Zuidlaardermeer is one of the largest lakes in the provinces of Groningen and Drenthe and is of natural origin. The River Hunze drains into the lake, and reedbeds, swamp forests and extensive areas of wet grassland surround it. These reclaimed polders are important feeding grounds for herbivorous water birds, while the lake is used for roosting by nationally protected waterbirds such as northern pintail (Anas acuta) and Eurasian bittern (Botaurus stellaris). The Site supports more than 1% of the regional population of the gadwall (Anas streptera) and plays an important role in flood regulation. It is used for science and research and provides water for agriculture. In 2014 the Site was aligned with the Natura 2000 site, resulting in a decrease in its area of nine hectares.