Abstract
Mountain lakes are increasingly affected by global change pressures. While there is growing evidence of impacts on ecosystem functioning, few studies considered changes in ecosystem services (ES). This study aimed (1) to examine the exposure of small and natural mountain lakes in the European Alps to global change pressures and (2) to estimate potential impacts on six relevant ES considering future climate projections and potential changes in water use. For 2455 lakes, we mapped the level of exposure to global change pressures, including climate change, atmospheric nutrient deposition, and anthropogenic activities (e.g., water use). Our results indicate that more than half of the Alpine mountain lakes feature a considerable level of exposure to global change. Hotspot analysis revealed spatial clusters of lakes with above-average exposure (23.7% of all lakes), mostly located in the central part of the Alps, while lakes with below-average exposure level prevailed in the south-western (19.3%) and eastern parts (10.6%). For 15 case study lakes, we quantified potential impacts on six key ES. The results revealed, in particular, potential negative effects on maintaining habitat and populations as well as aesthetic value, but contrastingly, also some positive effects for outdoor recreation, research and education. Our findings suggest the need for a comprehensive integration of mountain lakes into current management and policy frameworks to ensure the ecological integrity and ES provision of mountain lakes. Interdisciplinary mountain lake research will be important to overcome uncertainties related to the coupling of limnological parameters and ES indicators.