^[1]Tour du Valat’s 2025 activity report is on line! As every year, the Tour du Valat is publishing its activity report, illustrated with magnificent photos and presenting our main achievements over the past year, the fruit of numerous collaborations with our partners, whether institutional, scientific, technical or financial.

More broadly, this report bears witness to our commitment, alongside you, to the necessary reconciliation between humans and nature. Exploring and deciphering the links between living things, experimenting, inventing solutions for tomorrow, talking, sharing and acting together. This is what drives us, and what you can discover in the pages of this annual report.

 

 

 

 

 

For each thematic team, find a project highlighted in the form of a focus:

• Migration: animal behaviour that influences ageing I p14-15
• Long-term monitoring of avian influenza I p18-19
• RESCOM: when nature becomes the solution to climate and societal challenges in the Mediterranean I p22-23
• From data to decision: a toolkit for spatially prioritising coastal wetland restoration I p28-29
• Mediterranean wetlands: responses to ongoing crises I p32-33

We hope you enjoy your reading!

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👉  ^[2]Download ^[1] the Tour du Valat 2025 activity report

You can find all our activity reports in the media library ^[3] section of the website.

From 10 to 12 April 2026, the Tour du Valat organised a new naturalist inventory at the Mas du Petit Saint-Jean, showcase of the Institute’s agroecological activities since 2016. On this occasion, around a hundred participants – amateur naturalists and experienced specialists alike –, from the Tour du Valat as well as several partner organisations across the country, came together to help improve our knowledge of the site’s biodiversity. 

Working together to study biodiversity

This inventory weekend is part of a long-term initiative to monitor biodiversity linked to the agroecological practices implemented on the domain. It serves two purposes: to improve our knowledge of the species present on the estate – particularly those essential to agriculture, such as pollinators, field plants and soil microfauna – and to demonstrate, in concrete terms, the positive effects of agroecological practices on biodiversity.

More than just generating scientific data, this inventory campaign helped to connect naturalists and promote knowledge-sharing. The friendly atmosphere during field trips and meals also encouraged exchanges between professionals and volunteers, creating a dynamic of knowledge transfer and collaboration.

The data collected is incorporated into the ‘Rewilding farms ^[4]’ network, thereby contributing to the comparative monitoring of biodiversity trends in agricultural environments.

Le Mas du Petit Saint-Jean in figures 76 hectares of natural habitats: marshes, montilles, sansouïres, pine forest 5 semi-permanent ponds to provide a habitat for amphibians and European pond turtles 22 nesting boxes installed for passerines, rollers and birds of prey 30 bat boxes mounted on posts to accommodate bats in the vineyards, where they play a role in controlling grapevine moths 5 hectares of vines 800 metres of fruit hedges 3 hectares of pear and sorb trees in agroforestry systems dedicated to timber production 4 hectares of orchard meadows combining almond, olive, pistachio, pomegranate and persimmon trees, which also provide fodder (mown) and are grazed in winter

Inventories conducted throughout the site, both day and night

The teams conducted a variety of surveys across the entire site, employing protocols tailored to different taxonomic groups: direct observations, night-time insect inventories (with the use of lights on white sheets), bird song monitoring, as well as specific capture and identification methods using various non-lethal traps.

This collaborative effort has significantly enriched local knowledge, notably with the observation of two species not previously recorded on the site:

• the European red-rumped swallow (Cecropis rufula) ;
• the Sawfly Orchid (O. Tenthredinifera subsp. neglecta.), a species of orchid never before observed in the Gard.

Under-documented taxonomic groups

The 2026 edition also provided an opportunity to further study taxonomic groups that had previously been less explored on the site. Lichens, for example, were the focus of particular attention, with seven new species identified. Fish surveys also were conducted, notably through angling campaigns. Finally, numerous observations of insects and arachnids, which often require meticulous identification using a binocular magnifying glass, will be added to the inventories over the coming months.

These results complement the existing data and contribute to a better understanding of the diversity of habitats present within the Mas du Petit Saint-Jean.

Outlook

Following the success of this latest edition, a third participatory inventory campaign is already being planned for June 2027. This will enable us to continue improving the scientific monitoring of the site and to consolidate long-term observations on the interactions between agricultural practices and biodiversity.

