A review of amphibian fauna of Sri Lanka: distribution, recent taxonomic changes and conservation

Abstract

The amphibian fauna of Sri Lanka comprises 120 species, including 107 (~90.0%) endemic species. They belong to five families: Bufonidae, Dicroglossidae, Ichthyophiidae, Microhylidae, and Rhacophoridae. Based on distribution, we recognized five zoogeographic zones for them, Central Hills, Dry Zone, Knuckles Range, Lowland Wet Zone, and Rakwana Hills. Fifty three species were reported from the Central Hills (48 endemics [90.6%] and 42 [79.2%] threatened species). 47 species were recorded from the Lowland Wet Zone, including 36 (76.6%) endemics and 28 (59.6%) threatened species. The Knuckles Range had 25 species, of which, 19 (76.0%) were endemics and 15 (60.0%) are threatened species. 19 species were reported from Dry Zone including seven endemics (36.8%) and four threatened species (21.1%). Out of 29 species, which inhabited in the Rakwana Hills, 26 were endemics (~89.7%) including 24 (82.8%) threatened species. Species diversity along the elevational gradient was also observed with the highest species richness in the mid-elevational localities. Family Ichthyophiidae can be considered as the least studied family. Recent rediscoveries and studies have helped to reduce the number of extinct species from 21 to 18. It is speculated that some of the other extinct species have to be rediscovered or probably were misidentified as other species. About 90% of Sri Lankan amphibians occur in the regions with the highest human populations where there are established agricultural lands. Loss of habitats, competition due to anthropogenic species and invasive species, pollution (cause for malformations, parasites, and other diseases), and climate change appear to be major threats.