PATTERNS, MECHANISMS AND RATES OF EXTINCTION AMONG INVERTEBRATES IN THE UNITED-KINGDOM

Information about the changing status and extinction rates of invertebrates in the United Kingdom during the past 100-300 years is reviewed. Although historical recording was more thorough in the U.K. than elsewhere, the data are patchy and difficult to interpret. Nevertheless, we conclude that the extinction rates of U.K. invertebrates have matched, and probably exceeded, those of vertebrates and vascular plants in the present century. The main reasons for decline are analysed. No clear pattern of threat was found among aquatic species, but there was a very clear pattern in terrestrial biotopes, where most endangered species inhabit either the earliest or latest successional stages. The former group consists mainly of thermophilous species, which may be relies from a period when U.K. summer temperatures were warmer, and which survived in warm refugia created by the land management of prehistoric man. These types of habitat have largely disappeared from modern biotopes, and their dynamics have also changed. In all systems, many invertebrates are too sedentary to track their habitats in the modern landscape.