Assessing the spatiotemporal patterns and driving factors of water erosion in the Ganges-Brahmaputra-Meghna River Basin based on RUSLE-Geodetector

The Ganges-Brahmaputra-Meghna (GBM) river basin, a critical transboundary river basin in South Asia, is increasingly affected by soil erosion. However, its spatiotemporal dynamics and underlying drivers remainpoorly quantified. This study comprehensively evaluates soil erosion intensity and its driving factors during 2000–2022 by the Revised Universal Soil Loss Equation (RUSLE) with Geodetector. The main findings are as follows: (1) The mean soil erosion intensity across the GBM basin is 1087.78 t∙km⁻²∙a⁻¹, with 68.76% of the basin experiencing mild erosion (< 500 t∙km⁻²∙a⁻¹).Spatially, erosion intensity is highest in the Southern Foothills of the Tibetan Plateau Area (SFA) (3099.84 t·km⁻²·a⁻¹) and is lowest in the Flood Plain Area (174.10 t·km⁻²·a⁻¹). (2) At the basin scale, no significant trend is observed in the GBM basin. In contrast, the SFA subregion shows a significant increasing trend of 34.38 t∙km⁻²∙a⁻² (P = 0.05). Projections indicate that 67.57% of the basin is likely to experience worsening erosion in the future. (3) Topography and NDVI dominates the soil erosion patterns in most of the region. However, in the eastern hilly area, the primary drivers are topography and precipitation, with a high Q value of 0.841. Notably, topography influence has weakened over time, while the influence of human activities has strengthened, highlighting the need for targeted management of land use and conservation practices to reduce soil and ecosystem degradation. These results can provide valuable insights for mitigating water erosion and optimizing conservation strategies within the GBM river basin.