Mass mortality of the endangered Purple Frog, Nasikabatrachus sahyadrensis Biju and Bossuyt, 2003, in the Nelliyampathy Hills, Southern Western Ghats, India

Abstract

The Purple Frog (Nasikabatrachus sahyadrensis) is a globally endangered, ancient relic-tual frog endemic to the Western Ghats, a biodiversity hotspot of India. Here, we present observations on mass mortality of this species at the Nelliyampathy Hills, a Reserved Forest interspersed by private coffee, rubber, and tea plantations. During 25 person-hours of surveying during January to May 2024 at three sites with various land uses, including Chernalli (a rubber plantation), Nooradi (a tea plantation + village), and Kaikatty (a forest), 185 sightings of Purple frog were obtained. Direct sightings included live tadpoles (N=100; Chernalli; January) and dead tadpoles (N=75; Nooradi; March), with indirect detection of adult males based on their breeding calls emanating from underground (N=10; Kaikatty; May). Our surveys documented the persistence of a breeding population of Purple frog and recorded a mass mortality event in the adjoining plantations. Mass mortality is a cause of concern and calls for better protective measures. Histopathological studies on tadpoles that are found dead without any traumatic injury are recommended to determine the cause of the mortality and to identify measures for preventing a reoccurrence.