Research

INTRODUCTION

River deltas are one of the most resource-rich and dynamic ecosystems in the world and thus provide diversified bundles of ecosystem services (ES; Millennium Ecosystem Assessment 2005). These characteristics make deltas attractive to human activities, with nearly 500 million people inhabiting the world’s 40 largest deltas (Arto et al. 2019). However, these regions are vulnerable to global changes (e.g., climate change, rising energy prices, agroecological transition), especially due to their low elevation, proximity to the sea, and decreasing sediment loads in rivers; consequently, deltas are sensitive to sea level rise, subsidence, coastal erosion, and river and marine flooding (Milliman et al. 1989, Ericson et al. 2006, De Souza et al. 2015, Dang et al. 2018, Arto et al. 2019, Eslami et al. 2021). Changes in precipitation and temperature influence their hydro-saline dynamics, which can influence ecological dynamics and human activities such as agriculture or fishing (Herbert et al. 2015). In turn, changes in human activities, especially agriculture or water management, can influence the biodiversity and ES of deltas (Syvitski 2008, Syvitski et al. 2009).

Due to the complex relationships between ecological processes and human activities, deltas have been conceptualized and studied as social-ecological systems (SES; McGinnis and Ostrom 2014). For example, studies of deltas have investigated human-environment interactions related to hydraulic engineering (van Staveren and van Tatenhove 2016), the resilience of delta SESs to human activities and the role of science and governance (Norgaard et al. 2009), crisis prevention, and adaptation to climate change (Garschagen 2010), and the influence of urbanization and strategies to address physical processes that threaten system equilibrium (Redeker and Kantoush 2014). However, these studies focused on specific social-ecological issues without considering interactions, feedback loops, and side effects within and between networks of human activities and biodiversity that influence the current and future sustainability and resilience of deltas. For the environmental dimension, most studies focused on provisioning ES (e.g., shrimp farming, fishing; Hossain et al. 2020), while ignoring regulating or cultural services and the intrinsic and heritage value of biodiversity. In this context, developing integrated models to represent and study these SESs seems appropriate to describe the interactions, feedback loops, and side effects related to human activities, biodiversity, and ES (Fulton et al. 2015, Hamilton et al. 2015, Mijic et al. 2024).

The Rhône River delta (southern France) is a Mediterranean major agricultural area that produces large amounts of cereals. In this area, farming activities and biodiversity are closely connected (Mathevet 2004), with a mosaic of natural habitats (ca. 68% of the area consists of lagoons, marshes, salt steppes, meadows, and woodlands) and agricultural habitats (ca. 25% of the area consists of cereal crops, vineyards, market gardening, and extensive horse and bull farms). The main crop rotations are based on rice (Mouret 1988, Chataigner and Mouret 1997, Mouret and Leclerc 2018), which influences freshwater inflow into the delta through irrigation from the Rhône (20–22,000 m³ per ha of rice; Heurteaux 1996). The diversity of natural and agricultural habitats, spatially arranged along strong hydro-saline gradients, makes the Rhône delta a biodiversity hotspot in France, in both the number of species and their heritage value (Galewski and Devictor 2016).

Recently, new external drivers have intensified in the region, especially those related to climate change (PECHAC 2022). In particular, increasing salinization of soils and the central coastal lagoon, in conjunction with larger water deficits, are poised to increase social conflicts related to water management (PECHAC 2022).

For several decades, complex issues related to hydro-saline dynamics have resulted in major conflicts over water management in the delta, which the current system of water governance is unable to resolve (Dervieux 2005, Jalbert 2023). Due to the increase in new and challenging issues related to adaptations to global changes, decision makers have called for more integrated approaches to SES to design sustainable management strategies (Cinotti et al. 2023).

Integrated assessment and modeling (IAM) is one way to integrate and make understandable diverse knowledge, data, methods, and perspectives in a holistic framework to address complex SES (Hamilton et al. 2015). IAM is based on the development of a modeling platform to explore interactions and feedback among social, economic, and ecological entities of a system. IAM has been developed for and applied to several regions and has been used widely at the interface between climate science and policy (van Beek et al. 2020), such as for the Rhine river delta in the Netherlands, for which it enabled a political analysis of water-management issues (Haasnoot et al. 2012). By drawing on transdisciplinary analyses, IAM can overcome the limits of disciplinary fields and focused studies.

Regarding the Rhône delta, a number of modeling tools have been developed in previous studies. For example, hydrodynamic and hydrological models have been used to better understand the management of its lagoons (Boutron et al. 2015, 2011, Loubet 2012), to predict dynamics of its reedbeds and waterbirds in response to water management (Lefebvre et al. 2018), and to predict the risk of coastal flooding (Paris et al. 2017). Agent-based and cognitive representations have focused on different entities of the delta: water management (Espinasse and Franchesquin 2005); agricultural systems (Delmotte et al. 2013); interactions among duck populations, farm decisions, and leasing of hunting rights (Mathevet et al. 2003a); as well as the use of reedbeds (Mathevet et al. 2003b). In addition, Niang et al. (2016) and Mallet et al. (2022a and b) developed models to explore relationships among agroecological infrastructure, farming practices, and farmland biodiversity. These models considered a narrow range of social and ecological entities and processes, and only a few considered the main human activities and biodiversity issues in the Rhône delta (Niang et al. 2016).

Here, we integrated generic and local knowledge into a conceptual integrated model of the SES of the Ile de Camargue, the central part of the Rhône delta. This conceptual representation aimed at overcoming the limits of previous focalized studies by providing an integrated representation of the main human activities in the Ile de Camargue and their relationships with biodiversity and ecological processes. The resulting conceptual representation takes the shape of entity-oriented interaction diagrams corresponding to non-equivalent views about the set of relevant entities and processes to be considered to describe the SES. We used this conceptual modeling approach to identify and highlight the main causal chains, feedback loops, side effects, and trade-offs among social and ecological subsystems that need to be considered for sustainable management of this SES. This integrated representation was intended to support the development of an IAM platform for local stakeholders to be used to explore the effect of management strategies on sustainability and resilience of the Ile de Camargue SES in the context of climatic and internal and external socioeconomic drivers.

METHODS

Study area: the Ile de Camargue

The Ile de Camargue lies in the center of the Rhône delta between the two arms of the Rhône River (i.e., Petit and Grand) and covers nearly 800 km² (Fig. 1). To the north, south-west, and south-east lie the city of Arles (ca. 50,000 inhabitants) and the towns of Saintes-Marie-de-la-Mer (ca. 1900 inhabitants) and Salin-de-Giraud (ca. 1200 inhabitants), respectively. The delta’s elevation ranges from 3 m below to 4 m above sea level, and much of the delta lies below mean sea level. The delta has a Mediterranean climate and is home to a wide range of biodiversity and human activities (Appendix 1).

Conceptual modeling approach and model development

We used a stepwise method to integrate scientific and local stakeholder knowledge into the conceptual model. First, we used the ARDI (i.e., Actors, Resources, Dynamics, and Interactions) method (Etienne 2009, Etienne et al. 2011) to identify the main stakeholders, their management entities, the resources used, and the main processes that influence these resources. This step led to the development of a conceptual model of interactions among human activities, resources, and governance systems (Etienne et al. 2011). Even if this initial representation remained coarse and had a relatively high degree of ambiguity (Sibertin-Blanc et al. 2019), we used it for a first identification of the main actors, resources, and processes of the SES and the relationships between actors and resources.

Second, to develop a formal representation with finer detail and less ambiguity, we used the SES modeling method of Sibertin-Blanc et al. (2019), which provides a formal graphical grammar to develop entity-oriented models that describe the structure (i.e., entities and their relationships) and related social and ecological processes. Actors (i.e., agents with autonomy) and material or cognitive resources (i.e., passive objects) are entities of the system. Processes are events that are likely to happen and change the state of entities or the relationships between them. Processes are classified as human activities, ecological processes, or socioeconomic processes.

To ensure the traceability, ease of development, and reading of the representations, we developed four complementary entity-oriented models, each of which addressed one main issue in the SES: i) governance of water resources, ii) agriculture, iii) bird, and iv) fish communities. We chose these two communities because they comprise the most important taxa in the delta and are considered good ecological and socioeconomic indicators of habitat dynamics in the Camargue (Bouchard et al. 2022b, Galewski and Devictor 2016), with several bird and fish species receiving specific attention due to conservation concerns (e.g., Greater Flamingo, European eel). The Ramsar report and the IUCN Red List identified eight threatened fish species in the Camargue, including the European eel.

