3.1 The following section presents the results of an ecological assessment of potential impacts resulting from the Project. A literature review and field surveys were undertaken to establish ecological baseline conditions and evaluate the ecological importance of habitats/species potentially affected by proposed works. The scale of possible ecological impacts resulting from the proposed works was assessed and necessary mitigation measures were identified. Residual ecological impacts were assessed, and ecological monitoring and audit requirements were identified.
3.2 The assessment follows the criteria and guidelines as stated in Annexes 8 and 16 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) and the EIA Study Brief No. ESB-158/2006.
Environmental Legislation, Standards and Guidelines
3.3 Guidelines, standards, documents and HKSAR Government ordinances and regulations listed in the followings were referred to during the course of the ecological impact assessment.
3.4 The Country Parks Ordinance (Cap. 208) 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.
3.5
The Forests and
Countryside Ordinance (Cap. 96) prohibits felling, cutting, burning or
destroying of trees and growing plants in forests and plantations on Government
land. Related subsidiary Regulations prohibit the selling or possession of
listed restricted and protected plant species. The list of protected species in
3.6 Under the Wild Animals Protection Ordinance (Cap. 170), designated wild animals are protected from being hunted, whilst their nests and eggs are protected from injury, destruction and removal. All birds and most mammals, including marine cetaceans, are protected under this Ordinance. The Second Schedule of the Ordinance, which lists all the animals protected was last revised in June 1992.
3.7 The Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) restricts the import and export of scheduled species. The Ordinance is primarily related to controlling trade in threatened and endangered species and restricting the local possession of them.
3.8
The amended Town
Planning Ordinance (Cap. 131) provides for the designation of coastal
protection areas, Sites of Special Scientific Interest (SSSIs),
Conservation Area,
3.9
Chapter 10 of the Hong Kong Planning
Standards and Guidelines (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. The appendices list the legislation
and administrative controls for conservation, other conservation related
measures in
3.10 Annex 16 of the EIAO TM sets out the general approach and methodology for assessment 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 habitat and ecological impact.
3.11 EIAO Guidance Note No. 6/2002 clarifies the requirements of ecological assessments under the EIAO. EIAO Guidance Note No. 7/2002 provides general guidelines for conducting ecological baseline surveys in order to fulfil requirements stipulated in the EIAO TM.
3.12 List of Wild Animals Under State Protection details Class I and Class II protected animal species under Mainland Chinese Legislation.
3.13 List of Wild Plants Under State Protection details Class I, Class II and Class III protected plant species under Mainland Chinese Legislation.
3.14 The International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species provides taxonomic, conservation status and distribution information on taxa that have been evaluated using the IUCN Red List Categories and Criteria. This system is designed to determine the relative risk of extinction, and the main purpose of the IUCN Red List is to catalogue and highlight those taxa that are facing a higher risk of global extinction. The IUCN Red List also includes information on taxa that are either close to meeting the threatened thresholds or that would be threatened were it not for an ongoing taxon-specific conservation programme.
Scope of Ecological Assessment
3.15 Existing literature documenting the ecology of the proposed works area was reviewed. Ecology surveys were conducted from February to July 2006. The surveys covered an assessment area within 500 m of the works site boundary, including the Pok Fu Lam Country Park and Special Area, and area likely to be impacted by the Project.
Literature Review
3.16 Previous assessment studies covering the assessment area were reviewed.
· Project Profile for Agreement No.
CE28/2004 (GE) Landslide Preventive Works at
· Environmental Impact Assessment
Report for Drainage Improvement in Northern
Ecological Survey
3.17 A six-month ecological survey covering both dry and wet seasons was conducted from February to July 2006. The surveys covered an assessment area within 500 m of the works site boundary, and comprised:
Terrestrial Ecological Survey
3.18 Habitat surveys were undertaken to determine the types, sizes and locations of habitats in the assessment area. The habitat surveys were conducted via a desktop review of aerial photographs, base-maps and other relevant maps and plans followed by site visits. Representative photographs of habitat types in the assessment area were taken.
3.19 Vegetation surveys were conducted by
direct observation to record species present, relative abundance and dominant
species in different habitat types in representative parts of the assessment
area. The position of any plant species of conservation interest was recorded.
Identification of species and status in
3.20 Habitat/Vegetation surveys of the assessment area were focussed on areas directly impacted by the proposed works, and conducted in both dry and wet seasons from February to July 2006.
Avifauna Surveys
3.21 Daytime avifaunal surveys were undertaken on a monthly basis from February to July 2006. Night surveys of the assessment area were conducted in February and May 2006. Avifaunal surveys comprising general walk-transect of the assessment area were undertaken with species present and relative abundance of species in different habitat types recorded. The walk-transect is provided in Figure 3.1. Birds were recorded visually and aurally. The location of bird species of conservation interest was recorded, along with any notable behaviour (e.g., breeding behaviour such as nesting and presence of recently fledged juveniles, roosting and feeding activities). Nomenclature and protection status of the species were made with reference to Viney et al. (2005) and Carey et al. (2001).
Herpetofauna Surveys
3.22 Herpetofauna (lizards, snakes, frogs
etc.) surveys of the assessment area were conducted, with species present and
relative abundance of species recorded. Amphibians were searched for by direct
observation, searching potential microhabitats (such as stream bank, small
water pond, pool, crevice, rock, leaf litter and rotten log), searching for
tadpoles in aquatic habitats and listening for calling animals. Reptiles were
searched for by direct observation, searching potential microhabitats, and
searching for signs of animals (e.g., snake-skins). The location of any
herpetofaunal species of conservation interest was recorded. Identification of
species and status in
3.23 Herpetofauna surveys were conducted at three survey days, in March and May 2006. Surveys were conducted during both the day and night.
Mammal Surveys
3.24 Mammal surveys of the assessment
area were conducted, with species present and relative abundance of species
recorded. Mammals (including bats) were searched for by direct observation,
searching potential microhabitats (e.g. palm trees as microhabitat for nesting
bats), listening for calling animals, and searching for signs of animals (e.g.,
burrows, faeces, feeding signs and footprints). The location of mammal species
of conservation interest was recorded. Identification of species and status in
3.25 Mammal surveys were conducted three times (February, April and May 2006), covering both dry and wet seasons in the assessment area. Surveys were conducted during both the day and night.
Terrestrial Insect Surveys
3.26 Species present and relative species
abundance of adult butterflies and odonates (dragonflies, etc) were recorded by
general walk-transect in the assessment area. The walk-transect is provided in Figure 3.1. Terrestrial insect surveys were
conducted two times in the wet season (May and July, 2006). Nomenclature and
protection status of the species were made with reference to Lo & Hui
(2005), Bascombe et al. (1999) and
Freshwater Community Surveys
3.27 Fish and macroinvertebrate
populations were surveyed three times in the wet season (April, May and June
2006), with species present and relative abundance of species recorded. Fish
were surveyed by direct observation and netting using aquatic hand nets at
various microhabitats. Surveys of macroinvertebrate populations were conducted
by kick-sampling with a 500mm mesh D-framed net. Three replicates were taken at the same point at
each stream sampling location as shown in Figure
3.1. Identification of species and status in
Impact Assessment
3.28 Potential ecological impacts arising from the Project were assessed following EIAO TM Annex 16 guidelines and the impacts were evaluated based on criteria in EIAO TM Annex 8.