As spring settles in after an exceptionally wet winter, the Camargue welcomes tens of thousands of birds returning from Africa, revealing its distinctive palette of colours, sounds and scents. Every moment is an invitation to contemplate this flourishing natural world, the result of a unique alchemy combining powerful natural processes with human activities that has shaped this amphibious landscape.

A natural heritage of international importance

The Rhône delta is one of the largest and most diverse wetlands in Europe and the Mediterranean. Located along major migratory routes, this iconic wetland is home to 400 bird species and shelters 103 threatened species listed on the European Red List of the IUCN. At the heart of a biodiverse “golden triangle” with the Crau and the Alpilles, the Camargue is internationally recognised for its ecological value. The French State recognised this early on: from the 1970s, it assigned the Camargue a primarily environmental vocation, while to the east, the Fos-Berre area was set on an industrial path, and to the west, Languedoc-Roussillon was dedicated to tourism development.

Over the decades, this environmental vocation has been reinforced. In 1986, the Camargue became the first French site designated as a Wetland of International Importance under the Ramsar Convention. UNESCO Biosphere Reserve, Regional Natural Park, multiple nature reserves, sites managed by the Conservatoire du Littoral… today, the Camargue brings together an exceptional concentration of protection statuses and labels recognising its unique ecological value.

One might therefore assume it is safeguarded from pressure. The reality is quite different.

A proliferation in infrastructure projects and a democratic deficit

Today, the Camargue faces mounting pressures. Several infrastructure projects threaten its integrity: a very high-voltage power line (THT) crossing both the Camargue and the Crau, a superhighway project impacting some of the Camargue’s rare peatlands, and a bridge facilitating heavy lorry traffic through the heart of the delta. Considered individually, each project already raises serious concerns. Taken together, their cumulative impacts could fragment habitats, disrupt hydrological balances, increase risks for local communities, and reduce the benefits they derive from a protected Camargue.

Beyond ecological impacts, another fracture is emerging: that of democratic dialogue.

Consultation efforts have indeed been undertaken, but to little effect. Despite clear opposition from citizens, protected area managers, farmers and other local stakeholders, the State has maintained its position and refused to explore proposed alternatives.

During the public debate organised in 2025 by the National Commission for Public Debate (CNDP) on reindustrialisation and decarbonisation projects in Fos-Berre, strong opposition was voiced against the overhead THT line, given its potential impacts on the environment, landscapes and local economy. An alternative solution was proposed (source: public debate report ^[9]).

However, following the debate, the State maintained its initial position, asserting the need to deliver an additional 4 GW of power capacity by 2030, achievable within that timeframe only via an overhead line. The CNDP’s recommendations, notably to initiate a conciliation process to develop a balanced solution, were not followed. Responses concerning the industrial rationale of the territories, raised during the debate, remain vague and overlook critical aspects such as sufficiency and the multiple roles of these areas.

The situation is similar for the Arles superhighway project. Following the public inquiry held in December 2025, the Commission’s opinion was unequivocal: it issued an unfavourable ruling on the project’s declaration of public utility, and a strongly unfavourable one regarding its socio-economic, environmental and health impacts. Despite these conclusions, public authorities have recently confirmed their intention to proceed with the project.

Ignoring the outcomes of consultation processes undermines confidence in democracy. Such decisions conflict with the right to public participation in environmental decision-making (Article 7 of the French Environmental Charter, as well as the international framework of the Aarhus Convention). This situation echoes the warnings raised by the United Nations Special Rapporteur on Environmental Defenders, Michel Forst, who, in his 2024 report ^[10], denounces an erosion of democratic safeguards and an increasingly weakened public participation, particularly in France.

Rethinking solutions to meet today’s challenges

The challenges are real, but the responses must not pit economy against environment, nor energy transition against natural heritage. They must be grounded in principles of energy, land and water sufficiency, and must definitively stop treating biodiversity as an adjustment variable.

The Camargue, a low-lying delta at the mouth of one of Europe’s most powerful rivers, lies at the heart of the challenges of this century. Its wetlands are not only the foundation of the region’s ecological, agricultural and cultural wealth; they also serve as vital climate buffers, major carbon stores, and a form of “life insurance” in the face of future change.

