Every morning, from May to July, Alana Bell puts on her waders and makes her way to the marshes and canals of the Tour du Valat estate, in search of European pond turtles. This small black turtle with yellow markings is the only species of freshwater turtle native to a large part of Europe. Unfortunately, this species is now under threat: the destruction and degradation of wetlands – its natural habitat – are the main causes of its decline.
To better protect this species, the Tour du Valat launched, in 1997, a programme to monitor European pond turtle populations across its estate. Thirty years on, this programme is still ongoing and has provided valuable insights into the species as a whole.
“At the Tour du Valat, this long-term individual monitoring programme is the second longest-running, after the one on flamingos. And, across Europe, it is the oldest Capture-Mark-Recapture programme dedicated to European pond turtles that is still ongoing! ” according to Anthony Olivier, the research engineer leading this project at the Tour du Valat
Although the scientific monitoring programme began in 1997, the first markings of individual turtles at the Tour du Valat were carried out by Alan Johnson in 1976.
These early efforts have proved valuable, as during recent surveys, European pond turtles tagged fifty years ago have been found alive. This is the case with European pond turtle No. 14, tagged in 1976. Now over 50 years old, this female is, to our knowledge, the oldest known individual of the species living in the wild.
However, the study of European pond turtles provides insights not only into the species itself : its longevity and highly sedentary nature make it a ‘sentinel’ species, capable of reflecting the variations occurring in its aquatic environment. For instance, articles based on Leslie-Anne Merleau’s PhD thesis have demonstrated the multi-contamination of these European pond turtle populations in the Tour du Valat Reserve by trace elements[5] (heavy metals), pesticide residues[6] and organic pollutants[7] (PCBs, phthalates, PAHs) present in the waters of the Camargue’s water channels and marshes.
The continuity of this unique monitoring programme owes much to the commitment of young researchers, students and volunteers from the Civic Service programme and/or the European Solidarity Corps. Each year, a lead volunteer conducts fieldwork under the supervision of Anthony Olivier. Since 1997, dozens of young people have taken part in these campaigns, helping to collect data on the 1,722 European pond turtles tagged to date on the Tour du Valat estate.
For many, this experience marks their first immersion in scientific fieldwork. They learn to observe, to collect data rigorously, and to interact with wild animals whilst minimising disturbance as much as possible. Beyond the technical skills, a holistic approach is being passed on: one that encompasses scientific protocols, the patience required to observe living creatures, and the responsibility that comes with accessing preserved natural areas such as nature reserves.
“During the year I spent at the Tour du Valat, monitoring European pond turtles was my biggest field project. Thanks to Anthony’s mentorship, I was able to discover a side of the scientific world I hadn’t known before. It was wonderful to get to know this species up close, day after day. I was thrilled to contribute to this project, and particularly to be able to observe individuals such as European pond turtle number 14, which was identified fifty years ago.”
Testimonial from Alana Bell, a volunteer with the European Solidarity Corps (ESC)
DWatch a video about the European pond turtle monitoring programme, produced by students at the MoPA school (in French):
Advocacy: when the acceleration of projects puts wetlands under pressure
From major infrastructure projects in the Camargue to legislative developments in France and Europe, a number of recent decisions have raised concerns about the priority given to environmental issues in policies. For the Tour du Valat, these debates highlight the importance of fully taking into account the services provided by wetlands, as well as available scientific knowledge, before any decision that could have long-lasting impacts on these ecosystems.
In the Camargue, the proposed extra-high-voltage aerial power line between Fos-sur-Mer and the Gard reached a new milestone on 13 May, when the Ministry of Energy initiated the procedure to examine its declaration of public utility. In response, fifteen nature conservation and civil society organisations, including the Tour du Valat, have issued a formal appeal to the government, reminding authorities that the Camargue cannot be sacrificed in the name of energy sovereignty.
A public consultation is open from 15 June to 15 July regarding the proposed Fos–Jonquières extra-high-voltage aerial power line. This stage enables town planning documents to be adapted to the project. Anyone can take part and have their say: your contribution matters! More information >>[9]
Other projects, like the Arles highway bypass or the Barcarin Bridge, could also have direct impacts on the Camargue. Yet this territory hosts natural areas recognised at international level.
An analysis of the cumulative effects[10] of these projects highlights significant risks in terms of land artificialisation, damage to sensitive ecological areas, and pressure on water resources.
Beyond environmental impacts, democratic concerns are also emerging. Several recommendations from the public debate organised by the National Commission for Public Debate (CNDP) have largely been ignored, and calls to explore alternative solutions with less impact have fallen on deaf ears. This situation echoes the Arles highway bypass project: despite the reservations and the investigating commissioner’s unfavourable opinion[11] on several aspects of the proposal, the project developer appears determined to move forward.
These local accelerations reflect a broader trend in which biodiversity considerations struggle to find their place in the face of economic and production imperatives.
At national level, the draft Emergency Law on Agricultural Protection and Sovereignty is a case in point. Certain provisions, notably Article 7, which directly affect wetlands, are causing serious concern. The Tour du Valat, alongside other organisations, is closely monitoring the debates and is taking action. More informations (in french) >>[12]
This law reflects a persistent view of wetlands as constraints on agricultural production. Yet their role is now well documented: they contribute to the resilience of water resources, mitigate the impacts of extreme weather events and store carbon.
At European level, signals are equally mixed. Following a previous term marked by the ambitions of the Green Deal, several key pieces of legislation could be reviewed as part of the ‘environmental omnibus’, notably the Water Framework Directive[13], as well as the Habitats and Birds Directives.
In Brussels, too, discussions regarding restrictions on the use of lead in hunting ammunition and fishing tackle are a major issue for waterbirds and wetlands. The Tour du Valat, which has long worked on lead poisoning and lead shot hunting in the Camargue, is closely following these discussions and contributing to advocacy efforts in support of its ban, with its partners like Wetlands International and Birdlife.
In a shifting political landscape, one conviction remains: wetlands cannot continue to be treated as mere variables to be adjusted. Faced with climate challenges, biodiversity loss and growing pressures on water resources, they are, on the contrary, an essential part of the solution.
