Evan Siemann is an Associate Professor of Ecology and Evolutionary Biology at Rice University. His research relates to a central problem in ecology; understanding the processes that determine the abundance of species in ecological communities. Specifically, Seimann is interested in the mechanisms that control species dominance and diversity, as well as the relative importance of top-down and bottom-up forces in ecological communities. He has investigated the factors that control insect diversity and community structure and, more recently, the role of herbivores vs. resources in promoting the success of an alien tree species, the Chinese tallow tree (Sapium sebiferum).

Specifically, Siemann is seeking to understand how local environmental factors (e.g., herbivores, fungal pathogens, resources, mycorrhizal symbionts, disturbance regime and recruitment limitation) interact with post-invasion evolutionary adaptations to determine the effects of Chinese tallow tree invasions of forests and grasslands throughout the southeastern United States. Siemann and collaborators have also recently begun establishing studies in the trees¿ native range in China, and in the Hawaiian islands where tallow trees have been introduced but are not invasive.

In addition to advancing basic scientific knowledge about alien species invasions, Siemann¿s research group is working on several applied research projects related to the control of exotic plant and animal invasions in Texas. These projects should contribute to better-informed land-management decisions.