The spread of cheatgrass also threatens wildlife. Fires in areas with native vegetation burn in patches, leaving some areas of wildlife habitat. But cheatgrass fires spread farther and burn hotter. In the end, only cheatgrass thrives.
The repeat wildfires in the Great Basin are especially hard on species that are dependent on sagebrush. It's a hardy plant, but it doesn't grow quicklysagebrush seeds become fully mature only after 20 years.
"We've lost 30 to 40 percent of the sage grouse habitat in southern Idaho in the last five years due to range fires," said Signe Sather-Blair, a wildlife biologist for the BLM in Idaho. As a result, the white-ruffed sage grouse, twice as large as its forest-dwelling cousins, is on the threatened list.
The destruction also affects other sagebrush-dependent wildlife such as mule deer, which graze shrubs rather than grass and use sagebrush to shelter their fawns.
Southern Idaho's largest contiguous sagebrush habitat spreads across 700,000 acres, according to Mike Pellant, a rangeland ecologist with the Idaho BLM. Of that total area, about 500,000 acres burned in the past three years; half of the acres that burned had already been affected by previous fires.
In the past two winters, the BLM planted sagebrush on the devastated countryside as part of a federally funded restoration program, which costs about $100 an acre to implement. Last summer most of the seedlings died from lack of snow and rain, so the BLM reseeded.
But, "this year is drier than last," said Pellant, who co-chairs a joint project called the Great Basin Restoration Initiative. "You have to accept that nature deals the cards."
"If we don't get the sage back, that area is never going to fully recover," he added.
Besides being highly flammable, cheatgrass is a scourge because its seeds have sharp points that injure livestock and wildlife that attempt to eat the grass, Pellant said.
Sather-Blair noted that in the early 1990s, many mule deer in the Great Basin died from starvation and poor diet. Livestock are also likely to be affected by the present austere conditions, which have prompted many ranchers to scale down operations. "A lot of the ranchers are reducing their numbers [of livestock] this year because the forage base isn't there," she said. "But we can't do that with wildlife."
"Going into next winter will be critical," she added. "It often happens in drought. There's not enough food left for winter."
Steve Huffaker, head of Idaho's Fish and Game Department, agrees. Although last year's fires had a "devastating effect on low elevation wildlife," the mild winter carried them through, he said.
Elk and other grazing animals in the high-elevation country are feasting on regrowth of native grasses that followed last year's fires. But if a hard winter follows this year's drought in the Great Basin, "that's when we'll see large losses," Huffaker said. "Deer, elk, and antelope carry most of their winter feed on their backs in October. If they're skinny in October, they're going to have a hard winter."
Meanwhile Pellant warns that farmers and ranchers in northern mountain states like Wyoming and Montana should beware of further encroachment by invasive weeds. "Cheatgrass adapts," he said. Over the past 100 years, cheatgrass has spread from the rangelands of the Great Basin southward into the desert and northward into lush ponderosa pine forests.
In northern Wyoming and Montana, the climate is colder and soils are different than those in the Great Basin and in the southern Rockies. As a result, native vegetation may be able to keep cheatgrass at bayif the ecosystem isn't irreparably disturbed as a result of the repeated fires.
Said Pellant: "This isn't just ecological stability. It's economic stability."
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