Traditional approaches to studying plant invasions have produced limited insights into the mechanisms underlying successful and widespread invasions. A wealth of reviews has indicated a need for biogeographically explicit experiments that consider a variety of biotic interactions, that include multiple populations of the invasive plant from its native and introduced range, and that utilize multiple plant species from each range to provide appropriate ecological context. This project will build on ongoing studies of the Chinese tallow tree, a species that is highly invasive in the southeast U.S., by simultaneously manipulating multiple biotic interactions in both invasive and native portions of the species' current geographic range. Field and greenhouse experiments in the US and China will be used to investigate the roles of aboveground (specialist and generalist herbivores, foliar fungi) and belowground (pathogenic fungi, mycorrhizae, herbivores) interactions in determining tallow tree success. The intellectual merit of this project is that it will enhance understanding of mechanisms that contribute to the success, or failure, of introduced species, and the relative importance of those mechanisms in native and new portions of the geographic range of an invasive species. The substantial and growing economic impact of invasive species contributes to the broader impact of this project; better understanding of mechanisms that contribute to the success of invasive species will help guide land and resource managers. Other broader impacts include training of graduate and undergraduate students, and a significant international collaboration with scientists at four Chinese institutions. This award is funded in part by the Office of International Science and Engineering.
