In addition to reducing vegetation that may mitigate the effects of increased carbon dioxide in the atmosphere, the clearance of large tracts of forest also is feared because it may reduce the diversity of plant and animal species. One facet of declining biological diversity is the loss of plants that have medicinal qualities. It is generally assumed that undisturbed, old-growth forests in tropical areas represent more plentiful locales for plants used by native healers. Because many modern pharmaceuticals have been developed from tropical medicinal plants, preservation of old-growth forests therefore is believed to be especially important. This project tests the validity of the assumption that underlies this belief by testing the hypothesis that areas from which old-growth vegetation has been removed in order to establish second-growth forests, cocoa plantations, or degraded pastures may actually be more significant sources of medicinal plants for native healers than are old-growth stands. Working in carefully selected sample sites near the Pau Brasil Ecological Reserve in eastern Brazil, the investigator will identify medicinal plant species in each plot with the help of local healers. Complementary inventories of plant species in each plot will permit generalization of the impacts of four general land-use regimes on the diversity of medicinal plant species. This project will provide new data and understandings of value in a number of different ways. It will expand information about native medical practices and about the uses of different types of plants by healers with different medical traditions. It also will provide a direct test of hypotheses dealing with the number and types of plants found in undisturbed forests and in sites that have been altered in different ways by human activity. The project therefore should enhance understandings of the impacts of human activity of biological diversity in an important environmental setting.
