Miscellany

Wu Kau Tang, protected areas and the persistence of absurdity

An update on the distribution of mangroves in the North East New Territories

Conservation of buildings and cultural heritages: stone-and concrete-eating microorganisms

Wu Kau Tang, protected areas and the persistence of absurdity

by G.T. Reels

Last year the remote village of Wu Kau Tang in the northeast New Territories received some unaccustomed media attention, as the site for a proposed Chinese medicinal herb garden and associated developments. This proposal has since slid out of the public spotlight, but is presumably still being pursued by its proponents. The planned development should be a cause for concern to conservationists and nature lovers alike, because Wu Kau Tang and the surrounding area represents one of the best unprotected biodiversity sites within the SAR.

Wu Kau Tang is surrounded by Plover Cove Country Park but, as with so many rural villages, is excluded from the protection that the country park offers. An area of approximately two square kilometres, comprising the village and its extensive abandoned agricultural lands, as well as stretches of several unpolluted streams (and a small part of the excellent fung shui wood), is excised from the park and largely unprotected (part of it is zoned as a Conservation Area). The author has resided in Wu Kau Tang for the past three and a half years. So, what is the wildlife that utilizes this area?

The abandoned fields to the east of the village, forming a series of marshes and low terraced hills, are frequented by Wild Boar (Sus scrofa), Barking Deer (Muntiacus muntjak and/or M. reevesi) and Ferret Badger (Melogale moschata). A remarkably large group of 20 or so Broad-billed Rollers (Eurystomus orientalis) was seen hawking for termites after heavy rain in April 2000, and huge Leschenault’s Rousette Bats (Rousettus leschenaulti) are frequently seen taking fruit in the village. Grey Nightjar (Caprimulgus indicus) and Savanna Nightjar (C. affinis) forage over the lowlands at night, and in March this year an Eastern Grass Owl (Tyto longimembris) was observed foraging over the same areas.

Black Paradise Fish (Macropodus concolor) are present in the marshes, one of which is also the only known site in the SAR for Hydrochidae beetles, as a result of which that particular marsh was recommended for protection (by extension of the country park boundary) in a report on freshwater wetland habitats commissioned by the then Agriculture and Fisheries Department (Dudgeon & Chan, 1996). The author is unaware as to whether any action has been taken on this recommendation.

Fish fauna in the streams passing through the area has not been thoroughly surveyed, but on a recent site visit by fish expert Bosco Chan, several individuals of Osteochilus vittatus were observed. There have apparently been no published records of this species in Hong Kong for thirty years. The author has, on two occasions, encountered terrapin traps in the same stream – a sure indication that the critically endangered Three-banded Box Terrapin (Cuora trifasciata) is present (although perhaps not for much longer). A dead specimen of the locally rare Banded Stream Snake (Opisthotropis balteata) was encountered on the village road beside this stream in 1999. The stream is also rich in dragonflies, and was recommended for protected status on the basis of its odonate fauna by Wilson (1997). Two species of Macromia (M. katae and M. urania) are present, while Gynacantha japonica and Macromidia rapida are abundant.

A pond and marsh area less than half a hectare in size within the village itself has been a breeding site for no less than ten amphibian species this spring, including Asian Common Toad (Bufo melanostictus), Günther’s Frog (Rana guentheri), Paddy Frog (Rana limnocharis), Three-striped Grass Frog (Rana macrodactyla), Chinese Bullfrog (Rana rugulosa), Brown Tree Frog (Polypedates megacephalus), Asiatic Painted Frog (Kaloula pulchra), Butler’s Pigmy Frog (Microhyla butleri), Ornate Pigmy Frog (Microhyla ornata) and Marbled Pigmy Frog (Microhyla pulchra). Sadly, this remarkable amphibian site is now directly threatened by construction of two new village houses. Other frogs present within the area include Spotted Narrow-mouthed Frog (Kalophrynus interlineatus) (Lau & Dudgeon, 1999), Lesser Spiny Frog (Rana exilispinosa) and Green Cascade Frog (Rana livida).

