The International Conference on the Conservation of High Mountain Lakes and Mires & 2nd International Meeting on the Conservation of High Mountain Lakes will take place in Vielha (Val d’Aran, Catalan Pyrenees) on 28, 29 and 30 October.

The conference will bring together specialists, primarily from the scientific and technical sectors, working on the conservation and ecological restoration of high mountain lakes, ponds, streams, peatlands, mires and other aquatic ecosystems. These environments are increasingly affected by pressures arising from climate change, hydrological alterations, land-use changes and the introduction of invasive species.

The aim of the event is to share the latest advances in this field. These include those linked to the LIFE RESQUE ALPYR project (2022–2026), through which a range of ecological restoration actions have been carried out across four Natura 2000 sites in the Pyrenees and the Alps. Key actions include the removal of introduced fish from mountain lakes, the functional restoration of peatlands and wet meadows, improvements to grazing management in these ecosystems, and the recovery of particularly sensitive species such as amphibians, mammals and aquatic invertebrates. In addition to presenting the outcomes achieved, including biodiversity recovery results, participants will share protocols and methodologies that could be applied in other regions of the world.

A program with international experts

The invited speakers include Roland Knapp (University of California), a world-leading expert in high mountain lake restoration and amphibian conservation; Helge Bardal (Norwegian Veterinary Institute), a specialist in the eradication of invasive species in freshwater ecosystems; Borja Jiménez-Alfaro (University of Oviedo), a leading researcher in plant biodiversity and mountain mire ecology; as well as researchers Lucia Bello and Rocco Tiberti (University of Calabria), specialists in the conservation of high mountain lakes and directly involved in the LIFE RESQUE ALPYR project. The program also includes contributions from representatives of the project partners and the protected areas where the restoration actions have been implemented.

The conference scientific committee comprises Teresa Buchaca and Marc Ventura (CEAB-CSIC), Rocco Tiberti (University of Calabria), Aaron Pérez-Haase (University of Barcelona) and Quim Pou-Rovira (Sorelló). They are responsible for ensuring the scientific quality of a program that will bring together some of the leading international specialists in the field.

The third and final day of the event will be devoted to a field visit to Muntanyó d’Àrreu Lake and the Clots de Rialba mires, two of the sites where LIFE RESQUE ALPYR has delivered ecological restoration actions. The excursion will allow participants to observe first-hand the results of the interventions carried out and to exchange experiences on the management and conservation challenges facing some of Europe’s most unique and vulnerable mountain ecosystems.

Further information and the full program are available via this link.

Restoring Unique Ecosystems in the Pyrenees and the Alps

High mountain aquatic and semi-aquatic ecosystems, including lakes, ponds, streams, peatlands and mires, support highly specialised biodiversity adapted to extreme environmental conditions. Despite their exceptional ecological value, they are among the habitats most vulnerable to the impacts of climate change and other human-induced pressures.

These environments provide essential ecosystem services, including water and carbon storage, hydrological regulation, and the conservation of numerous rare or threatened species. Their protection is therefore considered a priority at the European level.

In this context, the LIFE RESQUE ALPYR project has contributed to generating scientific knowledge and management tools that can support the restoration and conservation of these ecosystems in other mountain areas across the Pyrenees, the Alps and elsewhere in Europe.

The event took place on 25 September at the Centre for Advanced Studies of Blanes (CEAB-CSIC) and, this year, focused on the conservation and restoration of ecosystems, under the theme “Knowledge at the service of nature”.

The evening began at the Enric “Kike” Ballesteros Auditorium with an introduction to the main concepts, questions and challenges related to the conservation and restoration of the natural environment. Afterwards, the activities moved to the Centre’s terrace, where participants had the opportunity to learn about various research projects, take part in outreach activities and talk directly with the scientific teams.

Among the participating projects was LIFE RESQUE ALPYR, which works to conserve and restore high mountain aquatic ecosystems in the Pyrenees and the Alps and protect the biodiversity they support. Through different conservation and restoration actions in the field, the project aims to reverse some of the impacts threatening these ecosystems and promote their recovery.

The LIFE RESQUE ALPYR activity introduced the public to the reality of high mountain aquatic ecosystems and the challenges they face. Through direct interaction with the project team, participants were able to discover why restoring these habitats is necessary, what actions are currently being carried out and how scientific research helps guide their recovery and conservation.

