Evaluation of wetland ecosystem health using geospatial technology: evidence from the lower Gangetic flood plain in India

The floodplain wetland habitat in the lower Gangetic plains of West Bengal played a significant role in protecting from environmental degradation like pollution, lowering groundwater table, natural hazards, and others as well as supports for human wellbeing. Thus, it is needed to investigate the health status of wetlands and suggest restoration strategies to protect the livelihood patterns dependent on wetlands. This paper presents the health of the wetland ecosystem by comprising the wetland ecosystem health index (WHI) in 2011 and 2018 at the block level of Malda district, as a part of the lower Gangetic flood plain using the pressure-state-response model (PSR model) and AHP method. A total number of six Landsat satellite images and statistical census data were used to determine the wetland health. Wetlands are classified as very healthy (2.81-3.33), healthy (2.41-2.80), sub-healthy (2.01-2.40), unhealthy (1.61-2.00), and sick (0-1.60) category on the basis of the wetland ecosystem health index score. The results of this study showed that the wetlands located surrounding English Bazar, Manikchak, Ratua-II, and Kaliachak-II blocks have a sub-healthy to very healthy condition in 2011 but changed to unhealthy to sick category in 2018 due to the increase of rapid urbanization, population density, and development activities. These areas have belonged to the sub-healthy to sick category in the year 2011 as well as 2018 due to high wetland pressure. Our observation reveals that the ecosystem service value provided by wetlands decreased by 62.51% and 20.46 in the observed period. Management of WEH should emphasize on large (>100 ha) and medium (51-100 ha) sizes of wetlands in the Diara region of West Bengal. Developing local-level institutions and setting restoration goals are useful strategies to manage wetland resources, and protecting biodiversity should be guided by the Government organization and NGOs.