PARENT SESSION
Symposium #3: The role of spatial extent in ecological pattern and process.
Sponsored by ESA Vegetation Section
Organized by: J. Nekola and H.H. Wagner.
Monday, August 6, 2001. 8:00 AM to 11:45 AM. Madison Ballroom B

Gravity models: from long-distance dispersal to local patterns of movement.

Bossenbroek, Jonathan ¹, ¹

ABSTRACT- Gravity models estimate dispersal patterns by predicting movements between discrete points in heterogeneous landscapes. Gravity models are based on the premise that movements of individuals are affected by the spatial arrangement of destinations as well as the attractiveness of those destinations within a given extent. Based on recreational boater records and the size and location of inland lakes, a gravity model was developed to predict the long-distance dispersal of zebra mussels (Dreissena polymorpha) into inland lakes of the Western Great Lakes region during the next 100 years. The results of this model suggest that total infestation of the inland lakes of the Western Great Lakes states is not imminent. On average, only 20% of the possible lakes within the study region were predicted to become infested. On a local scale, gravity models can be used to explore movement pathways of individual organisms. I have developed gravity models to explore the impact of landscape heterogeneity and extent upon movement pathways within simulated landscapes. These trials were conducted to analyze the potential use of gravity models to simulate the movements of ground-dwelling beetles. If an organism's dispersal or movement is affected by distance and the attractiveness of specific destinations, gravity models may represent another important class of model that can be used to predict the spread of native and non-native species through heterogeneous landscapes.

KEY WORDS: gravity model, disperal, spatial interaction, migration