The study finds that the longer species were listed under the act, the more likely they were to be improving in status and the less likely to be declining, suggesting ESA conservation measures act cumulatively over time. Separately, species for which "critical habitat" had been designated for two or more years appeared more likely to be improving and less likely to be declining than species that did not have critical habitat for at least two years. Likewise, species that had recovery plans for two or more years appeared more likely to be improving and less likely to be declining than others, and species with dedicated recovery plans appeared to fare better than species protected by multi-species recovery plans. Other protections afforded by the ESA, such as protection of individual animals from unregulated "take," also had apparently beneficial effects on species' conservation status. The benefits of ESA protections did not appear to favor animals over plants. Taylor and his coauthors urge that the $153 million estimated cost to complete work on the backlog of ESA listings and critical habitat designations be fully funded, and endorse a recommendation that the recovery program budget be increased by $300 million.
The study is described in detail in the April 2005 issue of BioScience, the monthly journal of the American Institute of Biological Sciences. Journalists may obtain copies of the article by contacting Donna Royston, AIBS communications representative.
BioScience publishes commentary and peer-reviewed articles covering a wide range of biological fields. The journal has been published since 1964. AIBS is an umbrella organization for professional scientific societies and organizations that are involved with biology. It represents 89 member societies and organizations with a combined membership of about 240,000.