Study on diversity of cladocerans (Cladocera: Branchiopoda) in some selected wetlands of West Midnapore district, West Bengal, India

Abstract

Cladocerans, also referred to as “water fleas”, are a special group of crustacean zooplankton, noteworthy for their highly nutritive value as “natural live feed” in aquaculture practices and also for maintaining ecosystem stability. Geographically, in eastern India, the district West Midnapore in West Bengal is a part of unique red lateritic soil region known as the “Rarh belt” or “Rarh Bengal”. Due to this characteristic edaphic and topographical feature the biodiversity status of the wetlands herein are of special significance. An attempt was made to record the cladoceran species diversity in three ecologically contrasting freshwater bodies (a fishpond, a village pond, and a forest pond) in Garhbeta I block, in the northern fringe of West Midnapore district, West Bengal, India. The study revealed the presence of a total of 16 cladoceran species among the three study sites. Chydoridae (56%) was found to be the dominant family followed by Moinidae (19%). The fish pond (13 species) contained the highest species diversity followed by the forest pond (10 species) and village pond (eight species) respectively. The study showed that cladoceran species diversity seemed to be positively correlated with presence of nutrients. The species diversity was associated with the eutrophication status, ecosystem stability and productivity levels of the wetlands. The maximum species diversity was found in the pre-monsoon and least in the monsoon period. Thus, increase in temperature indicated a positive correlation with species diversity. The Shannon-Weiner index (H’) value ranged between 1.81 and 2.50 among the three sites, indicating overall moderately stable ecosystems. The one-way ANOVA results indicated that the variation in H’ value across different seasons was not statistically significant, but statistically significantly differed among different sites. Similar trends were seen for species evenness index and other diversity indices as well. Bray-Curtis cluster analysis based on species distribution indicated Site I and Site III were more similar as compared to Site II. However, as the recorded species count was less than the overall species diversity (63 species) recorded in the region, further studies are recommended for greater exploration of the group in the area.