Sites of Conservation Importance
3.29 The proposed works area was partly fall within the boundary of the existing Pok Fu Lam Country Park and Special Area. Under the approved the Peak Area Outline Zoning Plan (S/H14/7), Pok Fu Lam Country Park and Special Area contributes to the conservation of the natural environment and recreational use where appropriate.
3.30 Pok Fu Lam Country Park is set in
foothills of
Summary of Literature Review
Habitat and Vegetation
3.31 Results of habitat and vegetation surveys for Po Shan Project Profile (Maunsell, 2005) identified several habitat types including mature secondary woodland, engineered cut slopes, residential developments and landscape amenity areas. Seven plant species of conservation interest were recorded within the secondary woodland habitat: the fern Lamb of Tartary (Cibotium barometz) protected under Hong Kong and Mainland Legislation, the locally protected Hong Kong Pavetta (Pavetta hongkongensis), Bird’s-nest Fern (Neottopteris nidus) and Rhododendron (Rhododendron spp.), Chinese Pholidota (Pholidota chinensis) and the locally common Small Persimmon (Diospyros vaccinioides) and Silver-back Artocarpus (Artocarpus hypargyreus) classified as critically endangered and vulnerable respectively in the IUCN Red Data List.
3.32 Hong Kong West Drainage Tunnel EIA
(Black & Veatch, 2006) identified 5 habitat types: natural woodland,
shrubland, fung shui woodland, urban plantation and stream/nullah within the
assessment area of the project. Two floral species of conservation concern were
recorded within the HKU1 study area near Pok Fu Lam included one tree species Artocarpus
hypargyreus and one shrub Pavetta hongkongensis. These species are
locally common and are protected by legislation in
3.33 Po Shan Project Profile (Maunsell, 2005) identified that secondary woodland habitat with the assessment area supported seven plant species of conservation interest. The fern Lamb to Tartary (Cibotium barometz) is listed as a Wild plant under State Protection (Category II) under Mainland Legislation, and is scheduled under Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586). Hong Kong Pavetta (Pavetta hongkongensis), Bird’s-nest Fern (Neottopteris nidus) and Rhododendron (Rhododendron spp.) are all listed under Forestry Regulation of Forests and Countryside Ordinance (Cap. 96). Chinese Pholidota (Pholidota chinensis) is listed under Forestry Regulation of Forests and Countryside Ordinance (Cap. 96) and scheduled under Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586). The locally common Small Persimmon (Diospyros vaccinioides) and Silver-back Artocarpus (Artocarpus hypargyreus) are classified as Critically Endangered (CR) and Vulnerable (VU) respectively in the IUCN Red Data List (Lu & Pan, 1998; Sun, 1998b). While Silver-back Artocarpus is also listed under State Protection (Category III) under Mainland Legislation.
Fauna
3.34 Six avifauna species of conservation
importance were recorded from the study area of Po Shan Project Profile
(Maunsell, 2005) including Yellow-crested Cockatoo (Cacatua sulphurea)
which is listed as critically endangered in the IUCN Red Data List and CITES
Appendix I. Other species recorded from either woodland habitat or at flight
over the study area including Lesser Coucal (Centropus bengalensis),
Greater Coucal (Centropus sinensis) and Hwamei (Garrulax canorus),
Peregrine Falcon (Falco peregrinus) and Black Kite (Milvus migrans)
are locally common and native to Hong Kong, but are protected under Mainland
Chinese and
3.35 Fauna of conservation concern recorded in Hong Kong West Drainage Tunnel EIA (Black & Veatch, 2006) included Belly-banded Squirrel (Callosciurus erythraeus styani) and Black Kite (Milvus lineatus) from study area W11(P), HKU1(P) and W10 near Pok Fu Lam These species are locally protected.
3.36 It is reported that an endemic
shrimp species, Caridina serrata, was also present at mid-level (Lung Fu
Shan) on
Summary of Current Survey
3.37 A habitat map of the assessment area is given in Figure 3.2 (Sheet 1) (Sheet 2). Representative photographs of habitats are given in Appendix 3.1. Photographs of plant species of conservation importance are illustrated in Appendix 3.2. Species recorded from the assessment area are listed in Appendix 3.3. More detailed descriptions of habitats and vegetation communities in the assessment area are given in the following paragraphs.
Habitat and Vegetation
3.38 Habitats found within the assessment
area include natural woodland, shrubland, developed area and freshwater
habitat. About 80% of the assessment area, particularly the area to be directly
affected by the proposed Project, is natural woodland. A total of 163 plant
species were recorded within the assessment area, about 82% of which are
native. Aquilaria sinensis, Aristolochia championii, Artocarpus
hypargyreus, Cibotium barometz, Diospyros vaccinioides, Pavetta
hongkongensis, Rhododendron championiae and Tutcheria spectabilis
were recorded within the assessment area. These species are either rare species
or protected in
Table 3.1 Number of Plant Species Recorded at Various Habitat Types within the Assessment Area
|
Habitat Type |
Size |
Number of Plant Species Recorded |
|
Natural |
~109 ha |
141 |
|
Shrubland |
~2 ha |
36 |
|
Developed Area |
~25 ha |
39 |
|
Freshwater Habitat |
~1200 m |
- |
Natural
3.39 About 109 ha of natural woodland was distributed at the south fringe of the assessment area. The woodland habitats are medium in age and have developed close canopy. Tree species reached a height of 10-15 m and some of them were mature trees including Machilus chekiangensis which is commonly recorded in the woodland. Understorey species consisted of a variety of tree, shrub and herb species.
3.40 A total of 141 floral species were found in the natural woodland during the surveys. Eight plant species of conservation importance were recorded, comprising shrub species Hong Kong Pavetta (Pavetta hongkongensis), Champion's Rhododendron (Rhododendron championiae), Long-leaved Birthwort (Aristolochia championii) and Small Persimmon (Diospyros vaccinioides), tree species Silver-back Artocarpus (Artocarpus hypargyreus), Incense Tree (Aquilaria sinensis) and Common Tutcheria (Tutcheria spectabilis), and fern Lamb of Tartary (Cibotium barometz). The locations of these plant species of conservation importance were indicated in Figure 3.2 (Sheet 1) (Sheet 2). However, the previously recorded Neottopteris nidus and Pholidota chinensis (Maunsell, 2005) were not observed during the current surveys.
3.41 Hong Kong Pavetta (Pavetta hongkongensis) is native and common
plant in
3.42 Champion’s Rhododendron (Rhododendron championiae) is native but rare
in
3.43 Long-leaved Birthwort (Aristolochia
championii) is native and rare species in
3.44 Small Persimmon (Diospyros
vaccinioides) is native species and highly abundant in shrubland and
woodland habitats in
3.45 For tree species, Silver-back
Artocarpus (Artocarpus hypargyreus) is
common in
3.46 Incense Tree (Aquilaria
sinensis) is a native and locally common species in
3.47 Common Tutcheria (Tutcheria
spectabilis) is a native plant species in
3.48 The fern Lamb of Tartary (Cibotium
barometz) is a native and common species in
Shrubland
3.49 Shrubland, with the size of 2 ha, was mainly distributed at northeastern side of the proposed works area and small patches at the east of the assessment area. Generally, shrubland is covering part of the hillside and engineered slope. Plant species diversity in this habitat was low, with only a total of 36 species of plant recorded during the surveys. It was mostly dominated by Miscanthus sinensis and no rare or protected plant species was recorded.
