The following appendix provides supplementary information on the ecological surveys conducted at Lung Kwu Chau including methodologies employed and detailed findings.
Terrestrial Ecology
Habitat/Vegetation Surveys
Methodology
Each representative habitat type was surveyed on foot on 17 February and 24 August 2001. Representative plant species encountered were identified and recorded to species level, where possible, and their relative abundance noted. In each habitat type, relative abundance and dominance of flora or fauna were identified.
Site Description and Results
Backshore
There is limited vegetation along the backshore between the existing jetty and the proposed jetty location owing to previous disturbance and modification of this ground. This corridor of flat ground appears to have been artificially made by arranging boulders into a bulkhead and has been surfaced with a layer of concrete/ gravel mix which is in a deteriorating condition. Much of this ground is bare (50%) with clumps of grasses and exotic weeds. Further toward the hillside, the backshore vegetation, which is not as disturbed has stands of Clerodendrum inerme. This vegetation continues behind the sandy shore where stands of screw pine and Hibiscus are also present. There are large boulders along the backshore. Representative plant species of the backshore identified in the field surveys are summarised in the following table.
List of representative plant species recorded in the backshore vegetation
|
Species |
Abundance |
Growth form |
Status in HK |
|
Ipomoea sp. |
Abundant |
Climber |
Common |
|
Clerodendrum inerme |
Frequent |
Shrub |
Common |
|
Lantana camara |
Occasional |
Shrub |
Common
|
|
Pandanus tectorius |
Occasional |
Shrub |
Common |
|
Hibiscus tiliaceus |
Frequent |
Shrub |
Common |
|
Bideus pilosa |
Frequent |
Herb |
Common/
exotic |
|
cf. Rottboellia sp. |
Abundant |
Grass |
Common |
Shrubland/grassland mosaic
The hillside vegetation mainly comprises low shrub and grassland mosaic. Rocky outcrops are interspersed with this vegetation. Some tall scrubland is found on the north west flank of the island. Representative plant species from the hillside scrubland/ grassland mosaic identified in the field surveys are summarised in the following table.
List of representative plant species recorded in the shrub/ grassland mosaic vegetation
|
Species |
Abundance |
Growth form |
Status in HK |
|
Rhodomyrtus spp. |
Abundant |
Shrub |
Common |
|
Gordonia sp. |
Abundant |
Shrub |
Common |
|
Hibiscus spp. |
Frequent |
Shrub |
Common |
|
Acacia confusa |
Occassional |
Tall
shrub |
Common/
exotic |
|
Casuarina
equisetifolia |
Occassional |
Tall
shrub |
Common/
exotic |
|
Leucaena
leucocephala |
Ocassional |
Tall
shrub |
Common/
exotic |
Avifauna Surveys
Methodology and Results
All bird species encountered in the major habitat types within the Assessment Area were recorded in the field. Surveys were undertaken in the dry (17 February & 3 November 2001 and 7 February 2002) and wet (24 August 2001) season. Species observed are summarised in the table below. None of these is considered threatened according to UNEP Red Lists. Winter visitors and common residents were the major avifauna. Two species of greater interest were observed. These were the Reef Egret which is quite uncommon in Hong Kong, but not that rare, and the White Bellied Sea Eagle of which there are estimated to be only 20-30 breeding pairs in Hong Kong. No White Bellied Sea Eagle nest was seen in field surveys.
|
Species |
Dry Season |
Wet Season |
|
Great
cormorant (Phalacrocorax carbo) |
Ö |
|
|
Little
Egret (Egretta garzetta) |
Ö |
Ö |
|
Reef
Egret (Egretta sacra) |
|
Ö |
|
White
Bellied Sea Eagle (Haliaeetus
leucogaster) |
Ö |
Ö |
|
Vega
gull (Larus vegae) |
Ö |
|
|
Black
kite (Milvus migrans) |
Ö |
Ö |
|
Common
Sandpiper (Actitis hypoleucos) |
|
Ö |
|
White
Throated Kingfisher (Halcyon smyrnensis) |
|
Ö |
|
Common
Kingfisher (Alcedo atthis) |
|
Ö |
|
Little
Swift (Apus nipalensis) |
|
Ö |
|
Barn
Swallow (Hirundo rustica) |
|
Ö |
|
Crested
Bulbul (Pycnonotus jocosus) |
|
Ö |
|
Chinese
bulbul (Pycnonotus sinensis) |
Ö |
Ö |
|
Blue
Rock Thrush (Monticola solitarius) |
|
Ö |
|
Palla’s
leaf warbler Phylloscopus proregulus) |
Ö |
|
|
Common
tailorbird (Orthotomus sutorius) |
Ö |
Ö |
|
Jungle
crow (Corvus macrorhynchos) |
Ö |
|
|
Japanese
White-Eye (Zosterops japonicus) |
Ö |
|
|
Crested
Mynah (Acridotheres cristatellus) |
Ö |
Ö |
General Wildlife Survey
Methodology
Surveys were conducted in both the dry (17 February 2001) and wet (24 August 2001) seasons. Signs or other evidence of mammal presence such as scats or burrows were actively searched for in potential mammal habitats. For reptiles, amphibian and insects (butterflies and dragonflies), techniques involved direct observation and active searching in potential shelter sites/hiding places in potential habitats where appropriate.