Lake Chad: New Scientific Study Reveals One of Africa’s Largest Concentrations of Waterbirds
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The new scientific study, “Monitoring major biodiversity stronghold in war zones: model predicts Lake Chad remains Africa’s most important wetland for waterbirds”, published in PNAS, estimates that Lake Chad supports nearly 2.5 million waterbirds, making it one of the most important wetlands for birdlife in Africa. Conducted in a region affected by insecurity, the research also suggests that some conflict zones may unexpectedly serve as refuges for biodiversity.
Lake Chad is often associated with the security, humanitarian, and climate challenges facing the region. However, a new international study highlights another reality: an exceptional ecosystem that continues to support remarkable biodiversity despite more than a decade of conflict.
Using aerial surveys conducted under rigorous scientific protocols and advanced spatial modelling techniques, researchers from Tour du Valat and the French Biodiversity Agency (Office Français de la Biodiversité – OFB), in partnership with the NGO Wings for Conservation and Chad’s Department of Wildlife and Protected Areas, produced the first comprehensive estimates of Lake Chad’s waterbird populations since 2008.
The results are striking: approximately 2.48 million waterbirds are estimated to use the site, making it likely the largest concentration of wetland birds on the African continent.
An Unexpected Refuge for Wildlife
Contrary to common assumptions, researchers found that some species have maintained or even increased their populations in recent years. Several conflict-affected areas even showed higher animal densities than more accessible sectors.
This pattern may be explained by a “refuge effect”. Reduced human activities—including fishing, grazing, and hunting—may have created favourable conditions for wildlife.
However, the researchers caution that these encouraging findings should not obscure a more nuanced reality. While some species appear to be benefiting from current conditions, others are experiencing worrying declines, highlighting the vulnerability of this globally important ecosystem and the need for continued monitoring and conservation efforts.
Is Biodiversity Monitoring Possible in Conflict Zones?
Historically, Lake Chad was widely recognised as a major site for migratory waterbirds, comparable to the Inner Niger Delta in Mali. However, due to conflict and the resulting security challenges, scientific monitoring—including the International Waterbird Census, which tracks population sizes and trends—has not been conducted regularly since the 2000s.
Without ecological data from these key sites, estimating the size and trends of bird populations becomes extremely difficult.
“By combining adapted aerial sampling methods with spatial modelling, we were able to estimate wildlife abundance across vast and difficult-to-access territories while limiting risks to observers,” explains Pierre Defos du Rau, one of the study’s authors.
A Global Challenge for Biodiversity and Food Security
Lake Chad plays a crucial role for migratory birds travelling annually between Africa, Europe, and Asia. Conserving this wetland is therefore an international responsibility.
Beyond its ecological importance, the site also supports local livelihoods. Waterbirds and the resources associated with wetland ecosystems contribute directly to the food security of many communities living around the lake.
In light of these findings, the researchers call for strengthened protection of Lake Chad through the creation of a large-scale protected area and the inscription of the site on the UNESCO World Heritage List.
Scientific monitoring of this kind is essential for understanding changes in wildlife populations and informing future conservation strategies.
At a time when wetlands are disappearing worldwide at an alarming rate, Lake Chad stands out as a natural heritage site of exceptional global importance, whose preservation is vital both for biodiversity and for local communities.
Publication reference:
Defos du Rau P., Godeau U., Carenton N., Dias J., Wachoum A.S., Trolliet B., Baddour K., Chaibo A., Morin G.P., Portier B., Suet M., Tormos T., Mondain-Monval J.-Y., Deschamps C. 2026. Monitoring major biodiversity stronghold in war zones: Model predicts Lake Chad remains Africa’s most important wetland for waterbirds. Proceedings of the National Academy of Sciences 123:e2603538123. doi: 10.1073/pnas.2603538123[14]
The new 2025 cuvées from the Tour du Valat agroecological farm have arrived!
This year, Tour du Valat wines are reinventing themselves with a completely redesigned visual identity.From Dune, Plume, Roseau, Élégante, Doré, Étoilé, and Pourpré Sauvage to Immortelle and Sultane, each new cuvée draws inspiration from a species or natural habitat emblematic of the Camargue wetlands.
Produced using organic farming methods, these wines derive their character from a terroir where agriculture and nature mutually enrich one another.At Mas du Petit Saint-Jean, the vines grow in tune with the natural equilibrium: cover cropping between rows, eco-grazing by sheep, pollinator-friendly hedgerows, bat boxes for natural pest control, hand-harvesting, and agroecological practices designed to meet tomorrow’s challenges.Some grape varieties have even been selected for their resilience to climate change.
The result?Limited-production wines, made on site, that tell the story of the species and environments they help to protect.
Beyond the pleasure of enjoying fine wines, every bottle supports the work of Tour du Valat, a research institute dedicated to the conservation of Mediterranean wetlands since over 70 years.
Plume evokes the pink flamingos that inhabit the ponds of the Camargue. Light, fresh, and sociable, it is the perfect companion for moments shared under the Mediterranean sun. Add food pairing.
Étoilé, a rosé de saignée, with more intense aromas, takes its name from the Great Bittern, an elusive bird emblematic of wetlands that finds refuge in the reed beds. A wine with real character, reflecting the species that inspired it. Add food pairing.
The Tour du Valat Agroecological Farm: Two Sites in the Camargue
Located in the heart of the Camargue, Tour du Valat manages two complementary sites dedicated to research, conservation, and agroecology.
The main estate, situated at Le Sambuc (Arles), spans 2,817 hectares, a portion of which is designated as a Regional Nature Reserve. It combines the protection of remarkable natural habitats – such as temporary marshes, sansouïres (salt marshes), salt meadows, and montilles (sandy ridges) – with traditional agricultural activities, including extensive cattle and Camargue horse rearing, as well as organic rice, wheat, and hay cultivation. This area is home to exceptional biodiversity: over 590 plant species, 300 bird species, and more than 1,600 invertebrate species.
In the Gard, in western Camargue, the Mas du Petit Saint-Jean (101 hectares) serves as an exemplary site where agriculture and biodiversity coexist, enrich and reinforce each other. It combines natural area management with diversified agricultural production (vineyards, agroforestry, and meadow orchards) and acts as a showcase site to demonstrate the compatibility of farming activities with biodiversity conservation.
