“Mount St. Helens is a place that teaches you we have an immense amount to learn about nature.”
This will be John Bishop’s 26th summer at Mount St. Helens. In that time, he has seen lupines, willows and huckleberries all emerge and flourish, only to be suppressed, at least temporarily, as herbivores showed up. The pattern is curious and fascinating to observe, and Bishop has seen it over and over.
Left barren by its May 1980 eruption, Mount St. Helens has proved to be fertile ground for environmental research as different species in turn colonize the landscape. At first lupines were dominant, now it’s willows and grasses, and huckleberries are becoming important as well.
“When re-forming the community depends on all the colonists coming from outside, not all will come at once,” said Bishop, professor in the School of Biological Sciences at WSU Vancouver. “If one plant can survive to reproduce, it can establish a patch that can spread unhindered, until it has found the insects that feed on it. But maybe their predators haven’t arrived yet, so the insect population grows until everything’s gone, if it isn’t stopped. Over time the predators and competitors arrive, build up and stabilize the interaction.”
A science playground
Bishop spends three to four days a week on the mountain each July and August, usually with a half-dozen assistants—students, recent graduates, volunteers. They return to the same territory—and the same plants—every year to see what has changed. They graph damages to the plants and try to exclude the herbivore from the plant to gauge its role. For example, Bishop has sprayed some of the willows to see if that helps them withstand a recently arrived weevil.
With support from the National Science Foundation for more than 15 years, Bishop seeks to understand all the mechanisms that control the new formation of plant and animal communities and soils on land that once had no seeds, no soil, no living things at all. He is exploring how plant and animal communities emerge, interact and function, as well as the role of nutrients.
“Mount St. Helens is a place that teaches you we have an immense amount to learn about nature,” Bishop said. “It’s kind of a science playground.”
It would be a mistake to call Mount St. Helens a pristine environment. “The monument is too small to prevent human influence,” Bishop said. Elk and rainbow trout, for example, are there through human intervention. Industrial forests, partially harvested each year, surround the mountain. Elk spend their summers there, but in the fall flee the forests and the sounds of chainsaws and helicopters for the more peaceful national monument grounds. Fish were introduced to Spirit Lake illegally after the Army Corps of Engineers built a tunnel that, while preventing overflows from a lake dammed by the avalanche of debris, also prevented natural colonization by other fish species that could have been part of the recovery.
Disturbance and diversity
A theory is emerging that natural catastrophes, such as volcanic eruptions, may be critical to the survival of some species. Bishop discovered that one of the herbivores feeding on lupine was a previously undescribed species of moth. Its host, a particular lupine, is uncommon elsewhere but has a population in the millions at Mount St. Helens. Because predators were missing, the moth was able to flourish and play a role in the ecosystem. As the community becomes more complex—with more plants, more animals, more predators and their predators—the effects of various species are suppressed.
The goal of Bishop’s research is to create an ecological model of disturbance and recovery showing how this system works. “Eventually we will see a decline in the effect of herbivores,” Bishop said. “But the same line of inquiry might be asked for other places.” A few years ago, he received a grant to study landscapes in Chile that had been affected by volcanic eruptions and glacial retreats. “The disturbances were not as huge as Mount St. Helens, but we saw hints of the same processes,” he said.
Next, Bishop hopes to study how carbon gets sequestered by volcanic soils. “Volcanic soils harbor a disproportionate amount of carbon compared to other soil types,” Bishop said. “It’s the best mineral soil for sequestering carbon of any on the planet. We don’t know how you go from a system where there is no soil, no carbon, to one incredibly rich in carbon.”