In 1984, a ranger stationed in the Ketchum Ranger District wrote to a local land manager about an invasive grass taking hold in Sawtooth National Forest.
“This piece of ground is in poor vegetative condition because it is infested with cheatgrass,” he warned.
That section of land, a few miles northwest of Hailey, Idaho, was lost. But 40 years later, a Boise State-led team has returned to the same area to tackle the same problem.
Led by School of the Environment Associate Professor Kelly Hopping and College of Arts and Sciences Interim Dean Marie-Anne de Graaff, the team has partnered with U.S. Forest Service managers and Idaho ranchers to fight back against cheatgrass.
Their solution? Deploy herds of sheep across central Idaho hillsides and track their impact on the cheatgrass-ridden landscape. As the herds move through, scientists follow behind, monitoring plants and taking soil samples.
Three years into the project, results suggest that carefully managed sheep grazing could give land managers a new tool in the fight against cheatgrass.
A dangerous invader
Cheatgrass dominates the sagebrush steppe—the ecological biome that covers much of southern Idaho—but it is a relatively recent arrival. Native to Eurasia, it spread to North America with European settlers in the 1800s and soon began to take hold in the West.
Now it covers millions of acres. Cheatgrass consumes water early in the season, leaving little for native plants. When summer heat arrives, it dries quickly, turning hillsides brown and fueling fast-burning wildfires.
Periodic wildfires are natural in many ecosystems, but cheatgrass uses them to its advantage. “It grows really fast and invests very little in anything other than producing seeds,” said Hopping.
Even after fire scorches a hillside, cheatgrass seeds lie dormant in the soil. Hopping’s team has found as many as 2,400 seeds in a single square meter. The following spring, cheatgrass re-emerges faster and stronger than local flora.
The damage ripples outward: livestock can eat cheatgrass when it’s green, but once the seeds harden, animals avoid it. Diverse wildflowers give way to monotonous brown slopes. And every dry summer, the invasive grass becomes tinder that threatens crops, wildlife habitat and nearby communities.
Past efforts to control cheatgrass with herbicides often killed native plants as well, making them poor options in Idaho’s backcountry. That’s why Boise State researchers are testing a different approach.
Looking forward by looking back
For a few weeks each spring and fall, herds of sheep graze outside Hailey, Idaho. But these flocks aren’t wandering at random—they’re part of a research effort to trample and consume as much cheatgrass as possible.
“Sheep may be uniquely suited for this terrain,” said Renee Kehler, a rangeland management specialist with the U.S. Forest Service. “Most targeted grazing projects have been with cattle, but we’re hoping sheep can help at higher elevations.”
For ranchers like Mark Henslee of Hagerman, who co-owns one of the herds, the project fits naturally into existing grazing permits. “This is one of our permits, so we’re already going to be here,” he said.
By blending Idaho’s ranching traditions with Boise State research, the project is testing a solution rooted in the region itself.
In the field
Boise State’s scientists don’t spend much time in white lab coats. Instead, they lace up boots and haul gear into the hills.
“You get your breakfast, you hike anywhere from 10 minutes to two hours to your designated study plot, you take your assessments, then you move on,” said Maddi Sorrentino of Eatontown, New Jersey (MS, biology, 2024), who worked on the project as a graduate student and later lab manager.
Teams collect data before herds arrive, work alongside sheepherders during grazing and return in summer to measure soil health and plant populations. Some sites are near the road; others require hours of hiking into Idaho’s backcountry.
It’s grueling work, but necessary. “We want to do research in a realistic enough way that it can inform land management,” Hopping said.
The results are promising. “I think what we’re finding is that we are significantly reducing cheatgrass,” Hopping said. “In just a couple of years, the native forbs and wildflowers have increased after fall grazing.”
Restoring parts of a lost world
In a diary entry from the summer of 1890, Wilmetta “Metta” Ellis, a recent arrival from Kansas, described a day in the Boise foothills:
“We finally reached the summit of the last mountain and here got the finest view of Boise Valley. I cannot begin to picture it with my pen as nature revealed it in its wildest beauty.”
Ellis’ foothills were painted with wildflowers and shrubs, with little or no cheatgrass. That world has since been transformed.
“We’re accepting that we’re not able to turn back the clock to previous landscape conditions,” Hopping said. But she remains hopeful: “Sometimes you will see these places that are full of wildflowers. If we can nudge degraded regions closer to that, that would be incredible.”
With support from the U.S. Forest Service, Idaho ranchers and Boise State researchers, targeted sheep grazing could become a key part of Idaho’s landscape management. Done at scale, it could help restore the beauty Ellis once saw, reduce fire danger to nearby communities and create healthier rangelands for generations to come.
Research Support
This research is supported by grants from the U.S. Department of Agriculture, the Northwest Climate Adaptation Science Center and Boise State’s Department of Biology.