Vertical stratification of bats in a Philippine rainforest'

Abstract

To sample the bat community in a lowland rainforest on Lwon Island, Philippines, mist nets were set in the subcanopy (3-16 m high) at a ground-level (0-3 m high). A total of 1325 bats was netted Subcanopy nets caught an average of 15 bats per net-night, the highest capture rate yet reported for nets in tropical forest (except at roost sites and over water). The suborder Megachiroptera represented 95% of captures in subcanopy nets but only 25% of captures in ground-level nets; the suborder Microchiroptera accounted for the remainder. Although subcanopy nets were set in natural forest gaps whereas ground-level nets were set under closed canopy, the diference in the representation ofmegachiropterans in net captures at the two vertical strata suggests that megachiropteran activity is substantially higher in the subcanopy. The vertical distribution of their food, primarily fruit, could account for such a pattern.