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by Nick Buhbe, M.S.

Forty years ago, the Endangered Species Act (ESA) defined a comprehensive approach for preventing extinction of critically imperiled species threatened by untempered economic growth and development. The ESA joined a number of conservation laws passed in the early 1970’s, including the Clean Air, National Environmental Policy Act, Clean Water, Coastal Zone Management, and Marine Mammal Protection Act. (100 years after the creation of the nation’s first national park at Yellowstone.)

Like many of the environmental and conservation laws in place today, the ESA is a result of multiple drivers over many years and coincided with a growing cultural awareness of conservation. Legislation to protect species began in the mid-1960’s, but the scope of the Endangered Species Preservation Act (ESPA) of 1966 was significantly limited: it targeted native game species such as buffalo and was limited to Federal lands. Growing recognition that wildlife needed to be protected both on and off Federal lands soon highlighted the need for revisions. In 1969, the budget was increased and invertebrates and non-native species were added to the law.

The 1973 Endangered Species Act, which remains to this day, is groundbreaking legislation as it completely rewrote the ESPA and recognized several new principles, including protection of critical habitats, incorporation of plant species, and preparation of recovery plans to return threatened populations to self-sustaining levels. Although recovery plans are closely linked to population sizes, habitat preservation is a central component of species conservation.

Today, 1487 species of plants and animals are listed as threatened or endangered in the United States (630 animal and 857 plant species, including listed subpopulations). Habitat of these species is regulated in several ways:

  • Directly through conservation on Federal lands (e.g., USFWS Refuges)
  • Indirectly through the regulatory process, which severely limits the circumstances of impacts to listed species
  • Through the implementation of Habitat Conservation Plans (HCPs), often in partnership with local stewards

As a result of the ESA and other environmental legislation, 21 species are no longer listed as endangered, including:

American Alligator (Alligator mississippiensis)
Bald Eagle (Haliaeetus leucocephalus)
American Peregrine Falcon (Falco peregrinus anatum)
Brown Pelican (Pelecanus occidentalis)
Gray Whale (Eschrichtius robustus)
Concho Water Snake (Nerodia paucimaculata)
Hoover’s Woolly-star (Eriastrum hooveri)

The success of species recovery efforts varies from case to case. Those with wide geographical ranges have in some cases recovered due in large part to other legislation. Both the Bald Eagle and Brown Pelican’s populations increased after pesticide regulations were implemented, and the hunting restrictions allowed the Gray Whale, Gray Wolf, and Columbian White-tailed Deer to recover.

More typically, protection of habitat plays a vital role for species with narrow geographical ranges or other habitat-dependent life history aspects. For example, the Concho Water Snake of central Texas is limited to small streams with adequate fish prey. It was delisted after specific criteria of its recovery plan were reached:

  1. Availability of “adequate instream flows” within the habitat ranges
  2. The presence of “stable, viable populations” in two reaches of the Colorado River and in the Concho River basins

In the case of California’s Hoover’s Wooly-star, the natural range of the plant included the Temblor Range, Cuyama Valley, and the southern portion of the San Joaquin Valley. Threatened by agricultural, urban and oil and gas development, the species was designated as threatened in 1989.

Recovery efforts begun in 1990 and were successful in discovering additional populations, characterizing species-specific qualities which indicated greater resilience of the species than previously thought, and achieving protection through participation of Federal, state and private entities on more than 114,400 hectares (286,000 acres). As a result, recovery plan criteria were attained: (1) 75 % of occupied habitat for each of four populations was secured and protected from incompatible uses; (2) 260 hectares (640 acres) or more of the occupied habitat were protected on the San Joaquin Valley Floor; (3) ongoing management plans were implemented; and (4) the four populations were, at minimum, stable through one precipitation cycle.

Although Hoover’s Wooly-star has been removed from the list, other species which co-existed in the habitat range are still listed as threatened or endangered. Habitat conservation plans listing the wooly-star also include the following endangered species (among others) which to varying degrees depend on similar habitat:

Giant Kangaroo Rat (Dipodomys ingens)
Blunt-nosed leopard Lizard (Gambelia silus)
California Jewelflower (Caulanthus californicus)
Longhorn Fairy Shrimp (Branchinecta longiantenna)

Range overlap of these and other species of concern illustrate the utility of Habitat Conservation Plans which seek to preserve habitat that benefits multiple species of concern. HCPs offer the potential for at least partial attainment of multiple objectives through strategic land conservation efforts.  While the ESA has resulted in significant efforts and successes with regard to preventing the extinction of imperiled species, work remains to ensure that progress toward species recovery continues over the next 40 years and beyond.