Participation in the Nit del CEAB was therefore an opportunity to bring this work closer to the public and to show how scientific knowledge can be translated into concrete conservation and restoration actions in the field, illustrating the theme that guided this year’s event: “Knowledge at the service of nature”.

In a friendly and participatory atmosphere, attendees were able to ask questions, share their concerns and reflect together on current and future environmental challenges, as well as on the role that science can play in addressing them.

• Ten months after the eradication programme, both lakes show a remarkable recovery in water transparency and biodiversity, including the return of amphibians and aquatic invertebrates, groups that had not been recorded since monitoring programmes first began in 2014

• The initiative, carried out within the framework of the European LIFE RESQUE ALPYR project, provides new evidence on the use of rotenone as a tool for ecological restoration

The first observations carried out following the intervention at the lakes of Tres Estanys del Mig and Tres Estanys de Baix, in Alt Pirineu Natural Park, confirm the complete eradication of minnows (Phoxinus spp.) and provide evidence of the first signs of ecological recovery. The presence of this fish in the Catalan Pyrenees is the result of its accidental introduction as live bait for recreational trout fishing, a practice that has caused significant alterations to these high-mountain ecosystems.

The intervention, carried out last September within the framework of the European LIFE RESQUE ALPYR project, involved the application of rotenone, a biodegradable piscicide, with the aim of restoring the ecological balance of these lake ecosystems and generating scientific evidence on the effectiveness and safety of this restoration methodology. This is the second pilot trial undertaken in lakes of the Catalan Pyrenees, following the intervention conducted in September 2024 in Lake Manhèra, in the Val d’Aran.

Data collected to date confirm that the intervention achieved its main objective, namely the eradication of minnows from both treated lakes. At the same time, the first monitoring results show clear signs of ecological recovery, including a marked improvement in water transparency and the return of amphibians and aquatic invertebrates, groups that are particularly sensitive to the impacts caused by this introduced species.

According to Barend L. van Drooge, researcher at the Institute of Environmental Assessment and Water Research (IDAEA-CSIC), “Monitoring of rotenone levels in the water has confirmed that it degrades at the rate originally predicted, with a half-life of between 10 and 20 days. This reduces its persistence in the aquatic environment and suggests a very limited impact on the ecosystem.”

Furthermore, no traces of rotenone have been detected in the river located downstream of the treated lakes. This result confirms that, as anticipated, the product remained confined to the treatment area and did not disperse beyond the lakes targeted by the intervention.

Restoring altered ecosystems

Fish introductions are one of the main causes of biodiversity loss in high-mountain lakes. Minnows are a species that has become established in numerous Pyrenean lakes as a result of their accidental introduction as live bait for recreational trout fishing. Their high reproductive capacity and adaptability favour their spread and cause significant disruptions to aquatic food webs.

The presence of this fish leads to a substantial decline in biodiversity, particularly among small aquatic organisms and amphibian populations, as it preys on amphibian eggs and alters the conditions required for successful reproduction. For this reason, its eradication is considered one of the most effective measures for promoting the recovery of high-mountain lake ecosystems.

Surveys conducted ten months after treatment revealed a highly positive response, with a notable recovery in both water transparency and biodiversity. The return of amphibians and aquatic invertebrates has also been recorded. These groups had not been detected since the first monitoring programmes began in 2014.

A benchmark experience for the conservation of Pyrenean lakes

The intervention at Tres Estanys represents the second pilot trial developed within the LIFE RESQUE ALPYR project, following the experience at Lake Manhèra in the Val d’Aran. In both cases, minnows were successfully eradicated and the first signs of recovery of the characteristic biodiversity of high-mountain lakes have been observed.

According to Quim Pou-Rovira, Director of Sorelló Estudis al Medi Aquàtic and Technical Lead of the intervention, “In the case of Tres Estanys, the challenge was particularly significant because the intervention was carried out in a larger and more complex system than Lake Manhèra, given that it involved interconnected lakes.” The results obtained demonstrate that this methodology can also be effective in larger and more complex lake systems.

An important difference between the two lakes treated in Alt Pirineu is that previous minnow control measures had already been carried out at Tres Estanys del Mig using mechanical methods such as nets, traps and electrofishing. Although these actions did not completely eradicate the species, they succeeded in keeping the population under control for several years.

According to Marc Ventura, researcher at the Centre for Advanced Studies of Blanes (CEAB-CSIC) and coordinator of the LIFE RESQUE ALPYR project, “The initial data indicate that ecological recovery is progressing more rapidly in Tres Estanys del Mig than in Tres Estanys de Baix and Lake Manhèra. One possible explanation is that previous efforts to control minnow populations helped preserve a latent reservoir of species within the sediments, which may now be facilitating a faster recolonisation of the ecosystem.”

