PROJECT DESCRIPTION
BACKGROUND
The area targeted by the project is in the ‘Aigüestortes i Estany de Sant Maurici’ National Park, which is a high-mountain landscape (3 000 m – 1 200 m) with impressive relief. It includes the Natura 2000 sites of Alt Pallars and Aigüestortes. Publicly owned land accounts for 98.36% (13 888 ha) of the park and 24.78 % of the Natura 2000 sites.
Perhaps the most notable features of the park are its water courses, with close to 200 lakes and countless streams. These provide important aquatic habitats, which cover 1.4% of the surface area of the park and are the main focus of the project. They are particularly important for priority aquatic species, such as Pyrenean desman (Galemys pyrenaicus) and the European otter (Lutra lutra). The national park is also included in the RAMSAR network.
However, these aquatic habitats have been impacted by human interference. Some lakes and rivers in the target area have dams and hydroelectric facilities, which were developed before the area was protected. These cause habitat fragmentation and – along with recreational activities – present the greatest threat to the conservation of the park ecosystems.
OBJECTIVES
LIFE LimnoPirineus aimed to restore targeted aquatic habitats in the Aigüestortes i Estany de Sant Maurici National Park and Alt Pirineu Natural Park. The project would restore the ecological functioning of eight high mountain lakes through the eradication – or significant reduction - of alien invasive fish species. It would establish new populations of targeted amphibian species - Rana temporaria, Alytes obstetricans and Euproctus asper - in the lakes where allochthonous fish have been removed.
The project would intervene to protect and restore the quality of peat bogs and tufa-forming springs that were under pressure from tourism and livestock. Additional targeted restoration measures would include hydraulic restoration at one site and experimental recuperation of peat bog habitats in an area formerly occupied by a small dam.
Other targeted interventions would include:
- Improving the conservation status of the listed habitat, Natural eutrophic lakes and its floating water-plantain (Luronium natans), in the Natura 2000 site at Estanho de Vielha, also targeted by the project; and
- Improving the Cottus gobio population in isolated headwater streams, as well as the establishment of a second population.
Finally, the project would create a viable seed bank of significant species of the targeted habitats that will allow the recreation of the habitats in case of strong anthropogenic impacts.
RESULTS
The LIFE LimnoPirineus project team restored standing water (lentic) habitats and aquatic species in the high mountains of the Spanish Pyrenees. Specifically, they restored the ecological functioning of high mountain lakes in Natura 2000 network sites through the eradication, or significant reduction, of invasive non-native fish species.
The results of the conservation actions were:
- Removal and control of invasive fish species, including complete eradication of non-native (allochthonous) salmonid species (Salvelinus fontinalis, Oncorhynchus mykiss and Salmo trutta) in three areas of the Aigüestortes Natura 2000 site (SCI).
- Eradication of minnow (Phoxinus sp.) in one lake of the Alt Pallars Natura 2000 site (SCI), and over 80% reduction in two other sectors of Alt Pallars and Aigüestortes sites.
- Recovery of structural quality and ecological function of the oligotrophic waters habitat (3110), in 8 lakes and 6 sectors of Aigüestortes and Alt Pallars sites.
- Establishment of new populations of the amphibian species Rana temporaria, Alytes obstetricans and Euproctus asper in the lakes during and after fish removal, at densities close to those normally seen in natural lakes.
- Population improvement of the native fish European bullhead, Cottus gobio, resulting in increased genetic variability in the Aiguamòg population in the Aigüestortes SCI, and the establishment of a second population at the Ruda stream, within the same SCI.
- Reduction of peat bog degradation, and Active raised bogs habitat (7110*) recovery in Molières (300 m2) and Plans de Sotllo (170 m2) areas with touristic pressure.
- Elimination of livestock pressure at the tufa‐forming springs of Obagas del Montsent de Pallars and Estanyeres, and at Estanho de Vielha, and a consequent conservation and improvement of Petrifying springs with tufa formation habitat (7220*).
- Peat bog restoration at the Font Grossa site, on around 200 m2.
- Hydraulic restoration of the peat bogs of Trescuro with a recovery of over 50% of the original inundated surface and the characteristic watering regime.
The project team also developed protocols for the removal of non-native fish from Pyrenean alpine lakes. They conducted a genetic study to describe the diversity and genetic flow between populations of the amphibians Rana temporaria, Alytes obstetricans, Euproctus asper and fish European bullhead (Cottus gobio) aimed at improving future management plans.
Project actions improved the conservation status of peat bogs, tufa‐forming springs and natural eutrophic lakes threatened by livestock or tourism pressure and/or hydrological deficit. The project team built new elevated platforms, and walking paths were redirected. They installed livestock water troughs to prevent animals drinking in lakes and springs. Fences were installed along forest roads, and stream discharge was improved to reduce hydraulic stress of peat bogs.
The project team replanted sphagnum mats and other ecosystem engineering species to regenerate peat bog, and an experimental procedure was developed to serve as a model for replicating this in other parts of the Pyrenees. They conducted extensive monitoring of the target species and habitats, to assess populations and conservation status, and the response to conservation actions. Dissemination actions raised the awareness of the public to the threats to the target species and habitats. The project team also networked with other scientific teams at conferences and other meetings and events.
Further information on the project can be found in the project's layman report (see "Read more" section).