It was here in the Camargue, at Tour du Valat, under the impetus of Luc Hoffmann, that the international movement for wetland conservation emerged in the late 1950s, leading to the creation of the Ramsar Convention, the first multilateral environmental agreement.

As the 67th Standing Committee of the Ramsar Convention takes place this week, a critical question arises: will France rise to its commitments and truly protect this jewel?

 

 

For the sixth consecutive year, the Tour du Valat opened the doors of its agroecological farm to the public, at the Mas du Petit Saint-Jean and as part of the ‘Le Gard de ferme en ferme’ festival, on 25 and 26 April. Let’s take a look back at these two beautiful days.

Located in the Gard region of the Camargue, the Mas du Petit Saint-Jean showcases the Tour du Valat’s agricultural activities. Spread across 100 hectares, it is an ambitious agroecological project where vineyards, orchard meadows, crops, fruit hedgerows, pastures and natural habitats coexist, enriching and reinforcing one another in the pursuit of sustainable agriculture.

On two sunny spring days, over a hundred visitors came to discover this unique project. Through visits and discussions with the Tour du Valat team, they gained a better understanding of the close links between agricultural practices and the preservation of biodiversity.

The weekend included a rich programme ^[11] of activities for everyone: guided walks through the vineyards, a tour of the winery, exploring biodiversity in the vineyards, an introduction to cyanotype printing, and a focus on the challenges of salinity affecting the vineyards and the Camargue.

At midday, farmer Stéphane Vidil regaled visitors with a delicious spit-roasted pork.

The wine tastings were also a great success, offering visitors the chance to discover wines produced using this agroecological model and to learn about enology.

We would like to warmly thank everyone who came to meet us during these two enjoyable days, which were full of fruitful discussions : we look forward to seeing you again next year.

Until the 2027 edition, if you’d like to discover our wines and support farming practices that are more respectful of the environment, please order using this form >> Click here [12]

Would you like to follow the latest news from the Tour du Valat agroecological farm? Subscribe to our newsletter >> Click here [13]

A few photos to remember this weekend:

 

Once again, tens of thousands of common cranes have taken up residence in the Camargue for the cold season. After a spectacular increase last winter, the 2026 population remains stable.

In January, the Tour du Valat coordinated the census of wintering common cranes (Grus grus) in the Camargue. This annual operation is carried out by around forty volunteers and staff from the Tour du Valat, the Camargue National Reserve, the Vigueirat Marshes Reserve, the Camargue Regional Nature Park, the Pont de Gau Ornithological Park and the Scamandre Centre. The results are then sent to the ‘Réseau Grues France’ and are used to monitor the evolution of the population of these migratory birds.

A total of 36,043 individuals were recorded across 18 dormitories. This figure confirms the exceptional increase seen in 2025 (39,800 individuals) compared with the years 2022–2024 (+45%).

An outbreak of highly pathogenic avian influenza has had a significant impact on common cranes across Europe, with the LPO observing a peak in mortality in France at the end of October ^[14]. Although a few cases have been detected, the virus has fortunately not spread amongst this species in the Camargue.

Follow the migratory route of a common crane! Use this interactive map to follow the movements of a common crane born in 2022, who was fitted with a GPS tracker in Estonia. From its birthplace in the Baltic states, it reached the Camargue in just a few weeks. This map shows the impressive distance travelled, the stopover sites and the routes these birds can take during their seasonal migration. Click here to see the map  [15]

 

 

The Mediterranean Basin is a global biodiversity hotspot that is currently afflicted by the combined pressures stemming from human activities and climate change. Nature-based Solutions (NbS) are emerging as a major tool that can protect populations and territories. Based on resilient ecosystems that can be true natural allies, they reconcile conservation, human well-being, and socio-economic development. This is the key objective of the RESCOM project, which is being coordinated by the Tour du Valat for the Mediterranean Biodiversity Consortium (MBC). It aims to deploy these solutions, which despite their many benefits are still underutilized in the Mediterranean region.