Long-term scientific monitoring

Although the eradication of minnows has already been confirmed in both pilot trials, the project partners stress that the full recovery of these ecosystems is a gradual process requiring long-term monitoring. For this reason, monitoring activities will continue over the coming years in order to assess changes in biological communities and document the recovery of the lakes’ natural ecological processes.

According to Marc Garriga, Director of Alt Pirineu Natural Park, “These initial results are very encouraging for the conservation of high-mountain lakes. Beyond the success of the intervention itself, the pilot trial demonstrates that it is possible to restore ecosystems that had lost a significant part of their biodiversity and to generate valuable knowledge for addressing similar challenges in other Pyrenean lakes.”

The intervention was coordinated and implemented by Sorelló Estudis al Medi Aquàtic, S.L. and the La Sorellona Association, under the scientific supervision of the Centre for Advanced Studies of Blanes (CEAB-CSIC) and the Institute of Environmental Assessment and Water Research (IDAEA-CSIC), with the direct support of Alt Pirineu Natural Park and Forestal Catalana.

We invite you to join a series of free guided outings to discover the high-mountain aquatic habitats of the Pyrenees, true ecological treasures that support remarkable biodiversity and are particularly vulnerable to environmental pressures.

These activities combine environmental education with exploration of the local landscape, offering routes suitable for all ages and designed for families to enjoy together.

• Time: 9.00 am to 2.00 pm
• Difficulty: Easy to moderate (between 2 and 6 km, with elevation gains of 100 to 450 m)
• Please bring: A packed snack, water, warm clothing and sun protection
• Free activities with compulsory advance registration

The outings take place in two exceptional protected natural areas:

Parc Nacional d’Aigüestortes i Estany de Sant Maurici

Bookings: info@salvatgines.com | +34 627 75 32 05

• 30 July: Investiguem els estanys – Visita a l’Estanyola del Gerber

Discover the wildlife and flora of the high-mountain lakes and learn about the conservation and restoration actions being carried out through the RESQUE ALPYR project. Difficulty: Easy, suitable for the whole family.

• 6 August: El secret dels prats de dall – Planes de Son

Learn about the natural value of traditional hay meadows and how their management helps to support biodiversity. We will also explore the conservation actions being implemented as part of the LIFE RESQUE ALPYR project. Difficulty: Easy, suitable for the whole family.

• 13 August: Investiguem els estanys – Visita a l’Estany Frescau i Colomina

Discover the wildlife and flora of the high-mountain lakes, the main threats they face, and their ecological importance. The excursion starts from the upper station of the Vall Fosca cable car. Time: 9.30 am to 2.30 pm (free transport provided) Difficulty: Easy, recommended for children aged 12 and over.

Parc Natural de l’Alt Pirineu

Bookings: info@salvatgines.com | +34 627 75 32 05

• 20 August: Estany de Muntanyó d’Àrreu i molleres de Clots de Rialba

At the lake, participants will learn about its natural values, observe local species, and discuss the introduction of fish and the restoration actions carried out through the project.

For those who wish, the walk can be extended to the Clots de Rialba peatlands. Although these are not part of the project area, they provide an excellent opportunity to discover peatland habitats and learn about their ecological significance. Difficulty: Moderate, recommended for children aged 12 and over.

• 27 August: Descobrim la mollera del Pla de Boet

Explore one of the Pyrenees’ most unique and threatened ecosystems and learn about the conservation and restoration measures being implemented through the LIFE RESQUE ALPYR project. Difficulty: Easy, suitable for the whole family.

• 5 September: Sortida familiar a la Font de la Tosca

Starting from El Fornet Refuge, this easy walk offers an opportunity to learn about the natural values of the park, its carbonated springs, and the restoration work carried out within the framework of the RESQUE ALPYR project. Difficulty: Easy, suitable for the whole family.

Don’t miss this opportunity to enjoy nature, learn something new, and reconnect with the outdoors. Reserve your place and come and explore the lakes and wetlands of the Pyrenees with us!

A recently published article in Eco.Mont – Journal on Protected Mountain Areas Research and Management helps answer these questions. The paper summarizes the ecological context of the project, the main conservation challenges facing high-mountain aquatic ecosystems, and the restoration actions being implemented through LIFE RESQUE ALPYR.

