 1 and 8 August 2001 and in the dry season on 22 February, 12 and 25 March 2002.

Aquatic Fauna

8.2.12 Freshwater aquatic fauna were investigated through direct observation and active searching, as well as kick sampling and sweep netting. Captured or observed aquatic invertebrates were identified to species or the lowest practicable taxonomic level and counted. During the freshwater fish survey, hook and line and hand-nets were used. Freshwater aquatic fauna surveys were undertaken in wet season on 17 August, 14 and 28 September, 1, 6 and 17 October 2001 and in the dry season on 12 December 2001, 8 and 21 January) and again in 26 February, 25 & 29 March, and 17 April 2002.

8.2.13 Aquatic fauna in Tai O Creek and Tai O Reedbed was sampled by using fine-mesh cast nets and a three-layer gill net in wet (17 October 2001) and dry (25 March 2002) seasons (Drawing No. 23400/EN/062). Ten replicates of cast netting were undertaken at three locations in Tai O Creek. Three-layer gill nets were deployed in Tai O Creek (four locations) and Tai O Reedbed (two replicates, collected during the time with tidal flow). Captured organisms were identified to species or lowest practicable taxonomic level and their sizes were measured.

8.2.14 Animals collected by these methods were identified on site as far as possible and released afterward to minimize disturbance to the natural habitats. Only those that required more detailed examination to confirm their identity were transferred to the laboratory for processing. This involved sorting and identification to the lowest practicable taxonomic level. Each taxon was then counted and diversity indices were calculated.

Night Survey

8.2.15 Night surveys (wet season: 26 August, 26 and 28 September 2001; dry season: 28 February, 7 and 22 March 2002) were undertaken in Ngong Ping, Keung Shan and Tai O, mainly focusing on nocturnal wildlife including mammals and amphibians, as well as Romer's Tree Frog Philautus romeri.

Marine /Coastal Ecological Surveys

8.2.16 Marine /Coastal Ecological Surveys were carried out from July 2001 to mid-April 2002, covering both dry and wet seasons. Results of field surveys, except dry season bentho survey, performed up to the end of March 2002 were incorporated in this report for impact assessment, while the results of remaining surveys performed in April 2002 (dolphins) and dry season bentho survey are summarised in Appendix 8P.

Sublittoral benthos surveys

8.2.17 Grab-samples from 9 locations were taken in Tai O Creek and coastal areas. The 9 locations for benthic ecological sampling are shown on the map in Drawing No. 23400/EN/062. Site H was intended to represent the main inflow/outflow to/from the western channel. Site G is approximately 200 m west of Site H. Site A was approximately 200 m from Site H. Site I was within the proposed sheltered boat anchorage, approximately 350 m further south from Site H and approximately 100m from the seawall.

8.2.18 Three replicates of grab-samples at each of the 9 locations were collected in wet (23 August 2001) and dry (26 February 2002) seasons. Samples were sieved using a 0.5mm sieve. Collected organisms were preserved for identification to the lowest practicable taxonomic level using a binocular dissecting microscope. At least 10% of the sorted and identified samples were re-processed by another specialist for QA/QC.

8.2.19 The species diversity (Shannon-Wiener index H') and evenness values (J') were calculated using the following formula (k is the number of categories and pi is the proportion of the observations found in category i):
k
H' = - å pi log pi
i=1

J' = H'/ H'max, in which H'max = log k

Natural shore and littoral survey

8.2.20 The coastal habitat types within the Study Area were identified during the surveys. Most of the shoreline within the Study Area was disturbed and modified. The intertidal artificial boulder shore (which was identified as semi-natural shore) located outside the saltpan was surveyed at three tidal-levels, low, mid and high on 1 August, 17 October for wet season and on 12 December 2001, 26 February and 25 March 2002 for dry season. 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 quadrate were identified and recorded to species level so that density (No./m2) could be determined. The species diversity and evenness (J') were calculated using the above formulae.

8.2.21 All suitable shores were surveyed for horseshoe crabs on 1 August, 17 October for wet season and on 12 December 2001, 26 February and 25 March 2002 for dry season. Surveys attempted to locate both adults and juveniles and were conducted by walking along the shoreline. Surveys covered all of the muddy and sandy shores and focussed on areas where local fisherman have observed horseshoe crabs. Any horseshoe crabs encountered were identified to species, counted and their location recorded.

8.2.22 Tai O Creek and estuary support extensive stands of mangroves of at least 5 species. Mangrove surveys were conducted on 1 August and 17 October 2001. Further mangrove surveys have been undertaken to identify the location and condition of mangrove stands. The density, average height and community structure, as well as the dominance, of the mangrove recorded within the Study Area was measured. Each patch was photographed and described qualitatively.

Dolphin Survey

8.2.23 Land-based visual surveys were conducted to estimate dolphin use of Tai O Bay and nearby offshore waters. Eight surveys were scheduled, four in the morning and four in the afternoon in wet and dry seasons; each survey covered at least 4 hours. The observation point is located at the ferry pier near Shek Tsai Po. Dolphin surveys were conducted on 7 September, 28 October, 15 November 2001, 16 January, 28 February, 7 and 25 March 2002. The last survey was conducted before mid-April 2002.

8.2.24 The locations of dolphin sightings were recorded on topographic maps. Number of dolphins, age class, distance from observers, and direction of travel were recorded on data sheets, together with remarks on behaviour. Sea state (measured on the Beaufort Scale), weather and visibility were recorded.

8.3 Baseline Ecological Conditions

Site of Conservation Importance

Lantau North and South Country Parks

8.3.1 Lantau North and South Country Parks were designated in 1978. They occupy a total area of about 7800 ha and cover most of Lantau Island. Ngong Ping Road within the Study Area lies on the southern boundary of Lantau North Country Park, while Kwun Yam Shan, Tai Fung Ngau and Muk Yue Shan on the southern part of the Study Area fall into Lantau South Country Park (Drawing No. 23400/EN/063). Lantau North and South Country Park encompasses a wide range of terrestrial habitats, from grassland to some of the finest forest in Hong Kong supporting a wide range of fauna such as insects, reptiles and a variety of birds.

Lantau Peak Site of Special Scientific Interest (SSSI) and Special Area

8.3.2 Lantau Peak SSSI and Special Area overlap in area and are located within Lantau South Country Park (Drawing No. 23400/EN/063). Lantau Peak Special Area, designated in 1980, has an area of 116 ha. Lantau Peak SSSI, with an area of about 227.5 ha, was also designated in 1980 due to the high species richness of the "scrub-forest" and the presence of rare plant species including Exbucklandia spp., Magnolia spp., Manglietia spp. and Illicium spp.

