Macrobenthos and their relationship with environmental drivers in Rushikulya, an Olive Ridley turtle rookery-associated tropical estuary

Summary

The Rushikulya estuary, located on the eastern coast of India in southern Odisha, is adjacent to the renowned mass-nesting site of the Olive Ridley turtle ( Lepidochelys olivacea ). Although there exists significant information on plankton and water quality, there is a dearth of knowledge concerning the macrobenthic community and, in particular, its relationship with the Rushikulya estuary environment. The main aim of this study was to analyze the macrobenthic community in the estuarine ecosystem and to identify the key environmental drivers influencing its structure. The study, spanning four seasons, documented 43 taxa, with polychaetes as the dominant group (66.97%), followed by gastropods (12.14%) and bivalves (2.46%). Hierarchical clustering identified four major macrobenthos groups, predominantly consisting of opportunistic and tolerant species. The distribution of macrofauna correlated significantly with salinity, nitrite, sand, and silt (Rho 0.672; significance 0.7%), with salinity emerging as the primary factor influencing spatiotemporal variations in macrobenthic structure. The M-AMBI and AMBI results indicated a slightly disturbed but good benthic community. These findings provide a novel characterization of the macrobenthic community and elucidate environmental drivers shaping biodiversity and ecological health. The study highlights the importance of macrobenthos as bioindicators for assessing ecological status and monitoring habitat changes, providing a baseline for evaluating the impacts of climate change and other environmental challenges in the estuary. This benchmarking is essential for guiding sustainable policies and environmental monitoring plans for the rookery-associated estuary.