The functional integrity of normally forested landscapes: a proposal for an index of environmental capital.

The report of the World Commission on Forests and Sustainable Development [(1999) Our Forests, Our Future: Report of the World Commission on Forests and Sustainable Development (Cambridge Univ. Press, Cambridge, U.K.)] has called attention to a global need to restore the functional integrity of nature. The assumption that the biophysical world is capable of supporting any intensity of economic and political activity is now obviously wrong. The failures are seen as global changes such as the global climatic disruption now underway. The global disruptions are the product of cumulative local disruptions. Despite a conspicuous need, the scientific community has been slow in developing tools to appraise the functional integrity of landscapes. The proposal is advanced that the first steps deal with forests because they are so large in their influences on global biophysics. Analyses carried out by the commission are elaborated here as an index of functional integrity in the forest zone. The proposal is based on a simple, transparent approach. The scale is 0-100 with 100 as the nominal climax. Decrements and increments are applied as the structural and functional integrity of the landscape varies with whatever cause. The unit of area for these trials has been 10,000 hectares. The index has been applied to extremes such as the large extractive reserves in Acre, Brazil (100), the once-forested landscape of Haiti (0), and a managed forest stand in Maine. The analyses offer a scalar system for defining how well landowners and governments are protecting the public's interests in the integrity of the habitat of all.