Long-Term Efficacy of Glyphosate for Smooth Brome Control in Native Prairie

Abstract

Effective control measures are required for the invasive forage grass smooth brome in native prairie to maintain native prairie diversity and function. The objective of this study was to assess the long-term effectiveness of glyphosate as a control method for smooth brome and to evaluate the subsequent recovery of native prairie species at Kernen Prairie near Saskatoon, SK, Canada. In 1999 and 2000, a total of forty 6- to 8-m-diameter patches of smooth brome were spot sprayed with glyphosate; community composition in each patch was monitored for 17 yr. Following glyphosate application, the abundance of smooth brome decreased, and recovery of native species richness and the abundance of important native species, including plains rough fescue, was observed. In the long term however, the elimination of smooth brome created empty niche space ultimately occupied by other invasive species, particularly Kentucky bluegrass. The spot application of glyphosate is thus an effective control method for reducing smooth brome in native prairie; however, maintaining desirable native species composition in this system posttreatment depends on other factors, including the presence of additional invasive species that may move in after the elimination of smooth brome.