Results
No evidence of herpetofauna, mammals, dragonflies or butterflies was observed during the surveys.
Marine Ecological Surveys
Intertidal Surveys
Methodologies
A representative location on the rocky boulders immediately adjacent to the proposed jetty location was surveyed using standard ecological survey methods in both the dry (17 February 2001) and wet (24 August 2001) seasons. A 10m transect was lain across 3 representative tidal heights; namely the high, mid and low rocky shore. A 50cm x 50cm quadrat was positioned at 3 locations at each tidal height. The percentage cover of sessile organisms and the density of mobile organisms was estimated.
On the sandy shore, 5 cores
(diameter about 10cm, length about 40cm) were sampled at high and low levels
along the sandy shore adjacent to the existing jetty. The samples were sieved through a 500mm mesh and stained with
rose bengal.
Results
No macroscopic invertebrates were present in the sand samples.
Results from surveys on the rocky shore are tabulated below. Note that an opportunistic inspection of the rocky shore biota at the proposed jetty location was made during a visit to the island on 20th March 2002. It was observed that there was no significant deviation in the species composition and abundance compared to findings from the previous year’s surveys. A single Collisella dorsuosa limpet was the only species seen that was not recorded in the previous surveys. The proposed jetty location comprises large boulders with large crevice spaces at the midshore inside which were observed many of the species recorded below.
Seasonal abundance of recorded intertidal organisms
|
Species (by tidal height) |
Dry Season |
Wet Season |
|
Mean density or cover |
||
|
High
shore: |
|
|
|
Ligia exotica |
4
per m2 |
9
per m2 |
|
Nodolittorina spp. |
26
per m2 |
21
per m2 |
|
Kyrtuthrix sp. |
14% |
13% |
|
Hildenbrantia sp. |
20% |
0% |
|
|
|
|
|
Mid
shore |
|
|
|
Monodonta labio |
8
per m2 |
7
per m2 |
|
Nerita spp. |
13
per m2 |
8
per m2 |
|
Siphonaria spp. |
6
per m2 |
5
per m2 |
|
Patelloida pygmaea |
2
per m2 |
4
per m2 |
|
Tetraclita squamosa |
3% |
3% |
|
Capitellum mitella |
1% |
1% |
|
Thais clavigera |
2
per m2 |
0
per m2 |
|
Green
turf (Ulva and Enteromorpha) |
20% |
2% |
|
Brown
turf (cf. Gelidium) |
5% |
<1% |
|
Hildenbrantia sp |
49% |
8% |
|
|
|
|
|
Low
shore |
|
|
|
Monodonta labio |
4
per m2 |
3
per m2 |
|
Tetraclita squamosa |
2% |
2% |
|
Saccostrea cucullata |
4% |
2% |
|
Capitellum mitella |
1% |
1% |
|
Septifera bilocularis |
<1% |
0% |
|
Green
turf |
68% |
3% |
|
Sargassum spp. |
4% |
0% |
Sub-tidal Surveys
Dive survey
Methodology
On 19 April 2001, two divers experienced in coral survey conducted a dive survey by traversing approximately 200m of rocky shoreline each side of the bay at a depth of approximately –2 to –5m C.D. Underwater visibility was poor (<0.5m) because the water was highly turbid.
Results
No corals were found on any natural hard substrata in the subtidal area in and around the bay. Gorgonians, which are highly tolerant to high turbidity conditions were, however, found in abundance attached to the shipwreck to the north of the bay. These gorgonians were identified as the blue coloured Euplexaura sp short seawhip. These gorgonians were growing among coralline algae and aggregations of bivalves (Septifera bilocularis). Also observed at this location, were 2 ahermatypic Tubastrea sp colonies. These however were completely dead.
To the south of the bay, the same type of gorgonian seawhip coral was also observed on rusting steel bars adjacent to the proposed jetty location. However, at this location, their abundance was sparse numbering a total of only 6 individual colonies. The rusting steel bars were derived from dumped building material.
Grab survey
Methodology
On 3 November 2001, a weighted ‘modified van Veen’ grab with a gape of 30cm x 30cm was deployed 3 times in the area in which dredging would take place for the proposed jetty construction. The 3 sediment samples were landed and taken back to the ‘mothership’ survey vessel. Each grab sample was tipped into a large plastic sorting tray and thoroughly sifted through, taking approximately 15 minutes per sample.
Results
The sediment comprised homogenous, viscous, watery, silty mud which was dark olive green in colour with darker wisps. No odour (to indicate anoxia) was detected. No macroinfauna were present in the sediment samples.