Developed Area
3.50 A total of 25 ha of developed area was recorded in the assessment area included roads, car parks, residential area and landscape plantation areas. This habitat supports little or no vegetation aside from planted trees. Thirty-nine plant species was recorded during the surveys, with about 52% of the vegetation as exotic species planted for landscaping purposes. Species commonly found include Litsea monopetala, Ficus microcarpa, Acacia sp. and Bauhinia sp. This habitat is highly disturbed in nature with limited ecological interest. No rare or protected plant species was recorded.
Freshwater Habitat
3.51 There were only two small and
seasonal stream courses within the assessment area, with total length of 1200
m. These stream courses were located at eastern and western side of the
proposed works area and flow from south to north. Substrate was largely
comprised of boulders in the upstream section and channelised in the downstream
near
3.52 Apart from seasonal streams, one small open drainage culvert was found at the north of the proposed works area. The culvert was made by cement with very small amount of water flow.
Fauna
3.53 Fauna recorded in the assessment area during surveys is listed in Appendix 3.4. The locations of the faunal species of conservation importance were indicated in Figure 3.2 (Sheet 1) (Sheet 2).
Avifauna
3.54 Twenty-five avifaunal species were
recorded in the assessment area. Typical urban species such as Eurasian Tree
Sparrow (Passer montanus), Oriental Magpie Robin (Copsychus saularis)
and Japanese White eye (Zosterops japonica) were recorded from the
developed area. Commonly recorded species in the shrubland habitat included
Chinese Bulbul (Pycnonotus sinensis), Red-whiskered Bulbul (Pycnonotus
jocosus) and Masked Laughing Thrush (Garrulax
perspicillatus). Among all these species, Hwamei (Garrulax canorus),
Large Hawk Cuckoo (Hierococcyx sparverioides), Arctic Warbler (Phylloscopus
borealis) and Red-billed Leiothrix (Leiothrix lutea) are
uncommon species in
Raptors
3.55 Up to 26 Black Kite (Milvus
migrans) were recorded at flight above the assessment area throughout the
survey period. The Breeding Bird Survey recorded breeding of Black Kite to
occur in widespread coastal areas, including
3.56 One individual of Collared Scops Owl
(Otus bakkamoena) was recorded in the natural woodland habitat during a
day survey in May 2006. Collared Scops Owl is common and widespread in
Other Birds
3.57 Two Greater Coucals were recorded
from the natural woodland habitat in April and July 2006. Greater Coucal (Centropus
sinensis) is relatively common and widespread in
Herpetofauna
3.58 Herpetofauna survey was conducted at three survey days, in March and May 2006, with no species recorded in March. Generally, herpetofauna were recorded in streams, natural woodland and developed area.
3.59 Four species of amphibians were recorded in the assessment area during the survey period, including Asian Common Toad (Bufo melanostictus), Green Cascade Frog (Rana livida), Lesser Spiny Frog (Rana exilispinosa) and Hong Kong Cascade Frog (Amolops hongkongensis). Green Cascade Frog was recorded at both eastern and western streams. Lesser Spiny Frog and Hong Kong Cascade Frog were recorded at eastern stream and western stream, respectively. Apart from amphibian in adult form, tadpoles of Hong Kong Cascade Frog (Amolops hongkongensis) were found at both eastern and western streams during the freshwater habitat surveys from March to May 2006.
3.60 The former two species, Asian Common
Toad and Green Cascade Frog, are common and widely distributed in Hong
Kong, and widely distributed in mountain streams in
3.61 Lesser Spiny Frog (Rana exilispinosa) is common and widely distributed in
3.62 Hong Kong Cascade Frog (Amolops hongkongensis) can be found in fast-flowing mountain streams
on
3.63 One species of reptile, Changeable Lizard (Calotes versicolor), was recorded from woodland habitat of the assessment area during the surveys, which is a common and widespread native species. No rare or protected reptile species was recorded.
Mammals
3.64 Two species of mammals, Pallas’s
Squirrel (Callosciurus erythraeus) and Short-nosed Fruit Bat (Cynopterus
sphinx), were recorded in the assessment area. Two individuals of Pallas’s
Squirrel (Callosciurus erythraeus) were recorded at tree crown of a road
tree at
3.65 Pallas’s Squirrel (Callosciurus
erythraeus) is a common and introduced species in
3.66 Short-nosed Fruit Bat (Cynopterus
sphinx) is a very common fruit bat found in urban areas of
3.67 Although Short-nosed Fruit Bat is
widespread in
Terrestrial Invertebrates
3.68 During the field surveys, one
odonate species, Wandering Glider (Pantala flavescens) and 7 butterfly
species, including Indian Cabbage White (Pieris canidia), Red Helen (Papilio helenus) and Paris Peacock (Papilio
paris) were
recorded from natural woodland, shrubland and developed area of the assessment
area. All recorded species are common and widespread in
Freshwater Communities
3.69 Freshwater communities recorded in the surveys tended to be species poor because of the small size of the stream courses. Dominant species recorded including Chironomid larvae, indicating some degree of organic pollution. Other species recorded such as Gastropoda (Radix plicatulus and Biomphalaria straminea), Odonata (Ophiogomphus sinicus) and Heteroptera (Buenoa sp. and Notomecta sp.). As mentioned in the result of herpetofauna survey, Anura (tadpole of Amolops hongkongensis) was also recorded at the eastern and western streams. However, no fish was recorded from the streams during the surveys. While, no endemic shrimp, Caridina serrata, was recorded during the current surveys.
3.70 In addition, two individuals of
Mountain Crab (Nanhaipotamon hongkongense) were observed hiding beneath
stones adjacent to drainage culvert located at the northern side of the
proposed works area. Mountain Crab is semi-terrestrial freshwater crab. It
normally appears at the hillstream clean water habitat (Dudgeon & Corlett,
1994). Although locally common in Hong Kong, Mountain Crab has an extremely
restricted regional and global distribution, and local populations in
3.71 In accordance with the EIAO TM Annex 8 criteria, the ecological importance of recorded habitats has been evaluated in Tables 3.2a - c below.
