Abstract ID: 3.9977 | Accepted as Talk | Talk/Oral | TBA | TBA

High mountain lakes and streams are particularly sensitive to environmental stressors. They have been extensively used in national and international research programs to assess the effects of air pollution related impacts, such as acidification and nitrogen enrichment, as well as the recovery following reduction in pollutant emission and deposition. High altitude freshwaters are also considered sentinels of climate change: physical, chemical and biological features are all affected by climate-related drivers, such as increasing temperature, changing precipitation regime and degradation of the cryosphere. To assess these impacts, time series of high quality environmental data, collected with standard methodologies, are needed. Networks such as the European LTER (Long-Term Ecological Research) and ICP WATERS (International Cooperative Programme on assessment and monitoring of the effects of air pollution on rivers and lakes) are examples of cooperative efforts in collecting, sharing and analyzing long-term ecological data, also in high mountain or remote study areas, to assess the effects of global environmental change. We present some case studies consisting in LTER mountain lake sites in the Central Alps, Italy, where chemical and biological data (macroinvertebrates ad diatoms) have been collected to assess the ecological status of the lakes in relation to changing environmental conditions. The lakes are also research sites of the LIFE Project MODERn NEC, dealing with the impacts of air pollution and climate change on ecosystems under the EU NEC Directive. Some of these lakes provide examples of successful acidification recovery thanks to the implementation of international protocol to abate air pollution, such as the Air Convention. Despite this positive change, the lakes are still sensitive to the deposition of pollutants: their water quality and biological assemblages are presently affected by nutrient inputs, including nitrogen, and climate-related drivers, such as increasing water temperature, lake level fluctuations, decreasing ice and snow cover in catchment. In addition, other pollutants than acidifying compounds, such as microplastics, which could be both atmospherically transported or introduced by local activities, need to be considered. Responsive chemical and biological indicators, to be regularly assessed in time, are crucial to support sustainable management and conservation strategies for these fragile ecosystems.