RESUMEN
Water conservation (WC) has emerged as one of the most vital services provided by basin ecosystems. Climate change, the conversion of farmland to forests, and the implementation of check dam projects significantly impact the WC function in the Malian River Basin (MRB) of the gully region, Loess Plateau. This study systematically and comprehensively reveals the variation rules of WC and the mechanisms of action of influence factors in the MRB and selects factors representing natural environmental changes and human activities, such as climate, geomorphology, vegetation, and soil, influencing the WC. The InVEST model and a modified formula were used to evaluate the WC and its spatial-temporal changes in the MRB. The response of influence factors to the WC was explored using a "geographical detection - spatial drive/inhibition - influence degree" framework. The results indicate that under the comprehensive influence of multiple factors, the spatial distribution of WC in the MRB remained relatively consistent over different periods, characterized by higher values in the southeast and lower in the northwest. The WC values in 1990, 2000, 2010, and 2020 were 2.57 × 104, 1.48 × 104, 2.19 × 104, and 1.93 × 104 m3, respectively. The interaction of two factors on WC had a more significant effect than single-factor interactions, particularly the interaction between Soil Saturated Water Conductivity (Ksat) and Annual Precipitation (Pre), Annual Evapotranspiration (AET), and Net Primary Productivity (NPP). Pre, Plant Available Water Content (PAWC), and Ksat are key positive drivers, while AET, Temperature (Temp), and Elevation (DEM) are crucial negative drivers. Climate factors had the largest explanatory power for the WC spatial pattern (34.03-36.54%), geomorphic factors had the least (16.60-17.50%), and vegetation factors more than soil factors. This study provides valuable insights for optimal water resource allocation and sustainable development of the gully region, Loess Plateau.