A review of Ramsar sites in Northeast India

Wetlands span 1500 million hectares and contribute 43.5% of overall ecosystem service value globally. With 35% loss globally since 1970, tropical wetlands are considered the most exploited and threatened ecosystem. Therefore, it is vital for identifying and comprehending driving factors contributing to the degradation of wetlands. This review examines wetlands of international significance located in Northeast India. The existing literature on wetlands, specifically Loktak Lake in Manipur, Deepor Beel in Assam, and Rudrasagar Lake in Tripura, has been meticulously examined. The findings indicated that Ramsar sites experienced persistent degradation due to factors including land use change, policy and management issues, and climate change, alongside other anthropogenic activities encompassing the release of domestic sewage, untreated industrial effluents, and with excessive fertilizer application, all of which exacerbate the overexploitation of wetland resources. In principle, water quality is evaluated via physicochemical as well as biological parameters. Consequently, the WQI (Water Quality Index) has been a significant tool for water quality evaluation. Wetlands are lentic water bodies, leading to the deposition of various toxic pollutants over time. The present study provides an overview of different indices including HMI (Heavy Metal Index), EF (Enrichment Factor), Igeo (Geoaccumulation Index) used for determining heavy metals contamination in wetland sediments besides nutrient loading effect on water quality. This review on Ramsar sites further suggests the integration of all the aspects of limnology for better sustainable management of wetlands.