Freshwater metacommunities: dispersal through space and time at multiple scales

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What determines community structure and dynamics? This basic and ages-old question is still very relevant today and forms the basis of my research program. My work to date has clearly illustrated that integrating local environmental and spatial dispersal processes in the regulation of community structure through the metacommunity concept is absolutely necessary to capture all the important processes structuring local communities. This research provided some clear observational evidence for the recently developed metacommunity frame work that studies sites interconnected to each other through dispersing species. However, two other important ecological determinants, temporal processes and species traits, are currently only implicitly included in metacommunity theory. Explicitly incorporating them in the metacommunity framework will be an important step in determining the fundamental causes for local, spatial, and temporal metacommunity dynamics, the long term objectives of my research program. I will employ cladoceran communities in the hydrologically dynamic Peace-Athabasca Delta as a model system for testing specific hypotheses. I will focus for the next 5 years on: 1) the patterns and causes of short term temporal metacommunity dynamics within a season; 2) the patterns and causes of medium temporal metacommunity dynamics between seasons; and 3) how individual species traits ultimately cause these metacommunity dynamics. The first two projects are structured as two complete PhD projects, the third project as a series of Master and Undergraduate research projects. These projects use a combination of observational and experimental approaches, together with modern molecular techniques and state-of-the-art statistical analyses. These novel research questions and results will expand the mechanistic basis of metacommunity theory by including the important temporal processes and species traits. In addition, it will provide the rigorous scientific basis for predicting ecosystem responses during stresses and recovery because of climate change in the Peace-Athabasca Delta.