These different entity-oriented models provide non-equivalent points of view to be used in parallel in order to grasp an accessible integrated representation of the SES and associated sustainability issues. A final diagram was developed to synthesize and highlight the relationships between the four submodels, using common entities across submodels to connect them. To do so we identified relationships listed in Table 1 which involved entities common to several submodels. We then provide a verbal description of the links between submodels emerging from this assessment.

Data collection

Developing an integrated conceptual model of an SES requires collecting heterogeneous knowledge (Sibertin-Blanc et al. 2019). We first collected information available in the scientific literature, technical reports, and management plans of environmental organizations. We also attended stakeholder meetings related to water management, creation of an artificial wetland to purify water, and reorganization of hydraulic networks.

In addition, we interviewed stakeholders from i) SMGAS, an organization that brings together the associations in charge of irrigating and draining the Ile de Camargue; ii) Tour du Valat, a research institute for the conservation of Mediterranean wetlands based in the Camargue, with specific expertise in biodiversity conservation, wetland dynamics, and agricultural ecosystems; iii) the French Rice Centre, an organization that brings together individuals (including farmers) and legal entities who help develop, improve, and promote rice in the Ile de Camargue; iv) INRAE for the integrated assessment and modeling expertise. These four organizations represent a wide range of expertise, which provided a good initial representation of the Ile de Camargue. Based on the interviews and information collected, we developed an initial version of the four entity-oriented diagrams from November 2022 to June 2023.

Validation of the diagrams

A first version of each entity-oriented diagrams was presented for strengthening and validation to local stakeholders and experts with transversal expertise in the themes covered by the diagrams. We used the snowball sampling method, in which the first stakeholders/experts connected us to other, which enabled us to improve understanding of the system iteratively. It led us to review the diagrams during five interviews (1-2 hours each) from July-September 2023. The interviews were organized around a set of predetermined open-ended questions to facilitate discussion. During the interview, stakeholders and experts were asked to assess, correct, and improve the initial diagrams by discussing which entities and processes should be modified or added. These interviews enabled to clarify the level of precision and number of entities needed to describe the SES structure and functioning.

In addition, we interviewed researchers from i) Tour du Valat, with specific expertise in biodiversity conservation and on the diagram of bird and fish communities; ii) French Office for Biodiversity (OFB) on bird community; iii) National Centre for Scientific Research (CNRS) on water governance, agriculture, bird, and fish communities.

In January 2023, we also organized a 2-hour workshop with local stakeholders each from SMGAS, Tour du Valat, French Rice Center, Vaccarès resident associations, Camargue National Reserve, Regional Natural Park, Center for International Cooperation in Agricultural Research for Development (CIRAD), Chamber of Agriculture, OFB, and Arvalis (an agricultural technical institute). During the workshop, we presented the objectives and challenges of the modeling approach and the four diagrams. Participants were divided into four groups, and a member of the research team facilitated the workshop. Participants were encouraged to express themselves and write down on sticky notes their thoughts about the main water-management, biodiversity, and agriculture issues in the region. This process identified gaps in the representation of processes and stakeholders in the diagrams. We then reported on the discussions (Appendix 7) and integrated the new issues raised by the workshop participants into the diagrams. This step enabled us to more precisely identify the main processes between the four diagrams and the relationships at the SES level.

Identification of relationships

Based on interviews and the workshop held with the various experts, researchers and stakeholders (refer to previous section), we identified the key relationships in the conceptual model. For each relationship, tagged with a dedicated ID, we described the nature and number of entities involved in the relationship (n-ary, N being the number of entities in the relationship, rXX, XX being the ID’s number). We distinguished 5 types of relationships. As commonly proposed in SES analysis framework (Binder et al. 2013, Kelly et al. 2013, Rodriguez-Gonzalez et al. 2020, Lu et al. 2021, Mijic et al. 2024) we identified:

1. interaction: when two entities influence each other (hereafter coded as ↔, binary)
2. feedback loop: a causal chain in which entity A influences a chain of entities, which then influences A to amplify (positive feedback loop; +→←, n-ary) or dampen (negative feedback loop; -→←, n-ary) the process
3. trade-off: antagonism between two competing processes, i.e., an increase in one decreases the other, which may require a social compromise (↓↑, n-ary).

To go further we also decided to highlight (Qiu et al. 2018):

1. causal chain: a succession of impacts between several entities (→→, n-ary)
2. side effect: when implementing actions to meet specific objectives has an unexpected negative or positive impact on other entities (→², n-ary).

RESULTS

Due to the continuous diking of the Ile de Camargue (sea-dike in the south, and dikes along both arms of the Rhône; Fig. 2a), all surface-water flows between the Rhône, the sea, and the Ile de Camargue are managed, except during rare large floods that breach the dikes (e.g., 1993–1994).

Water-flow processes

Water flows to and from the Rhône River

Except for a few gravity-fed flows (Fig. 2a), most water flows between the Rhône and the Ile de Camargue are pumped (No.e1 and e2 in Fig. 3) to fill irrigation canals (No. e3) and empty drainage canals (No. e4; Appendix 2a). Water drained from agricultural land may contain pesticides and nitrogen leached from crop fields. In 2009, 90% of the pesticide active ingredients found in the Camargue’s lagoon and canal water were due to rice cultivation (Comoretto et al. 2007). Water analyses showed low pesticide contamination in irrigation canals, high contamination in drainage canals, and chronic contamination of marshes and lagoons by drainage water (SNPN 2020). Thus, local agricultural activities strongly influence water, pesticide, nitrogen, and salt flows into the Vaccarès Lagoon System through the drainage canals (No. e10 and e11 in Fig. 3). In addition, management of the Vaccarès hydraulic structures (No. e11, e12 and e13 in Fig. 3) can lead to high water levels which, together with the wind, causes salt water from the Vaccarès to migrate into the drainage canals, impacting their salinity (↔, binary, r1). Some outlets of the drainage (No. e17) and irrigation canals (No. e18) lie at the “former saltworks” (No. e14), another system of lagoons (De Wit et al. 2019). Water inflows depend on the management of each control sluice gate of these outlets.

Connections to the sea

As a dike separates the Vaccarès Lagoon System (No. e10) from the Mediterranean Sea (Fig. 2a), the two can exchange water directly only via the Impériaux lagoon (Fig. 2b), through hydraulic structures at La Fourcade (No. e12) and the Pertuis de la Comtesse (“Valve Tampan pond”, No. e13). The former saltworks consist of several lagoons, most of which are connected to each other and to the Vaccarès Lagoon System by hydraulic structures (Appendix 2b). As the former saltworks contain several natural connections to the sea (Figs. 2b and 3), under certain opening conditions of the internal sluices gates of the former saltworks and of the Valves of the Tampan pond (No. e13) , the Vaccarès Lagoon System can exchange indirectly water with the sea, which involves interactions between them (↔, binary, r2; Boutron et al. 2021).

When the sea level is high, such as during a storm, the Vaccarès Lagoon System can become directly connected to the sea if the Pertuis de la Comtesse (No. e12 Fig. 3) is opened, which influence the total salt mass of the lagoon system (→→, 4-nary, r3), which will drive its salinity.

Groundwater flows

The hydro-saline dynamics are influenced by whether the fields (No. e5) are flooded to grow rice (No. e6), as flooding a field limits saline upwelling in it by keeping the salt below the rice’s root zone (→→, 4-nary, r4; Appendix 2c). This flooding counteracts the Mediterranean precipitation regime (i.e., high in winter and low in summer), as it provides large volumes of water in summer (→→, ternary, r5; Torres-Rondon 2013). However, flooding can increase the salinity of surrounding non-submerged fields (→², ternary, r6; Fig. 3), as the higher water pressure in the rice fields can redirect the groundwater and its associated salt toward them (Torres-Rondon 2013). The same process occurs when marshes (No. e8) are flooded, but when water level is too low, salinity increases. When a high surface area around the Vaccarès Lagoon System (No. e10) is flooded, high water pressure blocks lateral inflow of groundwater from the Vaccarès lagoon (brackish water) into the surrounding area, and can even reverse it (→→, 4-nary, r7).

A complex structure and governance of water management

Irrigation and drainage

The canals and pumping stations are managed and maintained by private farmers (e.g., landowners near the banks of the Rhone) or farmer associations (e.g., land further inland; No. e24 in Fig. 3., Appendix 3a; Mathevet 2004). The ability to pump water is based on the type of crop, the location of the salt wedge in the Rhône, the price of irrigation water, and the cost of energy required to run the pumps (No. e26).

