Endangered species are living things threatened with extinction—that is, the dying off of all of their kind. Thousands of species of animals and plants are endangered, and the number increases each year. Some examples of endangered species are blue whales, orangutans, rhinoceroses, sea turtles, tigers, whale sharks, and whooping cranes. Among endangered plants are running buffalo clover, Santa Cruz cypress, snakeroot, and many species of cactuses.
Each species of plant and animal plays a part in the delicate balance of its ecosystem, its relation to other living things and the environment. Thus, the extinction of large numbers of species threatens the survival of other living things, including human beings. As more species have become endangered, ecosystems have become unstable or collapsed. Fortunately, people have increased their efforts to protect endangered species. See Wildlife conservation (Values of wildlife conservation).
Most biologists consider a species endangered if they expect it would die off completely in less than 20 years if no special efforts were made to protect it, or if the rate of decline far exceeds the rate of increase. Until the last few centuries, species became rare or died out as a result of natural causes. These causes included changes in climate, catastrophic movements in Earth’s crust, and volcanic eruptions.
Today, species become endangered primarily because of human activities. Species mainly become endangered because of (1) loss of habitat, (2) wildlife trade, (3) overhunting, and (4) competition with domestic and nonnative animals. An increasing number of species are threatened by human-created climate change.
Loss of habitat
poses the greatest threat to the survival of wild species. Most animals and plants are specially adapted to live and reproduce in a specific environment or habitat and cannot survive when it is destroyed. The destruction of virgin forests by loggers and settlers and the conversion of natural grasslands into pasture for livestock have eliminated vast expanses of wildlife habitats. Marshlands have been drained for farmland and building projects. Coral reefs and many marine environments have become polluted, overfished, and even dynamited to obtain tropical fish and corals. Tropical rain forests contain the greatest variety of animal and plant life on Earth, and they are being destroyed more rapidly than any other type of wild habitat.
Wildlife trade
involves the capture of animals for pets, zoo specimens, and research subjects, and the killing of animals for their fur or other body parts. The capture of wild animals for commercial use has greatly endangered many species. The Spix’s macaw, a parrot of Brazil, became extinct in the wild because so many were captured for private bird collectors. Many primates, including the orangutan, have become endangered by the illegal killing of the mothers to capture their babies for zoos and pet dealers. Gorillas, chimpanzees, and other primates are killed for their meat, which is sold in African markets.
Other animals have been killed in such large numbers for their fur, hides, tusks, or horns that they became severely endangered. Rhinoceroses, wild chinchillas, and chiru (Tibetan antelopes) are among these. It is often illegal to hunt such endangered animals in the countries where they live. Some protected animals, such as the chiru, have recovered enough to be removed from lists of highly endangered species. But protected animals are often still poached (hunted illegally). Poaching has seriously reduced the number of African elephants. See Elephant (Protecting elephants).
Overhunting
and overfishing have brought numerous species to the brink of extinction. The Asiatic lion, numerous fishes, and many species of pheasants have become endangered because people have hunted them for food and trophies. Many species are killed by people who believe that the animals threaten their livelihoods. Livestock owners, for example, may shoot, trap, or poison wild animals that they consider a danger to their herds. Farmers and ranchers in North America have nearly eliminated the red wolf and many species of prairie dogs, and herders in Africa had at one point almost wiped out the Ethiopian wolf. Some people in the fishing industry blame seals, which eat fish, for reductions in their catch. Fishing crews have killed so many Mediterranean monk seals that only a few hundred survive.
Competition with domestic and nonnative animals
is a major threat to numerous plants and animals. On many islands, native birds, mammals, and reptiles have become endangered after people introduced domestic animals. Livestock overgraze vegetation, eliminating habitat. Domestic cats prey on birds and small mammals. Rats escape from ships and infest islands, killing small birds and their eggs. In mainland areas, stocking of game fish threatens native fish, and nonnative plants and animals crowd out many native species.
Climate change
threatens an increasing number of species. Earth’s climate naturally changes over thousands of years, but industrial activities have changed long-term weather patterns in only a few hundred years. Many plants and animals have difficulty adapting to such rapid climate change. Recent climate change has raised Earth’s average temperature and increased extreme weather, such as hurricanes. These effects can lead to disastrous habitat loss. For example, a rodent called the Bramble Cay melomys went extinct after floods from the rising ocean overwhelmed the island of Bramble Cay, the only place where it lived. Species that can move to a new area encounter new threats, such as competition with native species.
Protecting endangered species.
Laws and conservation programs are helping to reduce endangerment worldwide. In the United States, the Endangered Species Act of 1973 protects endangered and threatened wildlife and plants from hunting, collecting, and other activities that harm them or their habitats. Since this law was enacted, the numbers of certain endangered animals, such as the alligator, bald eagle, and peregrine falcon, have increased so much that they have been removed from the endangered list or reclassified from endangered to threatened status.
Many wild species are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This treaty, drawn up in 1973, aims to control trade in wild animals and plants, their parts, and products derived from them. Over 170 countries have joined the treaty. CITES bans trade in rhinoceros horn, cheetah fur, sea turtle shells and meat, and certain whale products. Elephant ivory was banned in 1989, but later CITES decisions have enabled such African nations as Botswana, Namibia, and South Africa to export limited amounts of ivory to Japan and other countries.
Loading the player...How do zoos help save endangered animals?
Various organizations publish lists of endangered species to improve public awareness. The IUCN (International Union for the Conservation of Nature and Natural Resources) compiles lists that include thousands of animal and plant species that are threatened or endangered.
Protecting habitat is the key method of preserving endangered species. Many governments and organizations have set aside nature preserves. Working to limit the harmful effects of climate change also helps preserve threatened habitats.
Some zoos and animal research centers conduct programs that breed endangered species in hopes of returning their offspring to the wild. The programs have greatly improved the outlook for such endangered species as the black-footed ferret and the California condor.
