US Geological Survey


Date of this Version



Published in The Endangered Species Act at Thirty, Volume 2: Conserving Biodiversity in Human-Dominated Landscapes, edited by J. Michael Scott, Dale D. Goble, & Frank W. Davis (Washington: Island Press, 2006), pp. 3-5.


More than thirty years after its passage, the Endangered Species Act (ESA) of 1973 continues to be a corners tone of U.S. biodiversity policy and among our most powerful environmentallaws. The ESA set the nation's biodiversity conservation policy on a path that emphasized species-based conservation and triggered action only when a species faced imminent extinction. However, promoting recovery has proven more challenging than the original designers of the law anticipated. The number of listed species has mushroomed from 78 in 1973 to 1,267 in 2005, while in that time only 13 species have recovered sufficiently to be removed from the list (Scott et al. 2006).

As described in The Endangered Species Act at 30: Renewing the Conservation Promise, the act has proven remarkably durable in spite of nearly continuous political assaults and legal and scientific challenges (Goble et al. 2006). The contributing authors to that volume describe a variety of factors responsible for the act's endurance. Public support for species conservation has remained strong, especially for high-visibility species such as the bald eagle (Haliaeetus leucocephalus) and grizzly bear (Ursus arctos horribilis) but also for less-charismatic taxa. The act has been championed by environmental groups in part for its power to control development, a role supported by a majority of the American public (Czech and Krausman 1997). Reforms have also been important to the act's continuance. In particular, implementation has evolved over the years from an absolute prohibition on take of endangered species to a more flexible permitting system, thereby defusing potentially explosive conservation conflicts on private lands. The act has also catalyzed administrative and legal reforms at all levels of government that have led to positive changes in natural resource management in rural areas and in urban open space planning.