Serving as a transitional area between land and sea, the Ria Formosa is a vast lagoon system that stretches for 60 km along the coast of the eastern Algarve. It covers an area of approximately 18,000 hectares. It is the most important wetland zone in southern Portugal and features a wide variety of habitats: barrier islands, marshes, sandbanks, dunes, saltpans, freshwater and brackish lakes, water courses, scrubland and farmland; all of which is also propitious to a tremendous variety of fauna and flora. Classed as a wetland zone of international interest, the Ria Formosa is particularly noted for its birdlife. The area is a winter home for birds from north and central Europe, as well as being on migration routes. From a botanical point of view, the particular highlight is the vegetation on the dunes and in the marshes. A true nursery for marine species, it is also an area where bivalve molluscs are produced.