Competition: US & Canada
I am a Professor of Biology and the Evolution, Ecology, and Behavior Section Chair at Indiana University, where I have been on the faculty since 2000. I completed a B.S. at the University of Illinois in Honors Biology in 1984, a M.S. in Ecology at the University of Michigan in 1987, and a Ph.D. in Botany and Genetics from Duke in 1992. I have authored or co-authored more than ninety scientific articles and have received the NSF Career Award, NSF OPUS Award, Fulbright Fellowship, Bullard Fellowship, and was recently elected as a Fellow of the AAAS.
My work integrates theory with empirical tests of population and community dynamics of plants and microbes. This work has contributed to a growing awareness of the large role of soil organisms play in structuring plant communities. I have developed a framework that integrates the dynamics of soil organisms into the dynamics of plant communities. We have found that soil communities change rapidly in association with particular plant species and that these microbial changes in the soil community can increase, but more often decrease the performance of that plant species. This negative feedback on plant growth can directly lead to the maintenance of plant species diversity in communities and the strength of this negative feedback correlates with the relative abundance of plant species in communities.
My lab also works to understand the factors that influence microbial dynamics on plants. Plants interact continuously with beneficial and pathogenic soil organisms. We have found that within interactions between plants and beneficial soil fungi, called mycorrhizal fungi, weakly beneficial fungi have a local scale competitive advantage over strongly beneficial fungi, leading to declining benefit of the fungal community to the plant over time. However, we have found that plants can allocate resources preferentially to the most beneficial fungus and that this preferential allocation can allow beneficial fungi to increase, provided that there is sufficient spatial separation of the fungi in the root system. Similarly, we have found that the changes in virulence of soil pathogens depends upon local competitive dynamics in spatially structured soil environments.
As part of my Guggenheim Fellowship, I will write a monograph that builds from the forces driving plant-microbe interactions to a general framework for understanding the dynamics of plant communities.