Invasions of native plant communities by exotic, weedy species are an important component of human-induced environmental change. This process may drastically and rapidly change the biodiversity of natural habitats, but the processes determining the degree and rapidity of such invasions are poorly studied. When an exotic or weedy species moves into a new habitat, it may undergo evolutionary change as it adapts to the novel environment and to a new community of species with which it interacts. If this evolutionary change results in improved growth, reproduction, and survival in the newly inhabited region, then evolution may play a major role in invasion success. This possibility has been little explored, and is the subject of this research project. The PIs have identified pairs of populations of the invasive plant, Bromus tectorum, where one population represents an introduced (or "invading") population, and the paired population is the source of the introduction. The proposed research will specifically test whether the introduced (i.e., invading) populations exhibit stronger competitive ability than the source populations from which they originated. The proposed work will improve our understanding of the mechanisms associated with the successful invasions of exotic plants. This research can give insight not only into mechanisms of invasion, but also into processes of microevolution, information much needed in these times of rapid global change.