Unique Yet Vulnerable Ecosystems

Mountain lakes, peatlands and wet meadows are among Europe’s most unique ecosystems. Despite covering relatively small areas, they host highly specialized biodiversity adapted to demanding and often extreme environmental conditions.

Over recent decades, these habitats have been exposed to numerous pressures. One of the most significant has been the introduction of fish into lakes that were historically fishless. The presence of trout and minnows has altered natural food webs and caused significant impacts on amphibians and aquatic invertebrates.

At the same time, overgrazing, the abandonment of traditional mowing, and forest encroachment into wetland areas have contributed to the progressive degradation of peatlands and wet meadows of high ecological value.

More Than Habitat Restoration

The article highlights a key idea: restoring an ecosystem does not simply mean protecting the species that live there. It means restoring the ecological relationships that keep it alive and functioning.

Several previous studies have shown that the recovery of aquatic communities can generate positive effects beyond the lakes themselves, benefiting species that depend on insects associated with these ecosystems, such as insectivorous bats and the Pyrenean desman.

Although the project’s final results will be presented in the coming months, this publication helps explain the questions that gave rise to LIFE RESQUE ALPYR and the scientific foundations behind each of its actions.

Reference: Buchaca, T., Tiberti, R., Pladevall-Izard, E., Bello, L., Mattioli, G., Pérez-Haase, A., Pou-Rovira, Q., Riera, C. i Ventura, M. (2026). The Restoration of Aquatic Ecosystems in the Alps and Pyrenees: A Case Study from the LIFE RESQUE ALPYR Project. eco.mont – Journal on Protected Mountain Areas Research and Management, 18(2S). https://doi.org/10.1553/eco.mont-18-2s44

The LIFE RESQUE ALPYR International Conference will take place from 28 to 30 October 2026 in Vielha – Pyrenees, bringing together researchers, conservation practitioners, protected area managers and technical professionals working on high mountain aquatic ecosystems and mires.

Conceived as a scientific and technical meeting with an international scope, the conference will focus on ecological research, restoration experiences, methodological advances and cross-site knowledge exchange related to high mountain ecosystems across Europe.

Main thematic areas

The scientific programme will be structured around three thematic sessions:

• High Mountain Lakes Conservation: ecology, impacts and restoration
• Mires and Wet Meadows: hydrology, vegetation and biodiversity restoration
• Cross-ecosystem Linkages: lessons learned, management approaches and transferability

Researchers and practitioners are invited to submit abstracts for oral presentations or posters related to these themes, as well as other research or management experiences connected to high mountain ecosystems.

Important dates

• Abstract submission deadline: 15 August 2026
• Notification of acceptance: September 2026
• Final programme publication: early October 2026
• Conference dates: 28–30 October 2026

For questions regarding abstract submission, registration or conference logistics, please contact the LIFE RESQUE ALPYR Conference Organising Committee at: liferesquealpyr@ceab.csic.es

Further updates and practical information will be published on the conference website.

The LIFE RESQUE ALPYR International Conference will provide a platform to share knowledge, strengthen collaboration and advance conservation and restoration strategies for high mountain ecosystems across Europe.

On the occasion of the International Day for Biological Diversity, the LIFE RESQUE ALPYR project highlights one of the major conservation challenges facing mountain aquatic ecosystems: the loss of biodiversity caused by the introduction of fish into lakes where they were not originally present.

High-altitude aquatic ecosystems are highly valuable reservoirs of biodiversity. Despite harsh environmental conditions, they host highly specialized biological communities adapted to cold, nutrient-poor waters and strong seasonal fluctuations. It is precisely this specialization that also makes them particularly vulnerable to any disturbance.

One of the most significant transformations has been the introduction of fish, mainly for recreational purposes. This process began centuries ago with the translocation of native trout from nearby rivers, but it intensified during the second half of the 20th century with the introduction of other non-native species such as minnows, used as live bait in sport fishing.

The ecological impact of these introductions goes far beyond simply adding a new species

Fish prey heavily on insect larvae, aquatic invertebrates, and amphibians, disrupting the food web and altering the functioning of the entire ecosystem. The consequences include algal proliferation, reduced oxygenation and water transparency, and the disappearance of species characteristic of these habitats.

However, the effects are not limited to the aquatic environment. Many terrestrial species depend on insects emerging from these lakes as a food resource, meaning that these imbalances can also affect birds, bats, and small mammals.

