Biodiversity patterns and the conservation of mammals in the Philippines

The Philippine Islands support one of the richest mammal faunas in the world; at least 180 species are present, about 115 of which are endemic (i.e., unique) to the country. Most species are limited to a single faunal region; each faunal region corresponds to a single island that existed from 10,000 to 18,000 years ago during a period of low sea level that was caused by one of the ice ages. Even small islands that remained isolated during the periods of low sea level (such as Sibuyan) have distinctive, unique faunas. The largest faunal regions (Greater Luzon and Greater Mindanao) each have sub-regions with several endemic species, the total number of such regions and sub-regions of biological endenism is about 15. Adequate protection of biological diversity requires that an effective and representative protected area exist in each of the 15 regions. Forty-four species of Philippine mammals, 37 of which are endemic, are now believed to be endangered to some significant degree. Endangered species occur in all of the faunal regions; an index of faunal endangerment ranks the Greater Negros-Panay faunal region as most critical, followed by Mindoro, Palawan, Sibuyan, Greater Sulu, and the Batanes/Babuyan region. Current sites in the Integrated Protected Areas System (IPAS) program include six terrestrial parks that will contribute to protecting terrestrial vertebrate diversity, these are on Greater Luzon, Greater Mindanao, Greater Negros-Panay, and Batanes. Significant gaps remain in the system. In order to maximize protection of both diversity of endemic species and individual threatened species, careful consideration should be given to Mindoro as the most crucial region, followed by (in appropriate order of importance) Southern Luzon (Mt. Isarog), Sibuyan, Western Panay, Palawan, Sulu, and Western Mindanao as the top-priority regions in the selection of the next set of IPAS sites.