Management of the hydraulic infrastructures as well as farming practices have a major influence on water quality in natural habitats (→→, 7-nary, r8). Pumping is expensive due to the cost of energy (No. e26, Fig. 3) and pumping costs are higher in winter than in summer due to season-specific electricity prices. Little water is pumped by canal owners (No. e24; e.g., hydraulic association or farmer) from the Rhône when water levels are high in winter, so that when precipitation is low in winter, water levels in the marshes are also low (→→, 7-nary, r9).

Coastal lagoons

Several environmental protection organizations and institutions are involved in managing the lagoons (Appendix 3b). The Water Executive Commission (WEC, No. e28, Fig 3.) is an informal association of local stakeholders that coordinates and manages the valves of the Pertuis de la Fourcade (No. e12).

The WEC’s management practices aim to keep the total mass of dissolved salt below a certain threshold. Water levels are managed to i) prevent high water levels to avoid flooding of surrounding areas, erosion of lagoon banks, and salinization of surrounding fields, as well as to facilitate agricultural drainage, and ii) prevent low water levels (along with high salinity) to promote fishing in the lagoons. Another objective is to maintain levels of water and salinity typical of Mediterranean wetlands, particularly in response to precipitation and evaporation, as desired by environmental and local authorities. These objectives may not be met in certain years due to annual variability in precipitation and evaporation, which is common in the Mediterranean climate, as well as the shallow depths of the Vaccarès Lagoon System and the complexity of its hydro-saline functioning. This creates frequent tensions between stakeholders, which requires making compromises in the management of the hydraulic infrastructure (↓↑, 5-nary, r10). Arbitration is needed among the minimum water level that fishermen desire, the variations in water levels and salinity typical of a Mediterranean ecosystem that environmental authorities desire, and the maximum water level that local residents and farmers desire (↓↑, ternary, r11). Another compromise is between long-term and short-term objectives (↓↑, 4-nary, r12): promoting the inflow of seawater into the Vaccarès Lagoon System can decrease its salinity when evaporation is too high (i.e., salinity of the lagoons higher than that of the sea), but doing so over the long-term will increase the salt stock in the system (→², 4-nary, r13). Similar issues exist for the valves at the north of the Tampan pond (Fig. 2a and No. e13 in Fig.3), which are managed by the Camargue National Reserve (Appendix 3b).

Ponds and marshes in the catchment areas

Marshes in the catchment areas are managed to favor species of interest for hunting or conservation and restauration project and receive water from the canals managed by farmers and farmer associations (→→, 4-nary, r14).

The importance of agriculture

Rice cultivation is the main reason that large volumes of fresh water are pumped from the Rhône into the Camargue (Mouret 1988, Chataigner and Mouret 1997, Mouret and Leclerc 2018). In most areas, submerging rice fields (No. e6 Fig 3 and 4) decreases salinity enough for them to be cultivated (for other crops), as many fields experience increased salinity and require rice cultivation to maintain agricultural value (Mathevet 2004, Torres-Rondon 2013). Rice yields of conventional farms are influenced by a reduced set of authorized herbicides, which hampers weed management when rice is grown more than one year in a row. In organic farming, long and diversified rotations can mitigate detrimental effect of weed on yield, but the lack of higher-value markets for intermediate crops challenges the economic viability of this approach. Farmers must adapt their practices to the specific characteristics of their land, as some may not have transitioned completely to organic farming due to the salinity of the soil, which prevents long rotations with non-submerged crops. Longer rotations decrease water requirements, including water from irrigation, which in turn salinizes the fields. However, when the soil becomes saline, irrigation is needed to continue cultivating the field (+→←, 6-nary, r15). At lower elevations with highly hydromorphic or salinized soils, rice monoculture is the sole option to keep fields cultivated; consequently, organic rice can be produced only at higher elevations. Market gardening has developed mainly on higher land with lower salinity, which can withstand long periods of non-submerged crops without damage from increasing salinity (Migairou-Leprince 2021). Due to the large decrease in rice area (from 24,000 ha in 1994 to < 12,000 ha in 2021; CFR 2021), the salinity of the aquifer is predicted to increase exponentially if no major irrigation occurs in areas near the Vaccarès Lagoon System. This increase could render much of the land unsuitable for crops (→², 5-nary, r16; Torres-Rondon 2013).

Nitrogen and pesticides (No. e19) applied to rice fields can leach and spread. To limit the spread of pesticides, farmers wait 3–5 days after spraying them before submerging a field. Water drained from the rice fields into canals (No. e4) can transport pesticides into the Rhône or the lagoons. As these natural habitats are biodiversity hotspots, the impact of pesticides on biodiversity conservation can place economic activities related to certain species, such as hunting, fishing, and tourism, at risk. For example, pesticides are suspected to have caused the collapse of the seagrass (Zostera noltei) beds in the Vaccarès lagoon (→², 6-nary, r17; Espel et al. 2019). The current ban on certain herbicides makes it more difficult to grow rice several years in a row. However, non-submerged crops cannot grow on hydromorphic soils due to the salinity, and without technical solutions, fields that are too saline may be abandoned (→², 4-nary, r18).

One side effect comes from the decrease in rice subsidies, with an expectation of an improvement in the ecological state of the Vaccarès Lagoon System (outlet of drainage waters) together with an increased carrying capacity for water birds and fish. Yet, this decision increased open-field market gardening, which as a habitat, supports a lower carrying capacity of waterbirds than rice fields and uses larger amounts of pesticides, which in turn are drained into the Vaccarès Lagoon System (→², 5-nary, r19). Livestock farming (i.e., cattle, sheep, and horses, No. e7 in Fig. 4) are part of Camargue’s cultural identity and contribute to its appeal to tourists (Blondel et al. 2013; Appendix 4a). Mixed farmers, livestock farmers, and crop farmers interact frequently, especially regarding fodder crops to feed the herds (Balma 2023). Selling fodder makes it more profitable to diversify rotations and enables farmers to feed their animals locally (→→, 5-nary, r20).

Interconnected economic activities and impacts on biodiversity

Birds

Waterbirds are emblematic species of the Ile de Camargue and are a major cultural and tourist attraction (Appendix 5a, Fig. 5). Waterbirds staging and breeding relies directly on flooded areas, salinity and quality of water. Water management has, therefore, a large influence on the presence and abundance of certain species, depending on the quality and quantity of water, which influences food availability (→→, 21-nary, r21).

Water-management decisions of the WEC (No. e28 in Fig. 5) and the Camargue National Reserve influence water levels and salinity in the Vaccarès Lagoon System due to changes in connections with the drainage channels, the sea, and the former saltworks, via the sluices gates No. e11, e12 and e13. This ultimately influence habitat conditions for waterbirds (No. e22; →→, 9-nary, r22).

Four types of hunting (Appendix 5a; i.e., communal, private, commercial, and business) result in differing hunting density across the region, with the highest density for communal hunting (Mathevet 2004). Managers of the hunting marshes must adapt the periods of flooding of the marshes to favor species of interest during the hunting season (No. e23). Flooding decreases the dryness and salinity of the soil that increased during the summer, which promotes the growth of seagrass beds that ducks use for foraging (→→, 4-nary, r23; Tamisier and Grillas 1994). Managers of hunting estates set up a fee system to authorize hunters to hunt on their property. Most of the marshes are filled via drainage canals, but some are filled via irrigation canals. Fertilizers and pesticides in these canals have resulted in eutrophication of the marshes, less diverse seagrass beds, and the proliferation of certain invasive plant species (Vallecillo 2019). Due to the diversity of habitats and managers, marsh management varies across the Ile de Camargue, with certain marshes under strong hunting pressure, while others are managed as a protected area, particularly those belonging to environmental protection organizations. The strategies of local stakeholders depend on their economic activity. Some farmers who manage a marsh may grow more rice nearby to attract waterbirds for hunting or instead alternate fields between a marsh and rice, depending on the potential profit from rice cultivation and hunting. The agricultural activity of a hunting manager can thus influence marsh management choices and, conversely, the hunting activity of a farmer can influence crop rotations in these fields. (↔, binary, r24).

