Characterization of river habitats and prediction of habitat features using ordination techniques

1. The extensive data collected from more than 5000 separate sites in England, Wales, Scotland and Northern Ireland now provide representative samples of the current state of river habitats in the UK. 2. While analysis and interpretation of these data will necessarily continue for some time, some preliminary conclusions and results have already emerged from the examination and interpretation of the complex and dynamic relationships between the many variables and attributes recorded in the course of the national survey. 3. In particular, it has been possible to provide an ordination of the survey sites based on four map-derived variables that facilitates prediction of at least some of the major habitat features. 4. This ordination and the resulting prediction of habitat features are described in this paper, together with a brief discussion of the implications of the analysis for river habitat management.