Table
3.2a
Ecological Value of Natural
|
Criteria |
Natural |
Shrubland |
|
Naturalness |
Natural. |
Natural. |
|
Size |
Area of this habitat within assessment area is approximately 109 ha. |
Area of this habitat within assessment area is approximately 2 ha. |
|
Diversity |
Moderate floral and faunal diversity (140 plant species recorded), moderate structural complexity. Dominated with native species. |
Low floral and faunal diversity (36 plant species recorded). |
|
Rarity |
Eight floral species (Hong Kong Pavetta, Pavetta hongkongensis; Champion's Rhododendron, Rhododendron championiae; Long-leaved Birthwort, Aristolochia championii; Small Persimmon, Diospyros vaccinioides; Silver-back Artocarpus, Artocarpus hypargyreus; Incense Tree, Aquilaria sinensis; Common Tutcheria, Tutcheria spectabilis; and Lamb of Tartary, Cibotium barometz) and five faunal species (Collared Scops Owl, Otus bakkamoena; Greater Coucal, Centropus sinensis; Pallas’s squirrel, Callosciurus erythraeus; Short-nosed Fruit Bat, Cynopterus sphinx; and Mountain Crab, Nanhaipotamon hongkongense) of conservation importance recorded from this habitat type. |
No faunal and floral species of conservation importance recorded from this habitat type during the surveys. |
|
Recreatability |
Habitat characteristics and species composition are difficult to recreate. It will take 40-50 years for the natural woodland to develop. |
Readily re-creatable. |
|
Fragmentation |
Fragmented by urban developments and foot paths. |
Habitat is not fragmented. |
|
Ecological linkage |
Habitat is not structurally or functionally linked to any high ecological value resources. |
Habitat is not structurally or functionally linked to any high ecological value resources. |
|
Potential Value |
Moderate to high. |
Low. |
|
Nursery Ground |
Provide potential breeding habitats for fauna such as bats. |
No record of significant nursery or breeding ground was found during the surveys. |
|
Age |
About 50-60 years, vegetation naturally restored after the World War II. |
Young. |
|
Abundance/ Richness of Wildlife |
Moderate species diversity. |
Low species diversity. |
|
Ecological Value |
Moderate to High. |
Low. |
Table 3.2b Ecological Value of Freshwater Habitat in the Assessment Area
|
Criteria |
Stream Course (East) |
Stream Course (West) |
|
Naturalness |
Largely natural at upper stream but the substrate was covered by cement near Po Shan road section. In addition, both are seasonal streams. |
|
|
Size |
The total length of stream is about 450 m. |
The total length of stream is about 750 m. |
|
Diversity |
Low stream floral and faunal diversity. |
|
|
Rarity |
Two faunal species, comprising Lesser Spiny Frog, (Rana exilispinosa) and Hong Kong Cascade Frog (Amolops hongkongensis) (in form of tadpole), of conservation importance recorded from the stream. |
One faunal species (Hong Kong Cascade Frog, Amolops hongkongensis) of conservation importance recorded from the stream. |
|
Re-creatability |
Readily re-creatable. |
|
|
Fragmentation |
Fragmented by urban facilities. |
|
|
Ecological Linkage |
Habitat is not structurally or functionally linked to any high ecological value resources. |
|
|
Potential Value |
Moderate. |
|
|
Nursery ground |
Nursery/breeding ground for fauna such as amphibians. |
|
|
Age |
Not applicable. |
|
|
Abundance/ Richness of Wildlife |
Low stream floral and faunal diversity |
|
|
Ecological Value |
Moderate. |
Moderate. |
Table 3.2c Ecological Value of Developed Area in the Assessment Area
|
Criteria |
Developed Area |
|
Naturalness |
Created habitat, most trees are planted. |
|
Size |
Area of this habitat within assessment area is approximately 25 ha, the plantations were mainly along the road within the assessment area. |
|
Diversity |
Low floral and faunal diversity (39 plant species recorded), low structural complexity. |
|
Rarity |
No floral and faunal species of conservation importance recorded from this habitat. |
|
Re-creatability |
Readily re-creatable. |
|
Fragmentation |
Habitat is fragmented. |
|
Ecological Linkage |
Habitat is not structurally or functionally linked to any high ecological value resources. |
|
Potential Value |
Low. |
|
Nursery Ground |
No record of significant nursery or breeding ground was found in the survey. |
|
Age |
Not applicable. |
|
Abundance/ Richness of Wildlife |
Low floral and faunal diversity. |
|
Ecological Value |
Low. |
3.72 Natural woodland habitat within the assessment area was considered of moderate to high ecological value because of moderate floral and faunal species diversity, moderate structural complexity and also the presence of plant and animal species of conservation interest.
3.73 Shrubland habitat was considered of
low ecological value, because of low floral and faunal diversity and most of
the species identified are common, widespread and typical of such habitat in
3.74 Streams in the assessment area were generally small and seasonal in nature. These freshwater habitats were considered of moderate ecological value, as they supported stream faunal species of conservation interest and highly natural in nature.
3.75 Developed area was highly modified
habitat supporting low diversity of plants and animals, and most of the species
identified are common, widespread and typical of such habitat in
3.76 In accordance with the EIAO TM Annex 8 criteria, the species of conservation interest are evaluated in Tables 3.3a and 3.3b below.
Table 3.3a Evaluation of Floral Species of Conservation Interest Recorded within the Assessment Area
|
Common Name |
Scientific Name |
Growth Form |
Status* |
Distribution |
|
Hong Kong Pavetta |
Pavetta hongkongensis |
Shrub |
Protected[1] |
Locally common |
|
Champion's Rhododendron |
Rhododendron championiae |
Shrub |
Protected[1] |
Rare |
|
Long-leaved Birthwort |
Aristolochia championii |
Shrub |
|
Rare |
|
Small Persimmon |
Diospyros vaccinioides |
Shrub |
Critically endangered[3] |
Locally very common |
|
Silver-back Artocarpus |
Artocarpus hypargyreus |
Tree |
Class III protected[2] Vulnerable[3] |
Locally common |
|
Incense Tree |
Aquilaria sinensis |
Tree |
Class II protected[2] Vulnerable[3] |
Locally common |
|
Common Tutcheria |
Tutcheria spectabilis |
Tree |
Protected[1] |
Rare |
|
Lamb of Tartary |
Cibotium barometz |
Fern |
Class II protected[2] Protected[4] |
Locally common |
*Sources: [1] Cap. 96 Forestry Regulation of the Forests and Countryside Ordinance. [2] List of Wild Plants under State Protection, SEPA, PRC (1999). [3] 2006 IUCN Red List of Threatened Species. [4] Cap. 586 Protection of Endangered Species of Animals and Plants Ordinance.
Table 3.3b Evaluation of Faunal Species of Conservation Interest Recorded Within Assessment Area
|
Common Name |
Scientific Name |
Conservation Status* |
Protection Status**, Distribution |
|
Avifauna |
|||
|
Black Kite *** |
Milvus migrans |
RC |
Class II protected species under mainland legislation. Locally common and widespread but with restricted roosting and breeding sites. Also protected in Cap. 586. |
|
Collared Scops Owl *** |
Otus bakkamoena |
- |
Class II protected species under mainland legislation. Locally common and widespread. Also protected in Cap. 586. |
|
Greater Coucal *** |
Centropus sinensis |
- |
Class II protected species under mainland
legislation. Classified as Vulnerable (VU) in the |
|
Herpetofauna |
|||
|
Lesser Spiny Frog |
Rana exilispinosa |
PGC |
Classified as Vulnerable (VU) in the IUCN Red List of Threatened Species. Locally common and widespread. |
|
Hong Kong Cascade Frog *** |
Amolops hongkongensis |
PGC |
Classified as Near Threatened (NT) in the IUCN Red List of Threatened Species. Locally uncommon. |
|
Mammals |
|||
|
Pallas’s Squirrel *** |
Callosciurus erythraeus |
- |
Common and widespread. |
|
Short-nosed Fruit Bat *** |
Cynopterus sphinx |
LC |
Common and widespread. Classified as
Indeterminate in |
|
Crustaceans |
|||
|
Mountain Crab |
Nanhaipotamon hongkongense |
PGC |
Common and widespread but with restricted regional and global distribution. |
* LC – Local Concern
(Habitat loss/damage in
RC – Regional Concern (Habitat
loss/damage in
PGC – Potential
Global Concern (Large, secure populations in
Refer to Fellowes et al. (2002) for further explanation of status.
