Can Plant Competition and Diversity Reduce the Growth and Survival of Exotic Phragmites australis Invading a Tidal Marsh?
The rapid proliferation of Phragmites australis in North America has challenged resource managers to curb its expansion and reduce the loss of functional tidal marsh. We investigated whether native plant competition could reduce the ability of Phragmites to invade a tidal marsh, and if plant diversity (species richness, evenness, and composition) altered the competitive outcome. Immature Phragmites shoots and four native halophytes were transplanted to small but dense field plots (~1,200 shoots m−2) comprising three community structure types (Phragmites alone, Phragmites + 1 native species, and Phragmites + 4 native species). Interspecific competition significantly reduced Phragmites aboveground biomass, shoot length production, density, and survival by approximately 60%. Additionally, plots planted with greater native diversity contained Phragmites with the lowest growth and survival, potentially indicating diversity-enhanced resource competition. Competition consistently reduced the growth of Phragmites even under favorable conditions: lack of strong tidal flooding stresses as well as elevated nutrient pools.
KeywordsBiodiversity Richness Common reed Invasive species management Halophyte Salt marsh
We thank Garrett Crow, Aaren Freeman, Thomas Lee, and Barrett Rock for their comments on previous drafts on this manuscript. We are also grateful to Jessica Devoid, Alyson Eberhardt, Joanne Glode, Gregg Moore, and Robert Vincent for their assistance in the field, and again Alyson Eberhardt and Paul Sokoloff for assistance with analyses. The manuscript was improved by the insightful comments by two anonymous reviewers and the associate editor, Dr. Morten Pedersen. Primary funding for this research was provided by the New Hampshire Coastal Program, Department of Environmental Services under NOAA grant nos. NA17FZ2603 and NA170Z1529, and by NOAA’s Restoration Center, grant no. NA05OAR4171149. Additional funding was provided by the New England Chapter of the Society of Wetland Scientists. Jackson Estuarine Laboratory contribution no. 494.
- Burdick, D.M., G.E. Moore, C.R. Peter, A. Leonard, and M. Dionne. 2009. Regional assessment of the relative performance of coastal wetland restoration in New England. Silver Springs: NOAA Restoration Center.Google Scholar
- Elton, C.S. 1958. The ecology of invasions by animals and plants. London: Bulter and Tanner.Google Scholar
- Haslam, S.M. 1971. The development and establishment of young plants of Phragmites communis Trin. Annals of Botany 35: 1059–1072.Google Scholar
- Keddy, P.A. 1989. Competition. London: Chapman and Hall.Google Scholar
- Lindroth, C.H. 1957. The faunal connections between Europe and North America. New York: Wiley.Google Scholar
- Marks, M., B. Lapin, and J. Randall. 1994. Phragmites australis (P. communis): Threats, management, and monitoring. Natural Areas Journal 12: 285–294.Google Scholar
- Peter, C.R. 2007. Can plant competition and diversity reduce the success of exotic Phragmites australis invading a salt marsh? MS thesis. Durham: University of New Hampshire.Google Scholar
- Rice, D., J. Rooth, and J. Stevenson. 2000. Colonization and expansion of Phragmites australis in upper Chesapeake Bay tidal marshes. Wetlands Ecology and Management 20: 280–299.Google Scholar
- Summers, C.G., and A.S. Newton. 1989. Relationship of herbivore-imposed stress to weeds in alfalfa. Environmental Entomology 18: 958–963.Google Scholar
- Tilman, D. 1982. Resource competition and community structure. Princeton: Princeton University Press.Google Scholar
- USDA. 1994. Evaluation of restorable salt marshes in New Hampshire. Durham: U.S. Department of Agriculture.Google Scholar
- Vasquez, E.A., E.P. Glenn, J.J. Brown, G.R. Guntenspergen, and S.G. Nelson. 2005. Salt tolerance underlies the cryptic invasion of North American salt marshes by an introduced haplotypes of the common reed Phragmites australis (Poaceae). Marine Ecology Progress Series 298: 1–8.CrossRefGoogle Scholar
- Warren, R.S., P.E. Fell, J.L. Grimsby, E.L. Buck, C.G. Rilling, and R.A. Fertik. 2001. Rates, patterns and impacts of Phragmites australis expansion and effects of experimental Phragmites control on vegetation, macroinvertebrates, and fish within tidelands of the lower Connecticut River. Estuaries 24: 90–107.CrossRefGoogle Scholar