Vietnam Primate Conservation Status Review 2002 - Hoang Lien ...

6 THREATS TO PRIMATES IN VIETNAM
Timber extraction by state forest enterprises and illegal loggers has resulted in the loss and degradation
of large areas of forest. From official sources, it has been estimated that about 80,000 ha of forest
were degraded for this purpose in 1991 (Pham Binh Quyen & Truong Quang Hoc, 1997).
Timber or non timber forest product collectors, who must often spend several days in the forest,
subsist on natural resources, including primate meat. Trees supporting fruits or bee nests are
sometimes cut down to facilitate collection. The collection of Cinnamomum sp. tree oil has been
reported to have a severe negative impact on the environment. The distillation process involves boiling
the wood, which requires a large quantity of firewood. It is estimated that for each tree distilled, 10 ha
of forest is negatively affected (Lambert et al., 1994; Le Trong Trai et al., 1996).
Habitat destruction is also associated with hydro-electricity, and other infra-structural development
activities. Hydro-electric dams cause a three-fold problem. Firstly, the reservoir may inundate large
areas of forest. It has been estimated that as much as 30,000 ha of forest is lost per year due to the
creation of reservoirs (World Bank, 1995; cited by Pham Binh Quyen & Truong Quang Hoc, 1997).
Secondly, human settlements must be relocated in other places, which often means forest areas.
Thirdly, areas surrounding the reservoir become more accessible to loggers and hunters. Such
consequences are illustrated in Luc Yen District (Yen Bai Province), where forest has been entirely
cleared following the building of the dam on the Red River (Pham Nhat, 1991). Currently several other
dam projects are in place in Vietnam, including one operation in Na Hang Nature Reserve (Tuyen
Quang Province) one of the last refuges of the critically endangered Tonkin snub-nosed monkey.
Development of the road network in an area of high biodiversity value does not only involve the
clearance of large areas of forest during construction. A road often also constitutes an impassable
barrier for many species, facilitates the exploitation of forest products, and may act as a focus for
settlement of migrants. These problems are associated with the current project to develop the Ho Chi
Minh (HCM) national highway, linking Ha Noi to Ho Chi Minh City. This new link will pass through
several areas of high importance for primate conservation. Of particular note is a link road between
highway 20 and the HCM highway which is currently undergoing construction. This will bisect
Phong Nha-Ke Bang National Park (Quang Binh Province). The park possesses the most important
population in the world of the endangered Hatinh langur (Trachypithecus laotum hatinhensis) as well
as 9 other species of threatened primates. This new route will seriously jeopardise a number of these
species’ sub-populations. Ngoc Linh Nature Reserve (Quang Nam Province) is similarly afflicted by
the HCM highway, one of the only places where the poorly known and recently described Greyshanked
douc langur (Pygathrix cinerea) has been recorded.
Special mention must be made of mining activities, principally gold mining. These have been frequently
reported in limestone areas in northern Vietnam and are of high importance in terms of primate
conservation in areas such as Kim Hy, Bac Kan Province (Geissmann & Vu Ngoc Thanh, 2000; Ngo
Van Tri & Lormée, 2000), and Na Hang, Tuyen Quang Province (Ratajszczak et al., 1992; Dang Ngoc
Can & Nguyen Truong Son, 1999). Large areas of forest are cleared for ore exploitation. Furthermore,
this activity attracts a large number of workers, who subsist on forest products or exploit them to
supplement their incomes.
Deforestation and habitat fragmentation are a major threat to the long term survival of primate
populations. Not only do these processes reduce the area of suitable habitat, and the number of
animals, but it also increases the accessibility of forest areas to people. Furthermore, these processes,
particularly habitat fragmentation, tend to isolate populations, leading to inbreeding. The long-term
consequences of inbreeding may include decreased resistance to disease and higher incidence of
infertility. The degree to which primates can disperse across areas of non-forest has not been clearly
demonstrated but it is unlikely that arboreal primates will travel significant distances across grassland,
scrub or cultivated areas to reach nearby forest patches.
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