APPENDIX F
There are four
patches of fung-shui forest within the 500 m zone of the alignment, and they
are located at Tsung Pak Long, Ho Sheung Heung, Chau Tau and Pun Uk Tsuen. “Fung-shui
forest” in ecological terms refers to those old-growth forest around rural
village that have never been completely deforested, and, therefore, represent
at least remnants of the original flora (Dudgeon and Corlett, 1994); this term
is used here simply to reflect the location of the forest and also provide an
indication of the age of those forest patches. It is noted that none of the four patches of fung-shui
forest identified by the Study Team was studied in a comprehensive Hong Kong -
wide fung-shui forest survey conducted in 1997 (Chu, unpublished).
The fung-shui forest behind Ho Sheung Heung village shows little sign of human disturbance. The closed upper-canopy is composed of mainly board-leaf evergreen tree species; and depending on the species, their sizes ranged from 8 m to 18 m in height, and the girdle width in terms of diameter at breast height (dbh) ranged from approximately 10 cm to 80 cm. This forest is structurally complex because of the dense under-storey growth and the presence of several climbing plant species. The canopy layer is mainly dominated by the tree species Cinnamomum camphora, Machilus orephila, Microcos paniculatus, Sterculia lanceolata, and Schefflera octophylla; whereas the under-storey of the forest is composed of tree saplings as well as the shrubs Psychotria rubra, Ligustrum sinensis, Ardisia quinquegona and Glochidion eriocarpum.
The fung-shui forest in Tsung Pak Long is comparatively smaller and more fragmented, and it’s species richness and structural complexity is considered to be very low, possibly as a result of the village expansion and the associated intensive human activities in the surrounding area. Although the canopy is closed and approximately 20 m or more in height, it is mainly composed of a few tree individuals (mainly Ficus microcarpa and Cinnamomum camphora) which have a very big crown spread (> 15m in diameter). On the other hand, the under-storey of this forest patch is only sparsely covered with vegetation, and species found are limited to those well-adapted to such disturbed environments such as saplings of Bridelia tomentosa and Dimocarpus longan, as well as other weedy herbaceous plants.
The fung-shui forests behind Chau Tau and Pun Uk Tsuen are similar in species composition and habitat characteristics. Both are dominated by Cinnamomum camphora and Celtis sinensis in the upper-canopy which has an estimated average height > 14 m. Other tree species commonly observed in the canopy layer are Litsea glutinosa, Ficus microcarpa, Sterculia lanceolata, Cratoxylum ligustrum as well as Microcos paniculatus. Human activity is observed to be moderate within these two forest patches, as the edge of both forests are planted with a high abundance of fruit trees including Dimocarpus longan and Litchi chinensis, a common practice of rural villagers; in addition, a number of graves were also observed within the forest area. Nevertheless, except for those areas near the fruit tree plantation and the graves, the under-storey growth of the two forest patches is found to be rich and dense, where saplings of native tree species, as well as other woody plants such as Litsea rotundifolia, Desmos chinensis, Ligustrum sinensis, Psychotria rubra and Cansjera rheedii, are very common.
It is noted that no protected or rare plant species were found or reported by other studies within the fung-shui forests of the Study Area. Although a protected plant species Michelia alba was reported by Binnie-Meinhardt JV (1999) in Chau Tau Village (location of the sighting not specified), it is suspected that this species was planted by the villager and may be exempted by the Forestry Regulation.
In general, the
ecological potential of forest habitat depends on a range of intrinsic and
extrinsic factors, such as the dimension, structural complexity and species
diversity of the forest, which in turn is related to the habitat heterogeneity
and hence the range of micro-habitat and resources that is provided to wildlife; on the other
hand, the level of disturbance and nature of the surrounding habitats also
affects the potential wildlife use of the habitat. Accordingly, with the exception to the fung-shui forest at
Tsung Pak Long Village, which is structurally and compositionally simple with
intensive human activities, the other three fung shui forests could provide
potential refuge for different wildlife, in particular mammal and avifauna
species which may be of conservation importance.
Lowland
Secondary Forest (LSF) within the Study Area is highly fragmented and
scattered, those larger in size are found around Lok Ma Chau, Pak Shek Au and
the foothill of Ki Lun Shan.
