Listening to Namdapha: Estimating the amphibian species richness of Namdapha Tiger Reserve using passive acoustic monitoring

Assessment of Amphibians at a large scale is a necessary first step towards conserving the most threatened vertebrate class. Overcoming the challenges of accessibility, manpower, safety and synchronisation, we conduct the first passive acoustic monitoring exercise in Namdapha tiger reserve, India, to estimate the amphibian species richness. We use incidence-based Chao, Jackknife and Bootstrap methods to estimate the amphibian richness. By detecting 19 amphibian species, the acoustic monitoring is fairly accurate in comparison to previously conducted active manual searches. The bias corrected estimate of species richness is marginally higher than the observed value. High species richness is not confined to a single habitat but is found to occur across diverse habitats. The acoustic analysis reveals that the dominant frequency of the amphibians are not different across the different habitats of the Namdapha tiger reserve. Overall the study underscores the accuracy of passive acoustics in monitoring the poorly known amphibians in India’s Protected area.