Concern over grazing marsh conservation in the face of pressures from intensive agriculture has become acute in England in recent decades. The importance of such areas is two-fold: they comprise important semi-natural habitats for both flora and fauna (especially birdlife) and they represent a landscape of historical and archaeological value. A full appreciation of the environmental background to traditionally managed marshlands therefore involves land use history and natural environmental factors such as their soils and their hydrology. There has been much research (by ecologists and others) into the sediment, nutrient and population dynamics of primary wetlands and much research into polderized landscapes by agricultural scientists and engineers. Despite concern over their conservation, relatively little has been published specifically about the environmental background of grazing marshes apart from that contained within surveys of their soils, ecology and site-specific management guidelines. This paper reviews the environmental background to traditional grazing marshes, and proposes a three-stage classification: primary (unembanked), secondary (embanked but minimally drained) and tertiary (intensively drained polderland). It suggests where future research priorities might lie, including how best to return former arable to pasture. © 1993 Academic Press Ltd.
