Passed by the U.S. Congress in 1973 and reauthorized in 1988, the purpose of the Endangered Species Act (ESA) is to protect and recover imperiled species and the ecosystems upon which they depend. The U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) administer the ESA. The USFWS has primary responsibility for terrestrial and freshwater organisms, while the responsibilities of NMFS are mainly marine wildlife.


Endangered, Threatened, and Candidate
Under the ESA, species may be listed as either endangered or threatened. Endangered means a species is in danger of extinction throughout all or a significant portion of its range. Threatened means a species is likely to become endangered within the foreseeable future. The USFWS also maintains a list of candidate species. These are species for which the USFWS has enough information to warrant proposing them for listing but is precluded from doing so by higher listing priorities.


Species Listing
The ESA requires species to be listed as endangered or threatened solely on the basis of their biological status and threats to their existence. When evaluating a species for listing, the USFWS considers five factors:

  1. Damage to, or destruction of, a species’ habitat
  2. Overutilization of the species for commercial, recreational, scientific, or educational purposes
  3. Disease or predation
  4. Inadequacy of existing protection
  5. Other natural or manmade factors that affect the continued existence of the species

When one or more of these factors imperils the survival of a species, the USFWS takes action to protect it. The Fish and Wildlife Service is required to base its listing decisions on the best scientific information available.


Protection and Take
The ESA protects endangered and threatened species and their habitats by prohibiting the “take” of listed animals and the interstate or international trade in listed plants and animals, including their parts and products, except under Federal permit. It is unlawful for a person to take a listed animal without a permit. Take is defined as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or attempt to engage in any such conduct.” Through regulations, the term “harm&tdquo; is defined as “an act which actually kills or injures wildlife. Such an act may include significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering.” Listed plants are not protected from take, although it is illegal to collect or maliciously harm them on Federal land. Protection from commercial trade and the effects of federal actions do apply for plants.


Species Recovery
The ultimate goal of the ESA is to “recover” species so they no longer need protection. Recovery plans describe the steps needed to restore a species to ecological health. USFWS biologists write and implement these plans with the assistance of species experts, other federal, state, and local agencies, tribes, non-governmental organizations; academia, and other stakeholders.


Critical Habitat
The ESA requires the designation of critical habitat for listed species when prudent and determinable. Critical habitat includes geographic areas that contain the physical or biological features that are essential to the conservation of the species and that may need special management or protection. Critical habitat designations affect only federal agency actions or federally funded or permitted activities. Federal agencies are required to avoid destruction or adverse modification of designated critical habitat.


Critical habitat may include areas that are not occupied by the species at the time of listing but are essential to its conservation. An area can be excluded from critical habitat designation if an economic analysis determines that the benefits of excluding it outweigh the benefits of including it, unless failure to designate the area as critical habitat may lead to extinction of the listed species.


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