A rating system for potential exotic bird and mammal pests

Abstract

Natural areas, natural resources, and agricultural production systems have been damaged by introduced species, and are jeopardized by future invasions. A rating system was developed to prioritize research and control efforts for preventing species invasions and eradicating established exotic pests. Four rating criteria were the species potential (1) to be introduced; (2) to establish; (3) to cause damage; and (4) to be controlled. Each species was rated independently for each criterion, and these ratings summed to provide a total score. The rating system was developed with 24 exotic bird and mammal species with well-known invasion and pest histories. We then rated the 14 bird and mammal species on the California Department of Food and Agriculture most unwanted exotic species list, and 10 other species. The rating system provided surprising objectivity for assessing the threat of species invasion and pest status. Of the 14 ‘most unwanted species’, four were rated as a low threat, and 13 of the 34 other rated species were recommended for this list. Certainly, this list should be lengthened. A quick-response apparatus was also developed to provide information on perceived exotic species threats. It consisted of a data base of expert contacts and citations on exotic pest species damage, biology, ecology, and control technology.