Echobank for the Bats of Western Ghats Biodiversity Hotspot, India

Abstract

Acoustic monitoring provides an effective and non-invasive means to survey many species such as bats, birds and frogs. However, the acoustic monitoring poses challenges in determining the species identity due to lack of reference recordings or due to similar call structures across species. Here we recorded bats from 30 different locations at varying altitudes (0-1,200 m) and latitudes (7-12N) using a full spectrum Pettersson M500-384 ultrasound detector. We used 2,070 pulses from 329 individual sequences of 20 bat species to standardise the echobank (catalogue of call characteristics). Discriminant function analyses (DFA) was carried out separately for the bats producing constant frequency (CF) and frequency modulated (FM) calls using frequency of maximum energy and end frequency, and shows an accuracy of 97.48% and 96.09% for CF and FM bats respectively. We also collated published reference calls for bat species in this region to develop a regional echobank for 42 species of echolocating bats from the Western Ghats. For six species, we report their echolocation calls for the first time. The echobank provides a useful tool for further conservation and monitoring studies in the wider region.