When Mount St. Helens erupted in 1980, the raging lava destroyed all living things in its path for miles. In a unique experiment, scientists released gophers onto some of the devastated areas of the mountain for just 24 hours. The positive outcomes of that short period have proven significant, and they remain evident even 40 years later.
When Mount St. Helens erupted in 1980, lava incinerated anything living for miles around. As an experiment, scientists dropped gophers onto parts of the scorched mountain for only 24 hours. The benefits from that single day were undeniable — and still visible 40 years later.
After the intense eruption settled, researchers speculated that gophers, by uprooting helpful bacteria and fungi, could assist in restoring the lost flora and fauna on the mountain. Two years later, they decided to put this hypothesis to the test.
“Though often viewed as nuisances, we believed they could take older soil, bring it to the surface, and trigger recovery,” explained Michael Allen from UC Riverside.
They were correct. However, the scientists were surprised to find that the effects of their experiment would still be visible in today’s soil, in 2024. A recent publication in Frontiers in Microbiomes describes a lasting change in the fungal and bacterial communities where gophers were introduced, compared to adjacent areas where they were absent.
“In the 1980s, we were mainly observing immediate reactions,” said UCR microbiologist Michael Allen. “Who would have assumed that dropping a gopher for just one day could leave a lasting impact 40 years later?”
In 1983, Allen, along with James McMahon from Utah State University, flew by helicopter to a site where lava had transformed the landscape into crumbling slabs of porous pumice. At that time, only about a dozen plant species could survive on these surfaces. A few seeds dropped by birds struggled to grow into viable seedlings.
After the scientists released several local gophers onto two pumice plots for a day, the area saw a remarkable explosion of new life. Six years after the experiment, there were around 40,000 thriving plants in the gopher plots, while the untouched areas remained largely barren.
This transformation was largely due to what can’t be seen with the naked eye. Mycorrhizal fungi invade plant root cells, facilitating the exchange of nutrients and resources. They offer protection to plants from soil-borne pathogens and, crucially, by supplying nutrients in desolate areas, they enable plants to establish and thrive.
“Aside from a few weeds, most plant roots aren’t efficient enough to obtain all the necessary nutrients and water on their own. The fungi transport these resources to the plants, receiving carbon in return to support their own growth,” Allen noted.
A second aspect of this research highlights the vital role these microbes play in the regeneration of plant life following natural disasters. On one side of the mountain, an ancient forest stood tall. Ash from the volcano blanketed the trees, trapping solar heat and causing the needles of pines, spruces, and Douglas firs to overheat and fall off. Scientists were concerned that this loss would lead to the forest’s demise.
Surprisingly, this did not happen. “These trees possess their own mycorrhizal fungi that absorbed nutrients from the fallen needles, which fueled their rapid regrowth,” explained Emma Aronson, an environmental microbiologist at UCR and co-author of the paper. “In some areas, the trees began to recover almost immediately. It didn’t all die as many had feared.”
On the other side of the mountain, the researchers studied a previously clearcut forest that had lost all its trees due to logging. Consequently, there were no fallen needles to nourish the soil fungi.
“Very little is still growing in the clearcut region,” Aronson remarked. “It was striking to compare the soil from this area with that of the old-growth forest.”
These findings emphasize just how much we still have to learn about restoring compromised ecosystems, noted lead study author Mia Maltz, a mycologist from the University of Connecticut who was a postdoctoral scholar in Aronson’s lab at UCR during the study.
“We must recognize the interconnectedness in nature, particularly concerning the unseen elements like microbes and fungi,” Maltz stressed.
