1. Upland Environments Research Unit, School of Environment and Development, The University of Manchester, Manchester M13 9PL, U.K., Department of Environmental and Geographical Sciences, Manchester Metropolitan University, Manchester M1 5GD, U.K., British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K., and School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, U.K.