The Site is a representative example of the coastal lagoons/talus complex forming the salt marshes typical of the Atlantic seaboard. Its habitats are home to over 20,000 waterfowl in winter, making up over 1% of the Western Palearctic population for several species. The site exhibits an exceptional assemblage of flowering plants including numerous rare or protected species. The very high level of primary production, the highly diversified aquatic environments, and the greatly differing salinity levels give rise to rich algal and invertebrate communities which in turn support the bird species present. The Site is important for numerous species of nesting, feeding, resting and wintering migratory birds and waders, and hosts almost 10% of the French Atlantic population of breeding pied avocet (Recurvirostra avosetta) and 7% of the global population of black-tailed godwit (Limosa limosa). The area has a remarkable ethnological and sociological history. Human activities include salt production, hunting, fish farming and shellfish hatcheries. The rise of tourism in the area might affect the conservation of the Site.