DIVERSITY AND ABUNDANCE OF MACROZOOBENTHIC COMMUNITIES IN A GANGETIC FLOOD PLAIN WETLAND OF WEST BENGAL, INDIAD. Sarkar (Paria)
Aquatic macrozoobenthic invertebrates are the most important group of organisms which have a crucial ecological role in the flood plain wetland ecosystems. They can indicate the habitat conditions by integrating bottom sediments and overlying water strata. The flood plain wetland locally named as Katiganga beel with an approx area of 33 ha is an open wetland of Murshidabad district of West Bengal was studied for its macrozoobenthic fauna on monthly basis from randomly selected 8 spots of the beel for two years (2019- 2020). The macro zoobenthic population of the beel Katiganga was recorded which comprised of maximum 46 no. of taxa throughout the investigation period. These taxa have been classified and grouped into Annelids (10 taxa), Molluscs (24 taxa), Insects (10 taxa) and Crustaceans (2 taxa). Molluscan population was found to be maximum in both the years of study contributing about 58-59% of the total macrozoobenthic fauna followed by Annelids (21%)> Insects (17-19%) and Crustaceans (2-3%). The Shannon (H) indices were highest for Molluscs (2.764-3.138) followed by Insects (2.0-2.286), Annelids (1.724-2.277) and Crustaceans (0.4101-1.0). Higher values of Margalef Richness Index (d) in the study (2.246-4.58) for Annelids, Insects and Molluscs represented the suitability of habitat for these organisms and indicated the presence of longer food chain and complex food web in the ecosystem involving these organisms in their stable community. The flow modification due to poor connectivity with the river Ganges, water depth, pollution received from adjoining catchment area can influence the composition, abundance, and diversity of macrozoobenthos.