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Listing Species under the ESA and Designating Critical Habitat

Aerial photograph of a lake on Annette Island in SE Alaska. ENRD/DOJ.

WMRS | Implementation of ESA and Related Litigation

Core Terms

The Endangered Species Act (ESA) authorizes two federal agencies to identify species as either threatened or endangered.

For most marine species, that agency is the National Marine Fisheries Service of NOAA or the National Oceanic and Atmospheric Administration in the U.S. Department of Commerce.

For terrestrial wildlife and non-ocean going fish, that agency is the Fish and Wildlife Service in the U.S. Department of the Interior.

“Endangered” species are those in danger of extinction now.

“Threatened” species are likely to become in danger of extinction within the foreseeable future.

Listing Species Under the Endangered Species Act.

There are two ways that a species may be listed under the ESA. One of the listing agencies may make a determination based on information before it that a species should be considered for listing. In addition, anyone may petition one of the agencies to list a species; the ESA requires the listing agencies to make a decision about that petition under a set of deadlines.

The listing agencies consider the following factors, set forth in the ESA, in deciding whether to list a species:

  • the present or threatened destruction of habitat;
  • overutilization of the species for commercial, recreational or other purposes;
  • disease or predation;
  • inadequacy of existing regulatory mechanisms; and
  • other natural or manmade factors affecting the continued existence of the species.

Barton Springs Salamander.  Courtesy of USGS.The listing agencies may not consider economic impacts in listing species. If a species is found to be threatened or endangered  based on the agency's consideration of the above factors, it must be protected under the ESA.

In the years since the ESA was enacted in 1973, many species have been added to the protected species list. Some, such as the Indiana bat, range across entire ecosystems and throughout several states. Others, occur in limited areas, such as the Barton Springs salamander which is found only in one park in Austin Texas.

Depending on the species resiliency, species may have to be protected from almost all human interference. Other species, such as the recently recovered bald eagle, can tolerate a fair amount of human activity nearby.

Impact of Loss of Habitat.

Indiana Bat has a range throughout several states.  Courtesy of Adam Mann, Environmental Solutions.Regardless of its range, most species that are listed as “threatened” or “endangered” are in trouble because of loss of habitat, though often other factors are a contributing problem. To address this, Congress also directed the listing agencies to designate critical habitat for species that are “threatened” and “endangered” so that the area essential to the species conservation has special protection.

Critical habitat designations can be very small or very large, depending on the needs and range of the particular species involved. In designating critical habitat, the listing agencies must consider economic impacts, and they may choose to exclude certain areas if the costs of designating an area outweigh the benefits, provided that the exclusion will not result in extinction.

Planning for Species Recovery.

Once a species is listed, the responsible listing agency will prepare a recovery plan, which is a “road-map” or guidance document for both federal agencies and other entities, to provide direction for recovering the species with a set of criteria for determining when the species will be considered recovered.

Recovery will be a long process for most species because their status as endangered or threatened results from effects occurring over many years. Information on recovery plans for particular species is available on the websites for the Fish and Wildlife Service and the National Marine Fisheries Service.


Updated May 15, 2015