Ngong Ping Site of Special Scientific Interest (SSSI)

8.3.3 Ngong Ping SSSI (Drawing No. 23400/EN/063) was designated in 1999 and has an area of approximately 14 ha, including part of Ngong Ping Stream and forested areas. It was a former tea plantation area and is of special scientific interest due to the presence and the confirmed breeding of the locally rare Romer's Tree Frog (Philautus romeri). The Ngong Ping valley was confirmed to support the largest population of the endemic Romer's Tree Frog.

Man Cheung Po Site of Special Scientific Interest (SSSI)

8.3.4 Man Cheung Po SSSI consists of the riverine habitat below Man Cheung Po including the Ng Yuen Garden of approximately 29.2 ha (Drawing No. 23400/EN/063). Man Cheung Po SSSI was designated in 1980 mainly due to the presence of the orchids and Ternstroemia pseudoverticillata. Man Cheung Po SSSI is located beside the boundary of the Study Area.

Terrestrial Habitat/Vegetation

Literature Review

8.3.5 Reviewing the results of biodiversity surveys of Hong Kong flora (Xing et al. 2000), there were 33 rare or very rare plant species recorded at "Lantau Peak" (mostly at montane forest or streamside habitat, Appendix 8B), which presumably is within or near the Lantau Peak SSSI. A total of 5 and 3 rare plant species were also recorded at "Tai O" and Ngong Ping" respectively (ibid.).

Survey Results

8.3.6 The field surveys identified that the Study Area is covered by a variety of terrestrial habitats including plantation, woodland, grass-shrubland, cultivated land, mangrove/marsh, fish pond, stream and urbanized areas. Plantation, woodland and grass-shrubland were the dominant habitat type recorded within the Study Area. Table 8.1 lists the area of each habitat type recorded within the Study Area.

Table 8.1 Habitat types recorded within the Study Area.

8.3.7 The Study Area and the locations of various habitat types are shown on Drawing No. 23400/EN/064 and photographic records of representative habitat types are shown on Drawing No. 23400/EN/065a&b. Species list of flora is given in Appendix 8C.

Plantation

8.3.8 A substantial portion of the Study Area was covered by plantation including Ngong Ping SSSI, the Buddha, along roads and hillside of Tai O and within Lantau South Country Park.

8.3.9 Ngong Ping SSSI was a former tea plantation area. Camellia sinensis as well as other planted trees including Acacia confusa were commonly found in this area during the surveys (Drawing No. 23400/EN/066). Understorey developed after abandonment of the tea plantation and was fairly high in species richness. Various native species including Symplocos lancifolia, Schefflera octophylla and Ilex asprella were found in the undergrowth. The genus Camellia is protected under Forestry Regulations. The presence of abundant fruiting and seedlings of Camellia sinensis suggests that this species has adapted to the local site conditions and is capable of colonising the area. In addition to Camellia sinensis, one tree species of restricted distribution in Hong Kong (Xing et al. 2000), Celtis timorensis, was also recorded.

8.3.10 Plantations in the remaining areas mainly comprise exotic species. The most common trees planted were Acacia confusa, Lophostemon conferta and Casuarina equisetifolia. Plantation on hillslopes and roadside mostly formed a pure, dense stand with little undergrowth. Plantation surrounding the Buddha at Ngong Ping included a variety of landscaping species and fruit trees.

Woodland

8.3.11 Young secondary woodland was mainly found at Tai O and Keung Shan. The open canopy had a height of 8 - 10 m and was dominated by Machilus chekiangensis, Pinus massoniana, Mallotus paniculatus, Rhus succedanea, and Sapium discolor. The understorey was densely vegetated and was composed of a variety of tree, shrub and herb species, including Acronychia pedunculata, Alangium chinense, Psychotria rubra, and Litsea rotundifolia.

8.3.12 Woodland was recorded mainly in ravines and adjacent to grassy or shrubby hillsides in the presence of shelter and water. The woodland had similar composition to the surrounding shrubland but with proportionally more tree species including Schefflera octophylla, Sterculia lanceolata, and Ficus hispida. The woodland could be considered as young and had moderate diversity. One tree species, Aquilaria sinensis, commonly found locally but is listed as a Category III nationally protected species in China and listed as vulnerable in the China Plant Red Data Book, was also recorded in the plantation and woodland habitats within the study area. Other than that, rare or protected plants were not recorded in the woodland habitat during the survey.

Grass-Shrubland

8.3.13 Grass-shrubland was mainly located on hillsides of higher elevation. Grass-shrublands were of various heights, ranging from 0.5m to 2m, dominated by Blechnum orientale, Rhodomyrtus tomentosa, Baeckea frutescens, Lepidosperma chinense, and Dicranopteris linearis. Grasses including Ischaemum spp., Eulalia speciosa, Cymbopogon sp., and Eragrostis sp. were also abundant in grass-shrubland of younger age at lower elevations. Grass-shrubland was considered to have moderate diversity, and was subject to fire disturbance. Some grass patches were also planted with exotic species including Acacia confusa and Lophostemon conferta along trails and paths.

8.3.14 Two orchid species, Arundina graminifolia and Spathoglottis pubescens, were recorded on grassy cut slopes of Ngong Ping Road (Drawing No. 23400/EN/066), with approximately 10 and 6 individuals of Arundina graminifolia and Spathoglottis pubescens recorded respectively. The orchid family (Orchidaceae) is protected under Forestry Regulations. These two species however are commonly found in grassland in Hong Kong (Siu 2000). The Chinese New Year Flower Enkianthus quinqueflorus and Farrer's Azalea Rhododendron farrerae were recorded on the hillside in the vicinity of the proposed pumping station (Drawing No. 23400/EN/066). Both shrub species are protected under Forestry Regulations although they are commonly found in shrubland habitats in Hong Kong (Xing et al. 2000).

Cultivated Land

8.3.15 All the formerly cultivated lands recorded within the Study Area had been abandoned. The plant species of the cultivated lands consisted of pioneer trees including Mallotus paniculatus, Sapium sebiferum, remnants of crops and fruit trees including Musa paradisiaca, Citrus maxima, Psidium guajava, and weedy species including Mikania micrantha, Lantana camara and Bidens pilosa. Some abandoned cultivated lands were flooded by streams during the wet season survey, and marshy vegetation had colonised those areas. The marshy vegetation included Isachne globosa, Wedelia chinensis, Eriocaulon sp., Cyclosorus interruptus and Impatiens chinensis. Neither rare nor protected plants were recorded during the survey.

Mangroves/Marsh

8.3.16 Mangroves/Marsh occurred mainly at abandoned fish ponds, disused saltpans and riparian zones of Tai O Creek, all of which were subject to tidal influence. Scott Wilson (2000) undertook a detailed study of distribution and composition of mangroves at Tai O. Comparison of habitat map and field surveys showed that this habitat has changed little since 1999. Therefore, their results were combined with the current findings for discussion here. Since mangroves and reeds were intermingled, the two habitats are collectively classified and described as Mangroves/Marsh in this study. Major mangrove stands, however, have been shown separately on the habitat map.