3 QUESTIONS FOR Olivier Thérond, MAELIA platform development coordinator
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Olivier Therond, an agronomist with a passion for modelling, is the development coordinator for the MAELIA platform. He answers our questions about the future scientific challenges facing MAELIA-Delta, the prospects for implementing the model in other regions, and the importance of engaging with local actors in order to design a decision-support tool that is as closely aligned as possible with the realities of the Camargue.
1/ What are the next scientific challenges for making MAELIA-Delta correspond even more closely to the reality in the field?
MAELIA aims to integrate academic and local knowledge on the structure and dynamics of ecological and socio-economic systems and their interactions. In its current version, MAELIA-Delta models the interactions between agriculture and daily water flows in plots influenced by the climate. To achieve our objective of modelling the Camargue, we still need to incorporate the representation of water flows in irrigation and drainage canals, their relationships with lagoons and marshes, and the dynamics of the bird and fish species on which conservation priorities are focused. We already have most of the building blocks needed for these modelling extensions; the challenge now is to link them together in a coherent way. We will then need to enable MAELIA-Delta to quantify management indicators that are meaningful to stakeholders in the Camargue.
2/ Do you think this approach could be applied to other areas facing similar challenges?
We have designed the developments to be as generic as possible, meaning they can be applied to any region whose general characteristics are similar to those of the Camargue: natural and man-made water flows, hydro-salinity dynamics arising from the interactions between hydrology and irrigated agriculture. MAELIA-Delta is therefore intended to be used in other deltas to support local stakeholders in defining their parameters for balanced water management. But one thing at a time: we first plan to further develop the model before rolling it out in other areas.
3/ How have discussions with managers and local stakeholders influenced the development of the model?
As with any modelling process aimed at supporting decision-making, the issues raised by stakeholders involved in managing a territory determine and frame the development work. In Rose Rodier’s PhD thesis,[1] we implemented a conceptual modelling approach based on gathering and formalising the knowledge of local experts on these issues. This conceptual model enabled us to define the modelling objectives in detail, that is the entities and processes to be represented, the scenarios to be simulated, and the indicators to be assessed. The modelling process was therefore organised to meet these needs; this ensures the tool is relevant for addressing the questions raised by stakeholders in the Camargue.
MAELIA-Delta, a new tool for exploring the future of the Camargue and supporting water management in a region under pressure
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The Rhône Delta is a complex socio-ecosystem where water shapes everything: landscapes, biodiversity, human activities, and the ecosystem services on which society depends. Agriculture, natural habitats, and water use constantly interact within a living, ever-evolving system.
Yet, against a backdrop of global change, this delicate balance is now under severe pressure. Anthropogenic factors (water management choices in agricultural and natural areas, crop types) and climatic factors (prolonged droughts, intense rainfall, rising sea levels) directly influence the hydro-salinity balance, a key parameter that influences the dynamics of habitats and species, and of human activities and related ecosystem services.
To better understand these complex interactions, in 2022 the Tour du Valat and INRAE started developing the innovative application MAELIA-Delta. It simulates the relationships between agriculture, water management, biodiversity, and ecosystem services in delta environments, whilst incorporating the central role played by hydro-salinity dynamics.
In addition to being a fundamental research project, this tool is designed to support concrete decision-making. It will enable stakeholders to collectively explore different water management scenarios and assess their consequences, to inform group decisions concerning major challenges such as climate change and rising energy costs.
The Camargue Island: highly diverse landscapes and land uses
In the Camargue, water is everywhere and everything depends on it. Its landscapes, biodiversity, and human activities are closely intertwined in a delicate balance.
This region is a vast mosaic of natural habitats (about 70% lagoons, marshes, salt scrub, grasslands, woodlands) and agricultural areas (about 25% rice farming, market gardening, open range horse and bull farms, and viticulture). This wide range of landscapes, shaped by contrasts in salinity and freshwater availability, makes the Camargue a biodiversity hotspot in France. Many species can be found here, and some with major heritage significance.
The Delta is a vital refuge for a vast number of waterbirds. Throughout the year, it hosts numerous species, including the iconic Greater Flamingo, and one of its largest breeding colonies in the Mediterranean. In winter, the Camargue becomes an important stopover site for cranes, geese, and ducks, as well as for numerous passerines.
This natural biodiversity is protected by a range of areas with different protection statuses: land-based protection (Coastal Protection Agency, Fragile Natural Areas), regulatory protection (National Reserve and Regional Nature Reserves, Regional Nature Park, Natura 2000), and designations (RAMSAR, UNESCO Biosphere Reserve). However, these protected areas are not isolated: they coexist with well-established agricultural activities, predominantly wheat and rice production (in 2023, 68% of all crops (SIT PNRSud 2026)). Increases in market gardening and fodder crops have been observed over the past twenty years; the latter are grown to meet the needs of livestock farming (grazing, hay) and for their roles in helping to improve soil quality (alfalfa) and in crop rotation (rice/wheat) (SIT PNRSud, 2026). Open range livestock farming is also an integral part of the Camargue landscape, contributing to its cultural identity, biodiversity, and appeal to tourists.
A territory shaped by water circulation
Behind these landscapes, water circulation in the Delta play a key role. The functioning of the Camargue depends not only on rainfall, evaporation, and exchanges with the sea and the groundwater, but also on freshwater drawn from the Rhône, which has been embanked since the 19th century.
This water flows through a complex network of agricultural irrigation and drainage canals. Some of it is pumped back into the Rhône, whilst the rest flows into various systems of ponds and lagoons, affecting their hydro-salinity balance, with consequences on biodiversity and various economic activities (fishing, hunting).
In the Camargue, a large proportion of natural habitats, species, and human activities depend directly on how water is allocated amongst the various ways the land is used. In such an interconnected system, the consequences of changes are often difficult to anticipate. Changes in agricultural practices, a succession of drier years or modifications to canal management can produce cascading effects on soils, lagoons, biodiversity, and human activities. Understanding these interactions across the entire Delta therefore requires a tool capable of simultaneously modelling water, land use, and ecosystems.
