IMPROVING THE MANAGEMENT OF THE SALTMARSHES OF HYERES (PROVENCE, FRANCE) USING AN ECOSYSTEM-BASED APPROACH

The management of saltmarshes, the complex ecosystem constituted by coastal wetlands and lagoons (SME - Saltmarsh Ecosystem), is often centered on the so-called 'heritage species' (rare, threatened and charismatic species). This 'species-centered' or 'taxon-centered' approach, a legacy from the 20th century, is fully understandable in areas where definitely and critically endangered species occur. However, an ecosystem-based approach, of course including species and higher taxa, but based upon the whole functioning of the ecosystem, from primary producers to e.g., detritus feeders and top predators, would present advantages of paramount importance. The ecosystem-based approach (EBA) involves the management of the interactions between functional compartments, and the search for equilibrium according to the supposed baseline, ecosystem services and management goals. This approach offers a basis for considering the current global change. A conceptual model of the whole saltmarsh ecosystem, including lagoon bottom, water body and terrestrial adjacent habitats, has been established. Taking into account the high diversity of saltmarsh environments physically and biologically as well, this model is a frame that should be adapted to each case study. Here, the authors focus on two case studies in Provence (Vieux Salins and Salin des Pesquiers), northwestern Mediterranean. The weaknesses of the traditional species-centered approach and the advantages of an ecosystem-based approach are highlighted through novel applications.