High mountain lakes and ponds provide essential ecosystem services and have a high conservation and aesthetic value. Due to their specific features, they may host specialized communities with still partly unknown ecology and biodiversity. They are also particularly sensitive to environmental stressors and are considered sentinels of global change. Mountain freshwaters are also extremely sensitive to climate change, being affected by increasing temperature, changing precipitation regime, and cryosphere thawing, with related impact on water quality and habitat conditions.

Although often considered pristine systems, lakes and ponds in high-altitude regions are threatened by both local and global anthropogenic pressures, which in many cases can compromise their ecological integrity, affect water quality and exacerbate conflict of interest for their use. Among local pressures, the increasing touristic pressure in many mountain areas represents an additional threat to mountain lakes, adding to the pervasive presence of fish introductions and livestock grazing: unsustainable recreational use may affect trophic status and ecological functioning of lakes by increasing nutrient loads and the level of emerging pollutants, whose toxic effects are still poorly understood. The potential or already evident effects of human pressure are even more relevant for freshwater systems not included in protected areas or not subject to any environmental legislation.

The combined effects of several pressures, including overtourism and water exploitation for different uses, need to be assessed through proper indicators. Research and monitoring programs, as well as restoration and conservation plans, should consider the interaction of different pressures and combine various approaches, from in-situ data collection, to remote sensing and modelling. Also, citizen science and other initiatives of participatory science may contribute to better knowledge and to raise awareness about the importance and vulnerability of freshwater ecosystems.

This session welcomes contribution from different disciplines and perspectives, possibly combining interdisciplinary approaches and focusing on the emerging threats to mountain lakes and ponds due to the increasing and changing nature of human activities in mountain areas. The objective is to share results and/or approaches and stimulate the discussion.