Contributions of Spatially Explicit Landscape Models To Conservation Biology

The practice of conservation is often a form of land management. One of the most powerful approaches for connecting the needs of a particular species with land usage is the linking of biologically-detailed models of that species dispersal and demography with geographic information systems (GIS). For example, juvenile spotted owls must depart their birthplace in search of unoccupied expanses of old growth forest. Maps that detail the scarcity, fragmentation, and location of remnant old growth stands dramatize how difficult a search these juvenile owls may face in heavily logged portions of the Pacific Northwest. By connecting these spatially detailed maps with a model of how owls disperse and reproduce, managers can construct logging plans that make the best of what little old growth might remain. We call such approaches spatially explicit population models (or SEPMs) because they assign habitats and owls to particular locations in space, and depending upon the number and placement of individuals, they predict population change as a result of dispersal, mortality, and reproduction. The emergence of user-friendly GIS software, the maturing of ecological theory pertaining to population dynamics in fragmented habitats, and the increased popularity of individual behavior simulation models have combined to produce a tremendous enthusiasm for SEPM’s (see Ecological Applications, issue #1, volume 7, 1995).