BAT FORAGING BEHAVIOR ACROSS VARIABLE STREAM STRUCTURES IN A NEOTROPICAL FOREST FRAGMENT
Tressie Kapono1, Rachel Blakey2.
1University of Hawaii at Hilo, Hilo, HI, 2Center for Ecosystem Science, University of New South Wales, Sydney, New South Wales, AU.
Bats are extremely important for plant pollination and seed dispersal and play a vital role in the health of natural ecosystems. Understanding the relationship between bats and differently structured habitats is important for conservation of this diverse group. Use of stream habitats by bats has been understudied to date. In this study, we analyze the relationship between stream width, bat activity, and phonic richness in a Neotropical forest fragment. We surveyed 10 different sites within the Las Cruces Biological Station, Costa Rica, stratified across a range of stream orders (ranging from 1st to 4th order). A key finding of our study was a relationship between stream size and total bat activity in Las Cruces. This is likely to be because emerging aquatic insects, gap areas, and flyways improve bat foraging habitat, leading to higher bat activity. While phonic richness did not change with stream width, differences in bat community response to stream width were detected with high frequency (51 - 60 kHz) calling vespertilionids showing the strongest positive relationship with stream size. In contrast, noise negatively affected bat activity. Our results indicate that in tropical forests, larger, slow flowing (less noisy) streams are more likely to attract greater numbers of bats.