A Survey of Bats in a Karst Landscape in the Central Philippines

Abstract

Karst landscapes are biologically diverse and unique ecosystems that are especially important to bats. As in other parts of Southeast Asia, cave roosting bats in the Philippines have suffered extensive human disturbance, and as a result, may be declining. Here we contributed to a region-wide effort to assess the status of cave bats by surveying bats in well-known caves and forest on limestone on Bohol Island in the central Philippines. We also assessed cave disturbance through physical signs and interviews. We observed and acoustically detected bats representing a total of 14 taxa in 23 of the 25 caves surveyed. Few species were present in most caves (median = 2 spp.) and only three caves had large numbers of bats (> 1,000). However, of the 29 bat species captured in forest, 19 are known to roost in caves, including the poorly known Philippine endemic, Hipposideros coronatus. Most surveyed caves experienced either current or historical human disturbance (88%), primarily by collectors of edible bird's nests, bats for food, and guano for use as fertilizer in rice fields. High species richness, signs of population decline, and high human disturbance all point to Bohol Island as an important conservation area for cave-roosting bats in the Philippines.