Modelling animal populations in changing landscapes

Models of Mobile Animal Populations (MAP models) simulate long-term land use changes, population trends and patterns of biological diversity on landscapcs of lo3-lo5 ha. MAP models can incorporate information about past land-use pattcrns and management practices and can project future pattcrns based on management plans. We illustrate this approach with an cxamplc of how implerncntation of a US. Forest Service management plan at the Savannah River Sitc in South Carolina, U.S.A., might influence population trcnds of Bachman's Sparrow Airnophila aestivalis, a relatively rare and declining species In southeastern pine forcsts. In this casc, a managerncnt plan, largcly designed to improve cond~tions for an endangercd specics, Red-cockaded Woodpeckcr Picoides borealis, may have a negative impact, at least in thc short term, on anothcr species of management conccrn, Bachman's Sparrow. In a parallel processing version of thc MAP models, a single landscapc that would ordinarily be too large or dctailed to be simulated on a single computer is subdividcd into a number of smaller landscapes, and each landscape is simulated in parallel, cither on a single multi-tasking machine or on a group of nctworkcd machines. With this approach we are attempting to detcrmine just how large a landscape must be bcfore thc dynamics of a population within it are morc or less indepcndent of factors beyond thc landscape boundaries.