The site is a coastal wetland dominated by humid dune-slacks, marshes, woodland and two connected freshwater lakes, which are among the largest of their kind in Europe. In 2014 the Site name and boundary were adjusted to follow the Natura 2000 site. Residential land was excluded while a natural area in the south was added, resulting in an increase in the area of 175 hectares. These ecosystems support a rich and vulnerable vegetation as well as endangered species of waterbirds such as the Eurasian bittern (Botaurus stellaris) and lesser white-fronted goose (Anser erythropus). The Site is an integral part of a dune system which protects the Netherlands from the North Sea. Land use is dedicated to tourism, military training, water management, dams, reservoirs and hydro-electric generation. Water abstraction and airborne pollutants are the main ecological threats to the Site.