Chapter Summary

Temperate broad-leaved forests and grasslands (biomes that make up most of North America and Europe) are among the most heavily human-dominated habitat type on the earth. The most biologically rich forests are the old-growth forests filled with ancient trees and relatively undisturbed ecological processes. While forests still cover about half the area worldwide that they did before humans became the dominant species on the planet, only about 22 percent of those forests retain old-growth characteristics. The most biologically diverse forests on the earth are the temperate rainforests of North America’s Pacific Northwest and the warm rainforests of the tropics. Both are threatened by logging for their valuable wood, but their loss would be a cultural and scientific disaster.

An innovative program for habitat and biodiversity protection involves debt-for-nature swaps in which long-term debt is forgiven if a country or a company agrees to protect natural areas. Many such arrangements have been worked out for developing countries. Conservationists are especially concerned about huge clear-cuts, in which all vegetation is removed over a large area. This method drives out wildlife and exposes soil to erosion. Seventy years of fire suppression in U.S. forests has allowed fuel to build up so that we now worry about huge conflagrations. Prescribed fires to reduce fuel loads would help solve the problem, but the public fears that even small fires could escape and threaten them.

Grasslands are among the most human-dominated of any biome. More than three billion domestic animals raised on pastures and grazing lands make a valuable contribution to human nutrition. Sustainable pastoralism can maintain ecosystem health on many grasslands, but too often overgrazing leads to habitat degradation and desertification. In some areas, rotational grazing and ranching of wild species can be useful approaches.

Parks, wildlife refuges, wilderness areas, and nature preserves occupy a small percentage of the earth’s total land area but protect valuable cultural resources and representative samples of the earth’s species and ecosystems. Parks are havens for wildlife and places for healthful outdoor recreation. Many are overcrowded, misused, and neglected, however. Pollution and incompatible uses outside parks threaten the values that we seek to protect. Wildlife is at the center of many park controversies. Is the purpose of parks to preserve wild nature or provide entertainment for visitors?

Marine refuges can protect the sensitive, old-growth habitats along coastlines and islands that serve as nurseries for a large percentage of oceanic biodiversity. No-take zones in these refuges not only serve as a sanctuary for threatened species but also replenish nearby areas open to harvesting. Coral reefs are among the most biologically rich but threatened habitats in the world.

The optimum size for nature preserves depends on the terrain and the values they are intended to protect, but in general, the larger the reserve, the more species it can protect. Establishing corridors to link separate areas can be a good way to increase effective space and to allow migration from one area to another. Economic development and nature protection can go hand in hand. Ecotourism may be the most lucrative and long-lasting way to use resources in many developing countries. Areas chosen for preservation often are lands of indigenous people. Careful planning and zoning can protect nature and also allow sustainable use of resources. Man and Biosphere (MAB) reserves provide for multiple use in some areas but strict conservation in others. Wilderness areas are defined as those where man is a visitor who does not remain. They possess outstanding opportunities for solitude and primitive recreation. Wildlife refuges were intended to be sanctuaries for wildlife, but over the years, many improbable and damaging uses have become established in them.