Spatial ecology and predator-prey dynamics

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A large body of theory suggests that most predator-prey systems should be prone to extreme cycles in abundance, yet such cycles are rare in nature. One plausible explanation for this paradox is that weak mixing of predators and prey produces asynchronous variation in local population dynamics. My long-term objective is to identify causal mechanistic links between movement processes, patterns of spatial distribution, and predator-prey dynamics. Spatially-explicit models and experimental trials will be used to evaluate the degree to which weak mixing serves to stabilize predator-prey dynamics. I propose to address this objective using a combination of theoretical, field and laboratory approaches. The proposed field work extends our ongoing observational studies of behavior and dynamics of a suite of large herbivores and carnivores in Serengeti National Park. It is based on a state-of-the-art combination of computer models of complex random walk processes, remotely-sensed landscape features, satellite GPS radio-collars, accelerometers, and animal-mounted video camera-collars to observe behavior even when animals are out of sight. The proposed laboratory work responds to an exciting new opportunity to use a one-of-a-kind facility at the University of Guelph, called the Limnotron, to test experimentally how movement processes contribute to spatial dynamics and food-web interactions under controlled conditions in massive aquatic mesocosms. In both cases, we study mobile populations of resources and their consumers whose behavior, feeding, movement, and demographic parameters can be estimated from observations of individuals, which are then related to spatial distribution patterns and population dynamics measured at coarser temporal and spatial scales. Theoretical modeling is well-integrated into both the field and laboratory programs, to fully explore the implications of movement and spatial dynamics for ecological interactions. These models will help us to forge conceptual links between spatial processes and their ecological consequences. This is an important step towards identifying the best means of conserving and managing complex natural ecosystems at a landscape scale.