Simplified diagram of the Camargue Island, situated between the two branches of the Rhône. The hydraulic infrastructure and pumping stations on the dykes of the Rhône and sea regulate the exchange of fresh and salt water between the catchment areas (a mix of agricultural land, natural wetlands, and hunting marshes) and the lagoon systems in the south.
MAELIA-Delta: a model to better anticipate the future of the Camargue
How might changes in agriculture, climate, and water management transform the Camargue in the coming years?
To answer this question, the Tour du Valat and INRAE have been developing MAELIA-Delta since 2022. It is a software model that can simulate the dynamics of interactions between water allocation in agricultural catchment areas and natural habitats, agricultural activities, key ecosystem services, and several emblematic species in the region.
In practical terms, this tool enables us to test various scenarios for the region’s future development: changes in agricultural practices, droughts, evolving water management policies, and more. The aim is not to predict the future, but to explore its possibilities. In this way, it will help us to better anticipate the consequences of future changes on the functioning of the entire Delta: both on natural habitats and on the human activities that depend on them.
The simulations focus on several benefits that ecosystems provide to the region:
provisioning services linked to agriculture, salt production, livestock farming, and fishing;
water regulation services, with a specific focus on mitigating the risks of drought and salinization;
cultural services, associated with iconic habitats (such as rice fields) and species (such as the Greater Flamingo), which embody great symbolic value for the region.
[20]Illustration of various spatialised datasets used in the spatialised digital representation of the Camargue Island. Sub-representation R1: the Camargue Island territory; R2: meteorological zones (Météo France); R3: soil classification (GIS Sol and Société Canal de Provence); R4: land use (Camargue Regional Nature Park Geo and Data services); R5: Hydrological Response Units (‘HRU’); R6: agricultural parcels (Graphic Parcel Register); R7: network of hydraulic canals. Adapted from Moulin (2024).
From field knowledge to a digital model
To develop MAELIA-Delta, researchers first sought to identify the key mechanisms that link water, human activities, and biodiversity. In her PhD thesis, Rose Rodier’s[19] extensive analytical work enabled her to identify the interactions between water management, agricultural activities, natural habitats, and certain iconic fish and bird species in the region.
This preliminary work was essential for identifying the processes that influence how the Delta functions and which must be incorporated into the model to produce realistic simulations. The aim was to develop a tool that can represent the sometimes-invisible links between the various uses of water and the Camargue’s ecosystems.
Using data available at the scale of the Camargue Island, researchers constructed a spatialised digital representation of the area in order to reproduce and analyse the processes highlighted in Rose Rodier’s thesis.
Adapting an existing tool to the specific characteristics of the Camargue
MAELIA (Multi-agent Modelling of socio-Agro-Ecological systems for Landscape Integrated Assessment) is an assessment and modelling platform designed to represent the spatio-temporal interactions between agricultural activities, water resources, and their management at the catchment basin scale.
The tool is based on a detailed representation of the local territory (agricultural parcels, farms, water networks, natural areas) and on a series of coupled models that can simulate ecological processes as well as the decision-making processes implemented by local stakeholders. It can therefore assess the consequences of different scenarios in terms of socio-economic and environmental impacts, such as water availability, agricultural yields, and soil quality.
However, the Camargue has specific characteristics that had not previously been taken into account in MAELIA. Unlike the catchment areas for which the tool was designed, the Camargue is a deltaic region in which the balance between freshwater and saltwater plays a decisive role. Groundwater upwelling, soil salinization, and the functioning of the Vaccarès lagoon system all have a significant influence on agricultural activities and related ecosystems.
What can MAELIA-Delta already simulate?
Teams at the Tour du Valat and INRAE have been working to adapt MAELIA to these specific conditions since 2022. Several modules have been developed to model rice cultivation and its irrigation practices, the hydro-salinity dynamics specific to deltas, the impact of salt on agricultural yields, and the central role of the Vaccarès lagoon system in water management across the Camargue Island.
Subsequent to the developments carried out by Rose Rodier in her PhD thesis[19], the current version of MAELIA-Delta can be used to simulate the hydro-salinity dynamics of the Vaccarès water system in various contexts: hydraulic infrastructure projects envisaged, the adaptation of management rules for all existing infrastructure, and the visualisation of the consequences of various climate change scenarios (sea-level rise, increased evaporation). These simulations can provide decision-making support for various regional projects, such as the Vaccarès Conservation Plan.
MAELIA-Delta interface for the Camargue Island
What remains to be done?
Several developments, which will be incorporated into future projects, are still required to achieve the objective of integrated water management modelling at the scale of Camargue Island. These include a more accurate description of how hydraulic canals and natural areas function, the modelling of hunting marshes, and links to the dynamics of plant and animal species.
In a region where every water-related decision can have repercussions for agriculture, the lagoons, biodiversity, and economic activities, having a tool that can explore the consequences of different choices is a major asset. By helping us better understand the interactions that shape the Delta, MAELIA-Delta will help to prepare the Camargue for the challenges it will face in the coming decades.
Bibliography
Béchet A., Rendon-Martos M., Rendon M.A., Amat J.A., Johnson A.R., Gauthier-Clerc M. 2012. Global economy interacts with climate change to jeopardize species conservation: the case of the greater flamingo in the Mediterranean and West Africa. Environmental Conservation 39:1–3.
Boutron, O., Paugam, C., Luna-Laurent, E., Chauvelon, P., Sous, D., Rey, V., Meulé, S., Chérain, Y., Cheiron, A., Migne, E., 2021. Hydro-Saline Dynamics of a Shallow Mediterranean Coastal Lagoon: Complementary Information from Short and Long Term Monitoring. JMSE 9, 701. https://doi.org/10.3390/jmse9070701[21]
BRL, 2004. Etude hydraulique et hydrobiologique des canaux de Camargue. Volume 1 : Etats des lieux – Diagnostique.
