In the arid steppe of the Great Basin, an invasive weed called cheatgrass has turned what was once a vibrant ecosystem into a tinderbox covering an estimated 25 million acres. Bureau of Land Management officials and scientists are exploring ways not only to mitigate the damage caused by wildfires but also to restore the Great Basin to a healthier status. Researchers are only just beginning to understand the complex relationship between fire, invasive weeds and native plants in the region, and it may be years before there is a well-defined plan to heal America¿s big sky country. "There¿s a pretty substantial group now that¿s looking at the big picture, beyond just killing weeds," says Tony Svejcar, a U.S. Department of Agriculture researcher in Oregon. "We really need to look at how these plants compete for resources."
In 1999 more than 2.2 million acres of land burned in the Great Basin (out of the 5.6 million acres of wildland consumed that year), according to Bureau of Land Management statistics. This year, heavy spring rains watered an abundance of cheatgrass, which blankets most rangeland, growing continuously between widely spaced native grasses such as sage. Cheatgrass dries out early in the summer--it was dry by June this year in most areas. Its wheatlike spiny seed pods make excellent kindling, easily ignitable by lightning, a cigarette butt or even the hot wheel rims of a car stopped by the side of the road. Because of that fine texture, "it burns really fast," explains John Szymoniak of the National Interagency Fire Center. "It¿s the same principle as starting a fire; you don¿t start a fire with a log."
Cheatgrass hegemony has become something of an ecological disaster for the Great Basin [see "Other Offenders" for information on additional weed invaders]. For ranchers who depend on wide expanses of open land for grazing, losing several thousand acres in a fast-burning range fire denies them use of that land not only for the rest of the year but also for up to three years after that, while the plants regrow. If the area is then dominated by cheatgrass, this provides food only for the brief few weeks that the weed is still green.
Furthermore, cheatgrass sprouts from new seeds every year. Although rainy seasons like this past spring can lead to bumper crops of cheatgrass, during a drought hardly anything grows at all, leaving ranchers with acres of bare land. "Production can be zero in a dry year," Pellant says. "In a wet year it can be as tall as a barbed-wire fence."
Before the invasion of cheatgrass in the late 19th century (it was brought in from central Asia), native grasses grew in clumps spaced one or two feet apart. Fires would advance slowly, having to always jump from plant to plant. Because the native plants stayed green until late summer, wildfires were more difficult to ignite, and an area would burn once every 40 to 100 years.
Cheatgrass, however, grows close together, leaving virtually no space between plants. Winds gusting 20 or 30 miles an hour on the plains can carry the front of a fire just as fast, forcing firefighters to literally race to keep up with the flames. In addition, dry cheatgrass throughout the summer means there is a greater chance of a fire starting. What used to be a 40-year fire cycle has shrunk to a five-year cycle. "I¿m standing out here now and the cheatgrass is already dry while the native grass is still green," Pellant reports, calling from Idaho on his cell phone. "This burned five years ago, and if there was a fire here now it would burn right through."
Cheatgrass can monopolize the nitrogen released into the soil by the flames and will out-compete the sagebrush. By the following spring, land that once bore a mixture of native plants and cheatgrass will be overrun with the weed. "Generally, there¿s cheatgrass already here, and the fire releases it to total dominance," Pellant explains.
The easiest way to keep cheatgrass from out-competing the native plants after a fire, says Dave Pyke, a rangeland research ecologist for the U.S. Geological Service, is to spread sugar on the charred ground. The carbon in sugar supplies a necessary nutrient for bacteria and fungi to take up nitrogen, thereby depriving it to cheatgrass seeds. "That¿s not a very cheap way to be able to do this," Pyke admits. He is investigating other sources of carbon, such as the green-colored mixture of grass seed and fertilizer that is sprayed onto new lawns.
Herbicides such as Round-Up and Plateau offer another effective method of discouraging cheatgrass. But rangeland specialists are wary of herbicides, after a brand called Oust, which the Bureau of Land Management used in the late 1990¿s, ended up destroying crops in southern Idaho. A group of 100 farmers have filed suit against DuPont, the company that manufactures Oust, for $800 million in damages.
Some researchers are looking into more organic solutions to eliminate cheatgrass. Among the ideas being considered are fungi and bacteria specifically targeted to attack it. Researchers are also experimenting with insects that eat cheatgrass and other invasive weeds but leave native plants alone. "That¿s a long-term research and long-term solution to find the right bug," says Steve Dewey, an extension weed specialist at Utah State University. "If you bring in the wrong bug, it would be another disaster."
Scientists are also beginning to look at long-range strategies for weed control. "Just spraying or just plowing or just throwing out bugs is not going to solve the problem," Svejcar says. "If we control a weed, that¿s fine, but what happens next?" Svejcar and his colleagues at the Eastern Oregon Agricultural Research Center hope to develop a model where noninvasive plants--those that do not reproduce prolifically and take over an area--can be used to counter invasive weeds. The noninvasive plants would use the resources in the ground before weeds like cheatgrass could gain a foothold. "We want to do what we can to make sure the weeds don¿t have those resources," Svejcar explains. "You do that by having a plant community that can use those resources before the weeds move in."
Pellant began the greenstrips program in 1985 to slow rapid-moving rangeland wildfires. Greenstrips are stretches of land up to 300 feet wide and 20 miles long where the cheatgrass has been cleared away--either with herbicides, prescribed fire or livestock grazing--and replaced with native grasses that stay green until late summer. "While we had funding in the 1980s and early 1990s, we established over 600 miles of greenstrips in the Great Basin," Pellant says. "Unfortunately, we were in an extended drought during part of this time, thus the greenstrips in some areas are only marginally established."
The Great Basin Restoration Initiative essentially aims to expand the greenstrips idea across the entire 25-million-acre area plagued by cheatgrass. Instead of creating narrow ribbons of native plants, the initiative will attempt to eliminate the cheatgrass from large areas and replace it with sagebrush and wheatgrass. The program does not have official funding, however--it is financed essentially with the loose change from programs such as the National Fire Plan. The initiative is also still experimenting with the best ways to control cheatgrass. "It¿s kind of a crapshoot some years," Pellant admits, "but by and large we¿re improving the technology and the techniques that we use."
The restoration process will take decades, and the Great Basin may never again return to its pre-cheatgrass health. "I¿m not sure that we¿ll eventually get rid of cheatgrass, but if we could have the native grasses coexist with the cheatgrass, then we would have really turned a corner," Pyke reflects. "I think we¿re closer now than we were 10 years ago, and 10 years from now we¿ll be closer still."
Dennis Watkins is based in New York City.