Nature-based Solutions driving collective action in the Mediterranean

The Mediterranean Biodiversity Consortium (CMB) ^[16] brings together several leading organisations like the Tour du Valat long involved in nature conservation in the Mediterranean. By pooling their expertise, these partners work together to protect the natural resources of the Mediterranean Basin. Their mission is to preserve the integrity of ecosystems (coastal areas, small islands, forests, wetlands, marine areas) in ways that can sustainably ensure the vital services they provide society, while revealing their full potential as sources of NbSs

This collective ambition is embodied in the RESCOM project (Making Mediterranean Ecosystems more Resilient), the CMB’s first flagship project, which is co-financed by the French Global Environment Facility, the MAVA Foundation, and the French Development Agency. Deployed across 15 pilot sites in the Mediterranean, the project supports natural area managers in implementing concrete management, conservation, and restoration actions in Albania, Egypt, Italy, Libya, Morocco, Montenegro, Tunisia, and Turkey.

These interventions are all conceived around Nature-based Solutions. By providing essential services – food security, water and wood supply, soil stabilisation, thermal regulation, carbon sequestration, flood risk mitigation, and protection against submersion or other natural phenomena – NbSs provide alternative or complementary solutions to grey infrastructure. They are also more resilient and economically advantageous in sectors such as land use planning, agriculture, water management, and health. They contribute to the quality of life of local residents and to local socio-economic development by supporting industries working toward the sustainable use of natural resources in the fishing, tourism, agricultural and other sectors.

Nature-based solutions (NbSs): a methodological concept promoted by the IUCN The RESCOM project is grounded in the concept of an NbS, as it has been defined by the International Union for Conservation of Nature (IUCN). Nature-based Solutions are defined as “actions aimed at protecting, sustainably managing, and restoring natural or modified ecosystems to directly address societal challenges in an effective and adaptive manner, while ensuring human well-being and producing benefits for biodiversity.” The NbS concept first appeared some fifteen years ago. The original definition was refined in 2016 by the IUCN, which also developed an international standard in 2020 that was revised in 2025. This standard is based on a set of criteria and indicators designed to guide those developing NbSs. The concept has thus gradually gained recognition and is now integrated into numerous public policies at national, international, and European levels, such as the European Union’s Biodiversity Strategy 2030, the European regulation on nature restoration, and the third National  Adaptation Plan (PNACC3). [17]

Test, adapt, adopt: rolling out NbSs in the Mediterranean

Although NbSs are increasingly valued as a response to major societal challenges, such as the fight against climate change, their application in the field must still overcome operational, financial, technical, social, institutional, and regulatory obstacles. In this context, in 2025 the CMB conducted an in-depth study to capitalise on Mediterranean experiences and draw operational recommendations from them. ^[18]

Key factors and experience sharing

Our study reveals that the success of NbSs depends on several factors: the broad involvement and effective coordination of local actors, strong political support, as well as communication and awareness-raising efforts that target people to accompany changing practices and foster the emergence of a shared vision for a specific territory. Nature-based Solutions require long-term funding to make them truly sustainable. They also require the deployment of a robust monitoring and evaluation system to measure both the effectiveness of ecological restoration and the socio-economic impact of the actions undertaken. RESCOM will enable local stakeholders (natural area managers, civil society organisations, local authorities, public administrations, research centres, economic operators and local residents) to be closely involved in the implementation of NbSs. In addition, ecological and socio-economic assessments enable interventions to be prioritised according to the specific challenges facing each territory.

Nature-based solutions: a flexible and scalable tool

Far from being “ready-made” solutions, NbSs must be shaped by the field. More than a rigid approach, they are a lever for dialogue and planning support.

They entail an iterative and flexible process, which can adjust to each site’s specific social and institutional realities and administrative and land constraints.

This experimental phase is a genuine collective learning process, the lessons of which feed into and reinforce the visibility and replicability of NbSs. RESCOM thus aims to build a community of practices that will bring together a wide range of actors around the Mediterranean Basin to foster the sharing and dissemination of solutions adapted to common climatic and societal challenges.

NbSs in action: examples from around the Mediterranean

Since the RESCOM project was launched in 2023, the CMB has been applying NbSs with a focus on the interactions and connectivity between terrestrial, coastal, and marine ecosystems, which are essential for species to move around and for maintaining major natural balances, such as water and nutrient cycles.

A focus on three sites covered by the project, on different shores of the Mediterranean Sea.