8.3.17 Six out of eight mangrove species occurring in Hong Kong were found in this habitat. These included Kandelia candel, Bruguiera gymnorhiza, Avicennia marina, Aegiceras corniculatum, Excoecaria agallocha, and Acanthus ilicifolius. Mangrove associates including Acrostichum aureum, Hibiscus tiliaceus and Clerodendrum inerme as well as the reed Phragmites australis were commonly found in the mangrove stands. The absence of a real intertidal zone and the steep gradients of saltpan bunds and fish pond bunds probably result in the dominance of pioneer mangrove species (Kandelia candel and Avicennia marina) and backshore mangrove associates, and poor representation of middle zone mangrove species (e.g. Bruguiera gymnorhiza) (Scott Wilson 2000).

8.3.18 The Tai O reedbed identified in Dudgeon and Chan (1996) is also included in this habitat. This is one of the largest Phragmites australis beds in Hong Kong (ibid.). Mangrove and mangrove associate species were commonly found in the reedbed.

Fish Pond

8.3.19 Fish ponds were found only at Tai O. All of them were abandoned or had not been recently managed, although fish nets were seen in some of these ponds and were presumably used for fish harvest. Grassy pond bunds were planted with trees including Dimocarpus longan and Melia azedarach. Due to the proximity to the coast and connection with tidal water, pond bunds were colonised by mangroves, mangrove associates and reeds, including Kandelia candel, Acrostichum aureum and Phragmites australis. Given time, and in the absence of management, the pond bunds will gradually degenerate and the water levels will drop. More mangroves and reeds will occupy the pond surface and the fish ponds will then be naturally restored to mangrove/marsh habitats.

Stream

8.3.20 Perennial streams were mainly located at Tai O (Tai O Creek), Keung Shan, and Ngong Ping. There are two major natural drainage systems in the Study Area, Sham Wat and Tai O catchment. The streams in Ngong Ping and near Sze Tse Tau Shan belong to the Sham Wat catchment. They eventually join and flow into the sea at the outlet in Sham Wat Wan. Tai O main stream collects all the flows from streams in Keung Shan and Ngau Kwo Tin and then drains into the sea through Tai O Creek. The upper reaches of most of these streams were natural and surrounded by woodland habitat, while the middle and lower reaches near villages or roads were subject to a certain degree of channelisation or bank reinforcement. The lower reach of the stream (upper reach of Tai O Creek) was subject to tidal influence and mangroves and mangrove associates had colonized the earthen bank. As a result, there is no real riparian zone for these streams. The plant species recorded along the stream habitat can be referenced to the plant lists for woodland and mangrove/marsh habitats (Appendix 8C).

Urbanised Area

8.3.21 This habitat includes all the roads, houses, temples and wastelands. The proposed pumping station at Ngong Ping is located on wasteland, which is also identified as urbanised area. Species recorded included some plantation species, mainly Acacia confusa, and weeds such as Lantana camara and Mikania micrantha. Neither rare nor protected plants were recorded during the survey. This habitat is of limited ecological value.

Coastline

8.3.22 Most of the shoreline within the Study Area was considered to be disturbed and modified. It was largely composed of boulders and was void of vegetation.

Animal Wildlife

Avifauna

Literature Review

8.3.23 A total of 48 bird species (Appendix 8D) were recorded at and near the Study Area during the Hong Kong Breeding Bird Survey between 1993 and 1996 (Carey et al. 2001). Surveys were carried out between March and August in each year, and covered spring migration and breeding seasons. Twelve species were identified as breeding species and most are common in Hong Kong (e.g., White-breasted Waterhen Amaurornis phoenicurus, Chinese Bulbul Pycnonotus sinensis). Nine of the 12 breeding species were recorded at or near Tai O and the other three usually nest in shrublands and forests.

8.3.24 Bird species of interest recorded at and near the Study Area during the Hong Kong Breeding Bird Survey included some raptor species listed in Appendix II of CITES and Class 2 protected wildlife of national importance in China (Black-eared Kite Milvus lineatus, White-bellied Sea Eagle Haliaeetus leucogaster, Crested Goshawk Accipiter trivirgatus, Bonelli's Eagle Hieraaetus fasciatus and Peregrine Falcon Falco peregrinus) (Xu 1995, Zheng and Wang 1998). The White-bellied Sea Eagle is primarily maritime (Viney et al. 1996) and is only recorded in Hong Kong and nowhere else in China since the 1950's (Zheng and Wang 1998). The Black-eared Kite and Peregrine Falcon can be found in many types of habitats (Viney et al. 1996). The Crested Goshawk and Bonelli's Eagle are inhabitants of forest (ibid.). These two species together with the Peregrine Falcon are listed as "rare" in the China Red Data Book (Zheng and Wang 1998).

8.3.25 Bird species of interest recorded within and near the Study Area during the Hong Kong Breeding Bird Survey included some species listed in Class 2 protected wildlife of national importance in China (Greater Coucal Centropus sinensis, Lesser Coucal Centropus bengalensis and Hwamei Garrulax canorus) (Zheng and Wang 1998). The Greater Coucal and Lesser Coucal are listed as "vulnerable" in the China Red Data Book (Zheng and Wang 1998).

8.3.26 Other bird species of interest recorded at and near the Study Area during the Hong Kong Breeding Bird Survey included the rare/uncommon resident species the Emerald Dove Chalcophaps indica, Oriental Skylark Alauda gulgula, Upland Pipit Anthus sylvanus, Black-throated Laughingthrush Garrulax chinensis and Red-billed Leiothrix Leiothrix lutea, and two rare/uncommon migrant species, the Red-winged Crested Cuckoo Clamator coromandus and Hainan Blue Flycatcher Cyornis hainana. The Oriental Skylark is mainly found in open areas with short grass and Upland Pipit mainly in grassy upland habitats (Carey et al. 2001). The others are mainly found in tall shrubland and forests (ibid.).

8.3.27 In addition to the Hong Kong Breeding Bird Survey, there were some records of avifauna at Tai O and Ngong Ping. Bird species of interest at Tai O included the rare/uncommon mangroves/marsh associated species (Reef Egret Egretta sacra, Purple Heron Ardea purpurea, Yellow Bittern Ixobrychus sinensis, Chestnut Bittern Ixobrychus cinnamomeus, Schrenck's Bittern Ixobrychus eurhythmus, Banded Rail Rallus striatus, Pheasant-tailed Jacana Hydrophasianus chirurgus) and rare/uncommon migrant species (Brambling Fringilla montifringilla, Black-browed Reed Warbler Acrocephalus bistrigiceps, Brown Shrike Lanius cristatus, Yellow-breasted Bunting Emberiza aureola) (Carey 1996, 1998, Green Lantau Association et al. 1998, Carey and Tai 1999, Scott Wilson 2000). Reef Egret, Black-eared Kite and Lesser Coucal are listed as Class 2 protected wildlife of national importance in China (Zheng and Wang 1998). White-shouldered Starling Sturnus sinensis, a rare resident, was also regularly reported at Tai O (Carey 1996, 1998, Carey and Tai 1999).

