America's Forgotten Ecosystem
Often maligned and frequently mismanaged, the country's most abundant native shrub is finally getting credit for its value to wildlife
- Michael Lipske
- Oct 01, 2000
FOR A RELATIONSHIP that began poorly, Tim Reynolds' romance with America's sagebrush country has endured exceedingly well. The ecologist has spent the past 25 years conducting wildlife research on the 900 square miles that make up the grounds of the U.S. Department of Energy's Idaho National Engineering and Environmental Laboratory--one of the best remaining chunks of a type of northwestern U.S. habitat called sagebrush steppe.
But Reynolds, reared in the Midwest, can't forget his first grim visit to the area in January 1975. "It was a gray day and there was this gray sea of snow," he says, "smothering the sagebrush" as far as he could see. With the temperature hovering at minus 22 degrees F, he recalls, "I had to ask myself: 'Why am I here?'" By the following spring, he had discovered the answer.
After spending many nights, "hearing coyotes singing, seeing the biggest moon and brightest stars on Earth, and waking up in the morning to sage grouse strutting," says Reynolds, he was thoroughly seduced by the sagebrush environment. "This place is infectious. I've been here ever since."
Reynolds isn't the first, and he won't be the last, to succumb to the subtle charms of a greenish gray native shrub that Mark Twain called "an imposing monarch of the forest in exquisite miniature." Like the coyote and the jackrabbit, sagebrush is a living symbol of America's wide open spaces. Romanticized in countless books, movies and television shows, the plant is now synonymous with the term "old West." It is also, according to some scientists and conservationists, a crucial source of habitat that has long been mistreated and misunderstood.
"The sagebrush environment represents one of America's forgotten ecosystems, one that has high value to Neotropical songbirds and other wildlife," says Tom France, an NWF attorney and western resource expert. "In the past, we've managed this ecosystem more with ignorance than with evil intent. But now that we better understand its ecological functions, we can't afford to continue managing sagebrush by ignorance alone."
More than a dozen woody sagebrush species grow from British Columbia down to Baja California and as far east as Nebraska. In all, the plants cover 150 million acres--the most abundant native shrubs in North America and an important component of the continent's vast grassland-shrub habitat. The heart of sagebrush country is the Great Basin, an immense region that encompasses most of Nevada, Utah west of the Wasatch Range, parts of southern Oregon and Idaho, and a sliver of eastern California.
In all, the Great Basin desert covers more than one-fifteenth of the territory of the United States, and sagebrush habitat accounts for nearly half of the Basin. "If you picked the right line you could move through the entire length and breadth of the desert from north to south, from west to east, always walking through aromatic sagebrush," writes Stephen Trimble in his definitive book, The Sagebrush Ocean.
Despite its name and aroma, sagebrush has no relation to the herb cooks add to stuffings. Sagebrush represents the North American branch of Artemisia, a worldwide genus that includes European wormwood, which is used to flavor vermouth.
Volatile oils in sagebrush leaves perfume the desert air after Great Basin thunderstorms. The same scent has long filled Native American sweat lodges. For centuries, humans turned to the sagebrush ocean as their pharmacy. Collected by Great Basin Indians and European settlers, the shrubs' leaves, flowers and branches have been burned, chewed, made into tea, steeped in brandy, or ground into powder to produce stimulants, painkillers, fever reducers, parasiticides, laxatives and other folk remedies.
More than a century ago, Mormon settlers in Utah judged land as fertile if it supported good sagebrush stands. Nowadays, miners seeking gold deposits assay sagebrush leaves for high concentrations of minerals absorbed by a root system that reaches 20 feet or more into the earth.
Aboveground, some sagebrush grows as tall as 15 feet. An evergreen, the plant produces two sets of small leaves every year. It is also capable of performing photosynthesis at extremely low temperatures. For wildlife, stands of the shrub serve as nursery, supermarket, even dance hall. About 100 bird, 70 mammal and 23 amphibian and reptile species in the Great Basin rely to some degree on sagebrush habitat for shelter and food. Some are sagebrush obligates--creatures such as the sage grouse, sage sparrow, sagebrush lizard and sagebrush vole that cannot survive without plenty of high-quality sagebrush and its associated perennial grasses and forbs. Pronghorn, too, depend on sagebrush for nearly 90 percent of their diet.
In winter, when snow blankets much of the Great Basin, sage grouse subsist almost entirely on the evergreen leaves of sagebrush--a neat trick. The plant's volatile oils wage chemical warfare on the digestive systems of most animals (one reason that cattle, and therefore cattle ranchers, dislike sagebrush). However, the grouse's digestive system mines the protein from sagebrush leaves--so much so that the birds actually gain weight in winter.
Throughout the spring, sage grouse males gather at dawn in sagebrush openings called leks to perform ritualized courtship displays to attract females. The strutting males (as big as small turkeys) fan their long, pointed tail feathers. They also inflate and deflate air sacs in their chests to generate loud popping sounds. The chest sacs can hold more than a gallon of air.
To nineteenth-century pioneers making the difficult trek west, the sagebrush ocean seemed like a charmless sea. In his diary, one disgruntled wayfarer complained: "Legions of leagues are covered with a wild growth of sage which seems designed by nature for nothing else than to feed a variety of feathered family known as Ôsagecocks.'"