** Information taken from various sources including Karsen et al. (1998), Carey et al. (2001), and Fellows et al. (2002). Protected under the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586).
***Protected under the Wild Animals Protection Ordinance (Cap.170).
Environmental Impact Identification, Prediction and Evaluation
Identification and Prediction of Ecological Impacts
3.77 Potential ecological impacts resulting from construction and operation phase activities have been identified, and are outlined in the following paragraphs.
Construction Phase
Direct Impacts
3.78 The primary potential impact resulting from the proposed works would be the direct impact to natural woodland habitat in the country park area due to construction of soil nailing and raking drains. The area of directly affected habitats is approximately 0.65 ha.
3.79 With on-site adjustment of the soil nail position, no tree felling would be required in the processes of drilling, and installation of soil nails and nail heads. For mature trees, however, potential impact on the plant rooting system would be resulted. Individuals of understorey plants are expected to be more susceptible to the potential damage during the drilling, installation of soil nails and nail heads, and construction of raking drains.
3.80 Two plant species of conservation importance, a number of Small Persimmon (Diospyros vaccinioides) and one individual of Common Tutcheria (Tutcheria spectabilis), were recorded in the proposed works area and would be directly impacted by the proposed works during the construction phase. Potential damage of individuals (Small Persimmon), damage of root systems and branches would possibly be resulted due to soil nail and nail head installation and raking drains construction.
3.81 Site access would be provided by
scaffolding & steps formed by steel. A schematic diagram of the scaffolding
is shown in Figure 5.4. The width of
site access would be approximately 0.6m and length of the access would depend
on the works locations and the actual site condition (such as the slope angle,
vegetation density, safety etc). The construction of the access would not
involve any slope cutting and the access is planned to avoid trees, no tree
felling would be required. The equipment would be transported and the workers
would access to the works area from the main entrance at
3.82 A site office, two-storey container
with approximately 5m high and 6m long, would be built in a developed area near
Po Shan Mansions along
3.83 In addition to direct impacts to habitats and vegetation, the proposed works have the potential to cause injury/mortality to wildlife. Although no substantial direct impacts to wildlife with high levels of mobility (e.g. avifauna and bats) are anticipated, animals with lower mobility such as frogs and crabs with a higher level of risk, and could potentially be injured/killed by construction phase activities.
3.84 Noise, generated by the operation of air compressor, drill rig, grouting machine, generator and concrete mixer during the soil nail installation, rock slope stabilization and raking drain installation, would cause disturbance to the wildlife nesting/inhabiting within and in the vicinity of the proposed works area. Of particular concern would be potential disturbance impacts to bat roost of Short-nosed Fruit Bat (Cynopterus sphinx) recorded from the western margin of the proposed works areas.
3.85 Indirect impacts to habitats and associated fauna adjacent to proposed works areas could be also resulted from increased human activities/disturbance. General increase in human activity could disturb wildlife utilising habitats close to the proposed works areas. Potential disturbance effects may include the avoidance of areas adjacent to the proposed works area, and reductions in wildlife density close to sources of disturbance.
3.86 Associated impacts to wildlife would arise, including restriction of wildlife utilisation (i.e. transit, feeding and roosting), degradation of habitat quality/ ecological function, as a result of temporary and permanent loss, isolation and fragmentation of ecological habitat. Habitats adjacent to the proposed works area could also be disturbed as a result of improper storage or dumping of construction materials
3.87 Potential impacts arising from the construction of the proposed landslide preventive works would also include the generation of construction dust. It is anticipated that dust would be generated mainly from soil nailing works, materials handling and wind erosion from the site. Dusts covering leaves could lead to lethal/non-lethal impacts due to a reduction in photosynthetic rates, abrasion and blocking of stomata.
3.88 Potential impacts would arise from uncontrolled dumping of construction waste, potential spillage of fuel, site run-off due to the installation of soil nails, rock slope stabilization works and construction of raking drains in the construction stage. The construction waste and runoff would contaminate the soil and hence cause impacts on the vegetation and the plant species of conservation importance.
3.89 Water-bodies potentially affected by the proposed landslide preventive works include a drainage culvert at the northern side and the eastern stream course in the vicinity of the proposed works area. Site runoff and drainage from the proposed works area, if uncontrolled, would enter the drainage culvert and stream causing potential water pollution and impact and hence impacts to the wildlife inhabiting.
3.90 Increased siltation could impact aquatic communities in watercourse (in particular the eastern stream course) adjacent the proposed works areas. Increased siltation would have a number of adverse effects on aquatic communities. In addition to direct physical damage (particularly to small invertebrate taxon) caused by larger particles (e.g., sand/gravel), small particles (e.g., silt) can clog the respiratory and feeding organs of invertebrates.
Operation Phase
3.91 No direct and indirect impacts to ecological sensitive receivers would result from operation of the proposed landslide preventive works.
Evaluation of Ecological Impacts
3.92 Potential ecological impacts to habitats in the assessment area resulting from the proposed works have been evaluated according to Table 1 of Annex 8 of the EIAO TM. The evaluation are summarised in Tables 3.4a-d below.
Table 3.4a Overall Impact Evaluation of Natural
|
Evaluation Criteria |
Natural |
|
Habitat quality |
Moderate to High. |
|
Species |
Eight floral and five faunal species of conservation importance recorded from this habitat type. There would be potential direct impacts to individuals of 2 floral species (Small Persimmon, Diospyros vaccinioides and Common Tutcheria, Tutcheria spectabilis) and one faunal species (Short-nosed Fruit Bat, Cynopterus sphinx) recorded on the fringe of the proposed works area. |
|
Size/Abundance |
Direct impact to approximately 0.65 ha of woodland by the proposed works, but no tree felling would be required. |
|
Duration |
Direct impacts would be short term. |
|
Reversibility |
Direct impacts to understorey vegetation would be reversible and temporary, as compensatory planting of shrub would be provided and the disturbed area is also subject to recolonization by the surrounding vegetation. |
|
Magnitude |
Moderate. |
|
Overall Impact Conclusion |
Low to Moderate. |
Table 3.4b Overall Impact Evaluation of Shrubland
|
Evaluation Criteria |
Shrubland |
|
Habitat quality |
Low. |
|
Species |
No significant records. |
|
Size/Abundance |
Direct impact to a very small scale of such habitat by the construction of site access would be required. |
|
Duration |
Direct and indirect impact to the shrubland is short term. |
|
Reversibility |
Direct and indirect impact to the shrubland is reversible and temporary. |
|
Magnitude |
Minor. |
|
Overall Impact Conclusion |
Low. |
Table 3.4c Overall Impact Evaluation of Freshwater Habitat
|
Evaluation Criteria |
Freshwater Habitat |
|
Habitat quality |
Moderate. |
|
Species |
Two amphibian species of conservation importance (Lesser Spiny Frog, Rana exilispinosa and Hong Kong Cascade Frog, Amolops hongkongensis) recorded from this habitat type. There would be potential indirect impacts to individuals of these two species recorded in the stream course at the eastern side of the proposed works area. |
|
Size/Abundance |
No direct impact to such habitat by the proposed works. |
|
Duration |
Indirect impact to the stream courses is short term. |
|
Reversibility |
Indirect impact to the stream courses is reversible and temporary. |
|
Magnitude |
Minor. |
|
Overall Impact Conclusion |
Low. |
Table 3.4d Overall Impact Evaluation of Developed Area
|
Evaluation Criteria |
Developed Area |
|
Habitat quality |
Low. |
|
Species |
No significant records. |
|
Size/Abundance |
Direct impact to a very small scale of such habitat by the construction of site access and site accommodation would be required. |
|
Duration |
Direct and indirect impact to the developed area is short term. |
|
Reversibility |
Direct and indirect impact to the developed area is reversible and temporary. |
|
Magnitude |
Very Minor. |
|
Overall Impact Conclusion |
Low. |
Construction Phase Impacts
Impacts to Habitats
3.93 The proposed landslide preventive work would be conducted within a natural woodland habitat in the country park area. Although the natural woodland habitat is considered of moderate to high ecological value, and provides roosting site for bats, the area of habitat affected is small in scale (0.65 ha). Besides, with on-site adjustment of the location of scaffolding, installation of soil nails and nail heads, and the construction of raking drains, no tree felling and slope cutting would be required. The impact to the natural woodland and the country park area is hence considered low to moderate.