Birds can damage crops greatly. For example, from 2007–2009, Greater Flamingos damaged ca. 2.1% of the area of rice fields (Ernoul et al. 2014). Flamingos enter fields after the rice is sown in early May and remain until rice germinates in June (Mathevet et al. 2002). In winter, common cranes often enter fields of recently sown wheat. Birds can cause high economic losses locally, forcing farmers to resow all or some of the fields (Nilsson et al. 2016). Farmers use several strategies to decrease bird impacts, such as planting hedgerows as a visual barrier for waterbirds and to decrease flamingo incursions in fields (Tourenq et al. 2001; →→, 7-nary, r25). Hedgerows also provide an ecological corridor for species that live in agricultural areas. Bird-scaring practices are deployed through exemptions to the regulation that prohibits the disturbance of protected species. Crop rotations also influence bird incursions, particularly through alternating the presence of rice fields (→→, 6-nary, r26). For wheat fields, farming practices and the availability of rice stubble provide alternate foraging areas and decrease the risk of crane incursion (Tour du Valat, unpublished data). Conversely, decreasing the number of natural or hunting marshes could encourage more waterfowl to visit agricultural habitats such as rice fields, which could increase yield losses (→→, 4-nary, r27). Extensive livestock farming maintains opens areas such as meadows, which constitute key habitats for some bird species.

Birds may also provide regulating ES to farmers. Flooding harvested fields in winter makes weed seeds available to waterbirds, which can decrease weed abundance (-→←, 4-nary, r28). Before recent increases in energy costs, this practice was found to be economically viable, despite the cost of irrigation (Niang et al. 2016).

The presence of waterbirds, such as Greater Flamingos and common crane, influences ecotourism in the Camargue, which is a bird-watching hotspot. For some stakeholders, there is a trade-off between attracting certain bird species for tourism or hunting and the potential impact of these species on crop yields (↓↑, 4-nary, r29). Another major trade-off is the relationship among pesticide regulations, rice area, and natural habitat conditions (↓↑, 4-nary, r30). When the French government strengthened regulations to ban certain herbicides to improve water quality and bird habitats, the rice area decreased because without pesticides, rice cannot be grown as a monoculture (→→, 7-nary, r31). This decreased the water available for marshes, which degraded habitat conditions by decreasing water levels and water area and, during dry spells, increasing saline upwelling, contrary to the initial objective (→², 4-nary, r32).

Fish

The quality and quantity of water influence fish communities and seagrass (Zostera noltei) beds (Espel et al. 2019), which in turn influence these communities indirectly (→→, 12-nary, r33; Fig. 6). Common lagoon species can tolerate fluctuations in salinity, while freshwater species prefer low salinity (Poizat et al. 2004). Hydraulic infrastructure plays an important role, especially as it connects environments, which may or may not provide ecological continuity. For example, marine species depend on connections to the sea, and opening or closing sluice gates can prevent them from moving and migrating (Poizat et al. 2004). Migratory fish also reproduce and migrate from the lagoons to the sea through these sluice gates (i.e., Pertuis de la Fourcade and Pertuis de la Comtesse). Thus, water management strongly influences the fish community of the Ile de Camargue (Crivelli et al. 2008, Bouchard et al. 2022a, 2022b). The sluice gates are opened according to certain criteria, especially water quality (i.e., salinity and agricultural pollutants), water levels (in the lagoons and the sea so direction and rate of flow), and the presence of fish (at the entrance of the structure). Fishing and the desire to encourage fish migration through improved connectivity can influence water management directly and thus indirectly the transport of salt into the area (→², 5-nary, r34; Appendix 5b).

The Beauduc lagoon, southern part of the former saltworks (Fig. 2b) is frequently connected to the sea, with similar fish communities (Appendix 5b). In the rest of the former saltworks, sluice gates are used to connect lagoons, which makes ecological continuity more complex, and opening or closing the sluice gates influences habitat conditions for fish and their potential movement (→→, 4-nary, r35).

Relationships at the whole SES scale

Beyond the highlighted entities, processes, and relationships for each of the four investigated themes (Figs. 3, 4, 5, and 6), we can highlight links between these themes (Fig. 7). Agriculture determines hydro-saline dynamics on agricultural land, natural habitats in the catchments, and downstream lagoon systems (Fig. 2a). The area of rice and submerged fields influences the salinity in agricultural and natural habitats, and the use of pesticides influences soil fertility, crop area, agricultural profitability, habitat conditions, as well as bird and fish communities (Fig. 7: B, F, and I). Conversely, the submerged fields are a secondary habitat for birds, which forage in the fields, and influences yields (Fig. 7: A). Water governance influences agricultural practices via water and pumping prices, decisions about restrictions, or implementing certain types of management (e.g., increasing/decreasing drainage water discharge into the Vaccarès Lagoon System, not pumping when salinity of the Rhône is high; Fig. 7: E).

Environmental protection organizations aim at promoting natural hydrological cycles and improving water quality to protect fish (Fig.7: H). In addition, to promote waterbirds protection by improving the quality of their habitat and quantity of food, it is essential to improve water quality in the lagoons, marshes, and agricultural plots (Fig. 7: C). Water management in the lagoons and marshes directly influences habitat conditions for waterbirds (e.g., food; Fig. 7: D). A decrease in rice area decreases water levels in the lagoons, which generally implies an increase in salinity, which can cause problems for fish and could decrease connectivity between lagoons and thus weaken ecological corridors for fish (Fig. 7: I). Depending on the direction and rate of flow, opening sluice gates may not help fish reproduction and downstream migration (Fig. 7: G). Water level objectives for fishing may conflict with farmers' objectives for agricultural drainage and pesticides (Fig. 7: J).

Synthesis of entities, processes and relationships

Based on the methodology of Sibertin-Blanc et al. (2019), we identified 101 entities in our SES, including 20 actors, 50 material resources, and 31 cognitive resources. We also identified 165 processes including 62 activities, 103 ecological processes, and 51 connections of actors to cognitive resources they consider. Furthermore, we highlighted 35 key relationships including 17 causal chains, 3 interactions, 2 feedback loops, 5 trade-offs, and 8 side effects (Table 1).

DISCUSSION

The study integrated a large body of generic (literature) and local knowledge about the Ile de Camargue SES to develop a conceptual model that describes interdependencies among human activities, hydro-saline dynamics, ecological processes, and biodiversity. Our resulting conceptual model provides a simplified representation of the SES in which selected entities and processes were validated and selected by a range of researchers, experts, and local stakeholders. This approach produced a robust and salient integrated representation of the complexity that stakeholders have to deal with. For example, 29 of the 35 relationships identified involve more than 3 entities, thus highlighting the complexity of this system. To our knowledge, this is the first time diverse disciplines and stakeholder expertise of this region were used to develop a formal conceptual model. This formal representation of the Ile de Camargue can provide stakeholders with an integrated view of the structure and functioning of this complex system, particularly related to social-ecological relationships. It could aid decision-making given the multiple interactions and thus help develop management strategies that increase the sustainability and resilience of the Ile de Camargue.

Methodological issues

Our process of conceptual model development was based on a stepwise approach, first integrating coarsely a wide amount of heterogenous information (ARDI diagram) and then reducing model ambiguity and improving relevance throughout the process of formal modeling using the Sibertin-Blanc et al. (2019) conceptual approach. Compared to other conceptual modeling approaches, such as qualitative signed digraphs or fuzzy cognitive maps, our methodology describes relationships between entities but places less emphasis on the mathematical formalization of relationships between variables (e.g., community, adjoint, or adjacency matrices) and the modeling of ecological community dynamics (Dambacher et al. 2003). However, compared to more qualitative cognitive maps, such as ARDI, it requires a much higher degree of formalization. This increased formalization allows it to be directly implemented in numerical models, notably agent-based models (Sibertin et al. 2019). Nevertheless, this objective of formalization can lead to more complex representations, which may be harder for stakeholders to interpret than more qualitative, less computer-oriented approaches.

The hypothesis of working with two taxa to represent biodiversity could be questioned, and other relationships with other taxa might have been highlighted. Yet, we believe that these two taxa are strategic for most stakeholders because of their socioeconomic importance in this biodiversity hotspot.

Finally, our conceptual representation does not hamper further refinement. Political Ecology theories could for instance deepen our approach by enriching the interactions and broadening the scope of our analysis with wider social, historical, and political perspectives. In particular : i) Common Property Theory, would allow to include the potential collective management of the water resource (Kerr 2007), ii) Gender Studies may allow to identify the influence of gender in decision-making in the area, for instance in the WEC as done on other systems with different political and economic contexts (Najjar et al. 2023, Padmaja et al. 2020), while iii) Critical Environmental History would anchor the model in a historical and contextualized understanding of human-environment relations, taking into account inequalities and socio-ecological transformations (Biggs et al. 2009, Cole 2016). This would be particularly useful to complement the analysis of water, reed, and biodiversity issues with information on economic activities (Mathevet et al. 2015).

