Spatial-temporal evolution and responses of ecosystem service value under land use change in the Yellow River Basin:A case study of Shaanxi-Gansu-Ningxia region, Northwest China.

The Shaanxi-Gansu-Ningxia region is located in the upper and middle reaches of the Yellow River Basin in the Northwestern China, with vulnerable ecosystems. It is important to define the regional pattern of ecological security. The ecological and economic issues in this region deserved more investigation. By integrating land use data and the socio-economic data from 1995 to 2020, and using spatial analysis and geodetector, we investigated the spatial-temporal variations of land use and ecosystem service value (ESV) and the driving forces of spatial variations of ESV in the region. The results showed that the cultivated land and unused land in the study area were decreasing, whereas the construction land and forest land increased from 1995 to 2020. The overall ESV in the region showed a "decrease-increase" trend, which decreased by 1.2% from 1995 to 2000 and increased by 1.0% from 2000 to 2020. Grassland provided the largest ESV, contributing a prominent regulation on function and service. The results of geodetector indicated that NDVI was the dominant driving factor for the spatial variation, while temperature and per capita net income of farmers were the important factors. There were mainly 32 types of the index of driving forces with the spatial difference of ESV (q value) being more than 30%. The q value of NDVI and soil type was nearly 46%. The spatial variation of ESV in Shaanxi-Gansu-Ningxia region was affected by the interactive enhancement among natural, socio-economic factors, and policy factors.