Modeling the functioning of the delta provides insights into integrated management approaches that reconcile agriculture with ecosystem conservation - CAMARGUE

Rose Rodier defended her doctoral thesis on March 31th, 2026. 

The Camargue (Rhône delta) is a complex social-ecosystem with important issues regarding biodiversity conservation and economic and cultural activities. In a context of global change, anthropogenic (water management in agricultural and natural areas, agricultural practices) and climatic (rainfall, evapotranspiration) drivers affect the hydro-saline balance. This hydro-saline functioning is a central element in the dynamics of the Camargue's habitats and species, and the associated networks of activities and services.

Summary

The Camargue, the Rhône Delta, constitutes a particularly complex social-ecosystem (SES), characterized by a strong interdependence between natural environments and human activities. This region, a biodiversity hotspot and home to major economic, agricultural, and cultural interests, is now facing the combined effects of climate change and shifts in water management and agricultural practices. Changes in rainfall and evaporation patterns, soil salinization, sea-level rise, and land use profoundly affect the hydro-saline balance, which is the cornerstone of the delta’s ecological functioning.
In this context, we have developed a conceptual model of the Ile de Camargue (located in the center of the Rhône Delta), within which hydro-saline dynamics, water management, economic activities (agriculture, hunting, fishing, tourism), and natural habitats interact. This model is based on four sub-models providing complementary representations of: i) water governance, ii) agriculture, iii) bird communities, and iv) fish communities. This conceptual framework highlights the relationships (causal chains, feedback loops, interactions, indirect effects, and trade-offs) between the various components of this deltaic SES.

Based on the knowledge we have gained about this delta, we have developed an integrated model called MAELIA-Delta. This model is an extension of the MAELIA platform, adapted for the simulation of hydro-saline dynamics and agricultural practices.

Then we developed several scenarios of climate change and of agricultural practices transition (crop diversification, development of agroecology, changes in rice-growing areas, etc.) to evaluate and demonstrate the model’s ability to simulate the processes at play on the Ile de Camargue.

In conclusion, this thesis highlights the central role of water management in balancing agricultural activities, soil salinization, and the preservation of natural habitats in the Camargue, and provides knowledge that stakeholders can use to design a more integrated management approach for the delta, that aims at reconciling agriculture and ecosystem conservation. In the medium term, the developed model can be applied to other deltas to assess the effects of climate change or agricultural transitions, and could be enhanced to better represent the interactions between hydrological networks, natural habitats, and biodiversity