Forty-three years ago, a few ground squirrels were released into the area devastated by the eruption of Mount St. Helens, and now scientists believe they were the unexpected heroes of the ecosystem’s recovery

When Mount St. Helens erupted on May 18, 1980, it took lives and erased landscapes in a matter of hours. The U.S. Geological Survey reports the eruption caused the loss of 57 lives, while ash fallout and other impacts hammered communities and ecosystems across the region.

Now here is the twist that still sounds like a dare. A team of scientists tried a one-day experiment that involved pocket gophers, and decades later, researchers are finding the underground effects are still visible in the soil and the plants it supports. If you have ever looked at a bare patch of dirt and wondered how nature even starts again, this story has an answer that starts below your feet.

A one day test that changed a mountainside

In the early 1980s, researchers fenced off small plots on the devastated mountain and placed a few local pocket gophers there for about 24 hours. It was a simple idea that leaned on the animals’ instinct to dig and move soil, even in a harsh, rocky surface that looked almost lifeless.

At the time, the area had only “about a dozen” plants clinging to the pumice, according to a University of California Riverside report. Six years after the gophers’ brief visit, there were about 40,000 plants thriving on the gopher plots, while nearby untouched ground stayed mostly barren.

Michael Allen, a microbiologist at UC Riverside, put the logic in plain terms. “They’re often considered pests,” he said, but the team believed the animals would bring older, microbe-rich soil up to the surface and create the conditions for recovery.

Why fungi can decide whether plants survive

The headline animal here is the gopher, but the real engine is a partnership between plants and fungi. Mycorrhizal fungi live in close association with plant roots, helping plants access nutrients and water while receiving carbon from the plant in return.

Allen explained that for most plants, roots alone are not enough in extreme environments. In the UC Riverside report, he noted that aside from a few weeds, many plants cannot efficiently get all the nutrients and water they need without fungal help.

If that sounds abstract, think of it like this. When a garden struggles, people loosen the soil or add compost because plants do better when the underground network is active. On Mount St. Helens, the “compost” was essentially microbes and fungi brought up from deeper layers by a small mammal doing what it always does.

What the new study found in the soil decades later

A research team led by mycologist Mia Rose Maltz analyzed microbial communities in recovering forests of Mount St. Helens using modern DNA-based tools, comparing plots with historic gopher activity to nearby plots without it, as well as areas shaped by different forest management histories.

The study reports that community composition for bacteria and fungi differed across these conditions, showing long-lasting “legacy effects” more than four decades after the eruption.

One detail helps explain why the early landscape was such a tough starting point. The paper describes pumice pieces around 0.4 to 0.8 inches across that initially contained no measurable carbon or nitrogen, essentially the opposite of what most plants need to get going.

The researchers also found that plots tied to historic gopher activity had more types of root-associated mycorrhizal taxa than similar plots without gophers. They report differences in soil carbon and nitrogen patterns as well, including signals that nitrogen levels in soils from lupine plots with gophers were higher than in lupine plots without historic gopher activity.

Old-growth forests had a hidden advantage

The UC Riverside report highlights another contrast that feels almost unfair, but it is important. On one side of the mountain, old-growth forest soils had their own microbial and fungal “memory” to work with after ash blanketed trees and needles dropped, and the forest did not collapse the way scientists feared.

Emma Aronson, an environmental microbiologist and study co-author, said the trees’ mycorrhizal fungi helped them pick up nutrients from fallen needles and fuel rapid regrowth. “The trees came back almost immediately in some places,” she said, adding that it “didn’t all die like everyone thought.”

On the other side, researchers looked at a forest that had been clear-cut before the eruption, which meant fewer trees and fewer needles to feed soil microbes. Aronson said there still was not much growing in that clear-cut area, a reminder that land use decisions made long before a disaster can shape how resilient an ecosystem is afterward.

What this means for restoration after disasters

It is tempting to read this and think the takeaway is “release gophers everywhere.” Not so fast. The more practical lesson is that soil recovery is not just a background detail – it is often the main event, and animals can act as “vectors” that move microbial life into places where it struggles to return on its own.

The Frontiers paper explicitly frames gophers as dispersal vectors and discusses how biotic interactions may prime ecological succession by creating microsite conditions where plants can establish. That is a useful idea for land managers dealing with volcanic terrain, mine reclamation sites, or fire-scarred slopes where the surface layer is stripped down and hostile.

It also nudges restoration conversations toward humility. Maltz said “we cannot ignore the interdependence of all things in nature,” especially microbes and fungi we cannot see, and the Mount St. Helens results make that sound less like poetry and more like a field report.

The bigger picture for climate and daily life

Mount St. Helens is famous for ash in the sky, but the long story is about chemistry and biology rebuilding from the ground up. The USGS says about 540 million tons of ash fell over more than 22,000 square miles during the main day of activity, and those kinds of shocks ripple through nutrient cycles and the living systems that regulate them.

The new research does not claim a simple climate fix, but it does reinforce something climate scientists and soil experts repeat for good reason. Healthy soils help regulate carbon and nitrogen cycling, and the living community underground can influence how quickly landscapes recover and how much life they can support over time.

In other words, the “invisible” part of nature is often the part doing the heavy lifting. The recovery story is still unfolding, but the message is already clear. 

The original study was published in Frontiers in Microbiomes.