BIODIVERSITY CONSERVATION

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.