• In Italy, the restoration of seagrass beds for coastal protection

With support from the project, teams from the Capo Carbonara Marine Protected Area (MPA), located in south-eastern Sardinia, Italy, have undertaken the restoration of 230 m² of Posidonia seagrass beds. This species, endemic to the Mediterranean, has been weakened by decades of human impact, particularly by trawlers that once operated in this MPA.

The technique used involves recovering Posidonia rhizomes that have been naturally uprooted by bad weather and replanting them in degraded areas. To ensure that the operation is successful, new eco-friendly mooring buoys will be installed to encourage boaters to avoid anchoring in the seagrass beds, one of the main causes of their degradation.

There are several benefits of restoring Posidonia seagrass beds. First, it stabilises the seabed and reduces the speed of currents, thereby limiting coastal erosion. It also supports the life cycle of many marine organisms by serving as a nursery, spawning ground, and refuge for fish and other marine organisms, which in turn directly benefits fishing. Finally, it contributes very effectively to carbon capture.

• In Albania, dunes and lagoons are being restored to limit coastal erosion

In the Divjakë-Karavasta National Park, located on the Adriatic coast of Albania, RESCOM is focusing on rehabilitating the dune ecosystem, which has been severely degraded by seaside tourism, hiking, and unregulated vehicle traffic throughout the year. The interventions planned will combine dune revegetation, the control of invasive species, and measures to protect and delimit strictly protected areas, in order to stabilise these fragile coastal landscapes and limit coastal erosion.

In addition, the project aims to improve the ecological status of the Karavasta lagoon, a RAMSAR site and an important wintering and breeding area for more than 200 bird species, including the Dalmatian Pelican, and to restore degraded woodlands in the surrounding hills. These integrated measures aim to strengthen coastal protection, improve water quality, and increase the area’s ecotourism appeal. They will also contribute to strengthening ecological connectivity and restoring species of conservation concern.

 

• In Tunisia, forest restoration and support for the development of alternative income-generating activities for local communities

In Tunisia, priority actions for the Oued Ezzen National Park, located in the north-west of the country, focus on reforesting areas near douars and villages. Local communities are involved in planting versatile native species such as the carob tree, which is endemic to the Mediterranean. These actions will allow them to harvest the carob pods and engage in silvopastoralism in these restored areas, thereby generating potential sources of income. These measures will also help to improve water retention, combat erosion and landslides, and support biodiversity.

The project will also test the natural regeneration potential of different species, helping to identify those that are able to withstand drought, fire and other extreme climate phenomena. Finally, the project aims to regulate tourist activities, which are currently unregulated, by developing an innovative co-management approach with local communities that is likely to generate economic benefits (training of guides, sale of local products, camping fees) and can be replicated elsewhere in Tunisia.

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Project manager: Marion Douchin ^[19] | [email protected] ^[20]

Team: Lisa Ernoul, Antoine Gazaix, Carol Mañoso Gimeno, Philippe Lambret, Arsène Marquis-Soria, Pauline Rocarpin, Salima Slimani, Marc Thibault, Elisa Tuaillon

Partners:

• • • Technical: organisations membres du Consortium Méditerranéen pour la Biodiversité (AIFM ^[21], MedPAN ^[22], MedWet ^[6], Initiative PIM ^[23], UICN Med ^[24], Conservatoire du littoral ^[25], WWF France ^[26]) et partenaires nationaux et locaux dans les sites pilotes (administrations publiques, organisations de la société civile locales)
    • Scientific: Instituts ou centres de recherche locaux dans les pays partenaires
    • Financial: FFEM ^[27], MAVA ^[28], AFD ^[29]

 

Yaprak Arda, Marine Programme Officer at IUCN Centre for Mediterranean Cooperation, answers our questions on the contribution of Nature-based Solutions (NbS) to biodiversity conservation in the Mediterranean, existing examples of implementation, barriers to large-scale deployment, and the role of the Mediterranean Biodiversity Consortium and the RESCOM project in accelerating their adoption.

