Forty years ago, ground scorched by a volcanic eruption was revived by ground squirrels, and the region continues to thrive today.

On May 18, 1980, the eruption of the Mount St. Helens volcano released 1.5 million metric tons of sulfur dioxide into the Earth's atmosphere, and the lava flow incinerated everything over an area of nearly 600 square kilometers. Three years later, wildlife experts turned to a team of local assistants — within 24 hours, they significantly accelerated the restoration of the environment in this area, and the effects are still felt today, reports Popular Science.

This is not about human volunteers, but rather a team of ground squirrels. The first phase of the experiment, conducted under the guidance of microbiologist Michael Allen from the University of California, began in 1983, three years after the eruption. On November 5, the team released several squirrels in two areas:

• Pumice Plain;
• Bear Meadow.

It is noteworthy that only a few struggling plants existed in these areas, likely sprouted from seeds dropped by birds, and the squirrels were allowed to do whatever they wanted for 24 hours. Clearly, the rodents engaged in what they do best — digging in the soil.

According to Allen, squirrels are often considered pests; however, they also bring old soil to the surface — which is precisely what the scientists hoped for. The team anticipated that the animals could assist in bringing vital, nutrient-enriching microorganisms to the surface, such as endosymbiotic rhizobial bacteria and mycorrhizal fungi.

The issue is that, except for a few weeds, the roots of most plants cannot be efficient enough to independently obtain the necessary nutrients and water. In fact, it is the fungi that transport these substances to the plants, receiving carbon in exchange, which is essential for their own growth.

Fortunately, the scientists' hopes were realized. After six years, researchers found that the work of the rodents led to the emergence of 40,000 healthy plants in both regions, along with the return of the local ground squirrel population. The scientists compared the results with areas that remained without the rodents, and the difference was striking.

More than four decades later, new soil samples taken from the same regions still indicated a better presence of fungi and bacteria than in areas where squirrels did not reside. According to another co-author of the study, mycologist Mia Maltz, their research highlights the importance of interconnected, resilient, and natural ecosystems.

Interestingly, in the 1980s, scientists simply wanted to test the short-term environmental response to the presence of squirrels, but the results indicate that even 40 years later, the effects of the rodents’ activities are still observable.