Post-fire vegetation cover, plant species diversity, and Ustilago bullata infection rates at Boise River Wildlife Management Area 2018-2019

Invasive-plant treatments often target a single or few species, but many landscapes are diversely invaded. Exotic annual grasses (EAGs) increase wildfires and degrade native perennial plant communities in cold-desert rangelands, and herbicides are thus sprayed to inhibit EAG germination and establishment. We asked how EAG-target and nontarget species responded to an herbicide mixture sprayed over a large, topographically diverse landscape after wildfire. We focused on how whole-community and natural EAG-pathogen treatment responses varied over years and physical properties of sites. We monitored plant cover and diversity in 41 pairs of plots located inside or outside areas (486 ha total) treated with a combined aerial broadcast spray of pre-emergent herbicide (imazapic) and weed-suppressive bacteria (Pseudomonas fluorescens, "MB906") to target EAGs after wildfires in southwest Idaho, USA.