Assessing Ecological Quality Dynamics and Driving Factors in the Irtysh River Basin using AWBEI and OPGD approaches

Climate change and human activities increasingly impact watershed ecological quality (EQ), particularly in large transboundary watersheds. This study introduces an amended Water Benefit-Based Ecological Index (AWBEI) to assess changes in EQ within the Irtysh River Basin (IRB) from 2000 to 2023. AWBEI integrates indicators like surface water abundance, latent heat, land surface temperature, vegetation, and soil indices. We used Google Earth Engine (GEE) to efficiently process these data. The spatiotemporal analysis showed significant spatial variation in EQ across the basin. Areas north of 55°N consistently had better ecological quality. Overall, the basin exhibited a slight improvement trend, though with notable variations. The study identified persistent significant degradation in 5.43% of the area, primarily in central and western regions. Driving factor analysis using the Optimal Parameters-based Geodetector (OPGD) model identified temperature (q-values 0.583-0.695) and precipitation (q-values 0.561-0.665) as primary natural influences, with GDP (q-values 0.431-0.480) as the main socio-economic factor. Strong interactions between these drivers were observed, emphasizing the need for integrated ecological management approaches that consider both direct effects and synergistic interactions among environmental and socioeconomic factors.