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by Tim Steury • photography by Robert Hubner
“No biological legacy.”
The phrase John Bishop uses to describe the effect of Mount St.
Helens’s eruption
on the main blast zone, the pumice plain, holds an understated charm. By now,
everyone has heard the story of Mount St. Helens—how it blew on a Sunday morning
in May 1980, after rumbling for weeks, an earthquake triggering an enormous
landslide, hot gas and rock debris blasting across the landscape at 1,100 kilometers
an hour, devastating 60 square kilometers and killing 60 people. But it is
impossible to accept the immensity of the mountain and the eruption’s
legacy, unless you are able to stand beneath the enormous crater on the pumice
plain—and
hear Bishop, an ecologist at Washington State University at Vancouver, talk
about lupines.
No biological legacy. Trees, birds, elk, bacteria, spring flowers, humans—all simply vaporized. A whole region was completely sterilized.
But this devastation left a rare and perfect laboratory, a clean slate on
which to observe the fundamental process of “primary succession,” the
reestablishment of life where there was none.
Here on the pumice plain, on a perfect August morning 23 years after the eruption, plumes of dust and ash blow off the volcano’s rim, now 1,200 feet lower than it was before the eruption. The students working for Bishop have scattered across the plain, checking experiment sites. Grasshoppers clatter around us, and a raven whoosh-whooshes overhead, toward Spirit Lake to the south. Elk scat is everywhere. The occasional rumble of rockfalls in the crater drifts across the plain. Life has returned to the pumice plain, but the echoes of cataclysmic drama are very much with us.
Imagine how startling it must have been, when in the midst of this devastation, scientists discovered a lone lupine plant barely a year after the eruption. How could it possibly have gotten there? Lupines are not mobile, says Bishop. Birds, which serve as distributors of many plants, don’t seem to care for lupine seeds. And lupine seeds are hard and heavy, lacking the adaptations of wind-borne seeds. Normally, lupines spread slowly. The seed heads shatter, the seeds fall to the ground and sprout, and the lupines march incrementally, albeit inexorably, across the landscape. Bishop has observed voles gathering seeds. But no vole journeyed across the barren pumice plain to plant a lupine.
So how else could that original seed have arrived, except by wind? Lupinus
lepidus var. lobbii is considerably smaller than most lupines. It is adapted to hot, dry, alpine conditions and grows mainly on the slopes of volcanoes. Its seeds are small, and the wind blows fierce in these mountains. So the seed could have—no, must have—arrived by wind. But the original plant’s conception is still no less mysterious, for a very basic reason.
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