Monsoon associated macroinvertebrate community dynamics in lakes of urban and semi-urban areasof Ranchi, North Eastern India.

Abstract

In Indian subcontinent monsoon affects billions of lives, even modest alterations in spatiotemporal pattern may lead to significant socioeconomic stress in the region. Monsoon also affect creation, rejuvenation, and sustenance of lakes. Freshwater lakes habitats various biological assemblages that translates in ecological quality of water. During monsoon, heavy inflow of runoff water can significantly alter species assemblages and their association with quality of water. This study evaluated changes in macroinvertebrates dynamics of Ranchi (urban) and Kanke (semi-urban) lakes located in Chota Nagpur Plateau, North-eastern India. Results indicated higher abundance of macroinvertebrate in Ranchi lake than Kanke lake. However, taxa richness was greater in Kankelake in comparison to Ranchi lake. Monsoon had higher impact on abundance of taxonomic order under family Gastropoda. Post-monsoon increase in abundance of Basommatophora (14%), Neotaenioglossa (14%), and Littorinimorpha (13%) were observed. Likewise, Architaeniogiossa, incertae sedis, Haplotaxida were least affected taxonomical orders during investigated seasons. Both lakes were dominated by collector-gatherers (CG), however, Kanke lake indicated richness in diversity of FFGs. CGs were also less motivatedby seasonal alteration before, during and after monsoon. In conclusion, pre-monsoon, monsoon and post-monsoon seasons largely affects abundance of macroinvertebrates in both lakes. Runoff rainwater supports macroinvertebrate development through addition of nutrients. This study indicated that Ranchi lake contains high abundance of scrapers (SC) and grazers (GZ), those are associated with higher anthropogenic activities. Likewise, higher taxonomical richness in Kanke lake indicated more diverse and healthy ecosystem.