3.94 For the construction of site access and site office, a small area of developed area and shrubland adjacent to the proposed works area would be directly impacted. These habitats are considered of low ecological value and the potentially impacted area due to the construction is very small in scale, the impacts are hence considered limited.
Impacts to Vegetation
3.95 In the processes of drilling, installation of soil nails and nail heads, potential damage on the vegetation within the proposed works area would possibly be resulted. However, with the on-site adjustment on the location of the installation of soil nails and nail heads, no tree felling would be required. Meanwhile, the potential damage to the root system of the vegetation would also be avoided and minimized by carefully placing of the soil nailing and raking drains on site. The impact to the vegetation is therefore considered minor.
3.96 The understorey vegetation including individuals of the a shrub species of conservation interest, Small Persimmon (Diospyros vaccinioides) and a tree Common Tutcheria (Tutcheria spectabilis), fall within the proposed works area under this Project might be directly impacted by the proposed works (refer to Figure 3.2 (Sheet 1) (Sheet 2)). The aforesaid species would be identified by detail vegetation surveys, the identified individuals would be labelled on site prior to the commencement of works. The soil nails near the individuals of these species would be carefully adjusted to avoid or minimize the potential damages. Given that Small Persimmon are locally common and widespread, and are not threatened in Hong Kong, the potential loss or damage of a relatively small number of individuals of the Small Persimmon would be a minor impact and no transplantation for Small Persimmon would be required. Nevertheless, the loss of this shrub in the understorey of the woodland habitat would be compensated by planting of suitable shrubs, including Small Persimmon, in the impacted areas under the Project. Furthermore, no tree felling of Common Tutcheria would be required. The potential impacts for both protected species are therefore considered minor.
Disturbance Impacts
3.97 Indirect impacts to habitats and associated communities, such as avifauna and terrestrial invertebrates, adjacent to the proposed works areas would be resulted from increased human activities/disturbance during the construction phase. Such impacts could arise from noise-generating machinery during soil nail installation, rock slope stabilization and raking drain installation, and general increases in human activity. With the use of effective quiet machinery, construction phase disturbance to the natural woodland in the country park area, other adjacent habitats and the wildlife inhabiting within and adjacent to the proposed works area is relatively minor in scale. Also, alternative woodlands are available in the Pok Fu Lam Country Park and Lung Fu Shan Country Park, the highly mobile fauna, such as birds, would simply re-locate alternative woodlands if disturbed. Hence, the disturbance impacts are considered minor.
Dumping/Dust Deposition
3.98 Impacts resulting from improper dumping of construction materials/wastes and deposition of dust on vegetation adjacent to works areas can be avoided and minimized to acceptable levels through the implementation of standard good site practice. The impact to the vegetation is considered minor.
Sedimentation/Water Quality Impacts
3.99 Sediment and runoff if uncontrolled, would carry pollutants (adsorbed onto the particle surfaces) into the streams and drainage culvert in the vicinity of the proposed works area. However, the impacts are considered limited as the two streams and drainage culvert are not within the proposed works area. Mitigation measures would be implemented to control construction site runoff and drainage from the works areas, and to prevent runoff and drainage water with high levels of suspended solids from entering nearby water bodies. With the implementation of adequate construction site drainage and provision of sediment removal facilities, it is anticipated that unacceptable water quality impacts on the two streams and drainage culvert would not arise.
Impacts to Fauna
3.100 The natural woodland habitat affected is
considered of moderate to high ecological value and provides a potential
roosting habitat for Short-nosed Fruit Bat. Only a small amount (about ten
individuals) of bats recorded in the palm trees at the margin of the proposed
works area would be impacted by the construction phase disturbance. The most
probable cause of disturbance to Short-nosed Fruit Bat would be disturbance
impact by noise generating construction works and increased human activities.
With the use of effective quiet machinery, construction phase noise disturbance
would be minimised. Although the bat roost (i.e. the two palm trees) would be
retained, in the worse-case scenario, the construction phase disturbance may
cause roosting bats to move away and result in the abandonment of roosting
site. This outcome would still be regarded as a relatively minor impact, as the
preferred roosting habitat (Palm trees) of this bat species is relatively
common in
3.101 Apart from bats, three avifauna species of conservation importance, including Black Kite, Collared Scops Owl and Greater Coucal, were also recorded during the surveys. The former one was recorded at flight above the assessment area, while the latter two were recorded in the natural woodland habitat. The most probable cause of disturbance to the bird populations would be disturbance impact by noise generating construction works and increased human activities. With the use of effective quiet machinery, construction phase noise disturbance would be minimised. In the worse-case scenario, the construction phase disturbance may cause moving away of the birds, however, this outcome would still be regarded as a relatively minor impact, as an alterative woodland is nearby at the uphill in the Lung Fu Shan Country Park and Pok Fu Lam Country Park. Hence the impact to the bird populations is considered low.
3.102 Two amphibians of conservation importance, Lesser Spiny Frog, (Rana exilispinosa) and Hong Kong Cascade Frog (Amolops hongkongensis) (in form of tadpole), were recorded from the eastern stream in the vicinity of the proposed works area. Site runoff and increased siltation would cause impacts and change the aquatic community structure of the inhabiting stream of these two species of amphibians. With the implementation of adequate construction site drainage and provision of sediment removal facilities, it is anticipated that there would be no discharge of site runoff and drainage into these natural streams and unacceptable water quality impacts on the stream would not arise, hence the impacts to the two amphibian species are considered minor.
3.103 Individuals of the Mountain Crab (Nanhaipotamon hongkongense), a semi-terrestrial crab, of conservation importance were recorded adjacent to the drainage culvert located near the proposed works area. Although the crab was recorded only 10m away from the proposed works area, in the worst worse-case scenario, the crab would move away from the potential foraging place in the proposed works area, this outcome would still be regarded as a relatively minor impact, as an alternative woodland habitat is nearby. Site runoff and drainage from the works area entering to the drainage culvert is another potential impact to the crab. However, with the implementation of adequate construction site drainage and provision of sediment removal facilities, it is anticipated that there would be no discharge of site runoff and drainage into this drainage culvert and unacceptable water quality impacts on the drainage culvert would not arise. Hence the overall impact to Mountain Crab is considered minor.
