Water yield is a key ecosystem function index, directly impacting the sustainable development of the basin economy and ecosystem. Climate and land use/land cover (LULC) changes are the main driving factors affecting water yield. In the context of global climate change, assessing the impacts of climate and LULC changes on water yield in the alpine regions of the Qinghai–Tibet Plateau (QTP) is essential for formulating rational management and development strategies for water resources. On the basis of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, we simulated and analyzed the spatiotemporal variations and the impacts of LULC and climate changes on water yield from 2001 to 2019 in the upstream regions of the Shule River Basin (USRB) on the northeastern margin of the QTP. Three scenarios were designed in the InVEST model to clearly analyze the contributions of climate and LULC changes on the variation of water yield. The first scenario integrated climate and LULC change into the model according to the actual conditions. The second scenario was simulation without LULC change, and the third scenario was without climate change. The results showed that (1) the InVEST model had a good performance in estimating water yield (coefficient of determination (R²) = 0.986; root mean square error (RMSE) = 3.012, p < 0.05); (2) the water yield significantly increased in the temporal scale from 2001 to 2019, especially in the high altitude of the marginal regions (accounting for 32.01%), while the northwest regions significantly decreased and accounted for only 8.39% (p < 0.05); (3) the spatial distribution of water yield increased from the middle low-altitude regions to the marginal high-altitude regions; and (4) through the analysis of the three scenarios, the impact of climate change on water yield was 90.56%, while that of LULC change was only 9.44%. This study reveals that climate warming has a positive impact on water yield, which will provide valuable references for the integrated assessment and management of water resources in the Shule River Basin.

Alpine grassland degradation in permafrost regions seriously affects the provision of ecosystem services, posing a threat to ecological security. Revegetation is a key strategy for the restoration of alpine grassland ecosystems on the Qinghai–Tibetan Plateau (QTP). However, there is a lack of comprehensive research evaluating ecosystem services after revegetation, especially in permafrost regions. In this study, we assessed the changes in ecosystem services following revegetation in the alpine permafrost regions of the QTP through on-site monitoring and sampling, using extremely degraded alpine grassland as a control. In addition, we analyzed trade-offs among ecosystem services and identified key drivers. Our results indicate that (1) revegetation significantly increased forage supply, carbon storage, and soil retention values (p < 0.05), while water retention and permafrost stability showed no significant changes (p > 0.05); (2) vegetation restoration effectively reduced the trade-offs among ecosystem services; and (3) the main drivers were vegetation coverage, precipitation, belowground biomass, and restoration duration. Overall, this study demonstrates that revegetation improves ecosystem services. The enhancement in these services provides valuable data for future research on ecosystem services in alpine grassland.

Permafrost degradation poses a significant threat to the organic carbon (C) pool primarily through regulating microorganisms. However, microbial responses and their associations with C loss across vertical profile remain unclear. Here, we used metagenomic sequencing to investigate bacterial communities in 125 samples from five 15 m-depth permafrost cores, spanning from the active layer to the permafrost layer along a degraded gradient on the Qinghai-Tibet Plateau. We find that α-diversity decreases, while stochastic processes and community stability increase from the active layer to the permafrost layer. Along permafrost degradation, these community attributes follow similar variations within the active layer but remain basically constant within the permafrost layer. The relative abundance and interaction of core taxa play important roles in maintaining community stability in the active and permafrost layers, respectively. Interestingly, degradation strengthens the negative effect of community stability on C storage, with this link being stronger in the active layer than the permafrost layer, further exacerbating C loss. Our findings provide novel insights into the capacity of microbial-mediated permafrost C sequestration and contribute to modeling C dynamic under future warming.