Rush pastures are extremely variable, both in their appearance and in their associated biodiversity interest. They typically occur on neutral soils with the better examples having an open structure and being relatively species-rich. By contrast, and more typically, most rush pastures tend to comprise a mosaic of closely-cropped grasses and tussocks of rushes, which support little of biodiversity interest. The quality of the habitat is related closely to the type and intensity of grazing associated with it. In the lowlands, in the absence of management, the rush pastures are most likely to be encroached by willow or birch scrub and eventually woodland. The reference state and the most common modified state of rush pasture are described below.