The LSF in Lok
Ma Chau is an open pine forest and the under-storey of which has been
periodically burnt by hill-fire, in particular those areas closed to the Lok Ma
Chau Road where a number of graves sites are present in the under-storey. This LSF was surveyed by ERM in 1998.
The report (ERM, 1998) stated that the Pinus
massoniana, growing to a height of about 15 m forms an open canopy at the
foothill, which is also covered by Mikania
micrantha and Ipomoea cairica.
Various common trees, shrubs and ferns have become established in the
understorey. These include Rhodomyrtus tomentosa and Dicranopteris linearis, Rhus chinensis and
Bridelia tomentosa; the shrubs Litsea rotundifolia and Helicteres angustifolia, the grasses Miscanthus floridulus and Panicum maxima, as well as the climbers Morinda umbellata and Paederia scandens. Moving uphill, woody cover decreases
rapidly, leaving the higher slopes dominated by grasses and ferns which are
maintained by fire. Apart from the
main road along the foothill and access to the grave areas, these woodlands are
fairly inaccessible due to the presence of a young, dense under-storey and
coverage by climbers at the foothill.”
According to
the field survey undertaken during the present Study, it is noted that the
eastern part of the forest is composed with a mix of Pine tree and other
board-leaf tree species such as Microcos
paniculatus and Celtis sinensis that
forming a semi-closed canopy, and the under-storey growth is found to be denser
with little grass or fern cover.
In addition,
there is a small patch of LSF within the 100m zone in the restricted area at
Lok Ma Chau which is also dominated by Pinus
massoniana and other board-leaf tree species that resemble the eastern part
of the open pine forest as discussed above.
The LSF patches
found in Pak Shek Au and foothill of Ki Lun Shan are very similar in nature and
composed of a mix of needle-shaped trees and other board-leaf evergreen species
in the canopy layer, such as Pinus
massoniana, Casuarina equisetifolia and
Cinnamomum camphora; common pioneer
tree species Ficus hispida, Sapium discolor, Rhus succedanea and Mallotus paniculatus; as well as other
common secondary forest species such as Celtis
sinensis and Litsea glutinosa. Given the relatively young age of these
two lowland secondary forests, a closed canopy is absent and the height varies
with species; however, the under-storey growth is found to be vigorous with a
number of common shrub species and weedy species being observed, such as the
shrub Litsea rotundifolia, Glochidion
eriocarpum and Psychotria rubra,
as well as the climbers Ipomoea cairica
and Mikania micrantha.
No species of
conservation importance was observed or reported by other studies for the lowland
secondary forests found within the Study Area, however, it is noted that the
population of the Pinus massoniana is
declining in Hong Kong because of the nematode infection.
The ecological
potential of LSF to be utilised by wildlife is similar to that of fung-shui
forest as discussed in previous section, and could provide shelter/cover and/or movement corridor for a range of
wildlife. However, given that all
of the LSF found within the Study Area are generally small in size and/or are
surrounded by developed areas, the wildlife that could be supported would
expect to be limited to common and wide-spread species.
Plantation Forest (PF) is defined as those forest patches comprising primarily fast growing exotic tree species, such as Acacia confusa and Eucalyptis sp.. This habitat type is mainly be found along roads or over cut-slopes where they have been planted for landscaping purpose. These patches are mostly simple in structure, low in diversity, small in size, elongated in shape and highly fragmented (Figure 4.1).
The canopy height of PFs varies and is
dependent upon the species composition and age of the plantation. For instance, the Casuarina equisetifolia bordering part of the San Sham Road and
around Kwu Tung/Pak Shek Au have an average height of about 15 to 20 m, whereas
those Acacia plantation in between the Fanling Highway and Castle Peak Road, or
those within Sheung Shui area, are usually less than 12 m in height. Nevertheless, under-storey growth at
each of the plantation forests within the Study Area was found to be generally
poor and mainly covered with cosmopolitan weeds such as the shrub Lantana camara, the grasses Panicum maxima and Imperata cylindrica, as well as the climbers Ipomoea carica and Mikania
micrantha. However, for those
relatively older patches, such as the one located
in Kwu Tung/Pak Shek Au, seedlings or saplings of certain native tree
species were also recorded, such as the pioneer tree species Macaranga tanarius, Celtis sinensis,
Bridelia tomentosa and Litsea
glutinosa; as well as the native shrubs Psychotria rubra and Ligustrum sinensis.