8.3.28 Other recorded avian species of conservation interest at Tai O included the rare Greater Crested Tern Sterna bergii, Whiskered Tern Chlidonias hybrida, White-winged Black Tern Chlidonias leucoptera and Common Tern Sterna hirundo. These tern species are primarily maritime.

8.3.29 A small night roost of the Black-eared Kite was reported in Tai O in 1995 (Carey 1996). The maximum count in 1995 was 31 birds (Oct - Dec 1995). The roost was also surveyed in 1996, with maximum count of 37 birds (Jan 96) (Carey 1998). There was no report of the roost in Hong Kong of the Black-eared Kite which is listed in Appendix II of CITES and is a Class 2 protected species of national importance in China (Xu 1995, Zheng and Wang 1998).

8.3.30 Bird species of interest at Ngong Ping included some rare/uncommon migrants i.e. the Brown Thrush Turdus chrysolaus, Mountain bush Warbler Cettia fortipes, Mugimaki Flycatcher Ficedula mugimaki, Brown Shrike, Tristram's Bunting Emberiza tristrami and Bonelli's Eagle (Carey 1996, 1998, Carey and Tai 1999). All are inhabitants of shrublands or forests (Viney et al. 1996). Bonelli's Eagle is listed in Appendix II of CITES and is a Class 2 protected animal of national importance in China (Zheng and Wang 1998). This species is mainly found in lightly wooded hillsides (Carey et al. 2001).

8.3.31 The Tai O egretry is located on a hillside plantation on the northeast slope of Fu Shan in Tai O (Drawing No. 23400/EN/060). Nesting pairs were recorded in 1995, 1999, 2000 and 2001 (Young and Cha 1995, Wong et al. 2000, Kwok et al. 2001, Wong and Kwok 2002), and Chinese Pond Heron Ardeola bacchus, Night Heron Nycticorax nycticorax and Little Egret Egretta garzetta were recorded breeding (Table 8.2). The nesting population at the Tai O egretry never comprised more than 3% of the total Hong Kong breeding population. However, this is the only nesting colony reported on Lantau Island to date. According to the local people, this egretry has existed since 1988, and before that nests were built on mangroves (mainly Kandelia candel and Acanthus ilicifolius) to the north of the Tai O egretry. Nesting ardeids in Tai O egretry on average flew for 440 (high tide) to 480 m (low tide) to feed, and mainly foraged on abandoned fishponds and mangroves/marsh on the east of the colony (Kwok and Dahmer, 2002).

Table 8.2 Total numbers of nesting birds at Tai O egretry (Young and Cha 1995, Wong et al. 2000, Kwok et al. 2001, Wong and Kwok 2002)

Survey Results

8.3.32 A total of 60 bird species were recorded within the Study Area, 40 species were recorded at sampling points in the Study Area (Appendix 8E) and 20 additional species were recorded outside sampling points but within the Study Area (Appendix 8F). Relative abundance and species richness in each type of surveyed habitat, based on the results of the point count method, are presented in Table 8.3. Both bird abundance and species richness recorded were highest in mangroves while lowest in grass-shrubland. Grassland habitats are generally low in diversity of avifauna (Dudgeon and Corlett 1994, Kwok and Dahmer, in press).

Table 8.3 Abundance and species richness of birds recorded within the Study Area in wet and dry season surveys

8.3.33 The recorded species are mostly common in Hong Kong (e.g., Common Tailorbird Orthotomus sutorius, Crested Myna Acridotheres cristatellus and Tree Sparrow Passer montanus). However, some rare/protected species were also recorded during the surveys. These included Reef Egret, Black-eared Kite, Crested Serpent Eagle Spilornis cheela, White-bellied Sea Eagle, Buzzard Buteo buteo, Greater Coucal, Lesser Coucal, Chestnut Bulbul Hemixos castanonotus, White's Thrush Zoothera dauma and Hwamei.

8.3.34 Buzzard, Greater Coucal, Lesser Coucal, Black-eared Kite and Hwamei are widely distributed in Hong Kong but are regarded as species of ecological interest. Reef Egrets are mainly found in coastal areas. Crested Serpent Eagle, Buzzard, White-bellied Sea Eagle, Greater Coucal, Reef Egret, Black-eared Kite and Lesser Coucal are listed as Class 2 protected animals of national importance in China (Zheng and Wang 1998). Crested Serpent Eagle, Buzzard, White-bellied Sea Eagle, Black Kite and Hwamei are listed in Appendix II of CITES (ibid.). Crested Serpent Eagle, Greater Coucal, Lesser Coucal and Reef Egret are also listed as "vulnerable" and "rare" in China Red Data Book.

8.3.35 Two rare species were recorded in the Study Area during the surveys. These were the Chestnut Bulbul and White's Thrush. Chestnut Bulbul is mainly found in old forests while White's Thrush can be found in many types of terrestrial habitats (Carey et al., 2001).

8.3.36 Ardeids (e.g., Grey Heron Ardea cinerea, Chinese Pond Heron Ardeola bacchus and Little Egret Egretta garzetta) are of conservation concern, despite of their commonness in Hong Kong. Breeding populations of Little Egrets and Chinese Pond Heron have declined gradually, and this may be due to reduction in wetland habitats in Hong Kong (Carey et al., 2001, Lansdown et al. 2000).

8.3.37 Five species were observed breeding within the Study Area (Table 8.4). All five species are common and widespread in Hong Kong (e.g., Magpie Robin Copsychus saularis, Great Tit Parus major).

Amphibian/Reptile

Literature Review

8.3.38 There were two amphibian species of ecological interest, the Leaf Litter Toad Leptolalax pelodytoides and Rough-skinned Floating Frog Occidozyga lima, recorded within or close to the Study Area (Appendix 8G). The Leaf Litter Toad is a fairly restricted and uncommon species in Hong Kong and has been reported in the hill streams near Ngong Ping (Lau and Dudgeon 1999). In Hong Kong, the Rough-skinned Floating Frog has declined drastically in recent years and is now only known in the marsh and wet cultivated fields at Tai O Leung Uk (ibid.).

8.3.39 A number of restricted and/or uncommon reptiles have also been recorded in the Study Area (Appendix 8G), including Chinese Forest Skink Ateuchosaurus chinensis, found in a plantation on Tai O Island; Dark Forest Skink Scincella modesta, reported from Keung Shan (Lazell 1996); Rufous Burrowing Snake Achalinus rufescens, found in the plantation, tall shrubland and forest at Ngong Ping; Buff-striped Keelback Amphiesma stolatum, found in a stream at Ngong Ping and in the Keung Shan catchwater tunnel; Mangrove Water Snake Enhydris bennettii, found near the mangrove at Tai O (Karsen et al. 1998); Golden Kukri Snake Oligodon cinereus, recorded from the grassland near Nei Lak Shan; and Coral Snake Calliophis macclellandi, recorded from Keung Shan catchwater. A Natricinae snake that is probably new to science and might represent an undescribed genus was recently found in the Keung Shan catchwater (Kolby and Lazell 2001).