Doubtless this catalogue of animal life can be added to by others. It certainly does not pretend to be comprehensive (and the author readily admits to being floristically challenged). But one would already be hard-pressed to find any comparable site of similar habitats within Plover Cove Country Park. Indeed, it seems an absurd paradox that so many of the obvious wildlife ‘hot-spots’ in the vicinity of this country park – Wu Kau Tang, Sam A Tsuen, Lai Chi Wo, Kuk Po – have been excised from it. Of course, this is an all too-familiar story (think of Sha Lo Tung, Wong Chuk Yuen, Sham Chung, Luk Keng ...). In the case of Wu Kau Tang, recent years have seen two separate proposals, from authoritative sources, to gain a greater level of protection for different habitats (marsh and stream) within the site, and to date neither of these has apparently been approved or acted upon. In the meantime, the developers are starting to take an interest.

Having done me the courtesy of reading this far into such a rambling article, the exasperated reader may well ask: "So what’s your point?" The point is simply this: that Hong Kong’s biodiversity is inadequately served by the current protected areas system, which often seems to go out of its way to exclude that biodiversity. And the question is: How can we change this, when faced with an administration which apparently attaches more importance to satisfying the interests of ‘indigenous’ villagers than to establishing an effective, conservation-orientated protected areas system? As a non-indigenous resident of Wu Kau Tang, I’d love to know the answer.

Bibliography

Dudgeon, D. & Chan, W.C. (1996). Ecological Study of Freshwater Wetland Habitats in Hong Kong. Report prepared for the Agriculture & Fisheries Department, Hong Kong Government.

Wilson, K.D.P. (1997). An annotated checklist of the Hong Kong dragonflies with recommendations for their conservation. Memoirs of the Hong Kong Natural History Society 21: 1-68.

P.20-21

An update on the distribution of mangroves in the North East New Territories

by Captain L.C. Wong

The North East New Territories, which includes Starling Inlet (Sha Tau Kok Hoi) and Crooked Harbour (Kat O Hoi), is one of the few remaining unspoiled areas in Hong Kong, primarily due to its remoteness. In this area, the distribution of mangroves was studied as part of a territory-wide survey by Tam and Wong in the mid 1990s, and a total of five mangroves was found in Starling Inlet and Crooked Harbour (Tam and Wong, 2000). However, five more mangroves were located during a waterbird study in the area since 1997 (Wong et al., 1999). In this paper, I would like to discuss an updated distribution of the mangroves in this region of Hong Kong and their use by other wildlife. The names of locations follow the Countryside Series North-East New Territories map (Edition 4) published by the Survey & Mapping Office, Lands Department. The mangrove species found there are based on casual observations.

Mangroves at Yim Tso Ha, Nam Chung, Luk Keng, Kuk Po, Yeung She Au and So Lo Pun are semi-natural habitats which are the result of abandonment of brackish water rice cultivation in the late 1960s. Only those along the coast are considered to be natural habitats.

(1) Sha Tau Kok

This mangrove is situated within the Frontier Closed Area (FCA), and is distributed along the coast from Sha Tau Kok Town to the Shek Chung Au Police Checkpoint. Although Tam and Wong (2000, and in more detail in their unpublished 1997 report to AFD) have described a mangrove with the name "Sha Tau Kok", this is at a different site outside the FCA. Kandelia candel is the main mangrove tree but Avicennia marina is also found. During high tide, egrets and herons use this mangrove as a roosting site. According to a 1981 aerial photo, there was previously a larger mangrove area off Sha Tau Kok which was destroyed by the expansion of the new Sha Tau Kok Town.

Another small mangrove (appro. 20 x 50 m) is found on the inland side of Sha Tau Kok Road. Mangrove species found there are Kandelia candel and Aegiceras corniculatum. Waterbirds that used this mangrove are Little Egrets, Chinese Pond Heron, Banded Rails (Gallirallus striatus) and Little-ringed Plovers (Charadrius dubius). Fiddler crabs (Uca spp.) were also found in the mangrove. According to the past aerial photos, this was once a coastal mangrove but has been cut off by the Sha Tau Kok Road, with a small channel that connects to the sea.

These two mangroves have no legal protection for conservation purposes but are within the FCA boundary and thus entrance is restricted to people with written permits. The North East New Territories planning study recognises this mangrove as one of the constraints to future developments.

