Volant and Small Non-volant Mammals of Dinagat Island, Philippines

Abstract

The Philippine province of Dinagat Islands supports a huge array of flora and fauna with a high rate of endemism, including three species of mammals found nowhere else in the world. However, anthropogenic activities such as mining are rampant on the island and present a grave threat to the island’s unique biodiversity. We conducted a survey of volant and small non-volant mammals in selected municipalities of Dinagat Islands to contribute to the current understanding of Philippine mammalian fauna. A total of 17 species of volant mammals were recorded among 420 individuals captured in mist nets, 11 species of which are fruit bats and six are insectivorous bats. As for small non-volant mammals, a total of eight species were recorded from 51 individuals captured using a combination of trapping, mist-netting, and transect walks. Among these, eight and six species of volant and non-volant mammals, respectively, were Philippine endemics. We also recorded six species listed under different categories of threat based on the International Union for Conservation of Nature (IUCN) Red List and the Department of Environment and Natural Resources Administrative Order (DENR-DAO). Four species were new records for the Dinagat Islands: Harpionycteris whiteheadi, Rhinolophus subrufus, Pipistrellus javanicus, and Myotis muricola – bringing the total number of recorded mammals on the island to 38 species. With our limited sampling methods, it is possible that some species were overlooked and that new records and novel species may still be discovered as more extensive surveys utilizing other sampling techniques, such as acoustic surveys and the use of different baits and traps, are conducted. Nonetheless, the presence of endemic and threatened species in all our sites – especially those with relatively intact forest – underlines the need for the continued protection of their remaining habitats. Furthermore, our findings emphasize the need for the proper rehabilitation and restoration of areas impacted by mining activities to provide additional habitat and resources for mammals on the island.