According to Dudgeon and Corlett (1994), plantation forest differs from natural forest of similar age in several ways, in particular the plant diversity and the poorly‑developed under‑storey which tend to reduce the diversity of the inhabited animal fauna. Given that most of the PFs found within the Study Area are closed to developed area, which further degrade the potential of this habitat type to support any wildlife of conservation importance.
Orchard is defined as wooded areas planted with fruit trees, and this kind of habitat is very common in rural Hong Kong. Within the Study Area, orchards are mainly to be found scattered in the Kwu Tung, Pak Shek Au and Chau Tau areas, either within the backyards or gardens of the village houses, or adjacent to village areas (Figure 4.1). This habitat type is in general small and fragmented, and with low species diversity because of specific management practices such as the clearance of under-storey weeds and the application of pesticide.
The most commonly planted fruit tree species are Dimocarpus longan, Litchi chinensis, Clausena lansium, Magnifera indica, as well as Citrus paradisi. The canopy height varies with the age and type of the species planted, and the under-storey is in general open with sparse weedy plant cover.
Given the
openness of structure and close proximity of this habitat type to human
settlement, it is unlikely that any species of conservation interest could be
found within orchard; nonetheless, it should be noted that Citrus plants are a
larval food plant for a number of butterfly species, and the fruit of Clausena lansium is a food item for
fructivorous wildlife such as some species of avifauna and fruit bats.
Agricultural
land has been categorised with reference to current management practices; on
this basis three types of agricultural habitat could be identified within the
Study Area:
·
wet
agricultural land – those agricultural areas which are actively cropped with
aquatic plants, usually flooded with water year‑round or seasonally and fully
covered by crops except during the time of harvesting;
·
dry
agricultural land - those area used for the production of non‑aquatic
agricultural produce; and
·
inactive
agricultural land - those disused or abandoned agricultural areas where active
management has ceased and colonisation by weedy plant species is evident.
Since the
permanency of these three habitat types is subject to the management practices
of the owner (or tenant), their coverage and distribution is reported on the
basis of the field-checking undertaken during the course of the current study.
Within the
Study Area, agricultural habitats are mainly to be found around Chau Tau Village, as well as the River
Beas and River Sutlej floodplain, i.e., the area in between Yin Kong, Ho Sheung
Heung and Tseung Pak Long – an area commonly known as Long Valley by local ecologists. Both of these two areas are covered by a mosaic of the three
agricultural habitats, and the “inactive agricultural land” is by far the most
abundant agricultural habitat type within the Study Area.
Examples of
produce cultivated in the “wet agricultural land” include the vegetables water
spinach Ipomoea reptans and water
cress Rorippa nasturtium- officinale;
whereas other vegetables such as lettuce Lactuca
sativa, chinese kale Brassica
alboglabra and flowering white cabbage Brassica
parachinensis were frequently recorded within the Study Area.
Generally
speaking, the structural complexity and species diversity of active
agricultural land is generally poor as a result of farming management practices
such as weeding (where unfavourable plants will be removed) and fertilising
(which favours the nutrient requirements of the crop species). Conversely, depending on the water
regime and the length of time the land has been unmanaged, inactive
agricultural land is usually structurally more complex with a greater species
diversity as species invasion increases in the absence of such management
activities. For instance, whilst
some of the inactive “wet” agricultural land within the Study Area was still
dominated by (uncropped) water spinach, a mix of wetland vegetation such as Commelina nudiflora, Rumex maritimus and Leersia hexandra was frequently
recorded from these areas.
Similarly, some of the inactive "dry" agricultural land has
been colonized by a mix of weeds in particular the grass Panicum maxima and the climbers Mikania
micrantha and Ipomoea carica.
