Competition is a central force shaping ecological communities. Classic competition theory predicts that the number of species that can coexist should be no more than the number of resources that are in limited supply. Natural communities, however, often harbor a large number of species, despite the typically small number of resources in limited supply. For example, one ha of Panamanian rainforest supports 18,000 species of beetle. How could such a large number of specie possibly coexist in nature without facing extinction? Ecologists have proposed a myriad of hypotheses explaining this discrepancy between theory and data. This project will experimentally test some of these hypotheses. The research will examine the consequence of changes in resource availability over time and the consequences of changes in resource availability across space for species coexistence. Work will be conducted in laboratory microbial microcosms containing bacteria-feeding single-celled protists and their bacterial resources. Results from this project will help scientists understand mechanisms of maintenance of species diversity in natural communities. Further, this project will contribute to educational outreach by training graduate and undergraduate students (including underrepresented minority students), providing case studies for undergraduate ecology courses, and facilitating science learning among K-12 students.
