Integrating urbanization into landscape-level ecological assessments

Economists and ecologists are often asked to collaborate on landscape-level analyses designed to jointly assess economic and ecological conditions resulting from environmental policy scenarios. This trend toward multidisciplinary projects, coupled with the growing use of geographic information systems, has led to the development of spatially explicit models that can be used to examine and project land-use change. Although spatial land-use models are still evolving, most published efforts have modeled the conversion of nonurban land to urban uses as a function of explanatory variables based on population density and the spatial proximity of land to roads, markets, and population centers. In this paper, we use a gravity model to describe the urbanization potential of forest and agricultural land as a combination of population and proximity. We develop an empirical model that describes the probability that forests and agricultural land in western Oregon and western Washington were transformed to residential, commercial, or industrial uses over a 30-year period as a function of urbanization potential, other socioeconomic factors, and geographic and physical land characteristics. Land-use data were provided by the USDA Forest Service's Forest Inventory and Analysis program. We use this empirical model to generate geographic information system maps depicting the probability of future land-use change that can be integrated with landscape-level ecological models developed for western Oregon's Coast Range.