Predicting effects of rainforest fragmentation from live trapping studies of small mammals in Sri Lanka

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M.R. Wijesinghe


This paper examines the impact of forest fragmentation on small mammals inhabiting the rainforests of Sri Lanka. Fifteen forests ranging in size from 145 to 11000 ha were live-trapped for five to eight nights each in both interior and edge habitats, yielding a total of 18400 trap nights. A total of 444 individuals belonging to 10 species of small mammals were captured. Multiple-regression analysis incorporating three indicators of fragmentation: patch area, shape index (perimeter/area) and degree of isolation, showed no significant effects on overall species richness of small mammals. This is likely because the decline of forest-adapted species from small forest fragments was accompanied by an increase in more tolerant and adaptive species. Patch size, however, had a significant positive effect on the abundance of small mammals. Of the two dominant species, the endemic Mus mayori was positively affected by patch area whilst Rattus rattus was not affected. Although no differences were evident between interior and edge habitats with respect to total species richness and abundance, endemics were more abundant in core areas while the reverse was true for the non-endemics. Core forest areas were significantly different from forest edges with respect to canopy cover, density of herbaceous vegetation, large trees and litter cover. These results suggest that forest fragmentation is detrimental to some forest specialists and beneficial to some generalists.

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Author Biography

M.R. Wijesinghe

Dr. Mayuri R. Wijesinghe is a Senior Lecturer in Zoology attached to the University of Colombo, Sri Lanka. Her expertise lies in the fields of Conservation Biology and Toxicology. Her research focuses on collecting baseline data on the distribution and habitat requirements of many rodents and shrews and on investigating reasons for their vulnerability to forest destruction and fragmentation. She also studies the impact of agrochemicals and heavy metal pollutants on the survival, growth, development and histopathology of larval stages of amphibians.