Discrepancies in the effects of the key factors on soil erosion on various temporal scales in the eastern Tibetan Plateau under global warming

Global warming increases the rainfall intensity and frequency in most regions, intensifying the urgency of investigating the influence of various factors on soil erosion. However, existing studies mainly investigate this issue on the monthly or annual scale. There remains a research gap regarding how these factors influence soil erosion on the event scale. In this study, the Min River Watershed (MWR), located in the eastern Tibetan Plateau, was chosen as the study region. Based on the daily measured hydro-meteorological and underlying data, the effects of precipitation, temperature, Land Cover (LC), connection, and runoff on soil erosion have been decoupled on the event and monthly scales using the Partial Least Squares-Structural Equation Model (PLS-SEM). Results show that the annual runoff, Suspended Sediment Concentration (SSC), and Sediment Flux (SF) were increased significantly (P < 0.05) from 2007 to 2020. On the event scale, the SF variation was more obvious than that of other variables, which may be caused by the inconsistent changes of rainfall amount and intensity. The parameters of Sediment Rating Curves (SRC) varied on different scales, indicating that the SF is governed by soil supply on the event scale but by runoff erosive power on the monthly scale. PLS-SEM results exhibit that SF is predominated by SSC on the monthly scale, but shifts to an equivalent balance between supply and transport capacity on the event scale, and connection significantly modulates SSC on the event scale. Precipitation remains a universal driver; event-based sediment dynamics are uniquely governed by multi-path cascading effects of temperature and vegetation on connection and runoff, reflecting a transition from simple hydrological forcing to complex biophysical interactions on the event scale. Results could enhance the understanding of the influence paths of various factors on soil erosion on multiple scales and support future soil erosion prevention under global warming.