Quantitative analysis of the community structure of tropical amphibian assemblages and its significance to conservation.

Amphibian community structure in five tropical sites was studied using dominance, diversity, evenness indices, niche breadth and overlapping scores and association analysis. Ten species of amphibians with average density/ha varying from 8 to 49 in different sites were collected. Rana limnocharis and Bufo melanostictus were respectively the dominant amphibia in paddy fields and other sites. Niche breadth scores indicated Rana limnocharis, Bufo melanostictus and Rana cyanophlyctis as habitat generalists indicating wide tolerance to environmental gradients. Five frog species i.e. Rana tigerina, Microhyla ornata, Ramanella variegata, Uperedon systoma and Polypedates maculatus were considered habitat specialists indicating narrow tolerance to environmental gradients. Niche breadth scores were found to be a function of the cumulative relative abundance value of different species. The niches of Rana limnocharis and Rana cyanophlyctis, Bufo melanostictus and Bufo stomaticus showed maximum overlapping. Rana tigerina showed maximum niche overlapping with Rana variegata in paddy fields and with Microhyla ornata when all sites were taken together. The coefficient of community index was maximum between the paddy fields and minimum between the paddy fields and forest site. Rana tigerina occurred very sparsely and analysis of data indicates that its population are threatened and require conservation measure.