Why Is Cheatgrass Bad?

Expert Mike Pellant with the Bureau of Land Management explains why this annual invasive grass is a problem and describes ways to stop its spread.

What is cheatgrass?

Cheatgrass is an annual invasive grass that is native to Europe and eastern Asia, not North America. It was brought over by European settlers in the 1800s.

This non-native grass outcompetes native vegetation in sagebrush country in the western U.S. Part of the reason it took over is because early settlers also introduced livestock like cattle and sheep. Our native grasses and forbs weren’t adapted to the uncontrolled overgrazing by these domestic livestock. When the native plants were eaten and couldn’t regenerate fast enough, cheatgrass filled the void and covered the bare ground.

Cheatgrass is now found in at least 49 states, although it’s mainly a problem in the Great Basin. This annual grass is adapted to thrive in areas with wet winters and hot, dry summers.

People are now used to seeing cheatgrass-dominated landscapes in portions of Utah, Nevada, Idaho, Oregon, and California, but it’s not what we should see.

Why is cheatgrass bad?

Wildfires, for one. Unlike perennial native grasses, cheatgrass is an annual grass that dies off each year and grows a new plant from seed each spring. It dies off between late April and June, depending on local precipitation patterns.

Unfortunately, this leaves tons of dry fuel just in time for the West’s fire season. Cheatgrass dries out much earlier than native vegetation, significantly lengthening the historic fire season.

Plus, cheatgrass has very fine leaves and stems, which makes it ignite easily and causes fire to spread rapidly. The plants also grow very close together, with up to 10,000 plants in a square-meter.

Basically cheatgrass is comparable to tissue paper covering the landscape — an easily-ignited fuel that carries fire quickly and spreads it rapidly.

Since native plant communities aren’t adapted to frequent wildfires, these fires create even more cheatgrass-dominated rangelands. Cheatgrass is adapted to efficiently use the increased nitrogen in the soil after a fire, and invades empty spaces created by the fire.

Cheatgrass creates a vicious cycle: wildfires promote more of the invasive grass, which then further increases the impacts and probability of wildfires.

How does cheatgrass impact wildlife and range health?

It short-circuits a lot of the important ecological cycles. For example, cheatgrass has a shallow root system. Most of the roots are concentrated in the top 12 inches of soil. This means the invasive grasses absorb much of the water and nutrients during the spring growing season, stealing limited resources from native plants.

The loss of native plants means losing their deeper roots systems, which create healthy soil. Roots of sagebrush and other native shrubs can grow up to eight feet deep. They help cycle nutrients in the soil and can use deeper water. Cheatgrass also changes the diversity and abundance of soil microorganisms, which may reduce the ability of native plants to grow in the future.

For sagebrush wildlife, the biggest threat from cheatgrass is the loss of their habitat. More wildfires equal less places for wildlife to live. And as diverse native plant communities are converted into a monoculture of cheatgrass, wildlife has less food to eat.

Cheatgrass doesn’t meet the needs of most wildlife species. It doesn’t stay green long enough to provide nutritious forage during the summer and fall. Plus, it doesn’t provide the vegetation structure that many species need for cover or nesting habitat.

How big of a problem is cheatgrass?

It’s massive. Aldo Leopold wrote an essay in the 1940s called “Cheat Takes Over.” He could see into the future, warning us to watch out for this invasive weed.

Sadly, he was right. Now cheatgrass is one of the biggest invasive species problems in the western U.S., estimated to cover 50-70 million acres. The magnitude of the problem tends to overwhelm us.

What can we do to reduce the risks?

We won’t get rid of cheatgrass, but we can try to keep it as a minority component of the plant community instead of the majority species.

We have a number of different approaches that can reduce or remove cheatgrass. These include herbicides, mechanical treatments, and targeted livestock grazing. However, simply removing cheatgrass does not solve the problems associated with it.

We also need to restore native plants that will successfully compete with it. For instance, deep-rooted perennial bunchgrasses are able to use water and nutrients not available to cheatgrass, and are very competitive once established. 

A shared goal between private and public landowners is to increase “Ecosystem Resilience and Resistance.” This means making sagebrush landscapes more resilient so they can bounce back after a wildfire.

Healthy native plants are more resistant to cheatgrass invasion. Caring for our perennial bunchgrasses is key to building resiliency back into the system.

Are there success stories for coping with cheatgrass?

The BLM, USFS and NRCS are working with local and state partners to rehabilitate burned areas and restore diverse native plants on public and private lands. This is done by quickly seeding plants like bluebunch wheatgrass and sagebrush. The good news is that rehabilitated burned lands don’t convert to cheatgrass. This decreases the risk of future wildfires.

We also have new pre-emergent herbicides that reduce cheatgrass before it even has a chance to grow. Applying these herbicides in soon after a fire can give perennials a better chance. When herbicides are combined with good grazing management, native plant communities are nudged in the right direction.

Many places are also planting greenstrips of fire-resistant vegetation in strategic locations to establish fuel breaks. Greenstrips help slow down a wildfire, giving fire suppression forces more time to put it out.

Another management approach is focusing spring livestock grazing in areas where cheatgrass is dominant. This reduces available fuels before the start of the fire season. 

How can landowners and managers learn more?

There’s always room for more education to expand our cooperative knowledge, and for getting more people onboard to support solutions to the cheatgrass problem.

The Great Basin Fire Science Exchange offers webinars and other resources to move the needle on invasive grasses. The University of Wyoming’s IMAGINE collaboration (which stands for “Institute for Managing Annual Invasive Grasses Invading Ecosystems”) provides virtual and field workshops for landowners and local land managers around the West.

To me, there’s no bigger issue for our western landscape than wildfires and reducing the fuels that feed them. Hopefully, people will build on what we have now, and we’ll have more solutions in the future.

MEET THE EXPERT

I’ve been involved with cheatgrass one way or another since I started working with the BLM as a range conservationist. I coordinated the greenstrip program for BLM when it first started in the ‘80s. As part of this program, I traveled to Russia twice to look at cheatgrass in its native environment and discuss solutions with scientists.

Later, I was the coordinator for the five-state Great Basin Restoration Initiative and worked closely with managers and scientists on strategies to reduce cheatgrass and restore native plant communities.

I’ve lived in Boise, Idaho for most of my career, but I think my early background farming in Kansas really struck a note with me. It gave me a strong interest in finding solutions to reduce problems on working lands. Plus, I like challenges, and cheatgrass is the ultimate resource challenge!

ABOUT OUR PARTNER

Bureau of Land Management manages public lands for multiple use across regions and landscapes, with partners and using sound science. More than half of all remaining habitat for the greater sage-grouse is on public lands, most of it managed by the BLM.

Sage Grouse Initiative, as part of Working Lands for Wildlife, partners with private landowners as well as agencies like BLM to ensure conservation efforts span both sides of the fence in 11 western states.