This award will support collaborative research between Dr. Peter Abrams, University of Minnesota, and Dr. Ragnar Elmgren, Stockholm University. They will study the effects of indirect interactions between pairs of species of bottom-dwelling invertebrates of the Baltic sea. Indirect interactions occur through the mutual effects of two interacting species on a third species. The studies will involve laboratory experiments to measure short-term effects and mathematical modelling to estimate long-term changes in population densities. It is important to understand indirect effects to be able to predict responses to changed conditions in natural species communities. The effects are potential determiners of the abundance of species in a community. One practical benefit of learning about indirect effects is being able to predict the consequences of perturbations to a community, such as from oil spills. Experimental measurements have lagged behind theory about the effects because of the complexity of studying most natural communities. The relative simplicity of the Baltic invertebrate community alleviates this problem and makes it possible to measure the effects. The American and Swedish scientists have complementary skills to do the research. Dr. Abrams is a theoretical ecologist who has worked extensively on indirect effects, and Dr. Elmgren is an experimentalist with broad experience studying interactions between Baltic invertebrates.
