The role of ecological heterogeneity in a long-term grassland restoration experiment

Many aspects of plant community structure and ecosystem functioning have been degraded by human disturbance to the environment, and may not return without human intervention through ecological restoration. Restoring biodiversity in disturbed ecosystems is a nearly-universal challenge, as well as an opportunity to test general ecological principles about species coexistence. This project extends an on-going 14-year test of whether heterogeneity in the environment creates vacancies and accessible resources that allow new species to establish and coexist in a community. Seeds of new species will be added to a prairie restoration experiment that was initiated in 1997. The experiment includes plots with up to four levels of soil heterogeneity, which has resulted in the development of plant communities that vary in the number and abundance of species among soil treatments and different years. The 14-year analysis of plant communities in this experiment demonstrated that plant diversity has declined over time, but more species have been maintained in plots with variable soil resources. If plots with greater ecological variability contain more resources for new species to exploit in space and time, then this study will demonstrate that the general ecological principle "heterogeneity begets diversity" can be applied to increase biodiversity in restored grasslands, where declining plant diversity over time is a common phenomenon. Further, this study will identify which plant traits contribute to successful establishment and persistence, which will inform species selection to maintain biodiversity over the long term.