Social-ecological relationships in the Rhône delta

Our study identified the main causal chains, interactions, feedback loops, trade-offs, and side effects of the Ile de Camargue SES thus providing new insights compared to those of existing disciplinary or issue-oriented studies of the Ile de Camargue. The modeling approach highlighted strong interactions between water management by farmers as a function of agricultural system dynamics (e.g., submerged or non-submerged crops, grasslands) and water management in natural habitats (e.g., lagoons, marshes). This is particularly due to the influence of farmers and irrigation/drainage associations on flows of freshwater into the region, which influences, especially through hydro-saline dynamics, the habitat conditions of waterbirds and fish, and thus other economic activities (i.e., hunting, fishing, protecting natural habitats, and tourism).

Our study highlighted several key side effects. Whether they are negative or positive depends on the stakeholder’s value and objective through which they are analyzed. For example, the reduction of rice-growing areas leading to saline rises may be considered as negative by farmers or stakeholders associated with agriculture but may be considered as positive by others due to the possible transformation of these plots into more natural habitats (e.g., pastures or salt marshes).

Several of the identified trade-offs are related to water management in the Vaccarès Lagoon System, which results in social compromises between long- and short-term objectives and the quality and quantity of water that enters the system (i.e., water can contain either more pesticides or more salt). The conceptual model indicates that several causal chains are not considered when managing these trade-offs. The WEC focuses on managing the sluice gates of the Pertuis de la Fourcade based on lagoon water level, salinity, and salt mass, as well as sea level. These decisions thus do not consider i) water, pesticide, and salt exchanges among areas of the catchment due to management decisions made by farmers and irrigation/drainage associations or ii) water and salt exchanges with the former saltworks due to management decisions made by former saltwork managers who did not consider the water-management decisions made by the collective drainage association of the Japon (Fig. 2b), which has two canals that transport water and pesticides into the former saltworks. This calls into question the water-management associations that currently exist in the Camargue, especially the WEC, which manages the connection between the Vaccarès Lagoon System and the sea. In fact, the likely weakness of the WEC lies in the fact that it is not a forum for discussing the multiple water issues in the SES, which prevents it from considering at the right scale the multiple relationships among water, pesticide, and salt fluxes highlighted in this study. Such a forum, able to discuss the Integrated Management of the Camargue SES does not exist which appears as a key missing piece regarding governance in our case. Furthermore, there are many barriers to knowledge and data integration, and thus to integrated decision-making, such as commercial interests, privacy concerns, and general lack of trust among stakeholders (Meyer et al. 2020). For instance, fishing in the southern lagoons of the Vaccarès Lagoon System every year is a commercial stake with a significant influence on the decision-making of the WEC. The fishermen, members of the WEC, are calling for the management of the hydraulic structures to ensure fishing activity during the current year, even though this management presents a significant risk of salinization of the system in the medium term (Boutron 2020). Another example is the inadequate administrative and geographical criteria of Agri-environment schemes (AES) supporting the maintenance of hedges to reduce the risk of damage caused by Greater Flamingo incursions into agricultural fields, which leads to the solicitation by farmers of more lucrative AES for less integrated practices (Ernoul et al. 2014). Scepticism due to a lack of understanding is also a significant barrier to integrated decision-making in the Ile de Camargue, and has for instance been identified as hindering the ecological restoration of the former saltworks (Terrisse et al. 2025). Our study highlighted that several relationships related to the future increase of the salt wedge in the Rhône are not usually considered when discussing: i) medium- and long-term agricultural strategies; ii) projects to restore wetlands in the Ile de Camargue catchment, which depend on the quantity and salinity of water in agricultural canals; and iii) projects to develop hydraulic structures to provide more water from the Rhône by gravity to reduce the risks of salinization without the cost of pumping. Not considering these causal chains is a major problem, and could cause many of these projects to fail. In addition, there is currently a lack of trust between agricultural and environmental stakeholders of the Camargue due to historical conflicts and different priorities. Our approach offers a ready to use modeling tool to overcome this issue and develop an ecosystem-based management strategy that will strike a good balance between socioeconomic development and ecosystem conservation (Frazão Santos et al. 2021).

Such a change will need a greater emphasis on the effectiveness of governance and institutions and their transformative change (Kelly et al. 2019, Stephenson et al. 2019). The assessment of the integrated management of the Gladstone Harbour system in Australia illustrates how a bottom up arrangement involving stakeholders sharing a common vision and consolidated by a memory of understanding provided a successful response to an urgent crise (Stephenson et al. 2023). Such a broad partnership with common vision, and adequate funding in the medium term could allow to overcome the weakness of the limited scope of the WEC in the Camargue SES. This is particularly necessary in views of the tensions surrounding the continuation of several stakeholders activities and the lack of trust between them. Our conceptual model provides stakeholders with an integrated representation of the main relationships and accordingly, offers the opportunity to gain a more comprehensive and shared understanding of sustainability issues in the area. It could enable to rethink their present water discussion tool (WEC) for a more global water forum.

Towards potential quantitative developments

Our conceptual modeling approach that be used to study other deltas by considering processes, interactions, and feedbacks. Conceptual modeling of a variety of deltas, e.g., of the rivers Ebro (Spain), Danube (Romania and Ukraine), and Po (Italy), could help identify social-ecological characteristics, similarities, effective management strategies, and promote the sustainability and resilience of these complex systems. Exploring the relationships between human and environmental systems could also focus on ES and analyze system functioning. Stakeholders in the Camargue currently do not use the ES framework; thus, doing so could supplement the current analysis to consider ES better. This study’s formal representation of the Ile de Camargue is a starting point for developing an IAM platform (Sibertin-Blanc et al. 2019) that could be used to explore quantitatively the positive and negative impacts of management strategies and external changes (e.g., climate change, Hamilton et al. 2015). Simulating the dynamics of this delta could be used to assess the system's resilience to potential climate and socioeconomic hazards, such as changes in farming practices, based on this conceptual model, instead of developing more empirical method. This IAM platform could be adapted from existing models such as platform MAELIA (Modeling of socio-agro-ecological systems for Landscape Integrated Assessment), which is a multi-agent platform for modeling and assessing socio-agro-ecological systems to assess scenarios of agricultural activities, water management, and climate change (Therond et al. 2014, Tribouillois et al. 2022b, 2022a).

LITERATURE CITED

Arto, I., X. García-Muros, I. Cazcarro, M. González-Eguino, A. Markandya, and S. Hazra. 2019. The socioeconomic future of deltas in a changing environment. Science of Total Environnement. 648:1284-1296. https://doi.org/10.1016/j.scitotenv.2018.08.139

Balma, F. 2023. Interactions Culture-Elevage et développement de la riziculture biologique en Camargue. Mémoire d’ingénieur SAADS, option RESAD, L’Institut Agro Montpellier.

Béchet, A., C. Germain, A. Sandoz, G. J. M. Hirons, R. E. Green, J. G Walmsley, and A. R. Johnson. 2009. Assessment of the impacts of hydrological fluctuations and salt pans abandonment on Greater Flamingos in the Camargue, South of France. Biodiversity Conservation 18:1575-1588. https://doi.org/10.1007/s10531-008-9544-8

Béchet, A., and A. Johnson. 2008. Anthropogenic and environmental determinants of Greater Flamingo Phoenicopterus roseus breeding numbers and productivity in the Camargue (Rhone delta, southern France). Ibis 150(1):69-79. https://doi.org/10.1111/j.1474-919X.2007.00740.x

Béchet, A., M. Rendón-Martos, M. Á. Rendón, J. A. Amat, A. R. Johnson, and M. Gauthier-Clerc. 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):1-3. https://doi.org/10.1017/S0376892911000488

Biggs, D., F. Miller, and H. C. Thai. 2009. Making and unmaking the Mekong Delta: water management in historical and contemporary perspective. Pages 203-226 in Contested waterscapes in the Mekong Region hydropower, Livelihoods and Governance. London, UK.

Binder, C. R., J. Hinkel, P. W. G. Bots, and C. Pahl-Wostl. 2013. Comparison of Frameworks for Analyzing Social-ecological Systems. Ecology and Society 18(4):26. https://doi.org/10.5751/ES-05551-180426

Blondel, J., G. Barruol, and R. Vianet. 2013. L’encyclopédie de la Camargue. Buchet-Chastel, Paris.

Bouchard, C., O. Boutron, J. Lambremon, H. Drouineau, P. Lambert, and D. Nicolas. 2022a. Impacts of environmental conditions and management of sluice gates on glass eel migration. Estuarine, Coastal and Shelf Science. 279:108139. https://doi.org/10.1016/j.ecss.2022.108139

Bouchard, C., H. Drouineau, P. Lambert, O. Boutron, and D. Nicolas. 2022b. Spatio-temporal variations in glass eel recruitment at the entrance pathways of a Mediterranean delta. ICES Journal of Marine Science 79(6):1874-1887. https://doi.org/10.1093/icesjms/fsac122

Bouteyre, G., and C. Toni. 1972. Géomorphologie et étude des sols sodiques des plaines alluviales: Exemple de la Camargue. Science des Sols 232.

