Diversity of wild mammals in some isolated islands of Vietnam

Abstract

Vietnam has 2,773 coastal islands with a total area of 1,720.8754 km2 which have geopolitical value as well as hosting economic development and eco-tourism; but they also contain much unexplored biodiversity. Recent studies on mammals have revealed rare species and begun to unravel patterns in the biodiversity on the islands. From 2008 to 2023, studies were conducted on some isolated islands, including: Cat Ba, Bach Long Vi (Hai Phong city) and Bai Tu Long (Quang Ninh province) (in the Gulf of Tonkin); Cu Lao Cham (Quang Nam province), Hon Tre (Khanh Hoa province), Con Dao (Ba Ria - Vung Tau province), Phu Quoc, Tho Chu, Hon Nghe (Kien Giang province) and Hon Khoai (Ca Mau province). These surveys recorded 42% of all species known from Vietnam for a total of 98 species and subspecies belonging to 21 families and 13 orders. Number of species recorded  varied among the islands with Cat Ba being the most diverse with 54 species. Number of species recorded from other islands were 43 for Phu Quoc, 28 for Con Dao, 27 for Bai Tu Long, 16 for Cu Lao Cham, 15 for Hon Tre, 8 for Tho Chu, 3 for Bach Long Vi, Hon Nghe and 2 for Hon Khoai. Twenty-five common species are evenly distributed in the islands of Northern, Central and Southern Vietnam. An additional 25 species are rare, endemic or otherwise unusual. Despite the limited data available from these surveys the emerging patterns of species diversity are consistent with biogeographic predictions based on island size and distance from potential source pools.