Báo cáo đa dạng sinh học tổ hợp bảo tồn Ba Bể-Na Hang: bao gồm Vườn Quốc gia Ba Bể, Khu Bảo tồn Thiên nhiên Na Hang và Khu Bảo tồn Loài và Sinh cảnh Nam Xuân Lạc
Ba Be / Na Hang Conservation Complex
The Ba Be / Na Hang Conservation Complex is a region of north-eastern Viet Nam based around Ba Be National Park and Na Hang Nature Reserve. The region is characterised by steep limestone hills, interspersed with non-limestone areas of more undulating topography. It supports a mosaic of land-use types, including fragmented primary forest patches, patches of secondary vegetation, and areas of permanent and shifting cultivation. The region supports high levels of botanical and faunal diversity including populations of two endemic primates: Tonkin Snub-nosed Monkey Pygathrix avunculus and Francois’ Langur Semnopithecus francoisi francoisi.
This is the final report of an assessment of the biodiversity of the Ba Be / Na Hang Conservation Complex undertaken as part of the PARC Project. The report presents the results of four separate field surveys undertaken over three years. These surveys assessed the diversity and abundance of vegetation, butterflies, reptiles, amphibians, birds and mammals (including bats).
In addition to areas surveyed within Ba Be National Park and Na Hang Nature Reserve, three sites outside their boundaries were also surveyed. These areas were in Dong Phuc, Ban Thi-Xuan Lac and Sinh Long Communes. The three sites support a large area of forest that complement the two larger protected areas to form part of the wider Ba Be / Na Hang Conservation Complex.
The data collected on biodiversity was used to evaluate the conservation importance of Ba Be National Park and Na Hang Nature Reserve and the surrounding areas and to identify threats to that biodiversity. The Ba Be / Na Hang Conservation Complex was found to support a great diversity of wildlife. The surveys documented 456 species of butterfly, 41 reptile species, 28 amphibian species, 51 mammal species (excluding bats), 51 bat species and 327 bird species.
The terrestrial vegetation of the conservation complex is dominated by lowland tropical forest on limestone. Dominant tree species include Teonongia tonkinensis(Moraceae), which is an important element of the lower canopy, especially on disturbed rocky slopes and where intensive felling has occurred. Burretoidendron hsienmu(Timaliaceae) is a common upper canopy tree. The lowland forest formations are characterised by a relatively simple canopy structure, lower canopy height, and the scarcity of climbing species. The tree species represented in higher altitude forests differ physiologically from those of lowland tropical rain forest, and plant families which are uncommon, or completely absent, at lower altitude form an important component of the canopy, including Lauraceae, Fagaceae and Podocarpaceae.
The field surveys recorded two butterfly species listed in CITES Appendix II (CITES 1998): Troides helena andT. aeacus. Both species are relatively common in Viet Nam, although their inclusion in CITES Appendix II reflects the potential threat posed by commercial exploitation. Another species of conservation concern recorded during the field survey was the papilionid Byasa crassipes, which is a candidate for inclusion in an updated Red Data Book of Viet Nam(Anon. 2000). Finally, several species recorded during the field survey are very rare not only in Viet Nam but also globally, for example Lethe violaceopicta (see Section 3).
Reptiles and amphibians
Six reptile and amphibian species recorded during the field surveys are listed in the 2003 IUCN Red List of Threatened Species(IUCN 2003): Vietnamese SalamanderParamesotriton deloustali, Burmese PythonPython molurus, Big-headed TurtlePlatysternon megacephalum, Keeled Box TurtlePyxidea mouhoti, Black-breasted Leaf Turtle Geoemyda spengleri and Chinese Softshell TurtlePelodiscus sinensis. Fourteen species recorded during the field survey are listed in the Red Data Book of Viet Nam(Anon. 2000), comprising nine reptile species and five amphibian species (see Section 4).
Twenty-one of the mammal species (excluding bats) recorded during the field survey are listed either in the 2003 IUCN Red List of Threatened Species (IUCN 2003) as Globally Threatened, Near-threatened or deficient data or in the Red Data Book of Viet Nam (Anon.2000). This included several species considered Endangered such as the Tonkin Snub-nosed Monkey, Asiatic Black BearUrsus thibetanus, and Particoloured Flying Squirrel Hylopetes alboniger (see Section 5).
Among the total 51 species of bats recorded, 14 species are of conservation concern: Lesser Dog-faced Fruit BatCynopterus brachyotis,Rhinolophus paradoxolophus,R. subbadius,R. borneensis, Shield Faced Leaf-nosed BatHipposideros lylei, Lesser Leaf-nosed Bat H.turpis, Tail-less Leaf-nosed Bat Coelops frithii,Myitos siligorensis,Scotomanes ornatus, Great Evening BatIa io,Pipistrellus pulveratus,P. cadornae, Schreiber’s Long-fingered Bat Miniopterus schreibersii, Hairy-winged BatHarpiocephalus harpia. These include seven of the nine bat species that are listed in the Red Data Book of Viet Nam(Anon. 2000), and ten of the 15 species listed in the 2003 IUCN Red List of Threatened Species (2003) (see Section 6).
The bird surveys found six species of conservation concern (based on BirdLife International 2001a). Four of these species are considered Near-threatened and were recorded in Na Hang Nature Reserve. The fifth species, Wood Snipe Gallinago nemoricolais considered Vulnerable and was recorded in Na Hang Nature Reserve. The sixth, White-eared Night HeronGorsachius magnificus, is considered Endangered and was actually recorded outside of either protected area at Lung Ly in the Ban Thi-Xuan Lac area, on 30 April 2001. This species is a restricted-range species (Stattersfield et al.1998) and was undoubtedly the key bird species recorded during the surveys (see Section 7).
Threats to biodiversity
The biodiversity surveys demonstrated the high diversity of fauna and flora surviving in the Ba Be / Na Hang Conservation Complex area. While it is probable that some large mammal species may already be extinct in the area, many species still persist. This should not lead to complacency. The integrity of the forests and the wildlife within them is threatened by fragmentation, inappropriate development, hunting, over exploitation of forest products, forest clearance for agriculture as a result of an increasing population, and livestock grazing.
To mitigate the identified threats, the survey work also provided prioritised recommendations for the future conservation of the area. Where feasible and appropriate, the recommendations were incorporated into on-going PARC Project programmes.
Expanding the protected area network
One of the major recommendations resulting from the biodiversity surveys was to expand the protected area system in the conservation complex. This recommendation was largely based upon the need to provide greater protection to species of national and global conservation significance, to mitigate the impacts of flooding from a hydropower dam, and to reduce forest fragmentation by placing more forest under protection. Each of the survey sites outside the protected areas was evaluated for conservation importance and recommendations were made regarding possible protected status. The South Xuan Lac Species and Habitat
Conservation Area has since been established adjacent to Na Hang Nature Reserve. Furthermore, PARC Project has been giving support to Tuyen Quang Province for the establishment of another protected area at Sinh Long, to the north of Na Hang Nature Reserve.
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