In 1980, Mount St. Helens erupted in Washington State, lava burning every living thing within miles.
Uncertain of the ecosystem’s future, scientists decided to launch an experiment, and they sent one animal to work along the scorched mountain for just 24 hours: Gophers.
In a new paper published this week, researchers have outlined the benefits of that one fateful decision, one that still has visible impacts 40 years later.
The idea was that the gophers would descend upon the area (after the lava had cooled, of course), to help dig up the land, introducing beneficial bacteria and fungi to help regenerate life in the Mount St. Helens ecosystem.
“They’re often considered pests,” University of California-Riverside microbiologist Michael Allen said of the gophers.
“But we thought they would take old soil, move it to the surface, and that would be where recovery would occur.”
That prediction wasn’t just right — it has had lingering effects decades later.
“In the 1980s, we were just testing the short-term reaction,” said Allen. “Who would have predicted you could toss a gopher in for a day and see a residual effect 40 years later?”
In the recent paper, researchers note “an enduring change in the communities of fungi and bacteria where the gophers had been, versus nearby land where they were never introduced,” according to UC Riverside.
Just three years after the eruption, researchers noticed that there were only about a dozen plants that had learned to thrive in the ecosystem, growing through slabs of porous pumice created by the lava.
After the gophers were introduced to those pumice-filled areas, the land “exploded” again with new life, scientists said.
Six years following the experiment, there were 40,000 plants thriving on the gopher plots.
Decades later, scientists can see the monumental regrowth of an old-growth forest, full of pine, spruce, and Douglas firs.
Although the ash and lava from the volcano seemed to have killed the trees, mycorrhizal fungi was reintroduced to the area, thanks to the hard-working gophers.
This fungi helps exchange nutrients in plant roots, protecting them from pathogens in the soil, providing nutrients in barren places, and ultimately, helping plants survive.
“With the exception of a few weeds, there is no way most plant roots are efficient enough to get all the nutrients and water they need by themselves,” Allen explained. “The fungi transport these things to the plant and get carbon they need for their own growth in exchange.”
That’s exactly what happened to the trees once covered in ash.
“These trees have their own mycorrhizal fungi that picked up nutrients from the dropped needles and helped fuel rapid tree regrowth,” said UC Riverside environmental microbiologist and paper co-author Emma Aronson.
“The trees came back almost immediately in some places. It didn’t all die like everyone thought.”
On the other side of the mountain, scientists say there still “isn’t much of anything growing,” a drastic comparison to the area that was saved by the support of the gophers — and the fungi they unearthed.
This research underscores the importance of recovery following natural disasters, especially in the ecosystems so many species depend on.
“We cannot ignore the interdependence of all things in nature,” said mycologist Mia Maltz, who worked in a UC Riverside lab during this study, “especially the things we cannot see, like microbes and fungi.”
Header image courtesy of David A. Hoffman (CC BY-NC-SA 2.0)
