Protecting endangered species

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, giant pandas, orangutans, rhinoceroses, sea turtles, snow leopards, tigers, 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.

Some endangered species

How species become endangered

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.

Loss of habitat

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

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 endangered many species. For example, the Spix's macaw, a parrot of Brazil, is nearly extinct in the wild because so many have been 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 are nearly extinct. Rhinoceroses, wild chinchillas, the Tibetan antelope, and snow leopards are among these. Although such animals are now protected by law in the countries where they live, they are still poached (hunted illegally). Poaching also has seriously reduced the number of African elephants.

Overhunting

Overhunting has brought numerous species to the brink of extinction. The Caribbean manatee, the Asiatic lion, the dugong, 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, while herders in Africa have almost wiped out the simian 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 fewer than 200 survive.

Competition with domestic and nonnative animals

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.

Reducing endangerment worldwide

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 150 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 a 1997 decision enabled the African nations of Botswana, Namibia, and Zimbabwe to export a limited amount of stockpiled ivory to Japan. The ivory from these three nations was auctioned to Japanese buyers in 1999.

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. 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.

Zoo breeding programs

Wildlife conservation has become one of the most important jobs of zoos. Zoos breed many endangered species to increase their numbers. Such captive breeding in zoos has helped save several species from extinction, including the European bison; the nene, also known as the Hawaiian goose; and the Arabian oryx, a type of antelope.

Zoos throughout the world trade and lend animals to one another to avoid inbreeding (breeding animals that are closely related to each other). Inbreeding can produce birth defects and can eventually weaken an entire population. A number of zoo associations share breeding information through the International Species Information System (ISIS), a computerized inventory of hundreds of thousands of animals cared for by zoos throughout the world. ISIS also maintains records on the ancestors of the animals to more accurately track the genetic background of the living animals.

The American Zoo and Aquarium Association sponsors the Species Survival Plan (SSP), a long-term plan to save some of the most seriously endangered species. Many major zoos in the United States and other countries participate in the SSP. There are dozens of SSP programs, each focusing on a different species or group of species. Participating zoos keep careful records of each animal's family lines and physical characteristics. Zoos use this information to determine which males and females to breed together. The goal is to develop healthy populations of animals that can someday be returned to the wild.

Zoos also participate in conservation projects outside their walls. For example, many zoos sponsor efforts to preserve the natural habitats of threatened species, such as the Asian bamboo forests of the giant panda and the South American tropical rain forests of the lion tamarin, a species of small monkey.