(2) Wu Shek Kok

This mangrove is situated in a sheltered bay near the Shek Chung Au Police Checkpoint. Tam and Wong (2000) named this mangrove "Sha Tau Kok" but, according to the countryside series map, this area is called Wu Shek Kok. This mangrove was mentioned by Murton (1972) during his study of the critically endangered Chinese Egrets (Egretta eulophote) in Starling Inlet. K. candel is again the main mangrove tree but Avicennia marina, Bruguiera gymnorhiza and Acanthus ilicifolius are also found.

These mangroves are zoned as "Coastal Protection Area’ according to the Luk Keng and Wo Hang Outline Zoning Plan No. S/NE-LK/2.

(3) Yim Tso Ha

This mangrove is situated between the abandoned Yim Tso Ha Egretry and Ho Pui Leng Village. Tam and Wong (2000) named this mangrove "Nam Chung" but according to the map, this area is called Yim Tso Ha. K. candel 2-3 m high dominates the mangrove. Aerial photos from the 1950s and 60s show that this area was brackish rice fields at that time. Abandonment of rice cultivation between the late 60s and the early 70s caused the gradual formation of the mangrove.

A coastal dragonfly of global conservation concern, Orthetrum poecilops, was first found in these mangroves in 1994 (Wilson 2001). Since the 1990s, this dragonfly has only been found in Hong Kong and Japan. In addition, this mangrove serves as an important feeding habitat for Night Herons (Nycticorax nycticorax) nesting on A Chau (about 0.6 km to the east). In the 1997 and 1998 summer breeding seasons, about half of the Night Herons used this habitat as a feeding ground (Wong et al. 1999). Cattle Egrets also fed on the visiting insects when the mangrove was flowering in the 1998 summer.

This mangrove is zoned as "Conservation Area" according to the Luk Keng and Wo Hang OZP map. However, agricultural use and tree plantation are listed as always permitted land uses, which do not require approval from the Town Planning Board.

(4) Nam Chung

There are two mangrove stands at Nam Chung. Tam and Wong (1997, 2000) named these mangroves, together with those in the Luk Keng area, as "Luk Keng", but according to the map this area is called Nam Chung. Apart from the mangroves around Nam Chung Lei Uk listed in Tam and Wong (1997), another mangrove is found near Nam Chung Yeung Uk. Some mangrove trees in front of Nam Chung Yeung Uk are regularly cut down for feng shui reasons. According to local beliefs, the view in front of the village should be open and blocked by nothing, so the mangrove in front the village was cut down. Past aerial photos indicate that the mangroves at Nam Chung were ricefields in the 1950s and 60s.

The coastal dragonfly, O. poecilops, was also found in the mangroves at the Nam Chung Yeung Uk and Lei Uk (Wilson 2001). These sites and Yim Tso Ha are the only recorded locations of this dragonfly in Hong Kong. Ten to twenty Common Teals (Anas cecca) were seen to roost and forage in this mangrove in the 2000/2001 winter. The mangrove at Nam Chung Yeung Uk also serves as feeding grounds for a variety of waterbirds, including egrets, herons, and kingfishers.

These mangroves are currently zoned as "Agriculture" on the Luk Keng and Wo Hang OZP. However, according to the consultation digest of the Planning and Development Study on North East New Territories (Anon 1999), Nam Chung is classified as "Wetland" with area of conservation interest / mangrove under the category of "No Go Areas".

(5) Luk Keng

This forms part of the "Luk Keng" site of Tam and Wong (2000). Mangrove species like K. candel 2-3 m high are found here.

It is zoned as "Conservation Area" according to the Luk Keng and Wo Hang OZP map. Again, agricultural use and tree plantation are always permitted.

(6) Mangrove along the south Starling Inlet coast

Along the coast of Yim Tso Ha, Nam Chung and Luk Keng, particularly at the sheltered bay of Nam Chung, mangrove plants are found, including K. candel, Acanthus ilicifolius, Aegiceras corniculatum, Bruguiera gymnorhiza and Excoecaria agallocha. The restricted Heritiera littoralis (Xing et al. 2000) has been planted at the rear of the mangrove. During high tide, these mangroves serve as roosting sites for egrets and herons. White-breasted Waterhen (Amaurornis phoenicurus) are also regularly seen there.

