Annual precipitation values (mm) were calculated as the mean value of the 10-km squares where the species occurs in Britain, Ireland and the Channel Islands. Climate data for 10-km squares were taken from baseline climate summaries of the UK Climate Impacts Programme (Hulme & Jenkins, 1998). These baseline summaries were constructed by interpolation of daily weather measurements from individual met stations, averaged over the 30-year period 1961–1990 (Barrow et al., 1993).
Barrow, E.M., Hulme, M. and Jiang, T. (1993) A 1961-90 baseline climatology and future climate change scenarios for Great Britain and Europe. Part I: 1961-90 Great Britain baseline climatology. Climatic Research Unit, Norwich, 43pp. (plus maps).
Hulme, M. & Jenkins, G. (1998) Climate change scenarios for the United Kingdom: summary report. Climate Research Unit, Norwich.