Invasive Weed a Fuel for Wildfires
By Patrick O’Driscoll
Western states work to defend landscapes as cheatgrass overruns areas
DENVER — Cheatgrass, a wispy Eurasian weed accidentally brought to the USA in the late 19th century, has become a 21st century headache across the West, fueling some of this summer’s most destructive wildfires.
The largest blaze in Utah history, the 567-square-mile Milford Flat fire last month raced across rangeland infested with the highly combustible, straw-colored plant. Bone-dry expanses of cheatgrass in Idaho and Nevada also stoked the 1,020-square-mile Murphy Complex fires, the largest to burn in Idaho in 97 years.
The federal Bureau of Land Management (BLM) estimates 2 million acres have burned in the Great Basin, the West’s expanse of sagebrush steppes vulnerable to cheatgrass fires.
The governors of Idaho, Nevada, Utah and Wyoming formally declared war this month on the invader, which now dominates between 25 million and 100 million acres of sagebrush in the Great Basin. They pledged cooperation in replanting charred areas before the weed can take root again. The BLM estimates cheatgrass invades 4,000 acres of new terrain a day.
"It’s exploding on us," says ecologist Mike Pellant, head of the agency’s Great Basin Restoration Initiative, which does research and rehabilitation. "We’ve been at war with cheatgrass for years now. It’s like the Dutch boy with the finger in the dike. You work hard in an area and make progress, and then somewhere else, (fire) happens all over again."
The initiative was born in the ashes of 1999, when more than 1.7 million acres of sagebrush burned in cheatgrass fires
Before cheatgrass, areas where sagebrush grew in clumps surrounded by bare ground might burn every few decades or as seldom as a century or two. Then cheatgrass began to transform the land. A winter annual, it matures weeks before native plants. Farmers and ranchers named it after the way it "cheats" crops out of water and soil nutrients.
Unchecked, cheatgrass carpets the sagebrush plain with hundreds of thousands of plants per acre. By early summer, the plants dry into explosive kindling, easily lit by lightning, a dropped match or a hot muffler. Cheatgrass fires burn hotter, faster and more intense than range fires of native perennials that need years of reseeding and care to return. By then, cheatgrass has taken over and set the stage for new fires within three to five years.
The toll: dead wildlife and wrecked habitat. Sagebrush is the main food or shelter for 170 native bird and mammal species, including sage grouse, pygmy rabbits and pronghorn antelope. This year’s fires might bolster putting the grouse on the list of endangered species.
These range fires scorch hayfields, destroy ranches and kill or dislocate livestock. At least 300 cattle are dead, 1,300 missing and 9,700 displaced in the Utah blazes. In Nevada, where 6million acres of sagebrush have burned since 1999, "the future of the charred habitat and its wildlife inhabitants is bleak," the state Department of Wildlife reported in July.
Global warming might be making the problem worse, according to research in the journal Global Change Biology in 2005 and 2006. The two studies by federal Agriculture Department scientists and researchers at Brown University note that cheatgrass thrives on carbon dioxide, the most abundant of the greenhouse gases that scientists say are causing climate change.
"Cheatgrass has got an answer to almost every angle of the environment and our attempts to control it," Pellant says. "You don’t graze it out. You don’t burn it out. It doesn’t die out in droughts."
State and federal agencies keep trying. Some strategies:
*Bioweapons. The U.S. Forest Service’s Shrub Science Laboratory in Utah is studying a fungus that attacks cheatgrass seedheads — called "black fingers of death" for the tendrils that kill the seeds. Another bio-agent, a bacterium that infects cheatgrass, is being tested at the former federal nuclear reservation near Hanford, Wash.
*Herbicides. The BLM, which manages 258 million acres mostly in a dozen western states, sprays weed killers on a fraction of that terrain annually. The agency hopes to triple the area next year to about 900,000 acres of various weeds, including cheatgrass. But herbicides are costly, averaging more than $70 an acre and usually needing repeat sprayings over several years.
*Reseeding. Land managers replant burned areas with native and benign non-native plants: sagebrush and wild bunch grasses and Eurasian perennials such as crested wheatgrass or forage kochia. Wheatgrass is popular for grazing. Kochia tolerates drought and can slow or even stop fires.
The need for native seed far exceeds supply. To reclaim this year’s burned acreage, "you need, like, 24 million tons of seed," says Cal Groen, head of the Idaho Fish and Game Department. "Already we’re four times past the seed availability." Reseeding is also pricey: up to $100 an acre.
*"Targeted" grazing. Some range specialists advocate using cattle, sheep and goats to control areas of cheatgrass during brief periods when it is palatable, especially when green in spring, before seed heads sprout.
Roger Banner, a range specialist at Utah State University in Logan, says native plants can’t reclaim burned range on their own.
"There’s not enough native plant seed to reseed 2% of the areas that burned," he says.
Pellant says he hopes public interest will help spur states and the federal government to put more money into restoration: "That sea of brown cheatgrass out there is not the way things should look."