Habitat conservation can be addressed in two major ways. First, we can critically analyze why the habitat is changing and can identify steps to be taken to arrest these changes. For example, we must determine the human needs currently being met by those who slash and burn tropical forests, and we must find alternatives to this devastating practice. These alternatives must meet those human needs without destroying the natural habitat and, in turn, the biological resources that depend upon that habitat. Perhaps no other scientific achievement would make a greater contribution to the maintenance of biological diversity in the tropics than would the development of practicable alternatives to slash-and-burn agriculture.

The second way of enhancing biological diversity is to set aside specific areas in which the current habitat is to be maintained. The establishment and maintenance of conservation reserves, parks, and wildlife refuges are examples of this means of maintaining biological diversity. Actions necessary to ensure the success of these protected areas must be taken. But we and others in the industrialized nations must not underestimate the difficulty of doing so. Questions such as the following must be addressed:

  • How much habitat and what kinds of habitats must be maintained?

  • Who will establish and maintain such habitat areas and at what cost in both economic and human terms?

  • Who will pay?


Systematic conservation can be defined as the conscious maintenance of the full range of natural diversity, e.g., species, communities, habitats, and ecosystems on a representative basis. Because we lack full knowledge of the identity and number of all species, let alone their distribution and habitat requirements, efforts to achieve systematic conservation must necessarily focus on higher levels of organization such as the habitat or ecosystem.

Although this is a much more tractable procedure than a species-based approach, it will nevertheless require both new research and a comprehensive synthesis of available information. Especially necessary are the review and integration of habitat classification systems and existing conservation area systems. It will also require the development of habitat size criteria to ensure the long-term security of those species each habitat type contains.

Worldwide, there are currently some 3,500 major conservation areas totaling approximately 4.25 million square kilometers (Office of Technology Assessment, 1987). These conservation areas can be grouped into 10 broad classifications, ranging from strict nature reserves to multiple-use natural resource lands. Broadly speaking, these areas represent some 178 of the 193 biogeographical provinces recognized by the International Union for the Conservation of Nature and Natural Resources as a first approximation of the diversity of Earth’s major habitat types. Globally, therefore, the nations of the world already have made a significant investment of land for the maintenance of natural communities and the perpetuation of their biological diversity.

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