The objective of this research is to experimentally investigate the effects of temporal variation in resource supply on the outcome and dynamics of competition between consumers. The proposed research would use planktonic rotifers (small, multicellular zooplankton) as model systems. Experiments would test the predictions that temporal variation in resource supply changes competitive outcome, slows the rate of competition exclusion, and allows competing species to coexist. These experiments would go beyond existing experimental studies by combining the following aspects: (1) using multicellular organisms instead of microbes, (2) using a temporal pattern of resource supply that is more realistic than that used in previous experiments, (3) measuring the effect of temporal variation in resource supply on the threshold resource concentration for positive population growth, and (4) predicting changes in competitive outcome, dynamics, and species diversity at different scales of temporal variation. %%% The question of the maintenance of species diversity in natural systems has intrigued ecologists throughout this century. Many theories have been proposed, but few are tested or testable. The notion that resources and resource competition controls community structure is compelling, but nature is highly variable. This is the first study to adequately test the role of resource variation in maintaining species diversity in communities. The results of this work will have important implications for understanding mechanisms controlling biodiversity in aquatic and terrestrial systems.
