Ecosystem service assessment of selected wetlands of Kolkata and the Indian Gangetic Delta: multi-beneficial systems under differentiated management stress

© 2019, The Author(s). A structured literature review using the search term ‘ecosystem services’ found few relevant studies relating to three contrasting wetlands in West Bengal: the unpopulated Sudhanyakhali Island in the Sundarbans National Park, the populated Gosaba Island separated from Sudhanyakhali Island by a narrow channel, and the East Kolkata Wetland (EKW). Subsequent structured review focused on the EKW using specific service-related terms located only 2 provisioning, 6 regulating, 1 cultural and 3 supporting services. Few services are currently recognized in the literature, with significant gaps in whole service categories. Significantly, there was no published evidence of a systemic overview of service production at these sites. Field observations and stakeholder dialogue informed assessment of ecosystem services using the Rapid Assessment of Wetland Ecosystem Services (RAWES) approach, adopted by the Ramsar Commission, on both islands and three discretely different areas of the EKW. The RAWES surveys found that 32 of 36 ecosystem services were produced from at least one assessed wetland site. Despite low sample size, statistically significant differences were observed in the range of services produced between the five wetland sites and the geographical range at which benefits accrued, explained by differing wetland characteristics and management regimes. Were decisions based solely on evidence provided by existing published knowledge, few ecosystem services would be considered and, potentially, whole ecosystem service categories might be overlooked. Importantly, there would also be no systemic account of service production and interdependencies. RAWES assessment serves as a practical, rapid and systemic approach, taking account of interdependent ecosystem services, supporting protection of the ecological character and achievement of wise use of wetlands. RAWES can also help redress perceptions that the values of peri-urban wetlands are currently under-represented

Development of a water quality index (WQI) for the Loktak Lake in India

Abstract The present work was carried out to assess a water quality index (WQI) of the Loktak Lake, an important wetland which has been under pressure due to the increasing anthropogenic activities. Physicochemical parameters like temperature (Tem), potential hydrogen (pH), electrical conductivity (EC), turbidity (T), dissolved oxygen (DO), total hardness (TH), calcium (Ca), chloride (Cl), fluoride (F), sulphate ( $${\text{SO}}_{4}^{2-}$$ SO 4 2 - ), magnesium (Mg), phosphate ( $${\text{PO}}_{4}^{3-}$$ PO 4 3 - ), sodium (Na), potassium (K), nitrite (NO2), nitrate (NO3), total dissolved solids (TDS), total carbon (TC), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) were analyzed using standard procedures. The values obtained were compared with the guidelines for drinking purpose suggested by the World Health Organization and Bureau of Indian Standard. The result shows the higher concentration of nitrite in all the location which is beyond the permissible limit. Eleven parameters were selected to derive the WQI for the estimation of water potential for five sampling sites. A relative weight was assigned to each parameter range from 1.46 to 4.09 based on its importance. The WQI values range from 64 to 77 indicating that the Loktak Lake water is not fit for drinking, including both human and animals, even though the people living inside the Lake are using it for drinking purposes. The implementation of WQI is necessary for proper management of the Loktak Lake and it will be a very helpful tool for the public and decision makers to evaluate the water quality of the Loktak Lake for sustainable management