Wednesday, August 5, 2009 - 2:10 PM

COS 76-3: Evolutionary declines in the soil-mediated impacts of Alliaria petiolata

Richard A. Lankau, University of Illinois

Background/Question/Methods

    Invasive species often evolve rapidly during or after introduction in ways that can exacerbate their impacts on native species, and native species can respond evolutionarily in turn. However, less is known about the longer term evolutionary trajectories of invasive and native species in the invaded range. Previous research suggested that genetic investment to allelochemical levels declined over a 50+ year chronosequence of A. petiolata invasion history.

Results/Conclusions

   In this study I found that the degree to which A. petiolata plants altered naïve soil microbial (bacterial, general fungal, and arbuscular mycorrhizal fungal) communities declined along this same sequence, in part in due to changes in allelochemistry. These differences translated into reduced impacts on native tree seedling growth. In addition, preliminary results suggest that soil communities may develop increased resistance and resilience to A. petiolata over time. Finally, field experiments show that these changes in A. petiolata populations and native soil communities can have important implications for the restoration of native plants.