Growing significance of vegetation succession following glacier retreat on high-mountain hydrological cycle

Climate-driven glacier retreat exposes newly ice-free terrain that is progressively colonized by plants, driving ecological succession and altering hydrological and biogeochemical processes in high-mountain ecosystems. Although hydrological impacts of glacier shrinkage have been widely explored, the effects of post-retreat vegetation succession remain poorly quantified. In this study, we apply a mechanistic ecohydrological model (T&C) that explicitly simulates plant migration and species range dynamics to assess hydrological responses to glacier retreat and vegetation succession from 1981 to 2099 under multiple climate change scenarios in a deglaciating ecosystem in the Swiss Alps. The results show that glaciers exert a first-order control on the hydrological cycle, particularly on runoff. Vegetation succession following glacier retreat plays a relatively minor role in hydrological processes initially, but its importance increases over time as glacier cover declines. The combined interactions among glaciers, vegetation and climate significantly modify hydrological regimes, with important implication for projecting future water resources, including changes in terms of magnitude and intra-annual (seasonal) variability, and water quality in high-mountain regions under continued global warming.