Flux et usages de l'eau de mer dans les marais salés endigués Charentais : Cas du marais salé endigué de l'île de Ré

The aim of the study is to determine how seawater is used in Ré island marine ponds (Charente-Maritime, France). Thus, we assessed the ecosystem functioning, estimated its historical evolution and determined the most suitable ways to improve current management processes. The knowledge of seawater management is essential to ensure wetland future and meet the numerous interests of wetland stakeholders, especially in term of seawater sharing. Consequently, it is necessary to consider the Ré island marine embanked wetland through its natural as well as human characteristics. Our work followed two research axes. First, a survey and a description of wetland activities were realized through their management types and their water use features, knowing that human practices are various and their characteristics (technics, economics, hydraulics) are not sufficiently known. Then, we considered relationships between this ecosystem and humans. In order to highlight the spatial activities diversity, hydraulic particularities and potential problems, our method is mainly based on GIS, investigations and risks analysis. Results demonstrate that Ré island marine embanked wetland is dominated by a mosaic of activities, established according to various spatial and management logics. We concluded that there are no real conflicts among wetland stakeholders, only few divergences about the current seawater management. Only a wise management could allow to preserve the natural and cultural inheritance while protecting the interests of each actor.