Boutron, O., 2020. Modélisation de scénarios de gestion prospectifs du Vaccarès. action CS14 du contrat de delta : “Suivi et amélioration de la qualité de l’eau du Vaccarès.”

Boutron, O., O. Bertrand, A. Fiandrino, P. Höhener, A. Sandoz, Y. Chérain, E. Coulet, and P. Chauvelon. 2015. An unstructured numerical model to study wind-driven circulation patterns in a managed coastal mediterranean wetland: the Vaccarès Lagoon system. Water 7(11):5986-6016. https://doi.org/10.3390/w7115986

Boutron, O., A. Loubet, A. Fiandrino, P. Höhener, A. Sandoz, Y Chérain, E. Coulet, and P. Chauvelon. 2011. Modeling of a managed coastal Mediterranean wetland with TELEMAC-2D: the Vaccarès lagoons system (Rhone delta, Camargue, France). Presented at the Proceedings of the XVIIIth Telemac & Mascaret User Club. Presented at the XVIIIth Telemac & Mascaret User Club, Chatou, France.

Boutron, O., C. Paugam, E. Luna-Laurent, P. Chauvelon, D. Sous, V. Rey, S. Meulé, Y. Chérain, A. Cheiron, and E. Migne. 2021. Hydro-saline dynamics of a shallow mediterranean coastal lagoon: complementary information from short and long term monitoring. Journal of Marine Science and Engineering 9(7):701. https://doi.org/10.3390/jmse9070701

Brochet, A. L., M. Gauthier-Clerc, R. Mathevet, A. Béchet, J. Y. Mondain-Monval, and A. Tamisier. 2009. Marsh management, reserve creation, hunting periods and carrying capacity for wintering ducks and coots. Biodiversity Conservation 18:1879-1894. https://doi.org/10.1007/s10531-008-9562-6

CFR. 2021. Bilan de la campagne.

Chataigner, J., and J. C. Mouret. 1997. Recherches et production rizicole en France. Cahiers Options Méditerranéennes n. 24(2).

Cinotti, B., B. Depresle, and C. Patier. 2023. L’adaptation de la Camargue au changement climatique.

Cole, C. 2016. From forest to delta: recent themes in South Asian environmental history. South Asian History and Culture 7(2): 208-219. https://doi.org/10.1080/19472498.2016.1143664

Comoretto, L., B. Arfib, and S. Chiron. 2007. Pesticides in the Rhône river delta (France): Basic data for a field-based exposure assessment. Science of the Total Environment 380(1-3):124-132. https://doi.org/10.1016/j.scitotenv.2006.11.046

Crivelli, A. J. 1981. Les peuplements de poissons de la Camargue. Revue D'Écologie 35:617-672. https://doi.org/10.3406/revec.1981.4130

Crivelli, A. J., N. Auphan, P. Chauvelon, A. Sandoz, J. Y. Menella, and G. Poizat. 2008. Glass eel recruitment, Anguilla anguilla (L.), in a Mediterranean lagoon assessed by a glass eel trap: factors explaining the catches. Hydrobiologia 602:79-86. https://doi.org/10.1007/s10750-008-9283-6

Dambacher, J. M., H. W. Li, and P. A. Rossignol. 2003. Qualitative predictions in model ecosystems. Ecological Modelling 161(1-2): 79-93. https://doi.org/10.1016/S0304-3800(02)00295-8

Dang, T. D., T. A. Cochrane, M. E. Arias, and V. P. D. Tri. 2018. Future hydrological alterations in the Mekong Delta under the impact of water resources development, land subsidence and sea level rise. Journal of Hydrology Regional Studies 15:119-133. https://doi.org/10.1016/j.ejrh.2017.12.002

Davranche, A., C. Arzel, P. Pouzet, A. R. Carrasco, G. Lefebvre, D. Lague, M. Thibault, A. Newton, C. Fleurant, M. Maanan, and B. Poulin. 2024. A multi-sensor approach to monitor the ongoing restoration of edaphic conditions for salt marsh species facing sea level rise: An adaptive management case study in Camargue, France. Science of the Total Environment 908:168289. https://doi.org/10.1016/j.scitotenv.2023.168289

De Souza, K., E. Kituyi, B. Harvey, M. Leone, K. S. Murali, and J. D. Ford. 2015. Vulnerability to climate change in three hot spots in Africa and Asia: key issues for policy-relevant adaptation and resilience-building research. Regional Environmental Change 15:747-753. https://doi.org/10.1007/s10113-015-0755-8

De Wit, R., A. Vincent, L. Foulc, M. Klesczewski, O. Scher, C. Loste, M. Thibault, B. Poulin, L. Ernoul, and O. Boutron. 2019. Seventy-year chronology of Salinas in southern France: Coastal surfaces managed for salt production and conservation issues for abandoned sites. Journal for Nature Conservation 49:95-107. https://doi.org/10.1016/j.jnc.2019.03.003

Delmotte, S., S. Lopez-Ridaura, J. M. Barbier, and J. Wery. 2013. Prospective and participatory integrated assessment of agricultural systems from farm to regional scales: Comparison of three modeling approaches. Journal of Environmental Management 129:493-502. https://doi.org/10.1016/j.jenvman.2013.08.001

Dervieux, A. 2005. La difficile gestion globale de l’eau en Camargue (France): le Contrat de delta. VertigO - la revue électronique en science de l'environnement https://doi.org/10.4000/vertigo.2411

Ericson, J.P., C. J. Vörösmarty, S. L. Dingman, L. G. Ward, and M. Meybeck. 2006. Effective sea-level rise and deltas: Causes of change and human dimension implications. Global and Planetary Change 50(1-2):63-82. https://doi.org/10.1016/j.gloplacha.2005.07.004

Ernoul, L., F. Mesléard, P. Gaubert, and A. Béchet. 2014. Limits to agri-environmental schemes uptake to mitigate human-wildlife conflict: lessons learned from Flamingos in the Camargue, southern France. International Journal of Agricultural Sustainability 12(1):23-36. https://doi.org/10.1080/14735903.2013.798897

Eslami, S., P. Hoekstra, P. S. J. Minderhoud, N. N. Trung, J. M. Hoch, E. H. Sutanudjaja, D. D. Dung, T. Q. Tho, H. E. Voepel, M. N. Woillez, and M. van der Vegt. 2021. Projections of salt intrusion in a mega-delta under climatic and anthropogenic stressors. Communications Earth & Environment 2:1-11. https://doi.org/10.1038/s43247-021-00208-5

Espel, D., N. J. Diepens, O. Boutron, E. Buffan-Dubau, Y. Chérain, E. Coulet, P. Grillas, A. Probst, J. Silvestre, and A. Elger. 2019. Dynamics of the seagrass Zostera noltei in a shallow Mediterranean lagoon exposed to chemical contamination and other stressors. Estuarine, Coastal and Shelf Science 222:1-12. https://doi.org/10.1016/j.ecss.2019.03.019

Espinasse, B., and N. Franchesquin. 2005. Multiagent modeling and simulation of hydraulic management of the Camargue. Simulation 81(3):201-221. https://doi.org/10.1177/0037549705053171

Etienne, M. 2009. Co-construction d’un modèle d’accompagnement selon la méthode ARDI: guide méthodologique 77.

Etienne, M., D. R. Du Toit, and S. Pollard. 2011. ARDI: A Co-construction Method for Participatory Modeling in Natural Resources Management. Ecology and Society 16(1):44. https://doi.org/10.5751/ES-03748-160144

Frazão Santos, C., T. Agardy, F. Andrade, L. B. Crowder, C. N. Ehler, M. K. Orbach. 2021. Major challenges in developing marine spatial planning. Marine Policy 132:103248. https://doi.org/10.1016/j.marpol.2018.08.032

Fulton, E. A., F. Boschetti, M. Sporcic, T. Jones, L. R. Little, J. M. Dambacher, R. Gray, R. Scott, and R. Gorton. 2015. A multi-model approach to engaging stakeholder and modellers in complex environmental problems. Environmental Science and Policy 48:44-56. https://doi.org/10.1016/j.envsci.2014.12.006

Galewski, T., and V. Devictor. 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(11)e0165542. https://doi.org/10.1371/journal.pone.0165542

Garschagen, M. 2010. Crises prevention and climate change adaptation in the coupled social-ecological systems of the Mekong delta, Vietnam: the need for rethinking concepts and policies. X. Shen, T. E. Downing, M. Hamza, editors. Tipping points in humanitarian crisis: from hot spots to hot systems, 45-55. Institute for Environment and Human Security, Bonn, Germany.

