How Landscape Connectivity and Heterogeneity Affect Wind Dispersal

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Dispersal, or the movement of organisms, their propagules, or their genes away from their source, is a critically important process and is increasingly receiving attention in ecology and conservation biology as landscapes and the movement pathways of organisms are altered by human activities such as habitat loss and fragmentation. The flow of air and water and the structural pattern of the landscape can interact to affect the dispersal trajectory of passive organisms like spores, pollen, seeds, larvae, and insects. For wind-dispersed seeds, wind velocity is the most important determinant of dispersal distance, which can be altered by landscape structure. Therefore, human-induced changes in local landscape structure (e.g., by habitat fragmentation) may lead to shifts in physical flows and dispersal trajectories. Understanding how landscape structural heterogeneity alters both the spatial distribution of habitat and how it affects dynamic flows will be critical for understanding and predicting how human-induced landscape changes affect the dispersal of passively-dispersed propagules. The investigator proposes to test how landscape structural heterogeneity alters the trajectory of wind-dispersed seeds using a controlled experimental landscape at the Savannah River Site in South Carolina. Wind dynamics in patches that differ in their connectivity and patch shape will be quantified and used to parameterize a model predicting the wind-dispersal of seeds. This model will then be experimentally validated. The research will help conservation biologists determine appropriate conservation actions for plants in heterogeneous landscapes undergoing global change, including habitat fragmentation and climate change.