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LANDSCAPE MODELING OF CHARACTERISTIC HABITAT SCALES, DISPERSAL, AND CONNECTIVITY FROM THE PERSPECTIVE OF THE ORGANISM
Walters, S. LANDSCAPE MODELING OF CHARACTERISTIC HABITAT SCALES, DISPERSAL, AND CONNECTIVITY FROM THE PERSPECTIVE OF THE ORGANISM. Presented at 19th Annual Syposium of the United States Regional Association of the International Association for Landscape Ecology, Las Vegas, NV, March 30-April 3, 2004.
A modeling framework was developed to investigate the interactive effects of life history characteristics and landscape heterogeneity on dispersal success. An individual-based model was used to examine how dispersal between resource patches is affected by four landscape characteristics: spatial contagion of hostile anthropogenic cover; percent hostile cover; interpatch distance; and variations in topographically-determined moisture level. The three model species ? long-, medium-, and short-range dispersers (LRDs, MRDs, and SRDs, respectively) ? varied in terms of maximum dispersal distance and land-cover-specific movement and mortality rates. The study explicitly addressed the relationship between spatial scales of species' movements and scale-dependent patterns in landscape structure. Species type, percent anthropogenic cover and patch configuration had the strongest direct effects on dispersal success. However, interactive effects of species traits and patterns of heterogeneity were of primary interest. Differences in the species' responses to patterns in land cover suggested that organisms can be discretely (versus continuously) categorized as short- (SRDs) versus long-ranging (M- and LRDs) dispersers. The distinction was defined by whether dispersal success did (the latter group) or did not (the former group) vary as a function of patchiness in hostile cover, and appears to be nonlinearly related to the species' maximum dispersal distance. The differences between the two disperser classes suggest alternative strategies for conservation and management ? specifically, that short-ranging species would benefit only from plans that maximize the amount of preferred land cover, whereas long-ranging dispersers might benefit from plans that also optimize access to preferred landscape conditions (i.e., management for effective dispersal corridors).
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY
ATLANTIC ECOLOGY DIVISION
POPULATION ECOLOGY BRANCH