Grand Experiments: A Review of Five Endangered Species Reintroductions in the US.

摘要

Striking changes in American society resulted in the passage of the Endangered Species Act (ESA) in 1973, one of many laws passed during the environmental era of the 1960s and 70s. In just a few decades, we as a society moved from vilification and elimination of many species (or indifference to their decline) to protecting them legally under the ESA---a ground-breaking law based on the belief that all species have a fundamental right to exist.;The ESA calls for Recovery Plans to be written and implemented for species listed as in danger of extinction, plans that are to be implemented cooperatively by both federal and state agencies. When a species has been extirpated from a region or area, its recovery plan may include reintroducing that species within areas of its former range. Reintroduction of species is inherently difficu those working in the field face a number of challenges: high cost, behavioral issues in captive populations, genetic viability of often small founding populations, and habitat availability, among others. Reintroduction programs may face hostility from some sectors of the public---and even legal action.;Some reintroduction programs have been held up as successes; some species have been approved for delisting. When I began my study, I wanted to understand how and why the ESA and endangered species reintroductions have become so controversial. I wanted to understand how species reintroductions worked. Some reintroduction programs have been held up as successes; some species have been approved for delisting. What are the criteria for success? How has recovery been defined? My primary objective was to find out if several high-profile reintroduction programs had resulted in success on the ground---and what parameters might contribute to that success. To answer this question, I conducted comparative case studies of five well-known reintroductions. Four of the species were on that first list in 1967: Black-footed ferret (Mustela nigripes), reintroduced 1991; California condor (Gymnogyps californianus), reintroduced 1992; Gray wolf (Canis lupus ), reintroduced 1995; and Mexican wolf (Canis lupus baileyi ), reintroduced 1998. The fifth, listed as threatened in 2000, is the Canada lynx (Lynx canadensis.);Reintroduction success can be defined in a number of ways: numbers of animals in captivity or in the wild, genetic diversity preserved, public support, or efficient use of resources. I chose to define success by numbers---numbers of animals in captivity and in the wild, and reintroduced population demographics relative to principles of conservation biology as exemplified by resiliency, redundancy, and representation. I judged success by examining: 1) each species current status; 2) US Fish & Wildlife Recovery Plan goals for each species; 3) The ESA's Five Factor analysis [§4(a)1]; 4) Other government documents evaluating the status of each species; and 5) Books and peer-reviewed articles discussing the status of each species' recovery.;In addition, I present the species' natural history, historical conservation status, and policy background. Finally, I provide my findings. Of the species reintroductions I analyzed, all were somewhat successful in that each has a robust captive population, and at least one population has been established in the wild. Extinction has been averted for all species. However, with the exception of the Northern Rocky Mountain wolf population, all have been dependent on human intervention or assistance for survival in the wild. Only the Northern Rocky Mountain wolf population has achieved some degree of resiliency, redundancy, and representation, and exceeded initial recovery plan goals. The most successful reintroduction was the Northern Rocky Mountain wolf population, and the least successful was the Mexican wolf.;The most common reason for lack of success is that the reason(s) for initial extirpation have not been mitigated. The most common factors that led to success were a large initial release number and large recovery area. Overall, a successful reintroduction program encompasses the following: 1) a wild-born population, 2) a large initial release population, 3) a large release area, 4) connectivity among multiple populations, 5) adequate prey, 6) species characteristics that are more generalist than specialist, 7) a protected area, 8) public support.;Keywords: reintroduction, ESA, recovery