Affiliation: | NERC Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS, UK;;NERC Centre for Ecology and Hydrology, Winfrith Technology Centre, Dorchester, Dorset DT2 8ZD, UK;;The Northmoor Trust, Little Wittenham, Abingdon, Oxon OX14 4RA, UK;;and Defra Rural Development Service, Government Buildings, 98 Epsom Road, Guildford, Surrey GU1 2LD, UK |