Articles

The responses of terrestrial ecosystems to globalenvironmental change, and the resulting impacts on the natural resources on which humans depend, are topics of great societal concern and current scientific interest (Vitousek 1994). Anthropogenic emissions of greenhouse gases are ex-pected to raise the mean temperatures of Earth’s surface by 1.4°C to 5.8°C during this century (Houghton et al. 2001). Such warming is likely to alter patterns of global air circula-tion and hydrologic cycling that will change global and regional precipitation regimes (Houghton et al. 2001). Corresponding changes in air and soil temperatures, soil water and nutrient contents, and concentrations of atmos-pheric carbon dioxide ([CO2]) are likely to alter the func-tioning of natural and managed ecosystems in terrestrial en-vironments. Because these changes will co-occur with ongoing changes in global land use and land cover that have alread