Rapid Assessment for Identifying Species of Greatest Conservation Need: Towards a Unified Approach

Identification of imperiled species ranges from rapid, qualitative, expert opinion-based assessments to time-intensive, quantitative assessments. The purpose of our study was to develop a methodology to rapidly quantify species of greatest conservation need by incorporating the concepts of resiliency, redundancy, and representation, which are used by the U.S. Fish and Wildlife Service to identify imperiled species. We compiled records of species occurrences (a measure of redundancy), commonality (a measure of representation), and reported absences (a measure of resiliency) for 50 species of fish within three ecoregions of the southwestern USA. We used multivariate analysis to describe interrelationships among reach, drainage, and region occurrences; percent rare occurrences; and percent absent among reaches. Weighted summations of species scores for principal component axes I and II were sorted from least (i.e., towards low redundancy, representation, and resiliency) to greatest, and species were ranked. With a few limitations, our methodology provided a revisable, documented, and transparent approach to aid in the identification of species of greatest conservation need.