endangered species, any plant or animal species species, in biology, a category of classification , the original and still the basic unit in the demarcation of plant and animal types. The species marks the boundary between populations of organisms rather than between individuals.
..... Click the link for more information. whose ability to survive and reproduce has been jeopardized by human activities. In 1999 the U.S. government, in accordance with the U.S. Endangered Species Act (1973), classified 935 native species as endangered or threatened, including animals such as the Florida panther, the Key deer, the San Joaquin kit fox, the northern spotted owl, the chinook salmon, the Karner blue butterfly, the snail darter, and the cave crayfish and plants such as the Hawaiian nehe and the clover lupine. Over 500 more species were so classified worldwide. The official list of endangered wildlife and plants in the United States is kept by the Fish and Wildlife Service; the National Marine Fisheries Service oversees marine species. In addition, many states keep their own lists. The International Union for the Conservation of Nature and Natural Resources maintains an international list, published as the Red Data Book.

Causes of Endangerment

Hunting, trapping trapping, most broadly, the use of mechanical or deceptive devices to capture, kill, or injure animals. It may be applied to the practice of using birdlime to capture birds, lobster pots to trap lobsters, and seines to catch fish.
..... Click the link for more information. , and poisoning to protect livestock have taken a great toll among predatory mammals and birds. Overharvesting is currently threatening species worldwide, especially food fish species such as the cod cod, member of the large family Gadidae, comprising commercially important food fishes. The cods include the hake and the haddock, all found in the N Atlantic and Pacific.
..... Click the link for more information. . A large number of species are threatened by introduced species, or "exotics," plants or animals that are introduced into a habitat and bring with them diseases or the ability to compete more effectively than native species. The now ubiquitous European starling, for example, purposely introduced into the United States in the 1890s, is displacing the native American bluebird and other species, and the brown tree snake, native to Australia and introduced to Guam during World War II, has preyed on native species of that island to the extent that nine bird species are now extinct. Another danger is hybridization with other species and subspecies.

Another important threat is destruction of habitat by chemical pollutants. For example, bird populations have suffered great losses because of insecticides insecticides, chemical, biological, or other agents used to destroy insect pests; the term commonly refers to chemical agents only.

Chemical Insecticides

..... Click the link for more information. . The chemicals they contain, such as DDT DDT or 2,2-bis(p-chlorophenyl)-1,1,1,-trichloroethane, chlorinated hydrocarbon compound used as an insecticide . First introduced during the 1940s, it killed insects that spread disease and feed on crops.
..... Click the link for more information. , accumulate in birds' bodies and interfere with calcium metabolism. As a result, the females lay eggs with extremely thin shells or no shells at all, so the embryos do not survive to hatching. Acid rain acid rain or acid deposition, form of precipitation (rain, snow, sleet, or hail) containing high levels of sulfuric or nitric acids (pH below 5.5–5.6).
..... Click the link for more information. has destroyed the habitats of many North American fish and amphibians by lowering the pH of surface waters. It is also changing the soil chemistry and harming many tree species.

Most serious of all, the destruction of physical habitat—by the drainage and filling of swamps and marshes, by the damming of rivers, by the leveling of forests for residential and industrial development, by strip mining, and by oil spills and water pollution—has left many creatures with literally no room in which to live and breed. For example, only 5% of the original forests in the 48 coterminous states, i.e., those forests that were present at the time of the first European settlement, are still standing.

Efforts to Protect Species

Many local, national, and international organizations, such as Greenpeace Greenpeace, international organization that promotes environmental awareness and addresses environmental abuse through direct, nonviolent confrontations with governments and companies. Founded in 1971 to oppose U.S.
..... Click the link for more information. , the Sierra Club Sierra Club, national organization in the United States dedicated to the preservation and expansion of the world's parks, wildlife, and wilderness areas. Founded (1892) in California by a group led by the Scottish-American conservationist John Muir , the Sierra Club
..... Click the link for more information. , and the National Audubon Society Audubon Society, National, one of the oldest and best-known U.S. environmental organizations; founded 1886 by George Cird Grinnell and named for John James Audubon .
..... Click the link for more information. , work to preserve habitats and heighten public awareness. Conservationists have pressed for habitat preservation through the establishment of new wildlife refuges wildlife refuge, haven or sanctuary for animals; an area of land or of land and water set aside and maintained, usually by government or private organization, for the preservation and protection of one or more species of wildlife.
..... Click the link for more information. and wilderness wilderness, land retaining its primeval character with the imprint of humans minimal or unnoticeable. In the United States, the Wilderness Act of 1964 established the National Wilderness Preservation System with a nucleus of 9 million acres (3.
..... Click the link for more information. areas and for public and private land-use land use, exploitation of land for agricultural, industrial, residential, recreational, or other purposes. Because the United States historically has a laissez-faire attitude toward land use, the land has been exploited at will for economic gain.
..... Click the link for more information. planning that would provide for development without habitat destruction. Some wildlife conservation organizations try to keep seriously endangered species viable with captive breeding programs, releasing new offspring into the species' native habitat when breeding is successful.

