Evaluating approaches to the conservation of rare and endangered plants

Nearly 25% of the estimated 250,000 species of vascular plants in the world may become extinct within the next 50 yr (Raven 1987), and 22% of vascular plant species in the United States are currently of conservation concern (Falk 1992). Plant conservation efforts received a critical boost with the passage of the Endangered Species Act of 1973 (16 USC 1531-1544: USFWS 1988a). The Act established a legal mandate of unprecedented proportions to promote the collection, analysis, and exchange of biological information. It requires that for each endangered or threatened species occurring in the United States, a recovery plan be developed which "delineates, justifies, and schedules the research and management actions necessary to support the recovery of a species" (16 USC, 1531-1544: USFWS 1988a).Schemske, D.W., B. C. Husband, M.H. Ruckelshaus, C. Goodwillie, I.M. Parker, and J.G. Bishop. 1994. Evaluating approaches to the conservation of rare and endangered plants. Ecology 75: 584-606