 

1. What does the concept of NbS bring to the field of biodiversity conservation?

Nature-based Solutions (NbSs) represent a significant evolution in biodiversity conservation. They explicitly connect ecosystem protection, restoration, and sustainable management to the delivery of societal benefits such as climate mitigation and adaptation, water and food security, disaster risk reduction, and socioeconomic development. NbSs place biodiversity at the core of development planning by recognizing that healthy, functioning ecosystems are essential infrastructure for human well-being. Through the IUCN Global Standard for NbSs, the concept also brings a clear framework to ensure that actions are evidence-based, inclusive, economically viable, and deliver measurable benefits for both biodiversity and society. In this way, NbSs help shift conservation from being seen as a sectoral objective to a cross-cutting solution embedded in economic and social policy.

2. The concept is still emerging, but are there any successful cases of implementation in the Mediterranean?

The Mediterranean already offers several promising examples of NbSs in practice, even if they were not always initially labelled as such. These include large-scale wetland restoration that enhance flood control and biodiversity, forest landscape restoration to reduce wildfire risk while boosting ecosystem resilience, and coastal ecosystem restoration — such as dunes, salt marshes, and seagrass meadows — to protect shorelines from erosion while supporting fisheries and carbon sequestration. Integrated water resource management approaches that restore river connectivity and natural floodplains also demonstrate how NbSs can simultaneously address water scarcity, climate adaptation, and habitat conservation in this climate-vulnerable region. Overall, these experiences show that NbSs can be successfully adapted to the specific social and ecological contexts of the Mediterranean.

3. What are the main obstacles to the large-scale deployment of NbS in the Mediterranean, and how can the CMB and the RESCOM project accelerate its implementation?

Key obstacles for scaling up Nature-based Solutions (NbSs) in the Mediterranean include fragmented governance frameworks, limited cross-sectoral coordination, and insufficient long-term financing. NbSs often require integrated planning across water, agriculture, urban development and conservation sectors, which is still difficult to reconcile with siloed public policies, short political and project cycles, land tenure complexities and competing land-use pressures. Active stakeholder engagement, clearer evidence on cost-effectiveness compared to grey infrastructure and stronger recognition of biodiversity as essential natural capital are also key issues.

In this context, the Mediterranean Biodiversity Consortium (MBC) and the RESCOM project can play a catalytic role. By promoting regional cooperation, aligning policy frameworks and facilitating knowledge exchange, they help to structure credible and measurable initiatives. Their action also helps to strengthen the skills of local actors, mobilise financing and develop replicable models adapted to the socio-ecological realities of the Mediterranean, and aligned with EU and international climate and biodiversity policies?

 

At the heart of our estate, a pine forest planted after the Second World War is home to small ponds nestled on a dune ridge that is thousands of years old. At first glance, they seem peaceful. Yet they tell a fragile story.

These ponds host a freshwater ecosystem vital to many species. Among them is the spadefoot toad (Pelobates cultripes): a small amphibian that is as discreet as it is endangered, choosing these ponds for reproduction each mating season. But over the past decade, something has been changing. The oak trees in the pine forest are dying. Some reed beds are losing their vitality. And the water… is gradually becoming saturated with salt.

Why ?

Less rain, more evaporation due to global warming… but perhaps also invisible exchanges with surrounding aquifers, whose salinity varies according to the seasons and the management of irrigation and drainage channels.

To understand these mechanisms, scientists at the Tour du Valat are closely monitoring changes in the ponds: salinity measurements every two weeks, installation of piezometers throughout the site, analysis of underground water movements…

The aim? To identify the causes and, if possible, take action to curb this phenomenon.

This winter, heavy rains have allowed the ponds to fill with fresh water, providing pelobates with optimal conditions for reproduction. Hope is therefore reborn for this protected species.

At the Tour du Valat, cultivating vines also means watching over these invisible balances. Here, each plot tells a story of agriculture and biodiversity coexisting together.

Identity card of the common spadefoot toadSize: 7 to 10 cm long Identification criteria: Its hind legs are equipped with ‘knives’, allowing it to burrow vertically into the sand. Its back is yellowish-grey dotted with chocolate brown spots. Behaviour: The Pelobates is only active on certain nights. During the day, it creates small underground burrows (except during the breeding season). Status: protected species Chant : A soft, muffled “ko-ko-ko” sound, reminiscent of a hen’s clucking, which can be heard in the audio below https://tourduvalat.org/wp-content/uploads/2026/03/PABLOD_1.mp3 [30] © Naturalist sound recordist and artist Pablo Diserens [31]

 

We are familiar with spectacular epidemics, such as those linked to highly pathogenic avian influenza, which struck our region during the winter of 2026. When birds die in large numbers, the impact is visible and immediately measurable. But in nature, most infections go unnoticed. They do not cause mass mortality or obvious symptoms. What’s more, dead birds often serve as food and quickly disappear from the landscape. Yet these infections can affect the growth, physical condition or reproductive success of animals — with potential long-term consequences for populations.