The potential for agricultural land to support animal wildlife is largely dependent upon the type of management practice (such as timing of mowing/tilting and application of fertilizer, pesticide and insecticide) which can vary significantly in accordance with the type and growing season of the crops. For example, because "wet" agricultural land functions as a "wetland" habitat, it may provide a range of resources to wildlife such as birds, amphibia, dragonflies, and other invertebrate fauna; in turn, those animal provide prey base and attract other wildlife higher up the food chain such as mammals, snakes and birds of prey. However, the relatively ephemeral nature of seasonal cropping results in actively managed wet agriculture having a low structural complexity. In areas of agricultural activity, changing patterns of cultivation provides for effective colonisation between areas as one area is taken out of wet agricultural production another is flooded for wet cropping. Such a changing mosaic ensures the retention of base prey areas and ensures the availability, within a linked geographical area, of resources for birds, herpetofauna and mammals.
In general, disused, inactive or abandoned agricultural land is often more valuable to wildlife as this type of habitat is usually over‑grown with vegetation of different growth forms and human activities is generally lower or even absence. This resulting diverse micro‑habitats and tranquillity can often provide an ideal refuge for wildlife, notably the wet "inactive" agricultural land may turn to marsh and provide important feeding and breeding ground for wetland-associated wildlife.
On the other
hand, a recent publication (Porcupine!, December 1998) has discussed the general wildlife use of agricultural land
in Hong Kong (Anon., 1998) and it is possible that some of the referenced
wildlife may be found within the Study Area given the similarity of most of the
agricultural land in Hong Kong (see Appendix Table F1 for a summary).
Table F1
Wildlife known to Inhabit
Agricultural Land in Hong Kong
|
Animal
Group |
|
Animal-habitat
Relationship |
Conservation
Status |
|
Medium-sized Mammal |
Barking Deer,
Porcupine, Ferret Badger, Seven-banded Civet |
Inhabit forest but utilising agricultural land for foraging, shelter and as movement corridors |
All protected |
|
Small-sized
mammal |
Ryukyu Mouse and
Small Asian Mongoose |
Both species are
highly adapted to agricultural land for foraging, feeding and nesting |
All protected |
|
Bats |
Japanese Pipistrelle Noctule Bat Lesser Yellow Bat Large Bent-winged
Bat Great Himalayan
Leaf-nosed Bat Leschenault's
Rousette Bat Short-nosed Fruit
Bat |
Foraging habitat for
both insectivorous and fruitivorous bats |
All protected |
|
Amphibian |
Asian Common Toad Rough-skinned
Floating Frog Gunther's Frog Paddy Frog Three-striped Grass
Frog Chinese Bullfrog Two-striped Grass
Frog Brown Tree Frog Narrow-mouthed frog Asiatic Painted Frog Butler's Pygmy Frog Ornate Pygmy Frog Marbled Pygmy Frog |
Breeding and
foraging habitats |
- |
|
Reptile |
Chinese Skink Buff-striped Keelback Plumbeous Water
Snake Banded Krait |
Nesting and foraging
habitats, also as movement corridors |
|
|
Bird |
> 84 species |
Foraging, roosting
and breeding habitats |
All protected |
|
Insects |
Species richness is
relatively low but with high abundance |
Foraging and breeding habitat |
- |
As with the
agricultural habitats, ponds within the Study Area are also classified into three different habitat
types depending on current management practices:
·
Fishpond
– those ponds actively managed for fish production;
·
Inactive
fishpond – those fishponds which are not actively managed for fish production;
·
Ponds -
those ponds which are shallower and actively managed for blood-worm production.
Within the
Study Area, fishponds are mainly to be found in San Tin, Lok Ma Chau and Ho
Sheung Heung areas, and is the dominant habitat type within the 200 m study
corridor. These are mostly active
and used for the polyculture of edible freshwater fish such as carp, mullet and
snakehead. In addition, high
numbers of various non-commencial species such as Tilapia and mosquito fish are
also present. It is noted that the shallow “pond” habitats located at Ho Sheung
Heung are converted from agricultural land and are used for raising blood-worm
as feed for fish.
