Distribution, habitat associations and conservation implications of Sri Lankan freshwater terrapins outside the protected area network

Abstract

Terrapins are integral to many freshwater ecosystems, yet are imperilled at a global scale. In Sri Lanka, terrapins are understudied; thus, much of their natural history and distribution status remain unknown. Such paucity of studies impedes conservation. In this study, 79 freshwater habitats located outside the protected area network of south‐western Sri Lanka were surveyed to document current population densities and habitat use of two terrapin species: Indian black terrapin (Melanochelys trijuga thermalis) and flap‐shelled terrapin (Lissemys ceylonensis). Local inhabitants were interviewed to assess human threats towards terrapins. Both species were recorded in low densities: 1–2 individuals ha−1. Indian black terrapin was found in half of the surveyed sites while flap‐shelled terrapin occurred in one‐third of the surveyed sites. Highly urbanized river basins had the lowest densities for both species while rural basins supported higher numbers. Basking was the predominant behaviour of both species and large woody debris and boulders were preferred as basking substrates, together with sparse‐canopy aquatic habitats with intact marshlands. Overharvesting for meat was a major threat for terrapins. Most local inhabitants were unaware of legislation on terrapin conservation and the ecological importance of terrapins. Human threats such as pollution, modification of aquatic and wetland habitats, and loss of riparian forests were frequently observed in surveyed sites. Terrapin populations outside the protected area are at risk as evidenced by lower population densities and a multitude of human threats. A landscape‐scale ecosystem‐based conservation approach is recommended for Sri Lanka's terrapins with incorporation of lands with different management regimes (privately owned, municipality managed) into the protected area network. Current environmental legislation should be revised to support buffer zone delineation for aquatic habitats, wetland restoration, and landscape‐scale connectivity.

A phylogenetic and taxonomic assessment of the Cnemaspis alwisi group (Reptilia: Gekkonidae) in Sri Lanka with a description of two new species from isolated misty-mountains

“…It is evident that conservation of isolated misty mountains is crucial in conservation of the unique fauna and flora of the island. It is also imperative to inform the general public, educators, natural resource and land managers, and private entrepreneurs about environmental legislation through printed and electronic media and outreach activities (Karunarathna et al 2017a(Karunarathna et al , 2017b.…”

An Overview of Ecosystem Service Studies in a Tropical Biodiversity Hotspot, Sri Lanka: Key Perspectives for Future Research

“…Most of the ecosystem services and related biodiversity studies in Sri Lanka are related to coastal, freshwater, or wetland ecosystems and are interdisciplinary in nature, and discussed resources, their utilization, environmental issues, and management options [30,[37][38][39][40][41][42][43][44][45][46][47][48][49][50], compared to the number of forest-related interdisciplinary ecosystem service studies [33,51,52]. Sri Lanka has assigned its forests primarily for conservation since 1989 due to their unique biodiversity and significance in the country's economy [34].…”

Climate Change Impacts on Tropical Reptiles: Likely Effects and Future Research Needs Based on Sri Lankan Perspectives

“…In contrast, South-Asian tropical biomes have only attracted minimal attention in the climate change literature, and this is particularly the case for the rich biodiverse Indian Oceanic tropical island nation of Sri Lanka. With respect to reptilian diversity in Sri Lanka, nine chelonian species in six families (five marine turtles, three freshwater terrapins, and one land tortoise) are recognized, of which one species (red eared terrapin, Trachemys scripta) has been introduced through the pet trade (Karunarathna et al, 2017). Two species of native crocodile and 118 lizard species are found in the country, and of these, 96 species are endemic to Sri Lanka.…”