The Managed Biological Reserve of Vire Vieille, Vignotte and Batejin covers 215 hectares on the east bank of the Lacanau lake. In particular, there is a swampy forest with its gently sloping dunes. The reserve sector is divided into five plots. “Islets” which belong to the State (ONF and Conservatoire du littoral) and to the General Council of the Gironde. In this area of large marshes, the primary objective is to preserve species and habitats considered remarkable and fragile. A space where specialists can also study this environment in peace. In order to communicate and make a small part of the area accessible to the general public, a pedestrian and educational path has been set up: The Berle trail. If this sector has been classified as a biological reserve, “it is because it is part of a humid back-dune system unique in Europe”.