Haasnoot, M., W. Van Deursen, H. Middlekoop, E. van Beek, and N. Wijermans. 2012. An Integrated Assessment Metamodel for Developing Adaptation Pathways for Sustainable Water Management in the Lower Rhine Delta. International Congress on Environmental Modelling Software 61.

Hamilton, S. H., S. ElSawah, J. H. A. Guillaume, A. J. Jakeman, and S. A. Pierce. 2015. Integrated assessment and modelling: Overview and synthesis of salient dimensions. Environmental Modelling and Software 64:215-229. https://doi.org/10.1016/j.envsoft.2014.12.005

Herbert, E.R., P. Boon, A. J. Burgin, S. C. Neubauer, R. B. Franklin, M. Ardón, K. N. Hopfensperger, L. P. M. Lamers, and P. Gell. 2015. A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands. Ecosphere 6(10):206. https://doi.org/10.1890/ES14-00534.1

Heurteaux, P. 1996. L’eau et la riziculture en Camargue. Pages in L’irrigation et Le Drainage: Pourquoi, Comment.

Hossain, M. S., J. Ramirez, S. Szabo, F. Eigenbrod, F. A. Johnson, C. I. Speranza, and J. A. Dearing. 2020. Participatory modelling for conceptualizing social-ecological system dynamics in the Bangladesh delta. Regional Environmental Change 20:28. https://doi.org/10.1007/s10113-020-01599-5

Ibaňez, C., D. Pont, and N. Prat. 1997. Characterization of the Ebre and Rhone estuaries: A basis for defining and classifying salt-wedge estuaries. Limnology and Oceanography 42(1):89-101. https://doi.org/10.4319/lo.1997.42.1.0089

Jalbert, J. 2023. La Camargue, un delta face au défi climatique. Annales Mines - Responsabilité Environmentale 112: 104-107. https://doi.org/10.3917/re1.112.0104

Johnson, A., and F. Cézilly. 2009. The Greater Flamingo, 1st ed. T & AD Poyser.

Kayser, Y., M. Gauthier-Clerc, A. Bechet, B. Poulin, G. Massez, Y. Cherain, J. Paoli, N. Sadoul, E. Vialet, G. Paulus, N. Vincent-Martin, P. Pilard, and P. Isenmann. 2008. Compte rendu ornithologique camarguais pour les années 2001-2006. Revue D'Écologie 63:299-349. https://doi.org/10.3406/revec.2008.6617

Kelly, C., G. Ellis, and W. Flannery. 2019. Unravelling persistent problems to transformative marine governance. Frontiers in Marine Science 6. https://doi.org/10.3389/fmars.2019.00213

Kelly, R. A., A. J. Jakeman, O. Barreteau, M. E. Borsuk, S. ElSawah, S. H. Hamilton, H. J. Henriksen, S. Kuikka, H. R. Maier, A. E. Rizzoli, H. Van Delden, and A. A. Voinov. 2013. Selecting among five common modelling approaches for integrated environmental assessment and management. Environmental Modelling and Software 47:159-181. https://doi.org/10.1016/j.envsoft.2013.05.005

Kerr, J. 2007. Watershed management: lessons from common property theory. International Journal of the Commons I, 89-109. https://doi.org/10.18352/ijc.8

Lefebvre, G., C. Germain, and B. Poulin. 2018. Mar-O-Sel v.3 : Un outil interactif pour promouvoir une gestion raisonnée des marais méditerranéens sous des conditions climatiques actuelles ou futures.

Levasseur, L., and E. Doutriaux. 1992. Le coin salé du Grand Rhône et les travaux de creusement du seuil de Terrin. Journée de l'Hydraulique 22:1-9.

Loubet, A. 2012. Modélisation de l’hydrosystème Vaccarès : contribution à une gestion adaptative des ressources en eau dans le delta du Rhône, France (These de doctorat). Aix-Marseille.

Lu, N., L. Liu, D. Yu, and B. Fu. 2021. Navigating trade-offs in the social-ecological systems. Current Opinion in Environmental Sustainability 48:77-84. https://doi.org/10.1016/j.cosust.2020.10.014

Mallet, P. 2022a. Rôle des infrastructures et des pratiques agroécologiques pour la conservation de la biodiversité dans les systèmes de grandes cultures en Camargue. Avignon.

Mallet, P., A. Béchet, T. Galewski, F. Mesléard, S. Hilaire, G. Lefebvre, B. Poulin, and C. Sirami. 2022b. Different components of landscape complexity are necessary to preserve multiple taxonomic groups in intensively-managed rice paddy landscapes. Agriculture Ecosystems and Environment 328:107864. https://doi.org/10.1016/j.agee.2022.107864

Mathevet, R. 2004. Camargue incertaine. Sciences, usages et natures. Buchet Chastel, Ecologie, Paris.

Mathevet, R., F. Bousquet, C. Le Page, and M. Antona. 2003a. Agent-based simulations of interactions between duck population, farming decisions and leasing of hunting rights in the Camargue (Southern France). Ecological Modelling 165(2-3):107-126. https://doi.org/10.1016/S0304-3800(03)00098-X

Mathevet, R., A. Mauchamp, R. Lifran, B. Poulin, and G. Lefebvre. 2003b. Interactions territoriales, dynamique des usages et de la biodiversité dans les zones humides du delta du Rhône: une approche par la modélisation multi-agents (Territorial interactions, uses and biodiversity dynamics within the wetlands of Rhone river delta: a multi agent modelling approach). Bulletin de l'Association de Géographes Français 80:417-429. https://doi.org/10.3406/bagf.2003.2353

Mathevet, R., N. L. Peluso, A. Couespel, and P. Robbins. 2015. Using historical political ecology to understand the present: water, reeds, and biodiversity in the Camargue Biosphere Reserve, southern France. Ecology and Society 20(4):17. https://doi.org/10.5751/ES-07787-200417

Mathevet, R., C. Tourenq, and F. Mesléard. 2002. Agricultural policies, land-use and waterbird conservation: the case study of a major Mediterranean wetland, the Camargue. Cybergeo European Journal of Geography. https://doi.org/10.4000/cybergeo.3755

McGinnis, M. D., and E. Ostrom. 2014. Social-ecological system framework: initial changes and continuing challenges. Ecology and Society 19(2):30. https://doi.org/10.5751/ES-06387-190230

Meyer, A., M. Bannister-Tyrrell, C. Mackenzie, A. Stegeman, and A. Cameron. 2020. Barriers to the adoption of a fish health data integration initiative in the Chilean salmonid production. Computers and Electronics in Agriculture 179:105853. https://doi.org/10.1016/j.compag.2020.105853

Migairou-Leprince, J. 2021. Diversification des exploitations agricoles et conditions d‘émergence de l’agroécologie en Camargue. Méthode du diagnostic agraire de la chaire d’agriculture comparée d’AgroParisTech (Mémoire). AgroParisTech, Paris (FRA).

Mijic, A., L. Liu, J. O’Keeffe, B. Dobson, and K. P. Chun. 2024. A meta-model of socio-hydrological phenomena for sustainable water management. Nature Sustainability 7:7-14. https://doi.org/10.1038/s41893-023-01240-3

Millennium Ecosystem Assessment. 2005. Ecosystems and human well-being: wetlands and water synthesis: a report of the Millennium Ecosystem Assessment. World Resources Institute, Washington, DC, USA.

Milliman, J. D., J. M. Broadus, and F. Gable. 1989. Environmental and Economic Implications of Rising Sea Level and Subsiding Deltas: The Nile and Bengal Examples. Ambio 18(6):340-345.

Mouret, J. C. 1988. Étude de l’agrosystème rizicole en Camargue dans ses relations avec le milieu et le système cultural : aspects particuliers de la fertilité (These de doctorat). Montpellier 2.

Mouret, J. C., and B. Leclerc. 2018. Le riz et la Camargue: vers des agroécosystèmes durables. Cardère Editeur Educagri, Paris.

