Spatiotemporal dynamics of soil erosion and its interactive mechanisms with NDVI in the Yellow River Basin, China

Soil erosion (SE) is a critical constraint on terrestrial ecosystem functioning and sustainable soil management. The Yellow River Basin (YRB), one of the most severely eroded regions in China, has long been affected by intense soil and water loss. To elucidate the spatiotemporal evolution of SE and vegetation dynamics under long-term ecological restoration, this study quantified SE intensity in the YRB from 1995 to 2024 using the InVEST Sediment Delivery Ratio (SDR) model. Vegetation dynamics during 2001-2024 were analyzed using MODIS NDVI data in combination with the Mann-Kendall test and Sen's slope estimator to detect trends and phase transitions. The GeoDetector model was further applied to identify the individual and interactive effects of land use/cover change (LUCC), topography, climate, and vegetation on SE and vegetation dynamics, with explicit comparisons among the upper, middle, and lower reaches of the YRB. The results indicate that vegetation cover across the YRB has increased significantly over the study period, exhibiting a pronounced southeast-northwest decreasing spatial gradient. Overall SE intensity declined, although the rates of change varied across different stages. Driver analysis reveals that LUCC is the dominant factor explaining the spatial variability of SE at the basin scale, with particularly strong effects in the middle reaches, where its influence is further amplified through interactions with topographic factors. Vegetation dynamics are primarily regulated by precipitation and jointly shaped by land use patterns. The relative importance of natural constraints and human activities differs markedly among the upper, middle, and lower reaches. By integrating long-term observations with a basin-wide and subregional perspective, this study provides quantitative insights into the coupled responses of vegetation restoration and soil erosion reduction in the YRB, offering scientific support for region-specific soil and water conservation and ecological restoration strategies.