3.104 Atyid shrimp Caridina serrata of
conservation importance was previously recorded from the streams in the
mid-level of
Operation Phase Impacts
3.105 No direct and indirect impacts to ecological sensitive receivers would result from operation of the proposed landslide preventive works.
Impacts to Species of Conservation Importance
3.106 Key impacts to species of conservation importance recorded from the assessment area have been described above. A summary of potential construction and operation phase impacts to all species of conservation importance recorded from the assessment area is provided in Table 3.5.
Table 3.5 Overall Impacts to Species of Conservation Interest.
|
Species of Conservation Interest |
Construction Phase Impacts |
Operation Phase Impacts |
|||
|
Common Name |
Scientific Name |
Description |
Evaluation |
Description |
Evaluation |
|
Flora |
|
|
|
|
|
|
Hong Kong Pavetta |
Pavetta hongkongensis |
Individuals of this species fall outside but adjacent to the proposed works areas would face potential indirect impacts, such as construction dust, which are considered minor. |
Very Low. |
No impact. |
No Impact. |
|
Champion's Rhododendron |
Rhododendron championiae |
Individuals of this species fall outside of the proposed works area, no impacts predicted. |
No Impact. |
No impact. |
No Impact. |
|
Long-leaved Birthwort |
Aristolochia championii |
Individuals of this species fall outside of the proposed works area, no impacts predicted. |
No Impact. |
No impact. |
No Impact. |
|
Small Persimmon |
Diospyros vaccinioides |
Individuals of this species recorded within the proposed works area. Individuals within the area of soil nail installation would be directly impacted. |
Low. |
No impact. |
No Impact. |
|
Silver-back Artocarpus |
Artocarpus hypargyreus |
Individuals of this species fall outside of the proposed works areas, no impacts predicted. |
No Impact. |
No impact. |
No Impact. |
|
Incense Tree |
Aquilaria sinensis |
Individuals of these species fall outside of the proposed works areas, no impacts predicted. |
No Impact. |
No impact. |
No Impact. |
|
Common Tutcheria |
Tutcheria spectabilis |
Individuals of this species recorded within the proposed works area. Individuals within the area of soil nail installation would be directly impacted. |
Low. |
No impact. |
No Impact. |
|
Lamb of Tartary |
Cibotium barometz |
Individuals of this species fall outside but adjacent to the proposed works areas would face potential indirect impacts, such as construction dust, which are considered minor. |
Very Low. |
No impact. |
No Impact. |
|
Common Name |
Scientific Name |
Description |
Evaluation |
Description |
Evaluation |
|
Fauna |
|
|
|
|
|
|
Avifauna |
|
|
|
|
|
|
Black Kite |
Milvus migrans |
Recorded at flight above various habitats throughout the survey period. Indirect impacts may result from disturbance caused by increased human activity and noisy construction phase activities. |
Low. |
No impact. |
No Impact. |
|
Collared Scops Owl |
Otus bakkamoena |
A single Collared Scops Owl recorded in the natural woodland habitat outside of the proposed works area. Minor indirect impacts may result from disturbance caused by increased human activity and noisy construction phase activities. |
Very Low. |
No impact. |
No Impact. |
|
Greater Coucal |
Centropus sinensis |
Two individuals of Greater Coucal recorded in the natural woodland habitat outside of the proposed works area. Minor indirect impacts may result from disturbance caused by increased human activity and noisy construction phase activities. |
Very Low. |
No impact. |
No Impact. |
|
Herpetofauna |
|
|
|
|
|
|
Lesser Spiny Frog |
Rana exilispinosa |
Lesser Spiny Frog was recorded from stream habitats at the east of the proposed works area. Potential indirect impacts may result from disturbance, site runoff and increase sedimentation to the stream course. |
Low. |
No Impact. |
No Impact. |
|
Hong Kong Cascade Frog |
Amolops hongkongensis |
Hong Kong Cascade Frog was recorded from stream habitats at the east of the proposed works area. Potential indirect impacts may result from disturbance, site runoff and increase siltation to the stream course. |
Low. |
No Impact. |
No Impact. |
|
Common Name |
Scientific Name |
Description |
Evaluation |
Description |
Evaluation |
|
Mammals |
|
|
|
|
|
|
Short-nosed Fruit Bat |
Cynopterus sphinx |
Bat roost was recorded within the proposed works area. Although palm trees with bat colony would be retained on site, individuals within the works area would be impacted by construction disturbance. |
Low. |
No impact. |
No Impact. |
|
Pallas’s Squirrel |
Callosciurus erythraeus |
Pallas’s Squirrel was recorded outside of the proposed works area. Minor indirect impacts may result from disturbance caused by increased human activity and noisy construction phase activities. |
Very Low. |
No Impact. |
No Impact. |
|
Crustaceans |
|
|
|
|
|
|
Mountain Crab |
Nanhaipotamon hongkongense |
Mountain crab was recorded near the drainage culvert adjacent to the proposed works area. Potential indirect impacts may result from disturbance, land contamination, site runoff and drainage to the culvert. |
Low. |
No Impact. |
No Impact. |
3.107 As discussed in Section 2.18 of this Report, only one project “Agreement No. CE 28/2004 (GE) Landslide Preventive Works at Po Shan, Mid-levels – Design and Construction” (under Environmental Permit EP-235/2005/A) has been confirmed at the time of writing to coincide with the proposed landslide preventive works. Landslide Preventive Works at Po Shan (under EP-235/2005/A) would involve installation of underground drainage adits, flexible barriers, soil nails and raking drains. The anticipated programme for the slope works is from June 2006 to June 2008, which would be concurrent with the Project which is scheduled to begin in August 2007. Landslide Preventive Works at Po Shan (under EP-235/2005/A) are not anticipated to directly impact high value ecological habitats. However, construction phase activities and increased human presence have the potential to disturb wildlife in the adjacent woodland habitats. This would add to general disturbance levels in the area resulting from the Project.
3.108 Overall, cumulative disturbance impacts resulting from the two projects are expected to have only temporary and minor ecological impact as the Landslide Preventive Works at Po Shan (under EP-235/2005/A) would affect habitats comprised of man-made slopes and a small area (0.02ha) of woodland habitats and most of the works would be conducted largely underground.
Mitigation of Adverse Environmental Impacts
3.109 Following EIAO-TM Annex 16 guidelines, mitigation measures are discussed in this section to avoid, minimise and compensate for identified ecological impacts.
Avoid
3.110 The location of the soil nail installation would be carefully selected and adjusted to avoid/minimise the damage of root system to the existing plants on slope surface. No tree felling would be required.
Minimise
3.111 Fences would be erected and installed along the boundary of the proposed works area before the commencement of works in order to minimise the disturbance to the natural woodland and shrubland habitats by preventing tipping, vehicle movements and encroachment of personnel onto the adjacent areas.
