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Invasive species have an ever-increasing impact on the ecological and economic functions of ecosystems. Cheatgrass (Bromus tectorum) is an invasive annual grass that is widely distributed throughout most of the western United States. Cheatgrass produces high amounts of fine fuels that can increase fire frequency and severity, altering vegetation composition and structure. Although cheatgrass can be used as early spring forage for livestock and wildlife, it may not be preferred, and therefore its suitability as a forage is questionable. The objective of this research is to determine if there is a direct, predictable relationship between pre-treatment vegetation condition and post-treatment increases in perennial grass biomass and other vegetation characteristics following treatment with two formulations of imazapic (liquid and granular). We sampled locations representing a gradient of cheatgrass to perennial grass biomass and canopy cover ratios prior to, and following, herbicide application across multiple sites. At each intensively sampled location we employed four different sampling methods to determine the ratio of cheatgrass to perennial grass using both biomass and cover.� At the Saratoga and Pinedale, Wyoming field sites, we collected pre-treatment data in 2015, aerially applied herbicides in September 2015, and collected post-treatment data in 2016. Initial post-treatment results indicate that both herbicide formulations reduced cheatgrass cover. Preliminary data analyses suggest the ability to identify cheatgrass abundances at which an increase in perennial grass biomass in response to herbicide treatment may be expected, but inter-annual variability in vegetation poses challenges. Post-treatment data will be collected on all sites in 2017, including two additional field sites near Sheridan and Hyattville, Wyoming sampled and treated in 2016, to further evaluate the response of cheatgrass and associated vegetation following imazapic application for cheatgrass control.