HERPETOFAUNAL SPECIES RICHNESS, DIVERSITY AND ABUNDANCE IN DIFFERENT HABITAT TYPES IN ENDANE BIODIVERSITY CORRIDOR, RATNAPURA DISTRICT, SRI LANKA

Abstract

The Endane Biodiversity Corridor (EBC), located in the Ratnapura District of Sri Lanka, serves as a reforestation initiative, connecting the fragmented Iharakanda and Walankanda forest reserves. Recently, the concept of biological corridors has gained significant attention due to its practical, evidence-based benefits. These corridors are designed to enhance connectivity between protected areas and fragmented habitats. Given this, the current study sought to assess herpetofaunal (amphibians and reptiles) species abundance, richness and diversity across different habitat types within the corridor and adjacent Walankanda Forest Reserve. Four habitat types were surveyed from the beginning of July to the end of January 2025: the restored area, productive tea area, home gardens within the corridor and forested habitat in the Walankanda Forest Reserve (WFR). Data were collected using line transects, pitfall traps and opportunistic surveys covering both diurnal and nocturnal periods. Diversity indices were used to evaluate ecological diversity, and statistical analyses using a linear mixed effect models were conducted to compare species composition between habitats. The Sørensen similarity index was used to measure the similarity in species composition between different habitat types. A total of 39 herpetofaunal species was recorded, including 16 amphibians and 23 reptiles, with high levels of endemism (81% in amphibians and 58% in reptiles) and six amphibian (Bufonidae, Dicroglossidae, Ranidae, Rhacophoridae, Nyctibatrachidae and Ichthyophiidae) and eight reptile (Agamidae, Scincidae, Gekkonidae, Colubridae, Natricidae, Elapidae, Viperidae and Varanidae) families observed. The highest number of amphibian species was recorded from the family Rhacophoridae, while reptile species richness was greatest for the family Colubridae. The most abundant amphibian species was Minervarya agricola (Jerdon, 1853). The most abundant reptile species was Calotes calotes (Linnaeus, 1758). Among the four habitat types studied, the highest amphibian and reptile diversity was recorded in Walankanda Forest Reserve. The lowest amphibian diversity was observed in the productive tea area, while the restored area showed higher amphibian species richness compared to the home garden. The home garden had the lowest reptile diversity across all indices, most likely due to human disturbance, while the restored area exhibited moderate diversity, indicating partial recovery. According to the Sorensen dissimilarity matrices, the highest dissimilarity was recorded between natural forest and modified habitats, with greater similarity between anthropogenic areas like productive tea area and home garden. Habitat comparisons within the Endane corridor revealed that marginal tea areas exhibited the highest amphibian diversity and species richness, while productive tea areas had the lowest diversity and species richness. Woodland 2 had the highest reptile diversity, likely due to its proximity to Walankanda Forest Reserve. The findings emphasize the importance of reforested habitats in maintaining herpetofaunal diversity and highlight the ecological significance of the Endane Biodiversity Corridor in species conservation and habitat connectivity