8.3.40 There are some other regionally or globally threatened reptiles including Reeves' Terrapin Chinemys reevesii, Burmese Python Python molurus, Copperhead Racer Elaphe radiata and Many-banded Krait Bungarus multicinctus, that have been recorded in the Study Area (Appendix 8G). Reeves' Terrapin, listed as "endangered" in the IUCN 2000 Red List, was found in a seasonal stream at Ngong Ping and in the wet cultivated fields at Tai O Leung Uk. Burmese Python (CITES Appendix II and China Red Data Book "critically endangered") was recorded in the Keung Shan catchwater. Copperhead Racer, listed as "endangered" in China Red Data Book (Zhao 1998), was found in the Keung Shan catchwater and in grassland at Ngong Ping. Many-banded Krait, listed as "vulnerable" in the China Red Data Book (ibid.), has been recorded from Tai O (Romer 1961). These records are summarized in Appendix 8G.

Survey Results

8.3.41 A total of nine species of amphibian were recorded during the surveys within the Study Area. Their distribution and relative abundance in different sites are shown in Appendix 8H. Among the recorded species, Romer's Tree Frog is an endemic species and is protected under the Wild Animals Protected Ordinance (Karsen et al., 1998) (Drawing No. 23400/EN/066, Drawing No. 23400/EN/067). Many tadpoles of this species were found in the seasonal streams at Ngong Ping. Indeed Ngong Ping is known to support the largest population of this endemic frog (Lau 1998) and has been designated as a Site of Special Scientific Interest (SSSI). Another probable endemic species, Short-legged Toad Megophrys brachykolos (Zhao and Adler 1993), was heard calling in the streams near Keung Shan. The other seven species of frog and toad (Asian common Toad Bufo melanostictus, Gunther's Frog Rana guentheri, Green Cascade Frog Rana livida, Three-striped Grass Frog Rana macrodactyla, Brown Tree Frog Polypedates megacephalus, Asiatic Pained Frog Kaloula pulchra and Ornate Pigmy Frog Microhyla ornata are common to abundant and are widespread locally (Karsen et al. 1998).

8.3.42 Six species of lizard and seven species of snake were recorded (Appendix 8H). Two species, Common Rat Snake Ptyas mucosus and Chinese Cobra Naja atra, are listed on CITES Appendix II and both of them were recorded in Keung Shan and Ngau Kwo Tin respectively. The Common Rat Snake is regarded as "endangered" while the Chinese Cobra is classified as "vulnerable" according to the China Red Data Book of Endangered Animals (Zhao 1998). The Indo-Chinese Rat Snake Ptyas korros is also listed as "endangered" in the China Red Data Book of Endangered Animals (ibid.), and it was recorded in the Keung Shan catchwater. All three species, however, are common and widespread in Hong Kong (Karsen et al. 1998). All recorded lizards (Chinese Gecko Gekko chinensis, Bowring's Gecko Hemidactylus bowringii, Changeable Lizard Calotes versicolor, Long-tailed Skink Mabuya longicaudata, Scincella reevesii and Chinese Waterside Skink Tropidophorus sinicus) are widespread and common to abundant in Hong Kong (Karsen et al. 1998). The remaining four snakes (Chinese Water Snake Enhydris chinensis, White-spotted Slug Snake Pareas margaritophorus, Red-necked Keelback Rhabdophis subminiatus and Checkered Keelback Xenochrophis piscator) are locally common and widespread (Karsen et al. 1998).

Mammals

Literature Review

8.3.43 There were 7 sightings of Chinese White Dolphins Sousa chinensis (individuals or groups) at Tai O Bay in March and April 1999 (Ecosystems Ltd 1999). Interviewed fishermen in Tai O reported that dolphins seldom enter Tai O Bay (ibid.). Recreational anglers reported regular sightings of dolphins in outer Tai O Bay. One resident in Tai O reported that dolphins enter the bay primarily during the sea-bass season (autumn), and they have been known to penetrate the bay as far as the 500 m from the saltpans (ibid.).

8.3.44 There are few records of terrestrial mammals from the Study Area (Table 8.5) (Appendix 8G). Among the eleven recorded species, some of them are of conservation concern, including Barking Deer Muntiacus sp., Ryukyus Mouse and a number of bat species. The Barking Deer, a species protected by the Wild Animals Protection Ordinance, has been recorded in the grassland near Tai O (Lau 1996). Ryukyus Mouse Mus caroli, a locally restricted species, has been recorded in the grassland at Ngong Ping. The Bamboo Bat Tylonycteris pachypus, locally rare and restricted, is protected under the Wild Animals Protection Ordinance and is classified as "rare" in the China Red Data Book (Wang 1998). It has recently been found in bamboo clumps near Keung Shan (William Suen, pers. comm.). The tunnel in the Keung Shan catchwater is also a roost site for Large Mouse-eared Bat Myotis chinensis, Common Bent-winged Bat Miniopterus schreibersii, Greater Bent-winged Bat Miniopterus magnater, Bicoloured Leaf-nosed Bat Hipposideros pomona, Rufous Horseshoe Bat Rhinolophus rouxi and Least Horseshoe Bat Rhinolophus pusillus (Ades 1999). All bats are protected locally under the Wild Animals Protection Ordinance.

Survey Results

8.3.45 Only one bat species was observed during the survey (Table 8.6a). At least two individuals of the Japanese Pipistrelle Pipistrellus abramus were seen foraging above the abandoned saltpans at Tai O, and three individuals above abandoned cultivated lands at Keung Shan. The Japanese Pipistrelle is protected by the Wild Animals Protection Ordinance but is widespread and common in Hong Kong (Ades 1999).

Relative abundance: + = 1-2, ++ = 3-5, +++ = 6-10, ++++ = over 10

8.3.46 Other mammal species recorded within the Study Area during the field surveys were of low conservation importance (Common Rat Rattus norvegicus and Sladen's Rat R. sladeni).

8.3.47 The only marine mammal recorded during the surveys in proximity to Tai O Bay was the Chinese White Dolphin. There were a total of 14 sightings of Chinese White Dolphins in waters off Tai O during surveys between September 2001 and March 2002. The results of the dolphin surveys are summarized in Table 8.6b and Drawing No. 23400/EN/068a, b, c, and d. The details of the sightings are presented in the following sections.

