STELLA staff coordinated the preparation of a complex and comprehensive study to evaluate the impact of the construction of a tourist resort (golf course, hotels, apartments) along the Atlantic Ocean and the dunes of the southwest coast of France. The study evaluated the impact on several rare plants and trees (royal osmund, common smilax, cork oak) and endangered species (otter, European mink, and genette). STELLA staff directed the preparation of a hydrogeological study to analyse the equilibrium between the salt and fresh water and evaluate the impact on the Lareuillot and Montagne du Bec wetlands. STELLA staff also estimated the impact on ecosystems within protected areas such as Etang Noir de Seignosse, Marais d'Orx, and Lac Noir d'Ondres. STELLA staff recommended and estimated the costs of various measures (during construction and operation of the resort) to mitigate or reduce the impacts.