Najjar, D., H. Nyantakyi-Frimpong, R. Devkota, and A. Bentaibi. 2023. A feminist political ecology of agricultural innovations in smallholder farming systems: Experiences from wheat production in Morocco and Uzbekistan. Geoforum 146:103865. https://doi.org/10.1016/j.geoforum.2023.103865

Niang, A., C. A. Pernollet, M. Gauthier-Clerc, and M. Guillemain. 2016. A cost-benefit analysis of rice field winter flooding for conservation purposes in Camargue, Southern France. Agriculture, Ecosystems & Environment 231:193-205. https://doi.org/10.1016/j.agee.2016.06.018

Nilsson, L., N. Bunnefeld, J. Persson, and J. Månsson. 2016. Large grazing birds and agriculture—predicting field use of common cranes and implications for crop damage prevention. Agriculture, Ecosystems & Environment 219:163-170. https://doi.org/10.1016/j.agee.2015.12.021

Norgaard, R. B., G. Kallis, M. Kiparsky. 2009. Collectively engaging complex socio-ecological systems: re-envisioning science, governance, and the California Delta. Environmental Science & Policy 12(6):644-652. https://doi.org/10.1016/j.envsci.2008.10.004

Padmaja, R., K. Kavitha, S. Pramanik, V. D. Duche, Y. U. Singh, A. M. Whitbread, R. Singh, K. K. Garg, and S. Leder. 2020. Gender transformative impacts from watershed interventions: insights from a mixed-methods study in the Bundelkhand Region of India. Trans. ASABE 63:153-163. https://doi.org/10.13031/trans.13568

Paris, F., R. Pedreros, A. Stépanian, T. Bulteau, and S. Lecacheux. 2017. Modélisation de la submersion marine en Camargue. Rapport final.

PECHAC. 2022. Le changement climatique et ses effets dans la Réserve de biosphère de Camargue. Etat des connaissances en 10 questions/réponses.

Poizat, G., P. Chauvelon, E. Rosecchi, A. J. Crivelli, P. Contournet. 1999. Passage de poissons du Rhône par les pompes d’irrigation de Camargue: premiers résultats. Bulletin Français de la Pêche et de la Pisciculture. 352:31-43. https://doi.org/10.1051/kmae:1999019

Poizat, G., E. Rosecchi, P. Chauvelon, P. Contournet, and A. J. Crivelli. 2004. Long-term fish and macro-crustacean community variation in a Mediterranean lagoon. Estuarine, Coastal and Shelf Science 59(4):615-624. https://doi.org/10.1016/j.ecss.2003.11.007

Qiu, J., E. T. Game, H. Tallis, L. P. Olander, L. Glew, J. S. Kagan, E. L. Kalies, D. Michanowicz, J. Phelan, S. Polasky, J. Reed, E. O. Sills, D. Urban, and S. K. Weaver. 2018. Evidence-based causal chains for linking health, development, and conservation actions. BioScience 68(3):182-193. https://doi.org/10.1093/biosci/bix167

Redeker, C., and S. Kantoush. 2014. The Nile Delta: urbanizing on diminishing resources. Built Environment 40(2):201-212. https://doi.org/10.2148/benv.40.2.201

Rodriguez-Gonzalez, P. T., R. Rico-Martinez, and V. Rico-Ramirez. 2020. Effect of feedback loops on the sustainability and resilience of human-ecosystems. Ecological Modelling 426:109018. https://doi.org/10.1016/j.ecolmodel.2020.109018

Sibertin-Blanc, C., O. Therond, C. Monteil, P. Mazzega. 2019. The entity-process framework for integrated agent-based modeling of social-ecological systems. Pages 57-86 in R. Boulet, C. Lajaunie, P. Mazzega, editors. Law, Public Policies and Complex Systems: Networks in Action, Law, Governance and Technology Series. Springer International Publishing. https://doi.org/10.1007/978-3-030-11506-7_4

SNPN. 2020. Rapport d’activité 2020. Société nationale de protection de la nature.

Stephenson, R. L., A. J. Hobday, I. Butler, T. Cannard, M. Cowlishaw, I. Cresswell, C. Cvitanovic, J. C. Day, K. Dobbs, L. X. C. Dutra, S. Frusher, M. Fudge, B. Fulton, B. M. Gillanders, N. Gollan, M. Haward, T. Hutton, A. Jordan, J. McDonald, C. Macleod, G. Pecl, E. E. Plaganyi, I. van Putten, J. Vince, and T. Ward. 2023. Integrating management of marine activities in Australia. Ocean and Coastal Management 234:106465. https://doi.org/10.1016/j.ocecoaman.2022.106465

Stephenson, R. L., A. J. Hobday, C. Cvitanovic, K. A. Alexander, G. A. Begg, R. H. Bustamante, P. K. Dunstan, S. Frusher, M. Fudge, E. A. Fulton, M. Haward, C. Macleod, J. McDonald, K. L. Nash, E. Ogier, G. Pecl, É. E. Plagányi, I. van Putten, T. Smith, and T. M. Ward. 2019. A practical framework for implementing and evaluating integrated management of marine activities. Ocean and Coastal Management 177:127-138. https://doi.org/10.1016/j.ocecoaman.2019.04.008

Syvitski, J. P. M. 2008. Deltas at risk. Sustainability Science 3:23-32. https://doi.org/10.1007/s11625-008-0043-3

Syvitski, J. P. M., A. J. Kettner, I. Overeem, E. W. H. Hutton, M. T. Hannon, G. R. Brakenridge, J. Day, C. Vörösmarty, Y. Saito, L. Giosan, and R. J. Nicholls. 2009. Sinking deltas due to human activities. Nature Geoscience 2:681-686. https://doi.org/10.1038/ngeo629

Tamisier, A., and P. Grillas. 1994. A review of habitat changes in the camargue: An assessment of the effects of the loss of biological diversity on the wintering waterfowl community. Biology Conservation 70(1):39-47. https://doi.org/10.1016/0006-3207(94)90297-6

Terrisse, A., M. Karner, J. Kaufmann, and L. Ernoul. 2025. Characterizing governance models for upscaling wetland restoration. Environmental Management 75:1155-1167. https://doi.org/10.1007/s00267-025-02132-2

Therond, O., C. Sibertin-Blanc, R. Lardy, B. Gaudou, M. Balestrat, Y. Hong, T. Louail, V. B. Nguyen, D. Panzoli, J. M. Sanchez-Pérez, S. Sauvage, P. Taillandier, M. Vavasseur, and P. Mazzega. 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.

Torres-Rondon, L. 2013. Etude et modélisation des transferts d’eau et de sel en milieu deltaïque agricole (Camargue-France). Université d’Avignon.

Tourenq, C., S. Aulagnier, L. Durieux, S. Lek, F. Mesléard, A. Johnson, and J. L. Martin. 2001. Identifying rice fields at risk from damage by the greater flamingo. Journal of Applied Ecology 38(1):170-179. https://doi.org/10.1046/j.1365-2664.2001.00581.x

Tribouillois, H., J. Constantin, L. Casal, J. Villerd, and O. Therond. 2022a. Introducing and expanding cover crops at the watershed scale: Impact on water flows. Agriculture, Ecosystems & Environment 337:108050. https://doi.org/10.1016/j.agee.2022.108050

Tribouillois, H., J. Constantin, C. Murgue, J. Villerd, and O. Therond. 2022b. Integrated modeling of crop and water management at the watershed scale: optimizing irrigation and modifying crop succession. European Journal of Agronomy 140:126592. https://doi.org/10.1016/j.eja.2022.126592

Ullmann, A., P. A. Pirazzoli, and A. Tomasin. 2007. Sea surges in Camargue: Trends over the 20th century. Continental Shelf Research 27(7):922-934. https://doi.org/10.1016/j.csr.2006.12.001

Vallecillo, D. 2019. Expériences de gestion cynégétique innovantes en Camargue: des pistes pour la chasse au gibier d’eau de demain. Faune Sauvage 323:33-39.

Vallecillo, D., M. Guillemain, C. Bouchard, S. Roques, and J. Champagnon. 2023. Influence of changes in local environmental variables on the distribution and abundance dynamics of wintering Teal Anas crecca. Biodiversity Conservation 32:4627-4649. https://doi.org/10.1007/s10531-023-02713-9

van Beek, L., M. Hajer, P. Pelzer, D. van Vuuren, and C. Cassen. 2020. Anticipating futures through models: the rise of Integrated Assessment Modelling in the climate science-policy interface since 1970. Global Environmental Change 65:102191. https://doi.org/10.1016/j.gloenvcha.2020.102191

van Staveren, M., and J. van Tatenhove. 2016. Hydraulic engineering in the social-ecological delta: understanding the interplay between social, ecological, and technological systems in the Dutch delta by means of “delta trajectories.” Ecology and Society 21(1):8. https://doi.org/10.5751/ES-08168-210108