8.3.48 Sightings on 7 September 2001: The survey was conducted during the flood tide from 0853 to 1225 hrs. The weather was mainly cloudy, with Beaufort conditions between 0-2. A total of three sightings of the Chinese White Dolphin were observed during the survey (Drawing No. 23400/EN/068a). The first sighting was recorded at 1041 hrs. One dolphin was sighted very close to the nearby rocky outcrops under Beaufort 2 conditions, apparently engaged in feeding activities as the animal was circling and chasing fish on the water surface. The dolphin was observed for 10 minutes and then disappeared. The second sighting was recorded at 1057 hrs. Two adult dolphins were observed far away from the observation site (at least 1.5 km away) under Beaufort 1 conditions, surfacing frequently and disappearing after several minutes. The third sighting was recorded at 1129 hrs. A group of approximately ten to twelve dolphins was sighted following and feeding behind active fishing pair-trawlers under Beaufort 0-1 conditions. The group of dolphins, including adults and juveniles, were observed porpoising at least 2-3 km away from the observation site, frequently leaping out of the water. A mother-and-calf pair was observed in the group. The group was moving northward along with the pair-trawlers, closer to the observation site at 1210 hrs, and disappeared from view at 1215 hrs.

8.3.49 No sighting of dolphins were recorded on the 28th October or the survey on the 15th November 2001.

8.3.50 Sightings on 16 January 2002: The survey was conducted during the ebb tide from 0832 to 1240 hrs. The weather was sunny with good visibility, and the Beaufort sea state was between 0-2. A total of four sightings of Chinese White Dolphin were made during the survey (Drawing No. 23400/EN/068b). The first sighting was recorded at 0902 hrs. One adult dolphin was spotted 800 m away from the observation site under Beaufort 1 conditions, surfacing several times and disappearing after a few minutes. The second sighting was recorded at 0946 hrs. A group of six to eight dolphins was spotted 1.5 km away under Beaufort 2 conditions. The group was composed of juveniles and adults and was very active performing frequent aerial behaviours such as spyhopping, breaching and head-slapping. They were moving in northeasterly direction, and at a later point the group was split up into 2 smaller subgroups. The first subgroup disappeared at around 0955 hrs and the second subgroup remained in the area until 1020 hrs. The third sighting was recorded at 1025 hrs. A group of three dolphins (one juvenile and two adults) was spotted near the rocky outcrop 500m away from the observation site under Beaufort 2 conditions. They were very active with a lot of aerial behaviour (i.e. breaching and spyhopping). The animals stayed very close to the water surface, presumably feeding at the time. At 1105 hrs, another three individuals (an adult with two young juveniles) joined the group which stayed nearly 50 minutes in the area before disappearing after 1115 hrs. The fourth sighting was recorded at 1240 hrs. A group of four large adult dolphins was spotted staying close to a marine police boat 2 km away from the observation site under Beaufort 1 conditions. The group split into two subgroups (two adults in each subgroup), and they were resting and moving slowly.

8.3.51 No sightings of dolphin were made on the 28th February 2001.

8.3.52 Sightings on 13 March 2002: The survey was conducted during the flood tide from 0930 to 1330 hrs. The weather was mainly sunny and windy, with Beaufort conditions 2-4. There was only one sighting of a Chinese White Dolphin during the survey, recorded at 1140 hrs (Drawing No. 23400/EN/068c). The dolphin was observed far away from the observation site (at least 2.0 km away) under Beaufort 2 conditions, surfacing frequently and disappearing after 1 minute.

8.3.53 Sightings on 25 March 2002: The survey was conducted during the flood tide from 1205 to 1605 hrs. The weather changed from cloudy to sunny during the day of the survey. There were six sightings of dolphins. The first sighting was recorded at 1450 hrs. Two dolphins, through to be a mother-and-calf pair, were seen following a single-trawler (Drawing No. 23400/EN/068d). The two dolphins were spotted 800 m away from the observation site under Beaufort 3 conditions. The second sighting was recorded at 1520 hrs, with one individual spotted 900 m away under Beaufort 1 conditions. The third sighting was recorded at 1534 hrs. One subadult was seen spyhopping and breaching at 800 m away from the observation site under Beaufort 3 conditions. The fourth sighting was recorded at 1545 hrs. The observed subadult was seen spyhopping at 900 m away from the observation site under Beaufort 3 conditions. The fifth sighting was recorded at 1550 hrs. A subadult was seen at 1 km away from the observation site under Beaufort 3 conditions. The sixth sighting was recorded at 1600 hrs. An adult was spotted 700 m away from the observation site under Beaufort 3 conditions.

8.3.54 Based on the result of the surveys, the Chinese White Dolphins were observed to utilize the offshore areas more frequently than Tai O Bay itself. The behaviour of chasing fish, breaching, spyhopping and following fishing boats indicated that the dolphins use the offshore area as their feeding ground. Feeding activities appeared to be the predominant activity of the dolphins recorded in the offshore area. Different age classes were observed in the areas during the survey, including small calves and juveniles. The offshore area of Tai O Bay is therefore considered to be important habitat of the Chinese White Dolphin.

Invertebrates

Literature Review

8.3.55 Nine species of dragonflies, including 3 rare and 2 uncommon species, were reported within the Study Area (Wilson 1997) (Table 8.7). All were recorded at or near Keung Shan. Sinosticta ogatai and Melligomphus moluami are endemic to Hong Kong (ibid.). Protosticta beaumonti and Stylogomphus chunliuae are only recorded in a few places in Hong Kong. All these species are inhabitants of mountain streams. A new genus of Platystictidae (Sinosticta) and a new species of Protosticta were recorded in a small wooded ravine stream draining the northwest slopes of Keung Shan (ibid.). A rare species Polycanthagyna erythromelas was reported as present in high abundance at this site.

Commonness and distribution: C = common, E = endemic, FC = fairly common, R = rare, UC = uncommon

8.3.56 Eight species of butterflies were reported by Bascombe in Ngong Ping in 1976 (Bascombe, unpublished data) (Table 8.8), of which there was one rare and three uncommon species, including Large Branded Swift Pelopidas subochraceus, Yellow Band Dart Potanthus parvus, Spotless Grass Yellow Eurema laeta and Common Tree Brown Lethe rohria. The habitats of these species are listed in Table 8.8.

8.3.58 Twenty-two species of butterfly, including Angled Castor Ariadne ariadne, Dark Veined Tiger Danaus genutia, Common Mormon Papilio polytes and Common Grass Yellow Eurema hecabe were recorded at sampling points during the surveys (Appendix 8J). All recorded species were common or very common in Hong Kong (Walthew 1997), and none of the recorded butterfly species are protected in Hong Kong or China. The relative abundance of butterflies recorded in each type of habitat in the Study Area is presented in Table 8.10. Both abundance and species richness of butterflies were highest in woodland, which might be related to the higher plant diversity in woodland habitat (Preston-Mafham and Preston-Mafham 1988). No butterflies were recorded in grass-shrubland.

