The evaluation of ecological resources in the countryside for conservation purposes

County planning authorities in the British Isles are currently preparing plans (Structure Plans) which will determine the future pattern of land-use and one input to these is the evaluation of the relative ecological quality of different areas. These evaluations are being made on the basis of various criteria, such as extent, naturalness, richness and diversity, although there is no general agreement amongst ecologists or planners as to how such information should be combined to produce a single index. One possible index is suggested and the results obtained in a trial application are described.