Resumen
Sustainable management of a region?s critical and valued ecosystem resources requires an understanding about how these resource systems might function into the future. In urbanized areas, this requires the ability to frame the role of resources within the context of urban dynamics and the implications of policy and investment choices. In this paper we describe a three-step approach to assessing the impact of future urban development on ecosystem services: 1) characterize key ecosystem resources and services, 2) forecast future land-use changes, and 3) assess how future land-use changes will affect ecosystem services. Each of these steps can be carried out with different levels of sophistication and detail. All steps involve a combination of science and process: the science provides information that is deliberated upon by stakeholders in public forums before conclusions are drawn. We then illustrate the approach by describing how it was used in two regions in the state of Illinois in the United States. In the first instance, an early application of this approach, a simple overlay was used to identify development pressure on an environmentally sensitive river bluff; this finding altered thinking about public policy choices. In the second instance, the more fine-grained analysis was conducted for several ecosystem services.