The normative dimension and legal meaning of endangered and recovery in the U.S. Endangered Species Act.

The ethical, legal, and social significance of the U.S. Endangered Species Act of 1973 (ESA) is widely appreciated. Much of the significance of the act arises from the legal definitions that the act provides for the terms threatened species and endangered species. The meanings of these terms are important because they give legal meaning to the concept of a recovered species. Unfortunately, the meanings of these terms are often misapprehended and rarely subjected to formal analysis. We analyzed the legal meaning of recovered species and illustrate key points with details from "recovery" efforts for the gray wolf (Canis lupus). We focused on interpreting the phrase "significant portion of its range," which is part of the legal definition of endangered species. We argue that recovery and endangerment entail a fundamentally normative dimension (i.e., specifying conditions of endangerment) and a fundamentally scientific dimension (i.e., determining whether a species meets the conditions of endangerment). Specifying conditions for endangerment is largely normative because it judges risks of extinction to be either acceptable or unacceptable. Like many other laws that specify what is unacceptable, the ESA largely specifies the conditions that constitute unacceptable extinction risk. The ESA specifies unacceptable risks of extinction by defining endangered species in terms of the portion of a species' range over which a species is "in danger of extinction." Our analysis indicated that (1) legal recovery entails much more than the scientific notion of population viability, (2) most efforts to recover endangered species are grossly inadequate, and (3) many unlisted species meet the legal definition of an endangered or threatened species.