Cheatgrass a Burning Problem
By BRODIE FARQUHAR Casper Star-Tribune staff writer
Casper, Wyoming - Tuesday, February 25, 2003
With the last relatively intact, large-scale sagebrush ecosystem in the lower 48 states, Wyoming doesn't have a severe cheatgrass problem -- yet.
"We used to think that eastern Idaho was immune to cheatgrass," said John Glenn, a fire management specialist for the federal Bureau of Land Management in Wyoming, speaking at a cheatgrass awareness conference in Casper on Monday.
Today, Glenn said, Idaho averages a yearly cheatgrass burn of 250,000 acres that is rapidly and perhaps irrevocably replacing a vast sagebrush ecosystem with a monoculture of cheatgrass. A cheatgrass burn is a fire that burns prairie dominated by the invasive weed.
Frequent fires destroy sagebrush and other species, leaving the opportunistic cheatgrass to enter and dominate disturbed areas. The fires destroy some, but not all cheatgrass seeds, leaving more than enough to take over an area.
Idaho sagebrush country went from a fire cycle of every 30 years to every other year, he said, with fires getting bigger, hotter and more frequent, and stands of cheatgrass spreading over the horizon.
"There's a lot of similarities between eastern Idaho and Wyoming," Glenn said, warning range managers and livestock producers that prevention is much easier and cheaper than eradication of cheatgrass and the restoration of native grasses, forbs and sagebrush.
He emphasized that the problem is still manageable in Wyoming, which averages a yearly cheatgrass burn of 27,000 acres.
According to various speakers, cheatgrass ( Bromus tectorum ) is an exotic annual grass that is widely distributed in the western United States. Pre-adapted to the climate and soils in the Great Basin Desert (parts of Idaho, Nevada, Oregon, and Utah), cheatgrass rapidly filled the void left vacant by native plants that were consumed during historic overgrazing. Native deer and sage grouse populations have been devastated by the loss of sagebrush.
Cheatgrass is a prolific seed producer at 1,800 seeds per square foot, said Jim Davis, a range biologist with the Utah Division of Wildlife. Cheatgrass seed can germinate in fall or spring, which gives it a competitive advantage over native perennials.
Davis opened the two-day conference with an alarming series of before and after photographs, showing the wholesale eradication of sagebrush communities and their replacement by cheatgrass, other weeds and juniper stands.
"I call this an ecological dead-end," said Davis, pointing to a slide of a field that had completely switched over from sagebrush to cheatgrass. Even where cheatgrass hadn't yet burned out the sagebrush, Davis said it prevented sagebrush seeds from sprouting, leading to decadent stands of old sagebrush plants that were increasingly primed for fire -- especially during a widespread drought.
Today, over 3.3 million acres of public lands in the Great Basin are dominated by cheatgrass, while some 100 million acres are either infested with or susceptible to cheatgrass invasion, Glenn said. By comparison, of Wyoming's 18 million acres under BLM management, 1 million acres are infested with cheatgrass and other exotic weeds, he added.
"We've got some cheatgrass up in the Big Horn country and around Thermopolis," Glenn said in a brief interview after his presentation. The biggest increase in Wyoming cheatgrass was seen in the wake of the 1996 fire season, Glenn said, after a 100,000 acre burn in the Big Horn Mountains. "That came after a wet year and the cheatgrass took off."
While cheatgrass has some value as a spring livestock forage, livestock may also make cheatgrass infestations worse by spreading the seeds, and by consuming or damaging competing plant species.
What's prevented cheatgrass from swamping the Wyoming sagebrush community?
"Drought has prevented cheatgrass from germinating," Glenn said. The trouble is, he said, cheatgrass seed can lie dormant for five or six years. "The drought is giving us time to increase public awareness," he said.
Susan Meyer, a research ecologist with the U.S. Department of Agriculture, warned the audience against complacency. "Just because you don't have it, doesn't mean it won't appear," she said.
The seed heads are designed to stick into or on clothing, wool or fur, she said, for efficient dispersal. If you've pulled stickers out of your socks, you've probably walked through cheatgrass, she said.
Control methods such as mowing, tillage, herbicides, early controlled burns and biocontrol are all partially successful, she said, but with problems that so far have prevented complete and certain control.
The cheatgrass conference continues today at the Parkway Plaza in Casper. Several case studies involving the use of "Plateau" herbicide will be presented.