Zooplankton Communities of Three Wetlands of Nagaland, NE-India: Richness, Ecology and Abundance

The limnological studies was carried out in three selected wetlands viz., Noune, Madladijam and Bolfangdisa wetland in Nagaland from December 2014 to November 2016. A total of 269 species (S) of net plankton with zooplankton (181 species) > phytoplankton (88 species) revealed species-rich assemblage and thus affirmed environmental heterogeneity of the sampled habitats; ~50% are noted to occur in all the sampled wetlands. Zooplankton is characterized by biodiverse nature (181 species) with higher mean richness (139±22 species) in the three wetlands individually. The study indicates distinct monthly variations with higher richness in Bolfangdisa (27-69, 46±11 species) > Madladijam (25-60, 43±9 species) than in the ‘semi-limnetic waters’ of Noune (16-45, 29±9 species) wetlands, thereby, affirming habitat diversity amongst these lentic ecosystems. The abundance of zooplankton followed an oscillating monthly variation in the three wetlands. The density of zooplankton ranged between 63-186 (102±30) n/l in Noune wetland, 102-188 (3142±26) n/l in Madladijam wetland and 73-221 (135±39) n/l in Bolfangdisa wetland. ANOVA registered significant zooplankton richness variations amongst wetlands (F2, 71=32.444, p =1.625E-09) and significant monthly variations (F23, 71=2.345, p=0.006) between them. Rotifera formed the most important quantitative component of zooplankton of the sampled Nagaland wetlands. The present study records high species diversity and evenness and lower abundance and recorded limited density variations between wetlands. CCA asserted differential cumulative influence along first two axes of seventeen abiotic factors on zooplankton assemblages with high influence in Madladijam (84.2%) and Bolfangdisa (73.3%) and low influence in Noune (53.8%). The present study provides limited insight on the influence of individual abiotic parameters on zooplankton asserted generalist nature of majority of taxa in terms of general abiotic factors, with factors associated with microhabitat being more important.