Changes in Snow Cover and Underground Ecosystems in the Northern Hemisphere

The snow cover changes driven by climate change are profoundly altering the structure and function of alpine ecosystems. Based on a review of the effects of snowpack variation on soil processes in terrestrial ecosystems of the Northern Hemisphere (with the most significant soil insulation effect observed at snow depths of 40-70 cm; increased snow cover accelerates carbon and nitrogen cycling, leading to their loss, with more pronounced effects in moist habitats), this study, combined with snow cover manipulation experiments in the alpine meadows of the Tibetan Plateau, focuses on examining the response of plant above-ground and below-ground functional traits to increased snow depth. The study found that increased snow depth significantly improved the water-thermal conditions of the shallow soil during the growing season, which in turn drove an "inconsistent response" in plant above-ground and below-ground parts: while there was no significant change in above-ground biomass, leaf chemical traits (carbon, nitrogen, and phosphorus concentrations) were significantly enhanced, and morphological traits (such as specific leaf area) decreased. In contrast, root biomass in the below-ground part increased significantly, and root morphology was significantly optimized (specific root length and specific root area increased, root diameter decreased). Further analysis indicated that variation in leaf traits was primarily driven by nutrient chemical properties, whereas variation in root traits was predominantly influenced by morphological adjustments. The sensitivity of below-ground processes in the alpine meadows to snowpack variation was higher than that of the above-ground processes. This differential response strategy reflects the trade-offs between above-ground and below-ground resource allocation, highlighting the adaptive strategy of alpine plants to prioritize root investment for enhanced resource acquisition under changing snow conditions. This study deepens the understanding of the cascading mechanisms of snow-soil-plant interactions and provides a theoretical basis for predicting the feedback of alpine meadow ecosystems to climate change.