Ernoul L., Wardell-Johnson A., Mathevet R., Sandoz A., Boutron O., Willm L., Arnassant S., Béchet A. 2021. Context in Landscape Planning: Improving Conservation Outcomes by Identifying Social Values for a Flagship Species. Sustainability 13:6827. doi: 10.3390/su13126827[22]
Galewski T., Devictor V. 2016. When Common Birds Became Rare: Historical Records Shed Light on Long-Term Responses of Bird Communities to Global Change in the Largest Wetland of France. PLOS ONE 11:1–18. doi: 10.1371/journal.pone.0165542[23]
Gaudou, B., Sibertin-Blanc, C., Therond, O., Amblard, F., Auda, Y., Arcangeli, J.-P., Balestrat, M., Charron-Moirez, M.-H., Gondet, E., Hong, Y., Lardy, R., Louail, T., Mayor, E., Panzoli, D., Sauvage, S., Sánchez-Pérez, J.-M., Taillandier, P., Van Bai, N., Vavasseur, M., Mazzega, P., 2014. The MAELIA Multi-Agent Platform for Integrated Analysis of Interactions Between Agricultural Land-Use and Low-Water Management Strategies, in: Alam, S.J., Parunak, H.V.D. (Eds.), Multi-Agent-Based Simulation XIV, Lecture Notes in Computer Science. Springer Berlin Heidelberg, Berlin, Heidelberg, pp. 85–100. https://doi.org/10.1007/978-3-642-54783-6_6[24]
McGinnis, M.D., Ostrom, E., 2014. Social-ecological system framework: initial changes and continuing challenges. Ecol. Soc. 19.
Moulin, Aurore. 2024. « Conception d’une représentation numérique et spatialisée pour la modélisation intégrée de l’île de Camargue ». Mémoire de Master, Université de Montpellier / Montpellier SupAgro. 43 pages.
Rodier, 2026. Modélisation intégrée des réseaux d’activités, des services écosystémiques, et de la biodiversité sur l’île de Camargue. Evaluation des impacts du changement climatique et de la transition agroécologique sur un delta. PhD report. Université de Lorraine. 249 pages.
Therond, O., Sibertin-Blanc, C., Lardy, R., Gaudou, B., Balestrat, M., Hong, Y., Louail, T., Nguyen, V.B., Panzoli, D., Sanchez-Pérez, J.-M., Sauvage, S., Taillandier, P., Vavasseur, M., Mazzega, P., 2014. Integrated modelling of social-ecological systems: The MAELIA high-resolution multi-agent platform to deal with water scarcity problems. Presented at the 7th International Environmental Modelling and Software Society (iEMSs 2014), International Environmental Modelling and Software Society, p. 1.
Tremoureux, M., 2019. Impacts de la gestion de l’eau en Camargue sur les services écosystémiques. Rapport de stage de Master 2 Gestion des Eaux et des Milieux Aquatiques, spécialité Zones Humides Méditerranéennes, Université Aix-Marseille, 41p.
Olivier Thérond, Laboratoire Agronomie et Environnement, Université de Lorraine, INRAE, France.
Rose Rodier, Tour du Valat / INRAE.
Funding partners
BIOSFAIR Metaprogramme[30], INRAE. Funding for Rose Rodier’s PhD scholarship (2022–2026).
Protected area managers across Europe are adapting to climate change
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New research shows how climate change is reshaping protected area management, though more funding and scientific knowledge are needed to facilitate the process.
The Natura 2000 network, the world’s largest network of protect areas, aims at protecting important species and habitats across the European Union. Its traditional approach to conservation has focused on maintaining ecosystems in their historical conditions, but in a world characterised by a changing climate this may not be possible anymore, requiring adapting the conservation strategies.
Researchers conducted a large-scale survey across Europe aimed at Natura 2000 protected area managers, to investigate how they perceive and address the effects of climate change on biodiversity. The survey was conducted as part of the Scenarios for Protecting European Avian Redistributions (SPEAR) project focused on bird conservation, which involved partners from several European countries.
The findings show that over half of the managers already perceive climate change as a threat to biodiversity, with the majority of them already accounting for the impacts of climate change when planning management practices. Managers are particularly concerned about warming and changes in precipitations.
“Climate change is not equally perceived as a threat throughout Europe, for example managers in the Mediterranean region are more concerned than managers in the Boreal region, where for example Finland is located,” says the study’s first author, Doctoral Researcher Giorgio Zavattoni from the University of Turku, Finland.
Managers who perceive that their protected areas are vulnerable to climate change are also more likely to implement adaptation strategies.
“It was encouraging to see that over half of the managers consider the effect of climate change in their conservation management strategies, not only by trying to resist its effect but also by dynamically adapting to climate change and acknowledging that it transforms ecosystems,” says Professor Jon Brommer from the University of Turku.
European Commission’s new guidance strengthens adaptation strategies
This study came out at the same time as the European Commission published a new guidance on Natura 2000 and climate change, which is dedicated to strengthening adaptation strategies. The Commission notice clarifies legal flexibilities in the Birds and Habitats Directives, needs for strategic planning, and identifies practical adaptation measures.
“This guidance is welcome, because our study points out that many protected area managers are eager to learn more about the implementation of adaptation strategies,” says Dr Elie Gaget from the research institute Tour du Valat, France.
“However, managers also flagged the lack of scientific knowledge and financial resources to implement cost-effective climate adaptation strategies.” adds Gaget.
This study highlights the urgent need for researchers to take an increasingly important role in aiding managers by producing actionable knowledge, while also funding and capacity building support are strongly needed.
In the Camargue, the temporary ponds created over 150 years ago are still not entirely similar to natural ponds
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Although often discreet in the landscape, Mediterranean temporary ponds are home to remarkable biodiversity. Fed by autumn and winter rains, they gradually dry up in spring before remaining dry throughout the summer. This natural alternation between wet and dry phases favours a highly specialised flora, capable of withstanding hydrological conditions that vary greatly year to year.
Long overlooked, sometimes drained in or altered, these ponds are among the most threatened habitats in Europe. Their conservation depends both on protecting existing ponds and on restoring, or even creating, new habitats.
In the Camargue, many natural ponds have disappeared or been severely degraded over the last two centuries, whilst others have been created by chance or to compensate for the widespread destruction of wetlands. But do these artificial ponds, over time, manage to regain the characteristics of natural ponds? This is the question a team from the Tour du Valat has sought to answer by comparing the vegetation of ponds created at different times with a set of natural reference ponds.