These mangroves are zoned as "Coastal Protection Area’ according to the Luk Keng and Wo Hang OZP map.

(7) Kuk Po

This mangrove is not listed in Tam and Wong (1997, 2000). Like the one at Nam Chung Yeung Uk, it is regularly cut down, probably for the same feng shui reasons, so only short mangrove trees are found currently. Past aerial photos indicate that the Kuk Po mangroves were ricefields in the 1950s and 60s. Intermediate Egrets (Mesophoyx intermedia), and Banded Rails were regularly seen during the bird survey in 1997/98. Apart from the mangrove, there is also a 6-8 ha Phragmites reed bed. In the 1998 summer, 2-3 newly-fledged Little Green Herons (Butorides striatus) were found around the reed bed suggesting that this bird bred there.

No conservation status is given to this mangrove.

(8) Yung She Au

This small mangrove is situated in Crooked Harbour and is not mentioned by Tam and Wong (1997, 2000). Only dwarf mangroves, mainly of K. candel, are found along the coast. Past aerial photos indicate that these mangroves were also once ricefields. There is also a 1 ha Phragmites reed bed and a Purple Herons (Ardea purpurea) were found there in August 1997.

No conservation status is given to this mangrove or the reed bed.

(9) So Lo Pun

This 1.5 hectare mangrove is situated in Crooked Harbour and is not mentioned by Tam and Wong (1997, 2000). Past aerial photos indicate that rice fields were the dominant land use in the lowlands of So Lo Pun. Dwarf (1-2 m) mangroves, mainly of K. candel, are found here. A rare seagrass (Xing et al. 2000), Zosteria japonica, was discovered in the mudflats adjacent to the mangrove in March 1998. In November 1997, a juvenile Wild Boar following an adult was seen at the mangrove. There is also a 1.5 ha tidal pond.

No conservation status is given to this mangrove or the pond.

(10) Lai Chi Wo

This mangrove has been well described by Tam and Wong (1997, 2000) and they identify it as one of three "extremely important stands". The seagrasses, Zostera japonica and Halophila ovata, can be found on the mudflats off the mangroves. There are also huge specimens of Derris trifoliata, a coastal plant.

The Lai Chi Wo mangrove is well-protected by zoning. The mangrove is a "Site of Special Scientific Interest" while the mudflats and the coastal areas are protected by the Yan Chau Tong Marine Park.

Mangroves in Starling Inlet, except those at Sha Tau Kok, Nam Chung and Kuk Po, are protected by zoning, while mangroves and other wetlands in Crooked Harbour are only protected by their remoteness. Even those protected by zoning as "Conservation Area" are still threatened by inappropriate land uses for which no permission is required. Further studies should be encouraged to investigate their ecological importance, and relevant conservation status should be given to these mangroves, in particular to those at Sha Tau Kok and Nam Chung, which are more easy to be threatened by urbanization and human disturbance.

Bibliography

Anon. (1999). Planning and development study on North East New Territories: Development proposals for Kwu Tung North, Fanling North and Ping Che / Ta Kwu Ling – Consultation Digest. Planning Department and Territory Development Department.

Murton, R. K. (1972). The ecology and status of the Swinhoe’s Egret, with notes on other herons in Southeastern China. Biological Conservation 4: 89-96.

Tam, N.F.Y and Y.S. Wong. (1997). Ecological study on mangrove stands in Hong Kong. Unpublished report to AFD.

Tam, N.F.Y and Y.S. Wong. (2000). Hong Kong Mangroves. AFCD and City University of Hong Kong Press.

Wilson, K. D. P. (2001). Orthetrum poecilops Ris – A marine dragonfly of conservation priority. Porcupine! 22: 5-6.

Wong, L.C., Corlett, R.T., Young, L. and J.S.Y. Lee (1999). Foraging flights of nesting egrets and herons at a Hong Kong egretry, South China. Waterbirds 22: 424-434.

Xing, F., S. C. Ng and L. K. C. Chau. (2000). Gymnosperms and angiosperms of Hong Kong. Memoirs of the Hong Kong Natural History Society 23, 21-135.

Fig. 1 The distribution of mangroves in the North East New Territories. The locations of these mangroves are based on a waterbird study in this area since 1997 (Numbers as listed in the text).