8.3.59 Two additional species, Yellow Pansy Junonia hierta and Common Lascar Pantoporia hordonia, were recorded within the Study Area but outside point count locations. Common Lascar is common or very common while Yellow Pansy is uncommon in Hong Kong (Walthew 1997). Yellow Pansy was recorded in abandoned cultivated lands and woodland in Keung Shan (Drawing No. 23400/EN/067). This species is usually found in open areas, and is recorded from a few scattered localities in Hong Kong (Bascombe et al. 1999).

Table 8.10 Abundance and species richness of butterflies recorded within the Study Area during the wet and dry season surveys

Aquatic Fauna

Literature Review

8.3.60 There is limited information on the aquatic fauna within the Study Area. Chong and Dudgeon (1992) reported that Lantau is an important area for native freshwater fish due to the abundance of relatively undisturbed waterways and freshwater marshy habitats. The eel Anguilla marmorata, listed in the China Red Data Book, was reported to occur in Lantau (Yue and Chen 1998, Chong and Dudgeon 1992).

Survey Results

8.3.61 Abundant freshwater crabs Somanniathelphusa zanklon were recorded in the middle section of the stream near the horse riding facility at Ngong Ping (Table 8.11). The density of freshwater crabs Somanniathelphusa zanklon (adults plus sub-adults) was estimated to reach 5-6 individual/m2 during the wet season survey. A lower density of about 4 individual/m2 was recorded in the dry season.

*Relative abundance: +++ abundant; ++ common; + occasional

8.3.62 All the three freshwater crabs, Cryptopotamon anacoluthon, Nanhaipotamon hongkongense and Somanniathelphusa zanklon, found in Hong Kong are endemic. Among the three species, Cryptopotamon anacoluthon is most common, and usually occurs at greater abundance in Hong Kong. The mountain crab Nanhaipotamon hongkongense is usually found in, or close to, upland streams with clean water in Hong Kong, and thus could be regarded as an indicator for degree of naturalness in stream habitats. Somanniathelphusa zanklon belongs to a different family (Parathelphusidae) to the above two species. This crab is usually found in lowland habitats such as rice fields, irrigation ditches, flooded furrows and slow-flowing streams and rivers (Dudgeon and Corlett 1994).

8.3.63 Atyid shrimp Caridina cantonensis and Palaemonid shrimp Macrobrachium sp. were recorded in Tai O main stream during both the wet and dry season, while local mitten crab Eriocheir japonicus and another Caridean shrimp Lender sp. were recorded only in the wet season (Table 8.11). During the surveys, abundant Caridina cantonensis were found in the upper course of the Tai O main stream, near the confluence of the streams from Keung Shan and Ngau Kwo Tin. The density of the Atyid shrimp might reach over 50 individual/m2 for both the wet and dry seasons.

8.3.64 The genus Caridina belongs to the Family Atyidae, Infraorder Caridea. The Atyidae has the first two pairs of pereiopods (walking legs) chelate and is characterized by well-developed tufts of setae for the collection of food. Caridina spp. are tiny animals with the body length around 2 cm. They are detritivores feeding mainly on leaf litter from riparian vegetation. Members of this genus are usually found in mountain streams with clean water. In Hong Kong at least three species of this genus have been reported, namely, Caridina cantonensis, Caridina apodosis and Caridina serrata. Caridina cantonensis is the commonest one, and can be found in various locations throughout Hong Kong.

8.3.65 During the survey on 28 September 2001, many dead fish were found in the Tai O main stream, while the stream from Ngau Kwo Tin was not affected as some sensitive fish species requiring a higher standard of water quality, i.e. Pseudogastromyzon myersi were recorded.

8.3.66 A diverse fish community was recorded within the Study Area with a total of 43 fish species, including Yaoshanicus arcus, Capoeta semifasciolata, Poecilia reticulata, Liniparhomaloptera disparis, and Lutjanus argentimaculatus, recorded in the freshwater streams from upper Keung Shan to Ngau Kwo Tin to Tai O. Thirty-four species of fish were recorded within the Study Area during the wet season surveys, while thirty-five species of fish were recorded during the dry season surveys (Appendix 8K). Similar number of freshwater fish species were recorded in the two seasons. No freshwater water fish were recorded at Ngong Ping during the surveys.

8.3.67 Except Anguilla marmorata, listed as vulnerable in the China Red Data Book (Yue and Chen, 1998), and Yaoshanicus arcus, endemic to South China (previously thought to be restricted to eastern New Territories in Hong Kong (Chong and Dudgeon, 1992), no recorded species are rare, endangered, or endemic.

8.3.68 Anguilla marmorata is listed as vulnerable in the China Red Data Book because it is widely hunted for its meat and is believed to be overfished, but this species may still be widespread in Hong Kong. Yaoshanicus arcus has recently been found on Lantau and is restricted to the northwestern portion of this island (Bosco Chan, unpublished data). It is locally common with restricted distribution in Hong Kong and is of moderate conservation value. Among the recorded freshwater species, Clarius fuscus, Gambusia affinis affinis and Poecilia reticulata are introduced species without any conservation significance.

Table 8.12 Freshwater fish of conservation value recorded within the Study Area

*Relative abundance: + = <10 individuals, ++ = 11-30 individuals, +++ = >30 individuals

Tai O Creek and Reed bed

Literature Review

8.3.69 The aquatic organisms caught by the methods of cast netting and tidal netting were mainly Leiognathus daura, Tilapia mossambica (renamed as Oreochromis mossambicus), Mugil affinis, Elops saurus and Scylla serrata (Scott Wilson, 2000).

Survey Results

8.3.70 A total of eleven species of aquatic organisms were caught in Tai O Creek and Tai O Reedbed by fine-mesh cast netting and three-layer gill netting during the survey period (Table 8.13 and Drawing No. 23400/EN/062). Raw data are presented in Appendix 8L & Appendix 8M. The total abundance of each catch, cast net or gill net, was low in wet season (less than 7 individuals), and higher in dry season (the maximum number of individuals caught in one location was 18). Among the caught organisms, Mugil affinis was the most frequently recorded species in wet season, while Penaeus penicillatus in dry season.

Intertidal Flora and Fauna

Literature Review

8.3.71 Intertidal fauna recorded in Tai O were mainly periwinkles (including Nodilittorina millegrana and Littorina scabra), Cerithidea rhizophorarum, Monodonta labio and mud skippers Periophthalmus cantonensis (Scott Wilson, 2000). A variety of mangrove and mangrove associates, including Kandelia candel, Avicennia marina, Bruguiera gymnorhiza, Clerodendrum inerme, Hibiscus tiliaceus, Acanthus ilicifolius, Acrostichum aureum, Excoecaria agallocha and Aegiceras corniculatum were recorded in Tai O intertidal areas (Scott Wilson, 2000).

