This IBA comprises Phong Nha Nature Reserve, close to the international border with Laos. The nature reserve is situated within one of the largest areas of contiguous limestone karst in Indochina, which also includes Hin Namno National Biodiversity Conservation Area in Laos, and the Ke Bang limestone area in Bo Trach and Minh Hoa districts, Vietnam. The topography of the Phong Nha area is characterised by precipitous karst ridges, which rise to elevations of around 400 m.
On the basis of the occurrence of three restricted-range bird species, Phong Nha lies within the Annamese Lowlands Endemic Bird Area. Six species in the this account were recorded by Eames et al. (1994) at the Rao Bong watershed, an area on the periphery of Phong Nha Nature Reserve.
Non-bird biodiversity: Timmins et al.(1999) recorded the following globally threatened primate species at Phong Nha: Assamese Macaque Macaca assamensis, Stump-tailed Macaque Macaca arctoides, Hatinh Langur Trachypithecus francoisi hatinhensis, Wulsin's Black Langur T. f. ebenus and White/Buff-cheeked Gibbon Nomascus leucogenys/gabrielle. However, Timmins et al. advise caution regarding the exact status and taxonomic identity of Wulsin's Black Langur. The globally endangered Red-shanked Douc Langur Pygathrix nemaeus nemaeus has been recorded by several authors, although the faliure of Timmins et al. to record this species led them to conclude that there may have been a major decline in the species at the site.Timmins et al. (1999) have also proviosionally recorded the occurrence of Southern Serow Naemorhedus sumatranesis at Phong Nha.
BirdLife International (2020) Important Bird Areas factsheet: Phong Nha. Downloaded from http://www.birdlife.org on 28/05/2020.