The Site is a seasonal lake, which currently features very little open water except during winter floods. Water drainage poses a serious threat to its ecological character; restoration works have aimed to increase lake levels without affecting the drainage of upstream land. Marshes now dominate the Site, and the habitat may be better classified as permanent freshwater marshes with pools. Other habitats include reed swamp, alkaline fen, wet woodland, wet and dry grassland, cutaway bog colonized by heath vegetation, scrub and wet willow woodland. A range of wintering waterbirds use the Site for foraging and roosting during the winter months; over 1% of the global population of whooper swan (Cygnus cygnus) are found. The Site is also used by mute swan (Cygnus olor), teal (Anas crecca), shoveler (Anas clypeata) and, intermittently, the near-threatened northern lapwing (Vanellus vanellus). Wigeon were once present in large numbers, but their numbers have decreased significantly. The Site is used for scientific and educational purposes.