Spatial and temporal variation in the diversity of malacofauna from Aripal stream of Kashmir Himalaya, India

Abstract

This paper presents the spatial and temporal variation in the diversity of malacofauna in relation to the water chemistry of the Aripal stream of Kashmir Himalaya. A total of 12 species were reported which belong to four families, Lymnaeidae, Physidae, Planorbidae, and Bithyniidae from class Gastropoda, and two families, Cyrenidae and Pisidiidae from class Bivalvia. The family Planorbidae contributed 34% to the total annual molluscan population followed by Lymnaeidae (28%) and Bithyniidae (18%). During the collection, Gyraulus sp., Planorbis sp., and Bithynia tentaculata were prevalent at all sites, with predominance of Bithynia tentaculata. Species richness and abundance were observed maximum at site A3 (down-stream) and minimum at site A1 (up-stream) while in the case of temporal variation, species richness and abundance were maximum in summer and minimum in winter. Shannon-Wiener index, Simpson index, Margalef index, and Pielou evenness index were used to calculate the diversity, dominance, richness, and evenness of molluscan species, respectively. Physico-chemical parameters revealed a non-significant spatial variation (P >0.05) except pH, total hardness, and alkalinity while a significant temporal variation (P <0.05) was observed in the physico-chemical parameters except dissolved oxygen. A significant positive correlation was seen between the molluscan species and total hardness. In the present study, the stone mining, channel morphology of stream, habitat heterogeneity, and physico-chemical parameters were also found to promote the spatial and temporal diversity of malacofauna.