Millions of hectares in western North America have been negatively impacted by cheatgrass invasion, which transforms high-diversity ecosystems providing many ecosystem services into low-diversity ecosystems providing few services. Cheatgrass can promote wildfire, and burned sites are highly susceptible to further invasion. Post-wildfire restoration generally involves spreading limited resources over extensive areas, and this approach often fails to meet restoration objectives. We investigated an alternative approach that may be able to weaken cheatgrass-fire feedbacks, protect remnant and restored sites, and reduce further invasion by focusing restoration resources in small, spatially strategic locations. We tested multiple methods for creating greenstrips (fuelbreaks made of native plants), subjected experimental greenstrips to targeted grazing treatments, and monitored seedling densities over two years. At a highly invaded Great Basin site, we found that seed rate, spatial planting arrangement (mixtures vs. monoculture strips), seed coating technologies, and grazing treatments had strong and interactive effects on seedling densities. Plots planted with a doubled seed rate had 50% more seedlings than those planted with an average seed rate. Within high seed rate plots, mixed plantings had 40% more seedlings than monoculture strip plantings (33�4 seedlings per m2 in mixed, high rate plots). Ungrazed plots had 40% and 90% more seedlings than spring- and fall-grazed plots, respectively. However, results were primarily driven by one planted species (Elymus trachycaulus) which was both highly successful and susceptible to grazing. At a minimally invaded Colorado Plateau site, planted seedling densities were much lower (1-2 per m2) and planting techniques had weaker effects. Our experimental greenstrips are still too young to function as fuelbreaks, and the long-term effects of targeted grazing remain unclear. However, second-year results showcase methods for creating dense stands of native perennials at invaded sites, and emphasize that biotic resistance, grazing, species identity, and intraspecific competition can all influence restoration success.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.