Survey Results

8.3.72 In total, 8 species of animals and 1 species of macroalga were recorded on the artificial boulder shore in wet season, and 9 species of fauna were recorded in the dry season (Appendix 8O, Table 8.14, Drawing No. 23400/EN/062). Animals recorded on the shores at the surveyed sites were largely herbivorous molluscs, including the nerite Nerita albicilla on the high (2.5 m above CD), mid (2.0 m above Chart Datum) and low (1.5 m above CD) shore, and periwinkles Littorina scabra on the high shore (Table 8.14). The species diversity and evenness are presented in Table 8.14, which indicated that the artificial boulder shore has low diversity in both wet and dry season, but the H' value is relatively higher in dry season. The predatory gastropod Thais clavigera (the common dogwhelk) was also recorded in the low shore region. Sessile filter-feeding barnacles such as the rock oyster Saccostrea cucullata were also common on the shores (Table 8.14). The mussel Septifer virgatus and the acorn barnacle Tetraclita squamosa were also recorded on the shores but in low abundances during wet and dry season. The macroalgae Ulva lactuca was recorded in wet season but was not found in the dry season survey.

Note: * - The species diversity and evenness excluded the sessile organisms which using percentage cover to represent their abundance.

Horseshoe Crab

Literature Review

8.3.73 Horseshoe crabs were reported to be occasionally sold in the Tai O market (Mott MacDonald et al. 1991). Huang et al. (1998) reported that adult Carcinoscorpius rotundicauda are "frequently fished from the subtidal mud" of north-west Lantau, including Tai O. Living adult horseshoe crabs Carcinoscorpius rotundicauda and Tachypleus tridentatus were reported in Tai O (Chiu and Morton, 1999). Interviews of local fishers were conducted to investigate the occurrence of horseshoe crabs in the proposed anchorage site at Tai O (Scott Wilson 2000). It was found that horseshoe crabs were occasionally caught inside Tai O Bay, and even in the intertidal portion of Tai O Creek. However no horseshoe crabs were found in the field surveys for Tai O Sheltered Boat Anchorage EIA. Only dead horseshoe crabs were seen entangled in abandoned fishing nets along the saltpan perimeter (ibid).

Survey Results

8.3.74 No signs or tracks of horseshoe crabs were recorded within the Study Area during the dry-season and wet-season surveys for the present project. Horseshoe crabs, three species of which occur in the South China Sea, are thought to be at risk from over-harvesting and in Hong Kong possibly from loss of habitat (Huang et al. 1998). Local fishermen noted that horseshoe crabs are more often seen on more sandy shores such as at Yi O, indicating that while Tai O is a suitable habitat, it is not the most preferred habitat (Scott Wilson 2000).
Benthic Fauna

Literature Review

8.3.75 A total 39 species of benthos, dominated by molluscs and polychaetes, were recorded from grab samples in Tai O Bay (Scott Wilson, 2000).

Survey Results

8.3.76 A total of 43 species and 4234 individual benthic organisms were recorded at the nine sites (Sites A to I, 3 replicates in each site) at Tai O in the wet season sampling, and 933 individuals from 34 species were recorded in the dry season sampling (Table 8.15).

8.3.77 Raw data for the wet season and dry season survey are presented in Appendix 8N. Six major taxa (Phylum) were recorded. Crustaceans dominated at Sites C, D, E and F (over 85%), and polychaetes dominated at Sites B and G (over 87%) in wet season. For dry season, crustacean still dominated at Sites C & F (over 60%) but polychaetes dominated at another 3 sites (Sites A, D & E) besides Sites B & G. At Site I, the abundance of polychaetes and crustaceans were similar in dry season (both about 45%). No rare species were recorded in the samples collected during the wet and dry season surveys. The amphipod Apseudes mortoni was the dominant species in wet season and comprised over 70% (2999 individuals) of the total abundance. The total number of individuals and density were highest at Site F in wet season (total number was 1959), which is located in the inner Tai O Creek, while lowest were at Site H (no living organisms recorded in both wet and dry seasons), which is located at the mouth of the Tai O Creek (Table 8.15). The total number of species recorded was highest at Sites B (19 species in wet season and 23 species in dry season), which is located away from the Tai O Creek, while lowest at Site H (No record in both wet and dry seasons) (Table 8.15).

Note: The percentage of the abundance (pooling the 3 replicates) of each taxa (Phylum) recorded in the site was presented as the number within the bracket.

8.3.78 The overall benthos species diversity (H') was low, the mean value ranging from 0.10 to 0.86 in wet season and 0.68 to 1.23 in dry season. The lowest H' was recorded at Site H (no living organisms recorded), which is located at the mouth of the Tai O Creek, while the highest at Site I in wet season and Site C in dry season, which are both located away from the mouth of Tai O Creek (Table 8.16a). For the Shannon-Weiner index (H'), a value of < 1 indicates low diversity, 1-2 indicates moderate diversity and a value of > 2 indicates higher diversity. The mean value of the evenness (J') recorded in the eight sites ranged from 0.13 to 0.86 in wet season and 0.33 to 0.63 in dry season. The evenness index reflects how similar the abundance values for each species are within an assemblage. For example, a value of 1 indicates that all species occur in equal abundance whereas a value close to zero indicates that one species has very high abundance and the other species are recorded at very low abundance. The evenness indices indicate that there were limited number of species of benthic organisms recorded within the sites and they were patchily distributed.

8.3.79 The identification of the benthic samples was audited and passed the QA check. The results of the benthic samples were re-processed (10% of the sorted and identified samples) by another specialist and matched the list of the species identified during the first identification work.

Mangrove

8.3.80 Mangrove refers to habitats with woody vegetation dominated by salt-tolerant species found on inter-tidal areas. Eight mangrove stands were identified within the Study Area (at Tai O) (Table 8.16b). Major mangrove species found in the Study Area included Kandelia candel, Avicennia marina and Aegiceras corniculatum. There were limited number of individuals of mangrove plants recorded within the mangrove stands A, C, F and H. The largest and most dense mangrove stands were recorded at site B.

8.3.81 Since the mangrove stands A, D to G are permanently submerged in water, epifaunal survey was not undertaken. Findings of the surveys for mangrove stands B, C and H indicated that the mangrove fauna in was dominated by the cerithid (Cerithidea rhizophorarum) and fiddler crabs (Uca spp.). Sesarma crabs (Pseudosesarma patshuni) and mud skippers (Periophthalmus cantonensis) were also common in mangrove stands B, C and H.

Table 8.16b Floral and Faunal Species Recorded in the Mangrove Stands Identified within the Study Area.

Relative abundance: ++++ = abundant, +++ = common, ++ = occasional, + = scarce

8.4 Evaluation of Habitats and Species

Habitat Evaluation

The ecological importance of the habitats identified was evaluated against the criteria in Annex 8 of the EIAO TMEIA. This evaluation is presented in Tables 8.17 - 8.25.