Assessment of the Impacts of Climate and Land Use Changes on Water Yield in the Ebinur Lake Basin

The Ebinur Lake Basin is an ecologically sensitive area in the arid region of northwest China. In recent years, the ecological environment in the basin has continued to deteriorate, and the ecosystem function has been seriously degraded. However, among the functions of the ecosystem in the Ebinur Lake Basin, the water production function is considered to be the core upholding the ecological equilibrium and security of the basin. Water production can reflect the environmental service function, which is essential for the economic vitality and ecological well-being of the basin. The factors that impact water yield are diverse; moreover, of these, climate change and land use conversion are particularly significant. Therefore, understanding how these changes affect water yield will help to formulate proper water management strategies in the basin. Using the InVEST model, this study examined how the water yield evolved and was distributed across the Ebinur Lake Basin between 2000 and 2020 while considering both the temporal and spatial dimensions. Using this foundation, the scenario analysis approach was utilized to explore the impact of climate change and land use conversion on water yield by controlling the variables, and the response of the water yield to climate and land use change was discussed. It was concluded that water yield was on an upward trend from 2000 to 2010, was on a downward trend from 2010 to 2020, and declined from 2000 to 2020 as a whole. Regarding the water yield distribution, higher-water-producing areas were found predominantly in the northwest and southeast and along the higher-altitude rim of the basin. Among the various land categories, the primary types were grassland and unused land, both of which equally and substantially contributed to the water yield, contributing over 85% to the overall water yield. The response of the water yield varied significantly among various land use types when their areas changed, and the land conversion over this period contributed to a slight decline in water yield across the basin. The influence of climate change on water yield in the Ebinur Lake Basin during the study period surpassed that of land use by a wide margin, constituting more than 86% of the total impact. This study can provide relevant information for relevant policies and decisions on the optimal allocation of land use in the Ebinur Lake Basin and can provide scientific development for the comprehensive evaluation of water resources and sustainable development of the basin.