A long-term study
To monitor the long-term changes in the ponds, the researchers compared the terrestrial and aquatic vegetation of 24 artificial ponds, created at different times (over 150 years ago, between 50 and 100 years ago, and less than 15 years ago), with that of 27 natural reference ponds spread across the Camargue.
For each pond, a series of surveys was carried out at various points in the annual cycle, from spring to late summer – in 2019 and 2020 for the reference ponds, and in 2020 for the artificial ponds – in order to account for the significant seasonal variations characteristic of these environments. The scientists recorded the composition of plant communities, their abundance by season, as well as parameters such as water depth, salinity and the physico-chemical conditions of the soil.
The aim was to understand what is restored… and what is not when temporary ponds are created. This original approach has enabled the observation of restoration trajectories over an exceptional period of more than 150 years.
First observation: the created ponds are home to a rich and diverse flora. The total number of species is generally comparable to that observed in natural ponds.
However, a detailed analysis of restoration trajectories reveals significant contrasts depending on the age of the ponds. Recently created ponds (less than 15 years old) are not yet fully restored, although some are already showing favourable trends and are becoming more similar to the reference ponds. In contrast, the oldest ponds (created in the 19th century or in the 1970s) appear, for the most part, to be much closer to natural communities.
These results confirm that wetland restoration is a slow process. Furthermore, certain plant communities characteristic of natural ponds remain absent, or are very rarely observed in the created ponds, particularly the rarest and most threatened species. Further analysis could help determine whether this absence is due to environmental conditions that are still unsuitable or to limitations on the dispersal of the species concerned.
Restoration is no substitute for conservation
The creation of ponds is a valuable tool for recreating habitats favourable to many plant species and strengthening the network of wetlands in the Camargue. However, certain ecological characteristics take several decades, or even several centuries, to re-establish themselves. Natural ponds therefore remain irreplaceable reservoirs of biodiversity and essential sources of recolonisation for restored habitats.
The study also highlights the importance of long-term monitoring: assessments carried out just a few years after restoration do not always allow us to gauge the true ecological trajectories of ecosystems, particularly in the context of climate change. More than ever, restoration and conservation appear to be two complementary approaches to secure the future of Mediterranean wetlands.
Publication reference:
Fontès H., Grillas P., Dutoit T., Gazaix A., Gaget E., Mesléard F. 2026. Vegetation trajectories over 150 years of temporary ponds created in the Camargue delta (Southern France). Restoration Ecology n/a:e70372. doi: 10.1111/rec.70372[36]
New data on European coastal wetlands to help achieve restoration policy objectives
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Europe’s coastal wetlands account for less than 10 per cent of the region’s wetlands, yet they play a disproportionately important role in mitigating climate change and adapting to its effects, whilst also hosting some of the continent’s richest biodiversity. To restore them effectively, we need to know where to prioritise action and which issues to take into account.
A new study, carried out as part of the Horizon Europe RESTORE4Cs project[39], offers a unique spatialised dataset that links three dimensions: habitats, ecosystem services provided to communities, and human activities, including the pressures these exert on ecosystems.
Six pilot sites representing Europe’s coastal regions
This work draws on insight from six coastal wetlands in Europe, spread across the Atlantic, Mediterranean, Baltic and Black Sea coasts: the Ria de Aveiro (Portugal), Marjal del Moro north of Valencia (Spain), the Camargue (France), the Eastern Scheldt estuary (Netherlands), the Curonian Lagoon (Lithuania) and the Danube Delta (Romania).
The Tour du Valat is participating in the project as the leader of Work Package 7, as well as being responsible for activities at the Camargue pilot site. It also contributes its scientific expertise on Mediterranean wetlands, alongside the University of Aveiro, which is coordinating the project, and all the European partners from the R4Cs project.
A database built on the basis of field expertise
The database was compiled using the expertise of the teams at each pilot site: these teams first mapped the landscape units, then linked them to ecosystem services, as well as the activities and pressures affecting them.
At each site, a participatory workshop brought together local stakeholders (public authorities, local governments, NGOs, fishermen, users, etc.) to prioritise the importance of various restoration criteria – thereby involving local stakeholders in the decision-making process, rather than treating them only as sources of information.
In total, the data collected comprises around 100 habitat records, more than 20,000 activity-pressure combinations and more than 1,600 ecosystem service records.
This data feeds into a ‘Toolbox’ for spatial prioritization : a decision-support tool that enables managers and decision-makers to identify where restoration can maximise co-benefits (climate, biodiversity, water quality). Comparable data has also been produced at European scale, using a different methodology adapted to that level; it is accessible via the R4Cs mapping platform.
These resources aim to make trade-offs between wetland uses explicit, and to support implementation of the EU Nature Restoration Regulation and the Biodiversity Strategy to 2030.
Applying this methodology on the Camargue pilot site, three restoration scenarios for 2050 emerged from a participatory process organised by the Tour du Valat, MedWet and Vertigo Lab, bringing together local stakeholders last November:
Adaptive management with nature-based solutions: a combination of grey infrastructure restoration and natural adaptation, through flexible water management and ecosystem-based solutions (buffer zones, controlled flooding, wetland restoration, resilient agriculture).
Naturally evolving landscape: gradual transformation of landscapes through reduced human intervention, by restoring ecosystems and changing land use.
Historical water management approach: resilience to the impacts of climate change by relying more heavily on infrastructure and engineering works.
The process involved 19 interviews to clarify the context and collect data, followed by a workshop attended by 14 local stakeholders, who were invited to propose indicators for each criterion based on their expertise. These criteria covered socio-economic aspects (agriculture, livestock farming, hunting, tourism, nature conservation, etc.) as well as environmental aspects (habitats, biodiversity, climate, water, etc.) and socio-cultural aspects (heritage, health, research, participation).
In terms of the preferences expressed, activities in the primary sector came top (11% of the weighting, driven mainly by agriculture and livestock farming), followed equally (10%) by activities in the tertiary sector (tourism and conservation), risk management costs (protection against flooding and submersion) and biodiversity. At the level of broad themes, however, it is the environmental dimension that emerges as the priority.
