ABSTRACT
One of the most sensitive indicators of ecosystem change is the response of native plant and animal species to alterations in land cover and management practices, and species response is of potential use in ecosystem risk assessments (Pratt and Cairns 1992; White et al. 1999). Here we describe one of several modeling approaches used to evaluate the alternative futures for Iowa watersheds described in Chapter 4: the potential impacts of habitat change on wildlife. In addition to the alternative futures, we also evaluated a reconstructed pre-European settlement landscape for a past perspective on changes in habitat for native species in the study watersheds. Our approach, modified from White et al. (1997), was based on the premise that the level of impact on a species increases as its habitat is depleted or degraded. Our work required a habitat map for each scenario (past, baseline, and alternative futures); a list of resident species; and an estimate of the suitability of each habitat for each of those species. Each scenario's impact on wildlife habitat was calculated as the median percent change in habitat for a given set of species relative to the baseline.
