Moorfrogs in polder habitat As a result of a field study and a literature review, information is presented about the habitat preference and management of Moor Frogs (Rana arvalis) in polders in the southern half of the Netherlands. A preference was found for habitats on peat soils covered by a thin layer of clay. Extensively grazed pastures (0.5 - 3 cattle/ha) were preferred in nature reserves. In agricultural areas Moor Frogs are found mainly on banks of ditches trampled by cattle. Ditches with floating vegetation are preferred for reproduction.