The multi-criteria analysis shows that the adaptive management scenario with nature-based solutions is the preferred option (confirmed by three normalisation methods). It offers the best balance between socio-economic, environmental and socio-cultural issues, whilst remaining the most acceptable locally. It should be noted that the ‘naturally evolving landscape’ scenario would enable a significantly greater reduction in the region’s greenhouse gas emissions, but at the expense of socio-economic activities.
Publication reference:
Oliveira B.R.F., Camacho A., Guelmami A., Schroder C., Bègue N., Bučas M., Cazacu C., Ciravegna E., Coelho J.P., Constantin R.G., Hilaire S., Kataržytė M., Morant D., Picazo A., Polman N., van Puijenbroek M., Raoult J., Rochera C., Ronse M., Sella L., Sousa A.I., Racoviceanu T., Rota F.S., Vaičiūtė D., Lillebø A.I. 2026. European coastal wetlands datasets and their use in decision-support tools for policy restoration objectives. Environmental Science & Policy 179:104386. doi: 10.1016/j.envsci.2026.104386[40]
Climatic and trophic drivers control long-term phytoplankton temporal trends in coastal lagoons
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Recent studies conducted in Corsican coastal lagoons show how phytoplankton dynamics evolve over the long term and highlight the joint—yet hierarchical—role of nutrient inputs and climatic conditions.
The study is based on a summer monitoring programme carried out over the past 17 years in four lagoons located on the eastern coastal plain of Corsica, within the framework of the European Water Framework Directive (WFD). Each year, several parameters are measured, including water temperature, salinity, nutrient concentrations (nitrogen and phosphorus), as well as various phytoplankton indicators (chlorophyll-a, abundance by size class, and pigment composition).
The scientists’ objective was to better understand how climatic variations (air temperature, rainfall and wind) and nutrient inputs influence long-term phytoplankton trends, which form the basis of the aquatic food web.
Different responses according to the trophic status of lagoons
The results show that the functioning and evolution of lagoons strongly depend on their exposure to nutrients.
In the most nutrient-enriched lagoons, phytoplankton dynamics are mainly determined by nutrient inputs, which lead to significant biomass peaks and promote the dominance of diatoms. In these eutrophic systems, climatic effects appear secondary and difficult to isolate.
Conversely, in nutrient-poor lagoons, the effects of climatic variations (warming, rainfall events and wind events) become more perceptible. Although their impact remains lower compared with that of nutrient inputs, climatic conditions influence phytoplankton composition: wind events stimulate biomass and favour large-sized organisms, whereas high temperatures favour small cyanobacteria adapted to warm, nutrient-poor waters.
Climate and nutrients: two drivers to be considered jointly
This study highlights that lagoons do not respond uniformly to environmental change. Phytoplankton trajectories are primarily controlled by trophic status, while climatic effects are expressed with varying intensity depending on the exposure of systems to nutrients.
The authors remind us that, in eutrophic systems, reducing nutrient inputs remains the priority and has already been identified in several studies as an essential restoration lever. However, they now stress the need to also integrate the coupled effects of climate into management strategies.
In the most preserved lagoons, low nutrient exposure promotes more stable functioning and provides an opportunity to detect climatic signals at an early stage, making these systems true “sentinels” of environmental change.
A conceptual diagram illustrating the relative influence of climatic and nutrient factors on phytoplankton trajectories in Corsican lagoons along a trophic gradient: oligotrophic lagoons (Diane and Urbino) are more strongly influenced by climatic factors, whilst the more eutrophic lagoons (Biguglia and Palo) are primarily influenced by nutrient inputs.
Ecosystems particularly sensitive to global change
In all cases, coastal lagoons appear particularly vulnerable to future changes, including rising temperatures, more frequent extreme events, reduced freshwater inputs, sea-level rise and changes in salinity.
In this context, the long-term monitoring of these environments is essential to anticipate their future trajectories, guide management actions and preserve the services they provide, including coastal protection, carbon storage, biodiversity, fisheries and shellfish farming.
Publication reference:
Moulin, A., Bec, B., Boutron, O., Derolez, V., Garrido, M., Pasqualini, V., Malet, N.,2026. Climatic and nutrient drivers affect long-term phytoplankton temporal trends in coastal lagoons. Marine Pollution Bulletin, 224, 119080. https://doi.org/10.1016/j.marpolbul.2025.119080[42]
Contacts:
Aurore MOULIN | University of Corsica, CNRS UMR 6134 SPE, ‘Water Management in the Mediterranean’ project: [email protected][43]
Olivier BOUTRON[26] | Directeur de recherche – Coordinateur du thème Dynamiques des zones humides et gestion de l’eau
Learn more:
Derolez, V., Bec, B., Munaron, D., Fiandrino, A., Pete, R., Simier, M., Souchu, P., Laugier, T., Aliaume, C., Malet, N., 2019. Recovery trajectories following the reduction of urban nutrient inputs along the eutrophication gradient in French Mediterranean lagoons. Ocean & Coastal Management 171, 1–10. https://doi.org/10.1016/j.ocecoaman.2019.01.012[44]
Ligorini, V., Garrido, M., Malet, N., Simon, L., Alonso, L., Bastien, R., Aiello, A., Cecchi, P., Pasqualini, V., 2023. Response of Phytoplankton Communities to Variation in Salinity in a Small Mediterranean Coastal Lagoon: Future Management and Foreseen Climate Change Consequences. Water 15, 3214. https://doi.org/10.3390/w15183214[45]
Pesce, M., Critto, A., Torresan, S., Giubilato, E., Santini, M., Zirino, A., Ouyang, W., Marcomini, A., 2018. Modelling climate change impacts on nutrients and primary production in coastal waters. Science of The Total Environment 628–629, 919–937. https://doi.org/10.1016/j.scitotenv.2018.02.131[46]
Funders:
ANR22-EXES-0016
PhD thesis co-funded 50% by the University of Corsica and 50% by IFREMER
From Corsica to Sardinia: gaining a better understanding of subsurface nitrogen and phosphorus flows and promoting the ‘Flux Admissibles mission’ initiative in the Mediterranean
In May 2026, Columba Martinez Espinosa, a research engineer with the Flux Admissibles (FA) mission – led by the Tour du Valat, Ifremer and the Rhône-Méditerranée-Corse Water Agency – took part in two complementary key events in Corsica and Sardinia. A training course in hydrogeology in Corte, followed by the International Nitrogen Workshop in Sassari, enabled her to both strengthen the technical skills required by the Mission and consolidate her connections with the scientific community working on nitrogen fluxes across the Mediterranean, in collaboration with agricultural stakeholders, researchers and European decision-makers.
