Glyphosate, steam and cutting for non‐native plant control in Alberta fescue grassland restoration

Question What are the effects of cutting, glyphosate application and steam application on abundance and diversity of non‐native grasses and forbs and non‐target native grasses and forbs in restoration of a complex disturbed fescue grassland? Location Waterton Lakes National Park, Alberta, Canada. Methods Cutting, glyphosate application and steam application treatments were implemented at three disturbed sites in an incomplete block design with a control. Plant communities were evaluated for four growing seasons, one before and three after management treatment implementation. Results Glyphosate reduced non‐native grass cover for three growing seasons following application and non‐native forbs for one growing season. Glyphosate led to significant increases in non‐native forb cover, more than double pre‐existing values 2 and 3 yr after application. Native species abundance and diversity were more negatively impacted by glyphosate on sites with higher abundance and diversity prior to management treatments. Low frequency cutting over 2 yr did not consistently control non‐native species, steam reduced non‐native grass cover at the most heavily invaded site. Conclusions Site‐specific conditions must be considered to develop effective control methods for non‐native species. No treatment effectively re‐established native grassland communities. Glyphosate application reduced non‐native grasses, but not non‐native forbs. When native forbs were abundant prior to management, glyphosate reduced them. Steam may have potential and should be further investigated. This is one of only a few studies to investigate methods to manage multiple non‐native species occurring with native species, rather than management of a single undesirable species, and is the first to assess steam as a management option for native grasslands.