ASSESSING NATIONAL CONSERVATION PRIORITIES - AN IMPROVED RED LIST OF BRITISH BUTTERFLIES

An objective method of determining national conservation priorities is vital to use scarce resources effectively, but no method is yet widel y accepted. The 'Conservation Cube' method of Avery et al. (1995: Ibis 137, 232-239), which includes three biological axes (National Status; International Importance, and European/global status), is tested for a highly threatened group of animals, British butterflies. The results are compared with Red Lists constructed using old and new IUCN criter ia. A new feature of both procedures is the evaluation of threat due t o rate of decline, and new thresholds are suggested to assess the decl ine of butterflies from published IO-km grid square distribution maps. The analysis shows that almost half (49%) of the 59 resident British butterflies are extinct or threatened: 8% are extinct; 12% are a high priority largely owing to their rapid rate of decline; whereas 29% are a medium priority owing to their moderate rates of decline. Most high priority species qualify as Vulnerable under the new IUCN criteria us ing UK guidelines, but many medium priority species fail to qualify. W e suggest that all globally threatened species are classified at least as Vulnerable at national level and that two new Lower Risk categorie s are created: Internationally Significant and Moderate Decline. The t wo procedures would then form a comparable, rational procedure for ide ntifying conservation priorities that is applicable to all animal grou ps for which distributional data are available. (C) 1997 Published by Elsevier Science Ltd.