Plant-soil Feedback: A Mechanism to Explain the Spread of Invasive Species

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

ABSTRACT: Positive feedback has been proposed as a mechanism that results in the stable persistence of alternative states of an ecosystem. Such feedback may operate through plant-induced alterations in soil microbial communities, which in turn alter plant communities through changes in nutrient dynamics. The recent replacement of native understory plant communities in eastern deciduous forests by apparently stable communities of exotic species provides an excellent model system in which to test the presence of soil-mediated positive feedbacks. Previous studies of this system have shown that the recent shift in community composition is related to changes in both nutrient cycling processes and microbial community composition. I propose greenhouse microcosm and field plot experiments to test whether plants drive changes in soil-based ecosystem processes by altering the soil microbiota, and whether these changes in turn promote the dominance of the exotics. The proposed studies will explicitly contrast a litter-driven above-ground mechanism with a root-driven below-ground mechanism. BROADER IMPACTS: If the hypothesis of plant-soil positive feedback created by altered nutrient cycling is supported, it would both demonstrate a plausible mechanism for the persistence of alternative stable communities and help explain the establishment of dominance by some exotic plant species. In addition, this project will train at least 1 graduate student and 3 undergraduates.