Most of the pond
bunds within the Study Area are dominated by common and widespread plant species
(Anon, 1995), such as Panicum maximum, Paspalum conjugatum, Alternanthera sessiles, Commelina nudiflora and Mikania micrantha, and sometimes isolated
trees such as Melia azedarach, Ficus
microcarpa, Dimocarpus longan and Clausena lansium were found planted along
the bunds or near village houses, in particular those fishponds found within
the San Tin area. On the other
hand, some of the fishpond bunds have been cleared and planted with Ipomoea batatas, Canna indica and Musa paradisiaca
to preclude grass growth (ERM, 1999). Emergent and/or submergent epiphyte is in general absent except
on those inactive fishpond where management was ceased (for example, the two
inactive fishponds in front of Ho Sheung Heung village as shown at Figure
4.1).
It is noted
that fishponds, ponds and agricultural land are inter-changeable, for
instances, several fishponds in Ho Sheung Heung have been converted into “wet”
agricultural land and cropped with water spinach; whereas certain agricultural
land has been converted into ponds for rearing bloodworms. This observation reflects the dynamic
nature of the land-use within the Study Area.
Pond habitats usually functioned as "wetland" and provide resources to wetland-associated wildlife, such as dragonflies, amphibia, and avifauna. In particular, those located at San Tin and Lok Ma Chau are part of the wider fishpond habitat resource of the Deep Bay area and perform comparative ecological functions to those within the RAMSAR site. However, as with agricultural land, the ecological value of ponds is related to the type and intensity of current management practices. For example, Tilapia and mosquito fish could provide food for birds (particularly during pond drainage), and the large quantity of chironomids larvae when hatched could attract lots of insectivorous birds and bats. On the other hand, those inactive fishpond with plenty of submerged or emerged vegetation along the pond bunds provide an ideal breeding grounds for amphibia and dragonflies.
The ecological importance of fishpond is also recognised by the Government. The Planning Department has commissioned a study on the ecological value of Deep Bay fish ponds, for which the Final Report and Executive Summary are available. The fishponds within the Study Areas are within the feeding range of several egretries (Mai Po Egretry and Ho Sheung Heung Egretry) and are considered to be a very important feeding ground for the resident ardeids.
Marsh habitat
within the Study Area is found at Ho Sheung Heung and San Tin (Figure
4.1). The marshland of the
Study Area is typically freshwater habitat that is usually overgrown with
grassy vegetation and often has areas of seasonal or permanent open water. Since
most of the marsh in Hong Kong is derived from inactive wet agricultural land
which has been abandoned for a considerable period, these two habitat types
are differentiated in this study by referencing the biological characteristic
and species diversity of the habitat.
Although the
level of human disturbance to this habitat is relatively low, the appearance
and other habitat attributes of the marshes in San Tin and Ho Sheung Heung are
quite different.
The one located
in San Tin is overgrown with herbaceous vegetation with an average height of
1.5m. ERM (1999) reported that
five species of herbaceous plant similar to that of the grassy pond bund were
found in the marsh, which is dominated by tall grasses and reeds including Panicum maximum and Phragmites communis.
It was also noted that there was a seasonal variation in both species
diversity and abundance in terms of the grass cover.
The marshes
located in between the agricultural land at Ho Sheung Heung are also covered by
herbaceous plants with an average height of about 0.5 to 1m, and the overall
coverage about 80%. This area is
dominated by grassy vegetation such as Panicum
repens, Digitaria disctrichum and
Leersia hexandra; as well as other
herbaceous plants Ranunculus sceleratus,
Rumex maritius and Polygonum hydropiper. It is noted that the species diversity
of the marsh found here is higher than that located in San Tin.
None of the
freshwater marshes found within the Study Area was covered in a freshwater
wetland study undertaken in 1996 (Dudgeon et al., 1996). However, it is known that the
freshwater marsh at Ho Sheung Heung supports one of the breeding populations of
the locally rare resident bird Painted Snipe, and more than 6 species of
Odonata (dragonflies and damselflies) were seen during the habitat survey
conducted for this Study. Other
ecological functions supported by the marsh habitat within the Study Areas
would be breeding habitat for amphibian and Odonata, as well as feeding habitat
for insectivorous avifauna, herpetofauna and mammals.
