The Restoration of Aquatic Ecosystems in the Alps and Pyrenees: A Case Study from the LIFE RESQUE ALPYR Project

High mountain aquatic and semi-aquatic ecosystems of the alpine biogeographical region harbour specialized biota, yet they are increasingly being degraded by non-native fish introductions, livestock pressure, afforestation and the abandonment of traditional wet meadow management. The LIFE RESQUE ALPYR project (2022–26) implements coordinated restoration actions across four Natura 2000 sites in the Pyrenees and the Alps, targeting eleven habitat types and several threatened vertebrate species. Building on prior LIFE initiatives in both mountain ranges, LIFE RESQUE ALPYR develops and tests replicable protocols for invasive fish eradication in lakes of varying sizes, livestock exclusion from sensitive waters and mires, clear-cutting and revegetation on afforested mires and the re-establishment of mowing in wet meadows. Here we present the project’s ecological rationale, study areas, objectives and methods, together with the expected outcomes and lessons learned to support transferability to other mountain protected areas. This approach integrates robust ecological monitoring and stakeholder engagement to ensure long-term biodiversity gains and to reconcile traditional land-use practices with modern conservation priorities. Evidence from comparable Alpine and Pyrenean systems shows that amphibian and aquatic invertebrate communities can recover rapidly following fish removal, while mire restoration and appropriate meadow management accelerate vegetation and trophic recovery, producing cascading benefits for riparian and semi-aquatic insectivores. Quantified outcomes include the complete removal of non-native fish from 22 lakes (55.4 ha); the reoligotrophication of 10 lakes; the restoration of ≥3 ha of wet meadows and ≥8–10 ha of mires by means of grazing-exclusion and afforestation-removal actions; and the development of operational protocols designed for replication in European mountain regions.