Over 400 years ago, the principles of managing meadows were well established and they helped to create the species-rich habitat now referred to as lowland wet grassland. This term may include virtually all river-valley grasslands and coastal marshes. These grasslands were formerly widespread, occuring throughout much of the British Isles. However, increasing urbanisation, land drainage, flood defence and changing agricultural practices (including conversion to arable, the switch from hay to silage, and herbicide – and fertiliser use) have considerably altered the habitat and destroyed much of its wildlife interest.