PARENT SESSION
Oral Session # 49: Invasive Species IV: Grasslands; Wetlands.
Presiding: F Hughes
Wednesday, August 6. 8:00 AM to 11:30 AM, SITCC Meeting Room 204.
Patterns in rhizome carbohydrate fluctuation in the invasive Phalaris arundinacea: implications for wetland restorations.
Reinhardt, Carrie*,1, Galatowitsch, Susan1, 1 University of Minnesota, St. Paul, MN, USA
ABSTRACT- The presence of invasive species in wetland restoration sites often preempts native vegetation reestablishment. Phalaris arundinacea is an invasive perennial grass especially problematic for wetland restorations because it often dominates drained sites and persists after reflooding. Although Glyphosate application is a popular control method for Phalaris, success with this method is routinely limited, possibly due to a failure to time application with the phenology of Phalaris. Because Glyphosate is translocated to rhizomes with carbohydrates, characterizing patterns in seasonal rhizome carbohydrate fluctuations should identify the period of maximum herbicide translocation to rhizomes. A three-year field study was conducted to determine changes in rhizome carbohydrate levels of Phalaris using near-infrared spectrometry. Rhizome carbohydrate levels generally followed a trend of depletion during early season vegetative growth, and accumulation during late season reserve acquisition. The maximum rate of carbohydrate translocation to rhizomes varied from year to year, suggesting that phenologic cues, rather than calendar date, must be used to predict carbohydrate movement. Results from this research suggest that predicting carbohydrate fluctuation is feasible and timing herbicide application with respect to phenology will do much to increase herbicide efficacy for Phalaris in wetland restorations, thereby increasing the potential for ecosystem recovery in these systems.
Key words: wetland, invasive, Phalaris arundinacea, restoration