Responses of hydrological processes to vegetation greening and climate change in subtropical watersheds

Study region: Xiangjiang River Basin (XRB) in subtropical China. Study focus: Vegetation changes have a substantial impact on the water cycle in watersheds. However, the responses of hydrological processes to vegetation changes in subtropical regions have not yet been thoroughly clarified. The primary objectives of this study were to quantify the sensitivity of hydrological variables to vegetation changes and to elucidate the contributions of vegetation greening and climatic changes to alterations in hydrological variables in the Xiangjiang River Basin (XRB). New hydrological insights for the region: Evapotranspiration (ET) exhibits a significant positive sensitivity to alterations in Leaf Area Index (LAI) in the XRB, while soil water storage (SW) and flow depth (Q) showed a significant negative sensitivity to LAI changes. Changes in LAI primarily result in increased ET and reduced SW and Q, while increased in precipitation leads to augmented ET, SW, and Q. Alterations in potential evapotranspiration have been associated with heightened ET and reduced SW and Q. From the perspective of relative contributions, LAI predominantly influences alterations in ET within the XRB; P and PET are the primary driver of shifts in SW; and P chiefly governs the variations in Q. Our results highlight the important impact of vegetation changes on hydrological variables in subtropical watersheds.