Nakai-Nam Theun: can development save one of South-East Asia's last wildernesses?

by Joe Tobias, Pete Davidson and William Robichaud, from OBC Bulletin 28, November 1998.

Nam Theun 2, a major hydropower development proposal, has focused attention on an important protected area which might hold the key to conserving some of the rarest and most highly threatened species of birds and mammals in South-East Asia. This article summarises the significance of Nakai-Nam Theun National Biodiversity Conservation Area in central Laos, sketches recent developments in the hydropower project, and looks to the future.

Introduction
Laos is a land-locked country separated from Vietnam by the Annamite mountains, an isolated range that is covered in several areas by huge tracts of relatively undisturbed montane evergreen forest. The largest of these, one of the most pristine wildernesses remaining in South-East Asia, is largely encompassed within Nakai-Nam Theun National Biodiversity Conservation Area (NBCA). A series of surveys conducted since 1994 by the co-operative programme of the Wildlife Conservation Society (WCS), the Centre for Protected Areas and Watershed Management (CPAWM) of the Lao Department of Forestry, and the World Conservation Union (IUCN) have revealed that the area has an extremely high biodiversity conservation value. Plans to develop a $2 billion hydropower project along the major river draining the area (the Nam Theun) have generated considerable controversy and promoted intensive research into the likely effects of such a development. Some of this research has been directed towards identifying appropriate mitigation for the damage that will inevitably be caused to the environment if a dam is built.

Nakai-Nam Theun covers approximately 3,445 km2 of the Annamite mountains and the adjacent Nakai Plateau in the provinces of Khammouane and Bolikhamxay. A proposed northern extension along the Vietnam border in Bolikhamxay would link Nakai-Nam Theun to the Nam Chouan proposed NBCA, and a minor southern extension would make the area contiguous with Hin Namno NBCA, a bizarre karst landscape of limestone hills and one of the most important sites for primate conservation in Indochina (1). A third proposed corridor would annex the Khammouane Limestone NBCA to the west. These potential additions expand the size of the protected area to nearly 5,000 km2, encompassing altitudes between 400 m and 2,700 m and a broad variety of habitats and species assemblages (2). The potential result is a composite of seven protected areas bridging an international border: in Vietnam, Pu Mat, Vu Quang and Phong Nha reserves, and in Laos, Nam Chouan, Hin Namno and Khammouane Limestone NBCA's, with the hub of these being Nakai-Nam Theun. If managed wisely and effectively, this ësuper-reserve' would rank amongst the most important sites for biological and cultural conservation in the world (2).

Red-tailed Minla
(Joe Tobias)

Habitat
The area is described in detail by Evans and Timmins (3) and IUCN (2). Semi-evergreen forest, deciduous dipterocarp forest and stands of pine are all found on the Nakai Plateau (now heavily deforested by salvage logging prior to the planned inundation of the c. 450 km2 reservoir area) and in the Annamite foothills to the east, grading into more exclusively evergreen forests as the land rises towards the Vietnamese border. Higher still, huge areas of montane fagaceous forest cloak the slopes, interspersed with patches of Fokienia hodginsii, a commercially valuable cypress-like conifer. On mountain-tops and above c. 2,000 m the fagaceous forest gives way to more stunted, rhododendron-dominated ericaceous cloudforest. A unique feature of Nakai-Nam Theun's proposed northern extension is the 'everwet' forests, found in narrow bands where low-elevation saddles (500-800 m) in the mountain chain enable the Vietnamese north-east monsoon to penetrate across the border, a phenomenon otherwise impeded by higher stretches of the Annamites.

Blyth's Kingfisher
(Joe Tobias)

Birds
A total of 405 bird species has been conclusively identified in Nakai-Nam Theun and the adjacent northern extension during a few months fieldwork.3,4,5 The final total, if provisional field records can be confirmed, will probably exceed 430 species. This is by far the highest avian species richness of any site yet surveyed in Laos and is the highest recorded in a single protected area in South-East Asia despite the relatively brief fieldwork conducted (as comparisons: 318 spp. recorded at Khao Yai National Park and 382 spp. recorded at Doi Inthanon National Park, Thailand; 330 spp. recorded at Bach Ma National Park and 270 spp. recorded at Cat Tien National Park, Vietnam). Of particular importance are no less than 11 Threatened and 27 Near-threatened bird species (Collar et al.(6) Appendix 1 lists these species, several of which are not reported by Evans and Timmins (3)).

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