Photo of the group of participants and the organising team at the training course in Corsica.
Finding the right balance between nutrient inputs and lagoon health
Since 2021, the FA mission, has been supporting the implementation of an approach aimed at better regulating nutrient inputs into French Mediterranean lagoons, with a view to restoring ecological balance, understanding the processes underlying their degradation, and proposing measures to support their recovery.
In concrete terms, it aims to determine the dynamics of nitrogen and phosphorous loads that lagoons can absorb. depending on site-specific and climatic conditions, as well as to understand how these nutrients are utilised by the various biological compartments, particularly primary producers, in order to identify assimilation thresholds compatible with sustaining ecosystem functioning. These inputs stem mainly from agricultural activities, urban discharges, one-off events such as floods and dam releases, as well as runoff.
To this end, the FA mission provides technical and scientific expertise to local stakeholders: defining sampling strategies, selecting calculation methods and supporting measurement systems to quantify nutrient fluxes. It also employs lagoon modelling via the GAMELag tool (‘Management and planning of Eutrophic Lagoon Environments’), which enables the simulation of lagoon dynamics and evaluation of different management scenarios.
By combining field measurements and modelling, the FA mission helps to identify concrete actions to reduce excess nutrients and maintain or restore the good ecological status of Mediterranean lagoons.
In Corte, a five-day intensive course on hydrogeology in the Mediterranean region provided an in-depth understanding of how coastal aquifers function. In particular, it explained how water flows in the subsurface, from catchment areas to springs and boreholes, as well as the methods used to study and analyse them in the field.
Led by teachers and researchers from the universities of Corsica and Pisa, the course alternated between theoretical sessions, field trips and practical work in two contrasting catchment areas, ranging from mountainous terrain to coastal lagoon environments. Participants collected physico-chemical data, used geochemical and isotopic tracers, and developed conceptual hydrogeological models to better understand groundwater system functioning. This work highlighted the exchanges between rock and water, the interactions between the surface and the subsurface, and the role of coastal aquifers in supplying the lagoons.
Acquiring these new skills will improve the representation of groundwater flow in the GAMELag model and enable hydrogeological factors to be incorporated in greater detail from Phase I onwards at the FA mission’s study sites, in order to better quantify the nitrogen (N) and phosphorus (P) fluxes reaching the lagoons.
A session dedicated to wetland hydrology, illustrated by the case of the Biguglia lagoon south of Bastia, has also opened up prospects for collaboration with CNRS UMR 6134 SPE.
In Sassari, participation in the Nitrogen Workshop, funded by the OurMED project, provided an opportunity to present the FA mission to an international community of experts specialising in nitrogen fluxes, at the intersection of water, energy and food nexus.
One of the main themes addressed was the quantification of N₂O (nitrous oxide) emissions linked to agricultural practices and the optimisation of fertiliser use and irrigation. A dedicated day was devoted to discussions with European decision-makers involved in the implementation of the Nitrates Directive.
In this context, the FA Mission shed further light on the eutrophication of lagoons, a phenomenon that is still often under-represented in nitrogen balances. In particular, it highlighted the central role of wetlands in nutrient pathways and the impacts of the agro-industry on lagoon ecosystem, while showcasing a successful example of cooperation among scientists, managers, local stakeholders and institutions.
A field day was devoted to the Arborea ‘living lab’. This agricultural plain, created by the drainage of former marshes and now heavily irrigated, is classified as a nitrate-vulnerable zone. It comprises more than 200 dairy farms and around 30,000 head of cattle across 6,000 hectares.
This site provides a concrete illustration of the effects of intensive farming on water resources: massive inputs of nitrogen and phosphorus, combined with highly permeable sandy soils, lead to high concentrations of nitrates in groundwater and to the eutrophication of the surrounding wetlands and lagoons classified as Ramsar sites.
The visit provided an opportunity for direct on-site discussion regarding the tensions between environmental requirements (the Nitrates Directive), the economic viability of the dairy sector and the objectives of restoring natural habitats. It also highlighted solutions that have been piloted to reduce nitrogen leaching into groundwater and lagoon ecosystems, in line with the issues addressed by the FA Mission in the French Mediterranean.
Contributions to the Tour du Valat and the FA Mission
By combining methodological reinforcement in hydrogeology with exchanges with the scientific community working on nitrogen, these two meetings help to improve the technical aspects of the FA Mission and to promote its results with a view to reducing eutrophication in Mediterranean lagoons.
The two events proved highly complementary: the training course in Corsica provides a solid foundation for better understanding and modelling subsurface nutrient flows, whilst broadening collaborations, strengthening hydrogeological expertise, and deepening the integrated understanding of catchment areas functioning. The workshop in Sardinia, meanwhile, provides an opportunity to observe in the field the consequences of nitrate-contaminated groundwater on a complex agricultural socio-ecosystem, as well as the efforts being made to restore a lagoon. In this context, although the FA Mission is based on highly technical work, it addresses an issue common to many contexts across the Mediterranean: eutrophication. As such, this mission provides concrete support to the Observatory’s team and helps to position the Tour du Valat as a leading institution on this issue, whose expertise can be drawn upon by its partners and other teams.
After several years of collaborative work, the national wetland mapping project in mainland France is reaching the end of its second phase. This project is led by PatriNat in partnership with the University of Rennes 2 and the Tour du Valat.
To mark the occasion, a feedback seminar was held on Thursday 26 March 2026 to share recent findings, methodological developments and prospects for using the data to support research and management policies. The proceedings of this seminar and the video recording are now available.