3.112 In order to avoid or minimize the damage to the plant species of conservation interest, including but not limited to Small Persimmon, Common Tutcheria, Bird-nest Fern and Chinese Pholidota, within the works area, a detail vegetation survey conducted by a suitably qualified botanist/ecologist with over 7 years relevant experience would be required to identify the individuals potentially affected by the proposed works. These identified individuals would be labelled on site prior to the commencement of works for better protection during construction phase.
3.113 Mitigation measures would be implemented to minimise the indirect impacts to the nearby stream course and drainage culvert by controlling construction site runoff and drainage from the proposed works areas to prevent any runoff and drainage water with high levels of suspended solids from entering the nearby water-bodies. Site runoff would be directed towards regularly cleaned and maintained sand traps, silt traps and where appropriate, oil/grease separators to minimise risk of sedimentation and pollution to the nearby stream course and drainage culvert. An outlet pipe extending above the slope surface would be installed to facilitate collection of discharge of air, water and grout from the drillhole inserted with soil nail during grouting. With this appropriate setup, spillage of grout during the grouting operation will be effectively controlled. Furthermore, debris and rubbish generated on-site would be collected, handled and disposed of properly. Hence, no site runoff and discharge to the nearby stream course and drainage culvert would be resulted.
3.114 To avoid/minimise the impacts to the groundwater, some special measures would also be applied during the drilling operation for the soil nailing works. Air would be used as the flushing medium instead of water. Hence, the groundwater would not be affected by the flushing medium of the drilling equipment. In addition, permanent casing would be provided to the drillhole of soil nail within the permeable colluvium layer as instructed by the Engineer, in order to minimize the impact to the groundwater table situated at the permeable soil stratum.
3.115 Noise mitigation measures include the use of quiet powered mechanical equipment and insulating fabric for drill rigs. Implementing such measures would minimise disturbance to habitats within and adjacent to the proposed works area, and the wildlife inhabiting. All construction activities would be implemented at daytime only. Measures such as noise barriers should be used to minimise disturbance to the bat roost identified close to the western side of the works area.
3.116 Good site practices should be incorporated into the contract clauses to minimise the construction dust impact to the vegetation within and in vicinity of the proposed works area. A number of practical measures would be implemented, comprising the use of regular watering, with complete coverage of any aggregate or dusty material storage piles, and re-schedule of dusty activities if high-wind conditions encountered.
3.117 Standard good site practice measures would be implemented and would include:
· Placement of equipment in designated works areas and access routes selected on existing disturbed land to minimise disturbance to natural woodland habitat.
· Construction activities would be restricted to the proposed works area that would be clearly demarcated.
· The proposed works area would be reinstated immediately after completion of the works.
· Open burning on proposed works sites is illegal, and will be strictly enforced.
· Waste skips would be provided to collect general refuse and construction wastes. The wastes would be disposed of timely and properly off-site.
· Any soil contamination with fuel leaked from construction plants should be removed off-site.
· Disturbance to existing vegetation should be minimised wherever possible. In particular, adequate protection should be provided for mature trees located within or adjacent to the proposed works area.
3.118 The understorey vegetation of the woodland habitats that affected by the proposed works would be reinstated by planting of suitable shrubs/herbs, including the Small Persimmon, within the impacted areas under this Project. Chinese Fan-palm (Livistona chinensis) would be planted near the existing bat roost to provide suitable habitat for the Short-nosed Fruit Bat after the completion of landslide preventive works.
Evaluation of Residual Impacts
3.119 With the proposed mitigation measures in place, no adverse residual impacts resulting from the construction and operation works of the landslide preventive works is expected.
Environmental Monitoring and Audit
3.120 An Environmental Monitoring and Audit (EM&A) programme is recommended to be established to check compliance with legislative requirements. All the recommended mitigation measures should be incorporated into the EM&A programme for implementation during construction.
3.121 A specific monitoring programme of the plant individuals of conservation interest identified within the proposed works area during the detailed vegetation survey should be carried out by a suitably qualified local ecologist(s) with over 7 years relevant ecological experience. Regular monitoring of the trees, shrubs and herbs should be conducted to check on the health and condition of the plants. Monitoring should be conducted twice a month covering the whole construction period.
3.122 The results of ecological surveys undertaken in this study identified 4 habitat types within the assessment area comprising natural woodland, shrubland, freshwater habitat and developed area. The identified natural woodland habitat is considered to have moderate to high ecological value. The freshwater habitat was regarded as of moderate value, and all other habitats, shrubland and developed area, of low value.
3.123 Eight species of flora and 8 fauna of conservation interest have been recorded from the assessment area during the surveys.
3.124 The key issue in terms of ecological impacts would include the direct impact on plant species of conservation interest and the disturbance impacts to woodland habitat and associated communities within/adjacent to the proposed works areas arising from the landslide preventive works during the construction stage.
3.125 Two plant species of conservation interest,
Small Persimmon and Common Tutcheria, would be directly affected by the
Project. Detail vegetation surveys should be conducted to identify the
individuals of plant species of conservation interest within the proposed works
area. The identified individuals would then be labelled on site prior to the
commencement of works. The soil nails near these individuals would be carefully
adjusted to avoid or minimize the potential damages. Since the shrub Small
Persimmon is locally common and widespread and is not threatened in
3.126 To avoid and minimize the impact to the vegetation, in particular understorey vegetation and root system of trees, the location of the soil nail and raking drain installation would be carefully selected. No tree felling would be required. The direct impact to woodland habitat is therefore considered low to moderate.
3.127 Other potential sources of ecological impact would comprise disturbance impacts to habitats and associated communities adjacent to the proposed works areas that would result from increased human activities/disturbance during the construction phase. Noise mitigation measures would be implemented to minimise the disturbance to habitats adjacent to the proposed works areas. In the worse-case scenario, the construction phase disturbance may cause moving away of the bats and birds, however, alternative bat roosting habitat and woodlands are nearby, hence the disturbance impact is considered low.
3.128 For the indirect impacts to the nearby stream course and drainage culvert, by controlling construction site runoff and drainage from the proposed works areas, runoff and drainage water with high levels of suspended solids would be prevented from entering the nearby water-bodies. Debris and rubbish generated on-site would be collected, handled and disposed of properly. Hence, no site runoff and discharge to the nearby stream course and drainage culvert would be resulted. The indirect impact to the watercourse and associated faunal community is considered low.
3.129 Impacts resulting from improper dumping of construction materials/wastes, construction site run-off and deposition of dust on vegetation adjacent to the proposed works areas would be avoided and minimised to acceptable levels through the implementation of standard good site practices.
3.130 With the implementation of the recommended mitigation measures, the construction works for the proposed works would not result in unacceptable impacts on ecological sensitive receivers. The implementation of all mitigation measures would be subject to regular audit.
3.131 Further operation of the landslide preventive work would not result in substantial increases in direct and indirect ecological impacts.
3.132 A specific monitoring programme of the plant individuals of conservation interest identified within the proposed works area during the detailed vegetation survey should be carried out by a suitably qualified local ecologist(s) with over 7 years relevant ecological experience. Regular monitoring of the trees, shrubs and herbs should be conducted to check on the health and condition of the plants. Monitoring should be conducted twice a month cover the whole construction period.
Ades, G.W.J. (1999): The Species Composition, Distribution and
Population Size of
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