Water-level management in wet grasslands for cattle grazing and amphibian conservation on the French Atlantic coast

A Nature Restoration Regulation was adopted by the European Union in 2024. Like all the Member States, France must translate this regulation into a national action plan to define how biodiversity loss can be halted and 20% of degraded ecosystems revitalised by 2030. As researchers have been called upon to explore operational responses to support this restoration, this article reports on a two-year experiment (2024–2025) conducted on a research farm located in the marshes of the French Atlantic coast. It illustrates how we addressed the challenge of translating the principles of adaptive management into an action-oriented approach. We hypothesised that this strategy would enable hydraulic management to reconcile two potentially antagonistic objectives: restoring wet conditions on a natural grassland to support biodiversity (here, an amphibian, the parsley frog), while maintaining productive use of the same field for a cattle herd. We collectively built the action logic of the project, in the form of a dashboard, with expected results and planned monitoring. We show that managing water levels in ditches so that they remained about ten centimetres higher than a standard way, during key seasons (winter and spring) created favourable conditions for hosting the parsley frog on the grassland, while also ensuring sufficient forage value for cattle, staggered over the summer period. We discuss the implications of this experiment for the coming years, particularly regarding how the approach could be scaled up to an entire hydraulic compartment within a more complex multi-stakeholder water governance system.