Evolution and Ecology
6342 Storer Hall
Population Biology Graduate Group
University of California, Davis
Evolution of Herbivore Defense in the Invasive Grass Spartina alterniflora: A Mechanism for Biological Control and Restoration
Since receiving the Coastal Wetlands Fellowship award, I have been conducting a combination of greenhouse experiments and field experiments to look at the susceptibility of an invasive grass, Spartina alterniflora , to an insect released for biological control, the planthopper Prokelisia marginata in Willapa Bay, Washington. Thus far, there is strong evidence that S. alterniflora in Willapa Bay is far less resistant to herbivory than S. alterniflora from the Atlantic coast. Insects have higher survival rates and grow faster on Willapa plants than they do on Atlantic plants. Furthermore, evidence suggests that this difference may in part be due to evolution of decreased resistance over the course of the plant's spread in Willapa Bay.
Currently, I am attempting to determine if similar patterns exist for the range of S. alterniflora tolerance to P. marginata feeding. This information will be particularly useful, because it will tell us to what extent the invasive grass may be affected by the biological control agent. I am completing a large-scale greenhouse experiment addressing this question. In addition, this summer I have established six common gardens in Willapa Bay. Three of the gardens are in areas currently infested by P. marginata , and the other three control gardens are in adjacent areas that P. marginata has not yet spread to. Year 1 of this experiment will be completed in late October. I plan to report these results to the Garden Club when they are available.
The award has been most helpful in funding my travel to Willapa Bay. It has also enabled me to hire a research assistant for this past summer, without whom I would not have been able to conduct many of my experiments at the same scale. The remainder has paid for greenhouse and field supplies. This fellowship has allowed be to dramatically increase the quality of the research that I have done over the past two years.