Quantifying these impacts represents a major scientific challenge in understanding the dynamics of wild populations. This is demonstrated by a recent study conducted by the Tour du Valat and its partners on the yellow-legged gull (Larus michahellis). The researchers focused on a blood parasite that they had recently described with their colleagues from the National Veterinary School of Nantes: Babesia sp. YLG, transmitted by a tick vector (Ornithodoros (Alectorobius) maritimus) found in nests.

Monitoring the infection to measure its effects

The main challenge? Assessing the effects of a parasite that does not make the bird visibly ill. As conventional blood smear analyses are not always sufficient to detect subtle infections, the team developed a high-precision tool: a qPCR assay. This molecular technique makes it possible to detect minute traces of the parasite in the blood and measure the amount of pathogen present in each individual.

For three years, the scientists monitored two colonies of gulls to observe how the parasite circulated and what its real effects were on the birds’ lives.

An infection with varying impacts depending on age

The results highlight the different effects of the parasite depending on the stage of life of the individual:

• Chicks are more exposed than adults: The parasite is omnipresent in young birds. It is transmitted from the nest via ticks. It has been observed that the more a nest is infested with ticks, the more likely the chick is to be infected with Babesia. Infection peaks at around 37 days of age and then decreases as the young bird’s immune system strengthens.

• Impact on growth: Scientists have observed a significant slowdown in growth in infected chicks, greater than that associated with the direct impact of ticks. However, in seabirds, growth rate often determines the chances of survival.

• Repercussions on parents: Infection is rarer in adults but seems to weaken their physical condition. A striking observation: chicks are less likely to fledge successfully when one of their parents is carrying the parasite. It is as if, when faced with infection, adults prioritise their own survival at the expense of investing in their young.

• Once the chicks have fledged, their infectious status or that of their parents no longer affects their survival or movements.

Challenges for conservation

Taken individually, these impacts may seem modest. While Babesia sp. YLG does not decimate colonies, it acts as an additional stress factor. In a world where seabirds are already facing food scarcity and climate change, these infections can influence long-term population dynamics.

This study therefore highlights the importance of also focusing on the most inconspicuous pathogens.

Future research should now focus on the long-term consequences of this infection on population and community dynamics, and examine its impacts on the evolution of these populations in a rapidly changing world.

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Publication reference

Buysse M., Ollagnier M., Souc C., Bruley M., Blanchon T., Leray C., Vittecoq M., McCoy K.D. 2025. Spatiotemporal Dynamics of Blood Parasite Infections and Impacts on Avian Health and Reproduction. Molecular Ecology n/a:e70178. doi: 10.1111/mec.70178 ^[32]

Contact

Marion Vittecoq ^[33] | Research Director – Coordinator of Health Ecology and Species Conservation Themes

The Rhône is one of the main sources of sediment and organic carbon for the Mediterranean Sea. Every year, it carries nearly 5.5 million tons of sediment – the equivalent of 2,000 Olympic swimming pools – and 173,000 tons of organic carbon, a volume comparable to what 870,000 trees can absorb in a year, to the sea. These inputs nourish marine ecosystems, support biodiversity, help to curb natural coastal erosion and slow down the retreat of the coastline, particularly in the Camargue and the Gulf of Lion. Without them, beaches and coastal infrastructure would be even more exposed to storms and rising sea levels. But this balance is fragile: in a century, dams have reduced these flows by 60%, while climate change is altering flood patterns, concentrating 70% of inflows in just 10% of the year.

