forces of environmental change (National Research Council, 1990, 1992; for reviews of work using the equation analytically, see Dietz and Rosa, 1994; Chertow, 2001). Debates about the relative importance of population vis-à-vis other driving forces, about whether the effects of population growth are always negative, and about whether effects are uniform across settings were common in the 1970s and 1980s, but they have since largely receded from the scientific literature. Researchers’ interests have focused increasingly on understanding the driving forces, including not only population, affluence, and technology, but also human values, social institutions, public policies, and more; their effects and interactions; the mechanisms by which they affect environmental outcomes; and feedbacks from environmental conditions to human activity. Just as demographic driving forces may lead to environmental outcomes in various ways, environmental conditions and changes may also influence population size, structure, and change.

By the early 1990s, human influences on the natural environment were understood to occur through two main processes: change in land cover and land use (including use of waters) and “industrial metabolism,” that is, the transformation of materials and energy for industrial production and economic consumption (National Research Council, 1988, 1990). Population and other driving forces operate through these processes to generate specific outcomes that act as proximate causes of environmental change (National Research Council, 1992). Proximate causes tied to land use and land cover change include conversion of forests into agricultural lands, of farm fields and pastures to urban uses, and of wetlands to agricultural or urban uses, all of which transform habitats for nonhuman species and alter biogeochemical cycles. Industrial metabolism generates other proximate causes, including releases of phosphates and heavy metals into waterways and of nitrogen, sulfur, and carbon oxides into the atmosphere. Accordingly, research on population-environment relationships has been dominated by two rather distinct streams of work: one focusing on effects mediated by changes in land use or land cover, and another focusing on effects mediated by materials and energy transformations. Efforts to integrate both kinds of human influence have been far less common (e.g., Lutz, 1994; Curran et al., 2002; York, Rosa, and Dietz, 2003; Rosa, York, and Dietz, 2003).

The limited resources available for this study have led us to select only part of this large field for coverage. This volume focuses on research in which change in land use or land cover is a key mediator of human–environment interactions, in which demographic variables figure prominently among the driving forces investigated, and in which efforts are made