The Endangered Species Act (ESA)—the key US law protecting species listed as threatened or endangered—focuses on boosting species' numbers until they reach recovery thresholds and so can be taken off the ESA list. Almost 1400 species are now listed. Yet as many as 84 percent of currently listed species with management plans will face threats to their biological recovery even after they are considered "recovered" under the act, according to an article by Dale D. Goble and his colleagues in the October issue of BioScience. These species will require continuing management actions. Goble and colleagues argue that individual, formal conservation agreements are the best way to help such "conservation-reliant species."
The ESA was intended to interact with state and local regulations to prevent extinction. However, say Goble and his coauthors, these regulations are often insufficient to maintain a species' population, and the ESA itself may hinder the spread of a species—for example, a landowner may not wish to create habitat for a species that will then require monitoring under the ESA. Individual conservation agreements might not only help species' biological recovery and accelerate their removal from the ESA list, Goble and his colleagues maintain—they might prevent some species from having to be listed in the first place. To be effective, such agreements should be tailored to the species, landscape, landowners, conservation managers, and sources of funding of each situation.
Recognizing that conservation reliance is a deeper and more widespread problem for ESA-listed species than initially thought, Goble and his colleagues distinguish two forms of conservation reliance—population-management reliance and the less direct, threat-management reliance. The former will involve interventions aimed at helping specific populations. The latter is suitable for species that can persist if threats are managed so that an appropriate habitat is maintained.
Both sorts are illustrated in articles in the October BioScience. Goble's article is part of a special section that includes three case studies of specific conservation-reliant species. Carol I. Bocetti and her colleagues discuss conservation management agreements that will ensure continued availability of habitat for Kirtland's warbler. J. Michael Reed and his coauthors assess the status of Hawaii's endangered birds and how continued management is needed to maintain the populations of these species. Finally, the plight of the Mojave desert tortoise and its continuing management needs are addressed by Roy C. Averill-Murray and his colleagues.
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