Seasonal changes in molluscan diversity of Western Ghat rivers of Karnataka, India

Molluscan diversity from the Western Ghat rivers of Karnataka was studied and 14 species of freshwater molluscs were recorded. Melanoides tuberculata was found throughout the study period whereas Brotia costula and Parreysia spp. were rarely observed. The species diversity of molluscs was more in pre-monsoon than post-monsoon. The molluscs were more abundant in the upstream of the rivers Netravathi and Souparnika than the midstream and downstream. Filopaludina bengalensis was restricted to the Sharavathi river and their abundance was observed in the midstream of the Sharavathi river. Kruskal Wallis test showed a significant difference in abundance and species rich-ness with the seasons. This shows that seasonal changes bring about variations in the molluscan diversity of the West-ern Ghat rivers of Karnataka.