In response to this situation, ecological restoration has become a key tool

The LIFE RESQUE ALPYR project, coordinated by CEAB-CSIC, is working to restore these ecosystems in the Pyrenees and the Alps by removing introduced fish and monitoring the recolonization by native fauna.

This is a slow and technically complex process. Depending on the type of introduced species and the characteristics of each lake, restoration may require several years of continuous fieldwork.

To assess biodiversity recovery, scientific teams combine classical monitoring techniques with advanced molecular tools such as environmental DNA (eDNA). This technology makes it possible to detect the presence of species from fragments of genetic material they leave in the water, without the need for direct observation.

In addition, the analysis of sediments accumulated at the bottom of lakes offers an exceptional historical perspective. This natural archive allows researchers to reconstruct what biodiversity was like before human disturbances and to better understand how far present-day ecosystems have diverged from their original state.

Marking the International Day for Biological Diversity, the project’s principal investigator, Teresa Buchaca, explains in this video why preserving high-mountain aquatic biodiversity is essential for maintaining the ecological balance of these unique ecosystems.

Continental aquatic systems are scarce environments covering only 2% of the Earth’s surface but of extraordinary ecological value. These ecosystems host highly specific and fragile biodiversity, with a high presence of threatened species. Although in the Pyrenees they are often perceived as largely untouched natural areas, human influence has been present and has contributed to their transformation.

In this context, the LimnoPirineus project worked to improve the conservation status of aquatic species and habitats of European interest in areas such as the Aigüestortes i Estany de Sant Maurici National Park, the Alt Pirineu Natural Park and Estanho de Vilac, in the Val d’Aran.

The exhibition has a dual objective: on the one hand, to raise awareness about the value, diversity and threats affecting these ecosystems; on the other, to present the results and conservation actions carried out by the project.

Now, with LIFE RESQUE ALPYR, this outreach tool remains active and accessible, reinforcing the commitment to conserving high mountain ecosystems. The exhibition can be requested for educational activities, institutions or events, with the aim of bringing this knowledge to as wide an audience as possible.

The insects that inhabit lakes are often larval stages that will metamorphosize and eventually emerge as flying adults. On land they are a vital food source for many terrestrial animals living around the lakes. Fish heavily predate on insect larvae, consequently reducing the number of insects that make it out of the water. This could result in less food for insectivores, such as spiders, predatory beetles and centipedes that live around these lakes.

As a part of the Life RESQUE ALPYR project, we studied 12 high mountain lakes in the Western Italian Alps. Four lakes were fishless, four lakes were undergoing fish removal, and four still had established fish populations. We placed traps near the lakes shore and farther away to capture ground-dwelling invertebrates, and we also sampled insect larvae to assess the prey availability, i.e. emerging insects.

What did we find?

Compared to lakes with fish, fishless lakes had much more emerging aquatic insects, confirming that fish reduce an important food source for animals on land. We also found more ground-dwelling predators near the lake shoreline, suggesting their habitat preference and importance of lake insects as a food source.

Interestingly, we didn’t observe any big differences in ground-dwelling predator numbers between lakes with and without fish. This suggests that while aquatic insects play a role in shaping nearby terrestrial communities, other factors may also influence predator abundance, and that more lakes are needed in future studies to get a clear picture of this relationship.

Although more research is needed to fully understand the impact of introduced fish on ground dwelling predators, our study highlights the important connection between lake and surrounding land ecosystems. Changes in one environment often trigger to responses in the other and understanding these relationships is essential in designing effective conservation strategies for these unique high mountain areas.

This news results from the Master’s Degree Project in Biology (2025) by Gea Lukšić (Department of Biology, Lund University), carried out under the guidance and supervision of Rocco Tiberti and Lucia Bello (Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria) and Anders Persson, Department of Biology (Lund University).

In this fourth —and penultimate— year, all planned conservation actions have been successfully carried out. In addition to the annual actions that have been repeated since 2022, this year stands out for the successful second application of rotenone, conducted in a broader and more complex setting. We have also completed the remaining interventions in the peatlands, in the area surrounding Lake Djouan in the Alps, and at Font de la Tosca in the Pyrenees.

The first results from the scientific and technical monitoring of the restored sites are encouraging: improvements are already becoming visible and are expected to be fully confirmed in the coming years.It has been an especially productive year for environmental education and outreach, with more than 1,000 participants. There has also been extensive dissemination of results within the scientific and technical communities, and significant progress has been made in knowledge transfer and replicability.

Want to know more? Read the newsletter here.