A protected coastal lagoon on the Atlantic edge of the Marais poitevin, safeguarding one of the last natural marine lagoons in France.
Réserve naturelle nationale de la casse de la Belle-Henriette
The Réserve naturelle nationale de la casse de la Belle-Henriette is a French national nature reserve located on the Atlantic coast of Vendée, in the Pays de la Loire region. Established in 2011, it protects about 337 hectares of coastal lagoon, dunes, reedbeds, and salt-influenced wetlands on the seaward edge of the Marais poitevin. The reserve is significant because it preserves one of the last natural marine lagoons along the Atlantic coast of France, a habitat that has largely disappeared elsewhere due to coastal development and changes in sediment dynamics.
The protected area stretches roughly five kilometers in length along the coast and ranges from about 500 meters to one kilometer in width, straddling the communes of La Faute-sur-Mer and La Tranche-sur-Mer. Almost all of its surface (around 97 percent) lies on the maritime public domain, between sand spits, dune cordons, and shallow tidal waters. The reserve is administered by the Ligue pour la protection des oiseaux (LPO), making it one of the few national nature reserves in France primarily managed by a bird-conservation organization.
Ecologically, the site combines dune, beach, lagoon, reedbed, and saltmarsh habitats in an unusually compact area, supporting hundreds of plant and animal species. It is recognized as an important site for nesting, migratory, and wintering birds, and for rare coastal flora such as the Jersey pink (Œillet de France). The combination of natural coastal morphology, salinity gradients, and a relatively undeveloped shoreline gives the reserve a strong conservation identity within the Atlantic French coast.
