Regional Mountain Conference

Mountain lakes are sensitive ecosystems that respond rapidly to environmental and climatic forcing, making them valuable sentinels of global change. Robust, long-term data are required to assess their functioning and vulnerability, but their remoteness and heterogeneity require coordination and cooperation. Established in 2009, the Lacs sentinelles network was created to address this gap. The network aims to improve understanding of lake physical, chemical, and biological dynamics, as well as how they respond to local and global drivers, by coordinating research and monitoring on mountain lakes, in the French Alps, the French Pyrenees and Corsica. The network is first and foremost a space for different professions (scientists, managers, users) working on mountain lakes to exchange information and problematics, design and carry out research projects, and finally synthetize and share information to relevant stakeholders or the general public. By facilitating exchanges within and among professions and providing an overview of ongoing investigations, the network strengthens coherence and complementarity across projects.

A pillar of the network is its observatory, that includes 34 lakes where harmonized protocols are deployed, whose comparable data constitute a basis for studies. Recent publications investigated key mechanisms behind hypoxia onset under ice, heterogeneous phytoplankton responses to climate warming, and long-term changes in zooplankton communities driven by interactions between local pressures and global stressors.
More recently, data from the mountain lake observatory contributed to an interdisciplinary project at the scale of the French Alps to quantify microthermal responses of three compartments (rock, soil, lake) to summer heatwaves. In parallel, the network skillset expended through the contribution of researchers in social sciences, to provide an integrated assessment of changing recreational practices around mountain lakes. Specifically, analyses of human activities and social perceptions of mountain lakes were assessed through surveys while chemical indicators were monitored throughout a gradient of lakes to evaluate lakes response to human presence in and around the lakes.
Finally, the network helps to create synthesis and outreach material for stakeholders and the general public to promote scientifically sound knowledge on mountain lakes as well as relevant conservation strategies under a changing climate.