We spent a week grubbing up the spiny knapweed by the roots. We piled the dead stalks high where everyone could see, hoping that other visitors would learn to uproot knapweed, too.
Invasive species -- introduced by humans -- commonly stow away on planes, trains and automobiles. We're so mobile that increasingly many of us are aiding such aggressive exotics as gypsy moths, kudzu vines and snakehead fish. Hostile exotics -- insects, plants, mammals, diseases and fish -- are overtaking the nation's most vulnerable habitats.
In economic terms, infiltrations by exotics cost the United States an estimated $137 billion every year, according to Cornell University researchers. In ecological terms, exotic species often degrade native habitats. They out-compete the indigenous species.
Earlier this year, Gov. Chris Gregoire signed a bill that established the Invasive Species Council for the state of Washington. The move was long overdue: The national Invasive Species Council was founded in 1999, and Idaho created its own equivalent in 2001.
In the Inland Northwest, spotted knapweed is the most pressing of exotic problems. Its launch a century ago, in a batch of tainted crop seed, catapulted it across millions of acres in the American West. An invasive thistle from Eastern Europe, it blooms with signature pink flowers that resemble tiny carnations. Those flowers compete with native species for declining pollinators before shriveling to seed heads in late summer.
Aridity is knapweed's friend. It not only flourishes without water, it is "alleopathic": It generates chemicals suited only to its kind. Knapweed kills off other vegetation and effectively stuns the land. As a non-native, it has no predators: Check out the hearty crop in People's Park in Spokane.
Every stalk also disperses up to a thousand seeds that remain fertile for some five years. Those seeds spread to other sites by hitching rides on the fur of animals, on human clothing, on the frames of automobiles, on river currents. To eradicate a knapweed-infested field can mean pulling it by hand, sterilizing the soil, and then replanting crops of native grasses.
& lt;span class= "dropcap " & E & lt;/span & very year, the U. S. Forest Service and the Sierra Club team up to combat knapweed in the Frank Church/River of No Return Wilderness, the largest designated wild area in the lower 48 states. Knapweed there is rapidly encroaching on the river corridor. Sierra Club volunteers and Forest Service employees use gloves and trowels to uproot the stalks.
The Salmon River Canyon in central Idaho is a priority because its isolation makes it vulnerable to invasion. The canyon is a bio-geographic island. As in Hawaii, mountains and water cut it off from other species, other lands. Its official Wilderness status also triggers certain safeguards.
Seasonal rangers Linda Hagedorn and Don Jeffery guided us through the canyon last July. On big oar rigs, they hauled the food and gear, stowing and rowing with grace and with skill. Range conservationist Howard Lyman, a Forest Service lifer, knew the invasive plants and what it takes to knock them out: He toted two tanks of herbicides along. As volunteers, our job was to uproot knapweed where we could, extract it with hand trowels where we had to, and help the rangers tend established camping areas.
Forest Service policies require rangers to "naturalize" the campsites, which means they need to dismantle fire rings, toss rocks into deep water, scatter charred wood remains, and create the illusion of virgin shores. They have legal language for authorization: The 1964 Wilderness Act says our species must be "only visitors" to official Wilderness. To demonstrate harmony with that law, every trace of humankind needs to be captured, hidden, held or "broadcast" -- this last a locution for dispersing toothpaste and detergents above high-water lines.
We volunteers on the Salmon River were visitors to the wilderness. We were not at home. We signed release forms and worked beside the tested veterans. As volunteers, we had to stay on task, pull our weight, never stray from duties. Only at day's end, after responsibilities fell away, could we loosen up. Only then could our rangers relax enough to share stories with us that afforded no embedded lessons.
As a tourist in the Salmon River Canyon, I was exotic and invasive as the knapweed but less well adapted. Loose rocks, fierce sun, thorn bushes, snakes, spiders, rapids, thistles and insects were a threat. If the water didn't drown me, a clunk on the head from a river rock might.
We humans invade wilderness with our lug-soled boots and trash, our technology and population pressures. We love wilderness to death. To let our invasive species have its way with "The Frank" would be a sad sham.
& lt;span class= "dropcap " & H & lt;/span & oward Lyman, as a "range con" or conservationist, goes between the agencies and the ranchers, who enjoy federal largess on public lands in the form of low grazing fees. Ranching has such a hold on the West that some federal employees become de facto wardens of cows, installers of fences and troughs. Some range cons even have to ride herd like cowboys to keep cattle out of seedlings and streams.
Exotic cattle, whose early ancestors were domesticated in rainy Asia, have the habit of wading in streams and eroding banks, tugging up native grasses by the roots. Running Angus and Herefords on arid soils creates ideal conditions for alien plants like spotted knapweed. There, a hoof print may remain for decades, for cow hooves hit algal crusts or cryptogamic crusts hard. Like the knapweed, cattle are exotics in the arid West.
Howard finally came to believe that my interest in conserving native weeds and grasses was sincere. He entered our camp at Big Mallard Creek and sat me down on precious folding chairs. He was cradling three of the best bunchgrasses -- native grasses that stabilize soil.
"This here's prairie junegrass," he said, as if formally introducing us, "Idaho fescue and bluebunch wheatgrass." I stroked the seed heads -- so wispy, nodding and fragile beside the spiny, seedy, forceful knapweed. Bunchgrasses are the gold standard for ruminant nutrition, the flora shown in classic western films. Against them, Howard judged the dozens of alien invaders.
Later that day, I watched him load a tank on his back and a spray wand in his hand. He was after fugitive Scotch thistle. It towered higher than either of us, in a camp where hunters had spread hay. I stayed well away, wary of blowback from the sprayer. When Howard finished, his shirt sweaty and face red, he shed the heavy tank and plunged into the river.
& lt;span class= "dropcap " & O & lt;/span & ur attempts to slow the spread of spotted knapweed in The Frank succeeded to a limited degree. Whole hillsides above the river, too steep to traverse safely, bristled with the thistle as we slid by on the current. In succeeding weeks, Howard would try biological controls, integrated pest management, by releasing beetles and weevils that eat flowers and roots.
By the time we returned to the civilization of Boise, Lewiston, Spokane, we were burnt by the sun and chapped by the wind. Our feet wore irregular tans from our sandals. Our hands were clenched like claws from pulling knapweed. In our dreams, we kept moving up and down, up and down across the waves that tried to eject us as we bounced downstream.