U.S. legislation affecting endangered species includes the various federal antipollution laws, the banning of DDT, the National Environmental Policy Act (NEPA) of 1969, and the Endangered Species Acts of 1966, 1969, 1973, 1978, 1982, and 1988. The landmark 1973 Endangered Species Act prohibits any trade in endangered species or their products and requires that federal agencies assess the impact on wildlife habitat of proposed projects—much as NEPA requires an environmental impact statement environmental impact statement, analysis of the impact that a proposed development, usually industrial, will have on the natural and social environment. It includes assessment of long- and short-term effects on the physical environment, such as air, water, and noise
..... Click the link for more information. . These laws are often the only tool that conservationists have to prevent the development or other exploitation (e.g., logging or mining) of important habitats, but enforcement is also hampered by litigation and a lack of funds. Despite these problems, in the years since 1973 the status of many species, including the bald eagle, American alligator, and black-footed ferret, became stable or improved.

The protection of species in the United States has, however, become highly politicized. Asserting that the enforcement of environmental rules unfairly burdens business, the Republican 104th Congress prevented any further species from being added to the U.S. list of endangered and threatened wildlife and plants for 13 months from 1995 to 1996. Despite the perception that enforcement of the laws affects the economy and impedes progress, only 1% of the 50,000 projects that raised endangered-species questions between 1976 and 1986 required further investigation because of possible serious impact on a species; most of those moved forward after some modification.

On the international scene, efforts have been made to halt the trade in spotted cats and crocodiles and to curtail whaling whaling, the hunting of whales for the oil that can be rendered from their flesh, for meat, and for baleen (whalebone). Historically, whale oil was economically the most important.

Early Whaling

Whaling for subsistence dates to prehistoric times.
..... Click the link for more information. and the taking of porpoises in tuna seines. A conference in Washington, D.C., in 1973, attended by 80 nations, drew up the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which protects more than 600 species of animals and plants. By the early 1990s some success had been achieved in banning the trade in rhinoceros horn, elephant ivory, South American parrots, bird eggs, and rare orchids, but poaching—for the high profits that can sometimes be gained from these items—continues to be a serious threat. In addition to CITES, the 1992 United Nations Conference on Environment and Development United Nations Conference on Environment and Development (UNCED) or Earth Summit, an 11-day meeting held in June, 1992, in Rio de Janeiro, Brazil, to discuss the global conflict between economic development and environmental protection.
..... Click the link for more information. (the "Earth Summit") produced an agreement to stem the depletion of the world's diverse species (see biological diversity biological diversity or biodiversity, the number of species in a given habitat. Scientists have variously estimated that there are from 3 to 30 million extant species, of which 2.
..... Click the link for more information. ). See also conservation of natural resources conservation of natural resources, the wise use of the earth's resources by humanity. The term conservation came into use in the late 19th cent. and referred to the management, mainly for economic reasons, of such valuable natural resources as timber, fish,
..... Click the link for more information. .

Bibliography

See T. B. Allen, Vanishing Wildlife of North America (1974); L. Regenstein, The Politics of Extinction (1979); S. Boyd, Endangered Species (1989); E. O. Wilson, The Diversity of Life (1992); D. Ackerman, The Rarest of the Rare (1996); D. Quammen, The Song of the Dodo (1996); and the Red Data Books published by the International Union for the Conservation of Nature.

endangered species

Any species of plant or animal threatened with extinction. International and national agencies work to maintain lists of endangered species, to protect and preserve natural habitats, and to promote programs for recovery and reestablishment of these species. The Species Survival Commission of the International Union for Conservation of Nature and Natural Resources (IUCN) publishes information online about endangered species worldwide as the Red List of Threatened Species. Separate books for animal and plant species are also published. In the United States, the Fish and Wildlife Service is responsible for the conservation and management of fish and wildlife, including endangered species, and their habitats. Its list now consists of about 1,200 domestic species of endangered or threatened animals and plants, and some 200 recovery programs are in effect.