An integrative approach to evaluate ecosystem services of mountain lakes using multi-criteria decision analysis

In view of the increasing demand for ecosystem services (ESs) and rising pressures from global change on mountain lakes, sustainable management strategies are increasingly needed. However, integrative assessments of ESs provided by small mountain lakes are lacking. This study adopted an integrative ES valuation perspective, applying multi-criteria decision analysis (MCDA) to four exemplary mountain lakes in South Tyrol, Italy. With the involvement of stakeholders, we identified five ESs of particular importance: provision of habitat, aesthetics, surface water, recreation, and representation. These ESs were weighted with respect to their perceived importance and quantified based on multi-metric indicators integrating biophysical and socio-cultural/economic aspects. The current ES provision of mountain lakes was then evaluated by applying PROMETHEE II. We showed that the quantity of ESs varied with distinct socio-ecological characteristics. Well accessible and larger lakes currently provide larger amounts of ES in high demand, such as habitat provision, aesthetics, and recreation, but remarkably, smaller and remote lakes also provide notable amounts of ES aesthetics. Our integrative approach provides insights to support sustainable ES management of mountain lakes considering future challenges that are potentially applicable in other regional contexts.