Cheatgrass — a highly invasive annual grass from Eurasia — is spreading across the West, posing what scientists call one of the most existential threats to western ecosystems.
Researchers with the University of Wyoming say the plant out-competes native grasses, fuels a cycle of hotter and more frequent wildfires, and erases sagebrush habitat critical for species like mule deer and sage grouse. Cheatgrass now affects roughly 26 percent of Wyoming’s land area — over 16 million acres — with major footholds in the Powder River Basin, the Bighorn Basin, and the Green River region.
State agencies, county weed districts, and rangeland managers are mounting an all-hands-on-deck response — including tens of millions of dollars in treatment funding, aerial spraying on hundreds of thousands of acres, and a promising new herbicide called Indaziflam, which can reduce the seedbank for multiple years.
But even supporters acknowledge the effort is falling behind the scale of the invasion. Wyoming set aside about $49 million for wildfire recovery and invasive control, less than half what was requested. Scientists warn the state could lose half of mule deer habitat within two decades if expansion continues.