A recent study published in March 2026, conducted by a research team including the Tour du Valat, used the SWAT-C (Soil and Water Assessment Tool – Carbon) model for the first time to quantify organic carbon dynamics in the vast Rhône River basin between 2002 and 2020. Results reveal that Alpine tributaries, such as the Durance and Isère rivers, contribute 70% of the organic carbon transported, mainly in labile form – a biodegradable fraction that is easily assimilated by microorganisms, actively participates in the carbon cycle and reflects the good health of ecosystems.

However, these figures are accompanied by significant margins of uncertainty. Although pioneering, the model still underestimates certain local variations, such as the precise impact of dams on fine sediments, and requires more detailed data to better predict, in particular, carbon degradation at sea and the cumulative effect of small tributaries. Furthermore, future scenarios – related to climate or dam management – remain difficult to model accurately.

So what can be done? Scientists insist on one point: before considering adaptation solutions, such as modifying dam releases, it is essential to improve the model by incorporating more field measurements and reducing its margins of error. One thing is certain: the Rhône is a veritable open-air laboratory for understanding how to reconcile water security, coastal preservation and the fight against global warming – a challenge that extends far beyond our borders and concerns all Mediterranean coastlines.

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Publication reference

Fabre C., Copard Y., Sauvage S., Radakovitch O., Piegay H., Sánchez-Pérez J.M., Fressard M., Boutron O. 2026. Integrated modelling of sediment and organic carbon fluxes in a large catchment: quantifying riverine contributions to the Mediterranean Sea. CATENA 264:109794. DOI: 10.1016/j.catena.2026.109794 ^[34]

Contact ^[35]

Olivier Boutron ^[35] | Research Director – Wetland Dynamics and Water Management Theme

After eight years of work to improve the conservation of marine habitats – including coastal lagoons – European Life Marha project (2018-2025), led by the French Office for Biodiversity with 13 scientific and management partners, has come to an end. As part of this project, the Pôle-relais lagunes méditerranéennes, supported by the Tour du Valat, assisted all stakeholders involved in the management of Natura 2000 sites in assessing the conservation status of Priority Habitat 1150* ‘Coastal lagoons’.

The main results were presented at the closing conference ^[36] on the 1st of April 2025 in Marseille.

Understanding in order to act

Mediterranean lagoons are a highly diverse habitat: some are permanent, others temporary, salty or slightly salty. This complexity makes them difficult to monitor. The Pôle-relais lagunes méditerranéennes, coordinated by the Tour du Valat in partnership with the Conservatoire d’espaces naturels d’Occitanie and the Office de l’Environnement de la Corse, has supported Natura 2000 managers in assessing these environments using a national method based on 12 indicators.

Résultats :

The results:

• More than 500 participants mobilised through 15 training courses and 17 workshops on implementing the assessment;
• The first mapping of habitat 1150* ‘Coastal lagoons’ habitat, using a standardised method covering nearly 86,000 ha along the French Mediterranean coastline, with 3,281 lagoons identified, 92% of which are permanent (46,205 ha in Provence-Alpes-Côte d’Azur region, 36,080 ha in Occitanie and 3,281 ha in Corsica).
• A map of the seagrass bed area of eight Natura 2000 sites produced using machine learning.

The assessment results at the Natura 2000 site level are mixed, with many indicators showing an altered or degraded state. However, one major positive result concerns the habitat area indicator. The Tour du Valat’s work based on remote sensing has shown that the habitat area has remained stable.

Using data for better management

While certain indicators reveal fragile areas (pollution, climate impact, etc.), assessments now make it possible to:

• Prioritise management actions,
• Adapt measures according to the pressures observed,
• Enhance knowledge of lagoons that have been little studied until now, such as small coastal lagoons not covered by the WFD.

All the data has been centralised in the OFB database and is accessible via interactive mapping, providing a valuable tool for managers and researchers.

Outlook

80% of managers say they are ready to repeat the assessment, but technical and financial support is still needed. The national method must be adapted to the diversity of lagoon types, and it is recommended that the Natura 2000 objective documents be updated to include specific action sheets for HIC 1150*. Mapping must continue to evolve and be enriched to meet the growing needs of managers.

These elements will be crucial to maintain the momentum on the managers side and to achieve long-term objectives. Assessing the state of these ecosystems is indeed a major challenge, essential to ensure the sustainable management of these fragile environments, which are true sentinels of climate change.

Read the full report in French >> ^[37]