Redefining the modified water benefit-based ecological index to evaluate the impact of cropland expansion on the ecological environment in an arid area

Global land-use changes have a significant impact on the environment and food security, and escalating human activity and uncontrolled agricultural land expansion pose a grave threat to regional ecosystems. This study aims to assess the challenges faced by the environment and food security, with a particular focus on the impact of land use change on ecosystems. The study selected the Ebinur Lake Basin, a typical arid region in China, as the object and analyzed the land type changes from 2013 to 2021 using the Google Earth Engine platform and the China Land Cover Dataset. We created an Improved Water-Benefit-Based Ecological Index (IWBEI) based on the poor air quality environment in the watershed, and then calculated the ecological index of the watershed. The results indicate that the grassland and bare land areas in the Ebinur Lake Basin have fluctuated and shown an overall downward trend. The trend of farmland expansion is to expand to surrounding areas on the basis of existing farmland. The overall center of gravity of cultivated land in the watershed is moving from northwest to southeast, mainly towards the water source area. The IWBEI index is more prominent in identifying cultivated land and wetlands in arid regions. According to IWBEI's calculations, the priority order of land types is: forest > cultivated land > wetland > water > snow > grassland > impermeable surface > bare land. The overall ecological environment quality of the watershed is showing a deteriorating trend. Therefore, relevant departments should pay attention to the impact of farmland expansion on the local ecological environment to avoid the continuous deterioration of the ecological environment. • The center of gravity of farmland in the watershed shifts northwest to southeast, mainly towards water sources. • The IWBEI index aims to improve regional air quality. • The IWBEI index outperforms the WBEI index in identifying farmland and wetlands. • Overall, the watershed's ecological environment is deteriorating.