The Site is formed by a part of Lake Velence, the second biggest lake in the country, and Dinnyési-fertő, an alkaline marshland with surrounding meadows supporting extensive reed and Scirpus beds. The floating marshes are among the most important habitats of the lake: they provide good conditions for plant species such as the orchid Liparis loeselii and Sphagnum mosses, as well as animal species including the weatherfish Misgurnus fossilis, which has a stable population in the area. The Site is an important breeding, wintering and staging area for numerous species of endangered waterbirds, such as the red-breasted goose Branta ruficollis, the marsh harrier Circus aeruginosus and the little bittern Ixobrychus minutus. It regularly supports an average of 25,000 to 30,000 waterfowls per year, and more than 1% of the individuals of the population of greater white-fronted goose Anser albifrons and greylag goose Anser anser. The wetland area plays an important role in water purification and climate regulation. Human activities include reed harvesting on the lake, grazing and mowing of the meadows in Dinnyés, and ecotourism. There is a visitor centre, a birdwatching tower and a research facility at the Site. The main threat is posed by illegal fishing.