Integrated eco-hydrological and vegetation productivity analysis of wetland landscapes in Madhubani, Bihar (2002–2024)

Abstract Wetlands are highly productive and biologically diverse systems that enhance water quality, control erosion, maintain stream flows, sequester carbon, and provide a home to at least one-third of all threatened and endangered species. Rainfall and temperature naturally and directly impact them, but other elements that influence these variables include transpiration, evaporation, and vegetation cover. To investigate the impact upon wetlands in the Madhubani district of Bihar, this study utilizes several multi-dimensional variables, viz., actual and potential evapotranspiration (ET and PET), gross and net primary productivity (GPP and NPP), annual rainfall, the Modified Normalized Difference Water Index (MNDWI), and the Soil-Adjusted Vegetation Index (SAVI). Satellite data of Terra-MODIS 8-day composite (500m) and Landsat series data from the USGS have been used for mapping the changes in wetlands in the Arc-GIS Pro environment. Modified Mann-Kendall (mMK) test and Sen slope have been employed for estimating rainfall trends.The study finds that annual rainfall in Madhubani has decreased over the period 1994–2024, negatively impacting the wetland ecology. The primary productivity witnessed a decreasing trend of GPP and NPP during the years 2002–2024, which resulted in a decreasing trend of seasonal and annual patterns of ET and PET. The past two decades have seen a decline in the spatial distribution of wetlands in Madhubani, resulting from declining trends of annual rainfall, evapotranspiration, and primary productivity.