How does the natural world maintain its astonishing diversity, especially among species that directly compete with each other? Theory predicts that constant changes to the physical environment over time and space and the transition from one scale to another (smaller to larger space, shorter to longer time) can account for species coexistence. To date, this prediction lacks rigorous empirical tests. The proposed project will use multi-scale field experiments and mathematical modeling based on field data to test the hypothesis that smaller scale environmental variation promotes broad-scale coexistence between invasive and native desert winter annual plants in the Sonoran Desert. Researchers will combine stable isotope analysis, aerial photographs, and field experiments to quantify a key mechanism underlying coexistence and the maintenance of biodiversity.
The project will provide a powerful model for scientists to conduct rigorous empirical tests on species coexistence across a broad spectrum of natural communities. Together with addressing a fundamental question in ecology, the project will foster an understanding of the dynamic nature of biological invasions, highlighting conditions under which an invasion is likely to cause problem. By informing land managers of those conditions, the project offers practical solutions to managing invasive species. The project is a collaboration between the University of Arizona and the US Marine Corps Air Station, Yuma, and results will be shared with military units and government agencies that must manage invasive species. This project will also train four undergraduate students, introducing them to the rigor and excitement of scientific discovery.