P.22-24

Conservation of buildings and cultural heritages: stone- and concrete-eating microorganisms

by Ji-Dong Gu

Microorganisms, including archaea, bacteria and fungi, are widely present in our environment and they were the first life form in the biological evolution process. They perform many favourable activities: degradation of plant debris and pollutants, recycling nutrients, fermenting food products for our consumption, and many more. At the same time, they are known disease-causing agents to aquaculture, land associated crops in agriculture, and ourselves. In addition, they are also responsible for degradation and deterioration of a wide range of materials including stainless steel, electronic insulating polymers and society’s infrastructure from highways, bridges to sewer pipes. Indeed, several highly publicized cases have been reported regarding microbial involvement in corrosion of sewer concret; as a result economic loss was not only high but was unanticipated by the local government. They are also involved in damage to historical buildings and cultural heritage materials.

Many ancient monuments and historical buildings provide a rich source of microorganisms enriched over time. When stone monuments were examined at two locations in metropolitan city, one was relatively non-polluted and the other was polluted due to heavy traffic nearby. Both hydrocarbons and sulfur oxides were higher at the polluted location than the nonpolluted one. We found that the populations of heterotrophic and chemolithotrophic bacteria were significantly higher at the polluted location than the nonpolluted one, indicating deposition of non-combusted hydrocarbons and sulfur oxides deposited on surfaces of the stone promotes selectively the population of these two groups of microorganisms. This was supported by laboratory experiments. When examing the chemolithotrophic group from these two locations, we found that the percentage of chemolithotrophic bacteria capable of oxidizing sulfur was much higher (approximately by 30%) at the polluted location than the nonpolluted location. What was more interesting in this investigation was that the growth of the sulfur-utilizing bacteria resulted in rapid decrease in pH of the culture medium. This suggests the mechanism of stone attack by the microorganisms is by means of acid production so that minerals can be dissolved and assimilated for their own growth. In doing so, the stone surface is corroded. In addition to this mechanism, the colonizing bacteria on surfaces of stone also synthesize polysaccharides forming complexes with metals of the stone.

Considering Hong Kong’s subtropical climate, high humidity and temperatures for a large portion of the year, building maintenance is a costly expenditure to any property owner. The surface of buildings with black, green, dark-green or even purple colour is a strong indication of a rich community of microorganisms and their biofilms on surfaces. To eradicate the microorganisms and inhibit their growth, frequent cleaning and application of new paint plus biocides are anticipated. From an ecological point of view, the surface microbial ecology is an interesting subject to investigate and such knowledge will provide for effective measures against biodeterioration. What is interesting in the whole process is the conservation of cultural heritage, old buildings, monuments and cultural materials with historical, religious value. Conservation is not simply to put them in an air-conditioned museum because a lot of them cannot be put into a museum due to site and size. In this case, preservation is an important subject for discussion. With reference to this new direction of development, the archaeological findings unearthed from the Disney Park project should be considered for conservation of these cultural objects.

The scientists engaged in this endeavour must have a passion for the art and appreciation of culture and people. Additional reward is the potential for isolation and identification of new microorganisms from previous unexplored niches (see Fig.1 below). Since each historical environment is unique in material composition, the microenvironment and microorganisms residing on the surfaces, the biology and conservation can truly go hand in hand.

Fig.1 A scanning electron micrograph showing a rich and diverse microbial community on the surface of the stone monument described above. Many bacteria (more than 90%) in their natural environment are not yet identified (Magnification 10,000´ ).

Bibliography

Gu, J.-D., T.E. Ford, and R. Mitchell (2000). Microbial degradation of materials: general processes. Pp. 349-365. In: Revie, R.W. (ed.) Uhlig’s Corrosion Handbook (2^nd ed.) John Wiley, New York.

Gu, J.-D., T.E. Ford, and R. Mitchell. (2000). Microbial corrosion of concrete. Pp. 477-491. In: Revie, R.W. (ed.) Uhlig’s Corrosion Handbook (2^nd ed.) John Wiley, New York.

Mitchell, R. and J.-D. Gu. (2000). Changes in the biofilm microflora of limestone caused by atmospheric pollutants. International Biodeterioration & Biodegradation 46: 299-303.

P.24-25