Plant detritus is the base of most food webs, but the effects of plant community change on food web dynamics have largely been ignored. As a result, it remains difficult to predict the effects of exotic plant invasions on native communities. A comparison of native and non-native plant species to determine whether non-native plant invasions have a general effect on food webs would facilitate predictions about the community level effects of plant invasions. Although most researchers assume that non-native plants are not sufficiently different from native plants to drive large changes within ecosystems, this assumption conflicts with recent empirical evidence documenting that even fine-scale genotypic or environmentally induced chemistry differences within plant species can have large extended effects on ecosystem processes. In this project, the investigators propose to determine nutritional quality of native versus non-native plant species to test directly the hypothesis that non-native plants produce lower quality detritus. By doing so, the study seeks clear evidence that impacts of non-native plant invasions are distinct from the levels of change that might occur as a consequence of shifts among native plant species. By attempting to reduce plant effects to aspects of plant detritus chemistry, the results of this project will facilitate predictions about the effects of other invasive plant species. This research will form the first step in testing the prediction that native plants, which decompose more rapidly and produce higher quality detritus, support greater algal productivity, zooplankton biomass, and amphibian abundance and biomass.
To carry out this research, the investigators will work closely with federal and state agencies that seek to manage threats to native ecosystems. This project explicitly supports postdoctoral training and graduate and undergraduate thesis research (6-10 undergraduate research theses will result from the proposed research). Because the lead PI is a first year, junior faculty member, this project will contribute significantly to developing his program at the University of Georgia. Finally, this project creates a partnership between two reputable natural resources programs, providing opportunities for students to interact with faculty from other relevant institutions.
