SOIL LEGACY OF INVASIVE PHRAGMITES AUSTRALIS FROM MANAGED AND UNMANAGED PLOTS

Phragmites australis ssp. australis, which is invasive in coastal areas of North Carolina, is thought to negatively affect native plant populations throughout its invaded range across North America. This study examines ecological impacts of invasive Phragmites on native plants through its effects on soil. We collected soil from four locations across southeastern North Carolina, from plots that had unmanaged Phragmites, managed (herbicide-treated) Phragmites, and adjacent areas that did not contain Phragmites and did not have a known history of management. In total, we used ten unique soil types—two sites with all three soil histories, and two sites with soil collected from just unmanaged Phragmites and adjacent plots. We then planted a rhizome or plug of one of two species of native marsh grasses, Spartina patens and Spartina alterniflora, or of the invasive Phragmites in each soil type (10 soil types x 3 species x 6 replicates = 180 pots). We kept plants in a greenhouse and measured metrics of survival and plant size over three months. We then harvested aboveground and belowground biomass for each plant. We compared growth metrics and biomass measurements between groups to determine whether Phragmites has a lasting soil legacy that impacts native plant growth in managed and unmanaged areas. The results of this study have the potential to inform management decisions regarding the use of herbicides to control Phragmites invasions.

Presentation Preference: Either

Primary Presenter: Tabitha Ormond, University of North Carolina Wilmington (tabithaormond23@gmail.com)

Authors:

Tabitha Ormond, University of North Carolina Wilmington  (tro1207@uncw.edu)

Zachary Long, University of North Carolina Wilmington  (longz@uncw.edu)

Beth Darrow, Bald Head Island Conservancy  (darrow@bhic.org)

Christopher Shank, Bald Head Island Conservancy  (shank@bhic.org)

Stacy Endriss, Virginia Polytechnic Institute and State University  (endriss@vt.edu)