Lac de Grand-Lieu. 01/02/95; Pays de la Loire; 6,300 ha; 47°05'N 001°40'W. Nature Reserve. The site's area fluctuates depending on climatic conditions. A shallow lake, dominated by macrophytic vegetation and three large floating forests and exhibiting features of a tropical wetland. Shaped by tectonic movements some 120 million years ago, the lake was well preserved until the 1960s, when the hydrologic regime was radically altered by large-scale human intervention. Coupled with agricultural pollution and urban effluent, these disturbances caused severe nutrient-enrichment. Over 200 species of birds, including 110 nesting species, and internationally important numbers of numerous species of migrating waterbirds and wintering Anatidae use the area. The site supports 500 important plant species, including many that are threatened or protected at national or regional levels. Human activities include fishing, hunting, hay production and grazing. It is also important for its archaeological, historical and ethnographic values. Ramsar site no. 714. Most recent RIS information: 1994.