These days, however, some sagebrush sages worry about the health of the habitat, much of which has undergone alarming changes. "Sagebrush habitat makes wonderful potato fields," says Reynolds. "When European settlers first came out here, they cleared and planted. And you can't say that that has ever stopped." In Idaho, agriculture is responsible for the loss of about 8.8 million acres of sagebrush. Elsewhere, some government range managers and livestock ranchers have used herbicides and other methods to remove dense stands of the plant and replace them with grasses for grazing, including some nonnative varieties.
Alien invaders are, in fact, another big problem. In a report issued last year, the U.S. Bureau of Land Management (BLM) warned that millions of acres in the Great Basin have been transformed from healthy ecosystems consisting of native species like sagebrush and bunchgrass to systems dominated by nonnative species. The alien plants have helped spur a cycle of wildfires that is incinerating native shrublands. In the summer of 1999 alone, 1.7 million acres of such lands in four states burned.
The fires bode ill for wildlife. At the Snake River Birds of Prey National Conservation Area in southwestern Idaho, 70 percent of the habitat has burned in the last 15 years. The area is home to the largest concentration of nesting birds of prey in North America. But less sagebrush there now means fewer ground squirrels and other prey--which rely on the plants for shelter--for the raptors.
A 1999 report prepared by the Western Working Group of the international bird-conservation coalition Partners in Flight warns that more than 50 percent of shrubland and grassland bird species in the Intermountain West show downward population trends. Sage grouse numbers have dipped more than 33 percent in the last 15 years, according to BLM studies. The birds have already lost about half of their historic nesting grounds in the West to various forms of development. As a result, private conservation groups recently petitioned the U.S. Fish and Wildlife Service to list populations of the species in Washington, southwestern Colorado and southeastern Utah as endangered or threatened due to loss or degradation of their habitat. NWF, meanwhile, is urging the U.S. Forest Service to implement its Sensitive Species designation to protect the sage grouse on public woodlands.
Last fall, the BLM--the nation's largest single manager of sagebrush habitat--proposed a Great Basin Restoration Initiative that, at a cost of tens of millions of dollars, would begin renewing degraded landscapes. Heading the agency's enemies list is a botanical invader from the Eurasian steppes: cheatgrass. Introduced accidentally to this country decades ago, probably with imported wheat grain, the grass spread quickly across the Great Basin.
"Once cheatgrass came in, the fires started," says Mike Pellant, a BLM ecologist in Boise. Wildfire was part of the natural order long before settlers and cattle moved into the West. But scientists believe that early fires came through infrequently, perhaps every 40 to 70 years, giving the sagebrush time to recover. Cheatgrass, a highly flammable annual, sped things up. Fires now occur every 3 to 10 years, killing sagebrush while cheatgrass reseeds itself and colonizes more territory.
The problem is compounded in some areas by the conflicting policies of such multiple-use agencies as the Forest Service and BLM, which are increasingly prescribing burns as part of their efforts to restore fire to the ecology of certain public lands. While conservationists agree that this represents an appropriate policy in many ecosystems, they maintain that sagebrush lands are targeted too often for controlled burns because they are accessible and because the fire briefly stimulates the growth of livestock forage. And unlike timber, sagebrush has no direct economic value.
"New research is finding that some sagebrush stands are 50 or even 100 years old, but such stands are becoming increasingly rare," says Tom France. "In some districts, the agencies want to conduct prescribed burns every 20 to 30 years, a policy that virtually ensures old-growth sagebrush stands, and their obligates like sage grouse, will disappear from those areas."
As the agencies try to reconcile their policies, scientists such as Mike Pellant continue to fight the spread of cheatgrass. Pellant heads up a BLM effort that for the past 15 years has created "green strips"--corridors of fire-resistant vegetation planted along roads and in other strategic locations to slow the cheatgrass-wildfire cycle and protect large blocks of sagebrush. Useful as that is, he calls the program "a Band-Aid to stop some of the hemorrhaging."
With cheatgrass present on 60 million acres of BLM acreage in the Great Basin, the immigrant weed is here to stay. "We're not ever going to go back in this country looking like it did before European man got here," says Pellant. "But if we can get some of those dominant native plants back, we really feel that we can manage cheatgrass."
Cheatgrass is not the only relentless invader of sagebrush country. People and their sprawling suburbs and cities also chip at the habitat. BLM ecologist Terry Rich tells an instructive story about the difficulty that organizers of an upcoming sagebrush conference had in picking a good location.
Hoping to host the meeting in a city with enough nearby sagebrush to allow field trips, the organizers considered Salt Lake City, Reno and Boise. "But you can't get to sagebrush from Salt Lake any more in less than an hour and a half, which seems amazing," says Rich. "Reno's getting worse, the weeds and people have sprawled out so much. We decided Boise's the best."
Even so, he notes that from his office in Boise, "We can't get into any good sagebrush in less than an hour. It use to be near our doorstep."
Washington, D.C., writer Michael Lipske frequently reports on conservation issues.
NWF Takes Action: Protecting Sagebrush and Sage Grouse
As part of its efforts to protect and recover the nation's grasslands, NWF is working to restore sagebrush steppe grasslands and once-thriving sage grouse populations across the birds' historic range. Arguing that the sage grouse is a "bellwether" species of the health of such sagebrush steppe, NWF and several of its western affiliates requested in June that the U.S. Forest Service afford the bird increased protection by designating it a Sensitive Species. Such a designation would require the Forest Service to take the sage grouse's well-being into account when planning actions that could harm the species or its habitat.