MODELING ANIMAL POPULATIONS IN CHANGING LANDSCAPES

Models of Mobile Animal Populations (MAP models) simulate long-term la nd use changes, population trends and patterns of biological diversity on landscapes of 10(3)-10(5) ha, MAP models can incorporate informati on about past land-use patterns and management practices and can proje ct future patterns based on management plans. We illustrate this appro ach with an example of how implementation of a U.S. Forest Service man agement plan at the Savannah River Site in South Carolina, U.S,A., mig ht influence population trends of Bachman's Sparrow Aimophila aestival is, a relatively rare and declining species in southeastern pine fores ts, In this case, a management plan, largely designed to improve condi tions for an endangered species, Red-cockaded Woodpecker Picoides bore alis, may have a negative impact, at least in the short term, on anoth er species of management concern, Bachman's Sparrow. In a parallel pro cessing version of the MAP models, a single landscape that would ordin arily be too large or detailed to be simulated on a single computer is subdivided into a number of smaller landscapes, and each landscape is simulated in parallel, either on a single multi-tasking machine or on a group of networked machines. With this approach we are attempting t o determine just how large a landscape must be before the dynamics of a population within it are more or less independent of factors beyond the landscape boundaries,