LAND CLASSIFICATION FOR STRATEGIC ECOLOGICAL SURVEY

Traditionally, ecological survey relies upon the intuitive interpretat ion of habitat patterns in the held. The statistical stratification de veloped for regional survey by the Institute of Terrestrial Ecology (I TE) is designed to minimise personal judgement in sample site location . The environmental strata within the classification are recognisable and give confidence to users from a variety of backgrounds. The method ology originated in the 1960s when multivariate statistics were develo ped and applied to ecological data. Initially, Great Britain (GB) was classified from environmental data recorded from 1200 out of the 240 0 00 km(2) of the National Grid. Logistic discrimination and discriminan t functions were used to assign the remaining squares to original clas ses and to reassign the original squares. The final classes differed s lightly from the initial divisions because the allocations use differe nt data sets and different techniques. Field surveys of ecological par ameters have been used to provide independent data for testing the cla ssification, to characterise the classes and to provide national estim ates of land coverage. The statistical rationale behind the methodolog y is described and the relevance of the experience gained during the d evelopment is discussed in relation to future work. Finally, applicati ons of the classification are described demonstrating its use as a fra mework in a variety of ecological studies. (C) 1996 Academic Press Lim ited