Invasive Grass Increases Wildfire Threat in Western States

By: - July 2, 2019 12:00 am

After a wet spring, Western states are experiencing a massive bloom of cheatgrass, a yellowish, knee-high and highly flammable grass that carpets rangelands across 13 states. In Nevada, samples show up to 3,000 pounds of the invasive plant growing per acre, according to the Bureau of Land Management.

The profusion of the weed could fuel major wildfires this summer. “The people I talk with think it’s more likely to be a rangeland fire year than a forest fire year,” said Mark Brunson, an environment and society professor at Utah State University.

Some state and federal leaders want to do more to fight cheatgrass and are drawing up action plans. But beating back the plant requires coordination between different agencies and levels of government, sustained commitment and funding.

And it can be hard to muster political will to spend money on addressing an invasive species that typically fuels wildfires in remote areas, far from major towns and cities.

“We have an uphill battle trying to get the attention of the public,” said Ken Mayer, a former director of the Nevada Department of Wildlife who’s working on an invasive species action plan on behalf of the Western Association of Fish and Wildlife Agencies.

While rangeland fires tend not to threaten homes the way forest fires do, they affect agriculture, watersheds and air quality, and could threaten more communities as more people move out West. Like all kinds of wildfire, they’re becoming bigger and more frequent partly because of climate change.

In northern Nevada, last year’s Martin Fire — which may have been sparked by Fourth of July fireworks — sped through cheatgrass to consume over 435,000 acres. Ranchers lost cattle, precious sage-grouse habitat burned, and the fire created a smoke plume visible from space.

Experts say there’s a clear link between cheatgrass, which covers more than 100 million acres across the West, and rangeland megafires. “I’m convinced that if we committed the resources to fighting and addressing the invasive issue, we would see a lessening in the size [of fires],” Mayer said.

Cheatgrass is an annual plant that shoots up in the spring and dries to a dusty tan color in the summer. In a dry year, cheatgrass might grow an inch. In a wet year, like this one, it might grow knee-high.

Federal, state and local land managers are trying to rescue ecosystems by spraying cheatgrass with herbicides, planting more native vegetation and grazing cows and sheep in cheatgrass-heavy areas.

The Western Governors’ Association is forming a cheatgrass working group and has agreed to address the issue with the U.S. Department of Agriculture. Mayer’s fish and wildlife group has been rallying state agency associations and nonprofits to support an invasive species action plan they will present to members of Congress and federal officials this fall.

There are steps that can be taken to reduce the cheatgrass threat, Mayer said. “That’s not the limiting factor at this point,” he said. The problem is “a commitment, policy and funding-wise, from the highest levels of federal and state government.”

From Sage Brush to Savannah

Cheatgrass, native to Eurasia, appeared in North America in the 19th century and has been spreading ever since. It’s been spotted in all 50 states, from sidewalk cracks in Chicago and front yards in Denver to remote shrub lands in Utah. In Nevada, the climate is so cheatgrass-friendly that the weed now covers millions of acres that once were dotted with native grasses, flowers and shrubs.

Cheatgrass starts growing in early spring, sucking nutrients out of the soil that native species such as sagebrush, rabbitbrush and bluebunch wheatgrass need. Eventually the weed can cover the landscape like an unbroken sea.

“Once you have it, it’s very, very hard for anything else to grow. So you get this monoculture,” said Elizabeth Leger, a professor and plant biologist at the University of Nevada, Reno. When cheatgrass dries out in the summer, she said, “it just becomes this unbelievably flammable, super-connected, fine fuel.”

After a wildfire, cheatgrass will regrow faster than native species. If fire torches the same area several times in a few years, it becomes all but impossible for native grasses and shrubs to recover, Leger said. “It’s really depressing.”

The cheatgrass infestation is so vast that it’s hard to address in a cost-effective way, Leger said. But experts say ecologists can try to prevent the weed’s spread and remove it from key areas to make ecosystems healthier.

Editor’s note: A previous version of this story incorrectly stated the status of a Nevada resolution. It didn’t pass the legislature.

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Sophie Quinton

Sophie Quinton writes about fiscal and economic policy for Stateline. Previously, she wrote for National Journal.