Kinds of conservation

This section divides the broad field of conservation into nine main categories. They are (1) biodiversity conservation, (2) water conservation, (3) ocean conservation, (4) soil conservation, (5) conservation of grazing lands, (6) forest conservation, (7) mineral conservation, (8) energy conservation, and (9) urban conservation. Each kind of conservation has different problems and solutions. Often, however, the management of one resource affects several other resources. For example, the conservation of forests helps conserve biodiversity, water, and soil. Forests absorb rain water and so keep it from running off the land too rapidly. They thus help prevent rain water from washing away the soil. Forests also provide homes for animals, plants, and other living things. In fact, a forest constitutes an ecosystem, a group of living organisms interacting with one another and with their physical environment.

This section deals mainly with conservation problems and practices in the United States. But much of the information applies to other countries as well. The section Conservation around the world discusses specific conservation concerns in other countries.

Biodiversity conservation.

Biodiversity, also called biological diversity, refers to the great variety of the world's living creatures. Animals, plants, and other living things make up an essential feature of nature, and they contribute to the beauty and wonder of life. Although biologists cannot agree on the true number of species on the earth, scientists have classified between 1,400,000 and 1,700,000 species. However, most specialists believe at least 4 million other species remain unstudied, and some scientists speculate that number may be more than 30 million. Different populations of a single species may also differ genetically from one another. That is, they possess different genes, the biological structures that carry specific traits from one generation to the next. Genetic differences add to biodiversity.

Through the ages, human activities have contributed to the extinction of numerous animal and plant species. Such extinct species include the passenger pigeon of North America and the Tasmanian tiger of Australia. Today, human activities threaten the survival of other animals and plants. Conservationists classify more than 8,000 species around the world as endangered (near extinction), and many other species that have been poorly studied may be equally in peril.

In the past, uncontrolled hunting was a major cause of endangerment and extinction. But today, many countries have laws that protect animals by regulating hunting and fishing. The destruction of habitat is the major threat to both animals and plants today. Although such legislation as the U.S. Endangered Species Act of 1973 protects the habitat of species listed as endangered or threatened, no laws protect the habitats of many other species whose numbers are dwindling. Development of land for homes, farms, industries, and transportation leaves fewer areas where wild animals and plants can live and reproduce. Pollution also damages natural habitats. Chemicals from sewage, industrial wastes, fertilizers, and pesticides build up in lakes and streams and in the soil.

Human beings also bring species of plants and animals from their native regions to other areas of the world. These nonindigenous species present a major threat to biodiversity. They often lack natural enemies in their new homes, enabling them to multiply quickly and drive out native animals and plants. The South American banana poka plant, for instance, has disrupted the native ecosystem of Hawaii. It has killed off many native trees and now dominates vast tracts of land. By destroying native trees, the banana poka threatens the existence of native animals that rely on these trees. Nonindigenous species can also harm people. One example, the South American red imported fire ant, has spread to North America and caused vast agricultural damage. In addition, many introduced species of animals and plants carry diseases that devastate native species.

A chief goal of conservation is to ensure the survival of animal and plant species. Conservation thus includes the enforcement of hunting and fishing laws, as well as laws protecting endangered species and regulating the importation of nonindigenous species. In many cases, an entire habitat requires protection and management. Some areas must then be set aside as national parks, state parks, nature reserves, and wildlife refuges. Farmers can help conserve such wildlife as rabbits and quail by leaving strips of natural vegetation along the edges of their fields. They can also reduce the use of harmful pesticides and fertilizers.

The populations of some species of animals and plants have dwindled to the point that they cannot survive in their natural environments. Zoos, botanical gardens, and other facilities attempt to breed these species in captive breeding programs. Sometimes they produce a large enough population for release into a protected area.