RARE SPECIES, THE COINCIDENCE OF DIVERSITY HOTSPOTS AND CONSERVATION STRATEGIES

SPECIES conservation in situ requires networks of protected areas sele cted for high conservation interest1-3. Throughout most of the world, however, there are neither the resources nor the time to carry out det ailed inventories for most taxa2,4 before designating protected areas. Site selection (on grounds other than availability) would be easier a nd more effective if two things were true: (1) habitats that are speci es-rich for one taxon are also species-rich for others5; and (2) rare1 species occur in, and therefore benefit from the conservation of, spe cies-rich habitats. Diversity (usually, species richness) and the pres ence of rare species are the most frequently cited criteria for site s election by conservationists6-8. Here, we use data on British plants a nd animals held by the Biological Records Centre (BRC)9 and the Britis h Trust for Ornithology (BTO), mapped on a grid of 10 km x 10 km ('10 km squares') to examine the extent to which species-rich areas for dif ferent taxa coincide, and whether species-rich areas contain substanti al numbers of rare species. The fine scale and high intensity of recor ding in Britain produces distributional datasets at least as good as a nd, in most cases, better than those available elsewhere. For Britain at least, we do not find strong support for either proposition. Specie s-rich areas ('hotspots'10) frequently do not coincide for different t axa, and many rare species do not occur in the most species-rich squar es.