Twenty-five years ago on May 18, at 8:32 in the morning, Mount St. Helens erupted, blasting ash, steam and superheated gases 80,000 feet into the atmosphere high above southern Washington. The north end of the mountain collapsed in the largest landslide in recorded history. Rock fragments and blasts of air that reached 1,350 degrees Fahrenheit rocketed down the slopes at up to 670 mph, destroying everything in their path.
When the dust settled days later, it revealed a desolate landscape of charred and splintered trees. Even 15 miles from the crater, the forest was reduced to ghostly, standing-dead snags. The eruption destroyed over 230 square miles of woods, meadows, lakes and streams.
But life returned — initially in the form of ecologists, who studied the devastation and searched for signs of how the ecosystem would recover. Charlie Crisafulli was a graduate student at Utah State University at the time, working with James McMahon, who studied ecological disturbances. Crisafulli, now an ecologist with the U.S. Forest Service’s Pacific Northwest Research Station, would spend the next quarter-century exploring how life returned to the volcano.
"Mount St. Helens is not about a research project," he says. "It is a special place. It lured me in and I have been held captive ever since."
Tall and lean, with the weathered face of a man who lives most of his life outdoors, Crisafulli focused at first on the way plants were recolonizing the landscape. But he became intrigued by the abundance of brownish-green boreal toads.
"This didn’t make sense," he says. "I knew they had been on the decline throughout the West." The four- to five-inch-long toads are listed as endangered in Colorado and New Mexico and designated as a protected non-game species in Wyoming. Yet here they were, in the middle of a wasteland, congregating in some areas by the thousands.
Crisafulli was hooked. He and his Forest Service crews surveyed every lake in Mount St. Helens National Monument, and discovered a startling number of toads. But it was at one small lake in particular that he finally unraveled the toad’s story.
Each June, Crisafulli and his team hiked out to the still-partially frozen lake, the name of which he doesn’t like to share. Hundreds of toads and a handful of northwest salamanders were already there, hopping and crawling across the snow toward the lake. The researchers waded into the water, pushed aside rafts of ice, and waited. The male toads arrived first, followed by the females. Pairs mated quietly, and females produced teeming masses of eggs, up to 12,000 apiece. A week to 10 days later, the eggs hatched, and by September, the tadpoles had metamorphosed into toadlets, which climbed out of the lake by the thousands. They dispersed up into the hills surrounding the lake, in a mass exodus so thick that the ground looked like it was breathing. Finally, the toads burrowed into the earth and hibernated until the next spring’s meltoff, when the cycle began all over again.
Crisafulli saw this, and thought about what had happened in May 1980. During the eruption, the frogs were still underground, safe under the dirt and snow. When they emerged in June, the verdant woods were gone, destroyed by the blowtorch winds and debris. Drawn by water, the toads hopped across the snow to the nearest lake, where, as the mountain continued to belch and rumble, a toady orgy ensued.
Oddly enough, the conditions were nearly ideal. Boreal toads prefer whatever warmth they can find, particularly in mountainous habitat. The tall trees that had once shaded the lake were gone, so the lake water was warmer than usual. And the warmer water increased the toads’ summer food supply of insects and arachnids, and helped the tadpoles mature more quickly. There were few predators around to bother them; most had been wiped out by the eruption.
Today, Crisafulli looks at the decline of the boreal toad elsewhere, and believes that Mount St. Helens holds an explanation. He hypothesizes that there’s just not enough disturbance in the Western landscape for creatures like the toad. Boreal toads may be an example of an early successional species, which moves into habitat altered by dramatic changes, such as as wildfire or volcanoes. In our haste to douse every forest fire over the past century, he says, we may have unwittingly led these toads down the path toward possible extinction.
Boreal toads are not alone in suffering from the consequences of the human dislike of change. Four species of fish — Colorado pikeminnow, humpback chub, bonytail chub, and razorback sucker — are now on the endangered species list because dams have thwarted the historic spring floods on the Colorado River. Those floods had provided nutrient-rich sediments and reworked sandbars to create gravel bars and backwater eddies — the habitat these fish need.
In landscapes where geologic and ecologic change is the rule and not the exception, disturbance must play an important role in the life of the ecosystem. Fires, volcanic eruptions, and floods regularly reshape broad swaths of the American West. Sometimes, entire ecosystems are devastated. But every time a cataclysm happens, the plants and animals recover.
It’s a lesson, perhaps, in patience: What we see today as a disaster may not be a disaster at all, just a clock resetting, a cycle starting over again.