Water courses
found within the Study Area include the River Beas, the Sutlej River and the
River Indus around Shung Shui and Ho Sheung Heung areas; several drainage
channels along both side of the Lok Ma Chau crossing; as well as ditches in
between the agricultural land within the Study Area (Figure
4.1).
It is noted
that each of the three rivers mentioned has already been seriously affected by
the construction activities associated with the Main Drainage Channel (MDC). It was reported in Maunsell (1997) that
the water quality of these three rivers is generally poor and grossly polluted
with domestic sewage or livestock wastes, and the water quality of the River
Beas and River Indus were classified as “very bad” by EPD in 1996 (EPD, 1996 as
quoted in Maunsell, 1997).
Although a nullah near the River Beas bridge at Ho Sheung Heung still
supports aquatic, emergent, and riparian vegetation that may provide some
wildlife habitat as suggested by Maunsell (1997), it is believed that this
section will soon be affected by the MDC project.
Those sections
of the drainage channel in San Tin/Lok Ma Chau which are subject to tidal
influence appear to have better water quality, whereas those found close to San
Sham Road or Castle Peak Road are grossly polluted with stagnant water and
strong odour. In the unlined
sections the stream and its banks supported a dense cover of grasses and herbs
such as Panicum maximum and Mikania micrantha.
The ditches found within the Study Area are mostly scattered among the agricultural land (earth‑lined) or rural village (concrete‑lined). These aquatic habitats were found to be heavily disturbed and were receiving high loadings of nutrients (from fertilizer) or domestic pollutants (from domestic discharge). The field observations made during the study noted that the water level of all of the ditches, except those flow through "wet" agricultural land, is very low and loaded with all kinds of domestic waste (Maunsell, 1999).
It is expected that wildlife use of this habitat type would be very limited due to the general poor water quality and disturbance they suffered; however, certain invertebrate species notably the chironomid larvae which is well‑adapted to such environments were found in high abundance and could provide abundant food prey to attract insectivorous animals.
Grassland-shrubland mosaic is mainly be found on the south-facing slope of behind Kwu Tung and northern hill-slope of Ki Lun Shan; these areas are composed of a mix of typical hill‑side vegetation, including the shrub Rhodomyrtus tomentosa, Breynia fructicosa, Litsea rotundifolia and Rhaphiolepis indica; the grasses Arundinella setosa, Cymbopogon sp., Eulalia sp., and Ischaemum sp.; as well as the fern Dicranopteris linearis. This habitat type suffers from frequent hill-fires as evidenced by the presence of the fire-indicator Dicranopteris linearis and the presence of significant numbers of hillside graves; it was noted during the habitat survey that part of this habitat near Chau Tau village was recently burnt.
The structural complexity and species diversity of this habitat type as a whole is considered to be low, given the frequency and level of disturbance it has suffered. No studies has been conducted to address the ecological value of regularly burnt hillside in terms of the wildlife it support, but the potential of this habitat in supporting species of conservation interest is considered to be limited given the openness and disturbed nature of this habitat. Nonetheless, several bird species of conservation interest that favour open hill-side has been recorded in this habitat behind the Chau Tau village, such as the Eagle Owl.
Wasteland is defined as those areas formed as a result of human activities and either wholly or partly covered by weedy or ephemeral vegetation. Within the Study Area, wasteland areas are usually small and fragmented and found along roads and paths, and in areas next to existing villages, buildings or open storage sites where the land is either newly formed or abandoned.
Generally speaking, this habitat type is open in structure and poor in species diversity, and dominated by the grasses Panicum maxima, Neyraudia reynaudiana, Imperata cylindrica; as well as the climbers Ipomoea carica, Paederia scandens and Mikania micrantha. Occasionally, some pioneer tree species such as Leucaena leucocephala and Macaranga tanarius were also found scattered among the wasteland.
Given the general disturbed and open nature of this habitat, wildlife use of this habitat type would likely be common and wide-spread species of little ecological/conservation importance.
Developed area
are those areas heavily developed or disturbed with very little or no
vegetation cover, such as open storage, villages, or the urbanised area. Ecological resources provided by this
kind of “habitat” is impoverished except some roadside weeds that may provide
food item for some common wildlife that are highly adapted to urbanised areas,
and no wildlife of conservation interest is expected within this habitat.
