The Marais poitevin, the second largest wetland in France, reflects the co-existence of natural processes and human agricultural interventions over centuries. This large area is remarkable for the diversity of its constituent environments: it consists of a complex network of “dry” marshes featuring dams, drainage channels, hydraulic works and farmland, “wet” marshes, and river valleys, limestone islands, polders, and coastal environments. The Site includes 33 habitats listed under the European Union’s Habitats Directive, including four “priority habitat types”. It is an area of great ecological richness, hosting a total of 58 mammal species, 337 birds, 33 fish, 54 odonates (an order of flying insects that includes dragonfly and damselfly groups), 63 butterflies, 17 amphibians, 140 molluscs and 9 reptile species. It is the breeding ground, feeding ground, nursery, and resting place for numerous species such as the critically endangered European eel (Anguilla Anguilla), the vulnerable western spadefoot (Pelobates cultripes), the lesser horseshoe bat (Rhinolophus hipposideros) and the allis shad (Alosa alosa). The Site supports 1% or more of regional populations of 13 wintering and migratory waterbird species, including northern pintail (Anas acuta), red knot (Calidris canutus), dunlin (Calidris alpina), black-tailed godwit (Limosa limosa), pied avocet (Recurvirostra avosetta) and common shelduck (Tadorna tadorna).