When Mt. St. Helens erupted in 1980, a green and vibrant landscape turned into a desolate ash and grey wasteland. But, within the grey barrenness, scientists conducted a courageous 24-hour study: they put pocket gophers in the blast zone. More than 40 years later, this short intervention has led to phenomenal results, with this rodent being credited for reigniting ecological recovery. By churning the volcanic crust, the subterranean rodents pushed much-needed nutrients and symbiotic fungi to the surface. These ‘ecosystem engineers’ are now given credit for expediting the forest’s restoration from the barren moonscape it once was into the life-rich habitat it is today. The secret to their success lay in a collaboration between animal behaviour and soil microbiology.
Scientists released Gophers on Mount St. Helens 43 years ago to rebuild a devastated ecosystem
According to UC Riverside College of Natural and Agricultural Sciences, in 1980, researchers, such as Dr Charlie Crisafulli and Dr James MacMahon, airlifted Northern pocket gophers (Thomomys talpoides) into the Pumice Plain. For only 24 hours, researchers kept pocket gophers in enclosures where their digging behaviours were observed. By moving the old, nutrient-rich soil through and on top of the new sterile volcanic soil, the pocket gophers helped to ‘re-inoculate’ the sterile substrate with beneficial organisms. Six years after the intervention, plots that had gophers were home to over 40,000 plants, while the plots that had only been untouched with no pocket gopher activity had virtually nothing.
The role of Mycorrhizal fungi in volcanic soil fertility
The reason pocket gophers had so much success in creating habitat for plants is due to their role as vectors for mycorrhizal fungi. Mycorrhizal fungi have mutualistic associations with the roots of over 90 per cent of plants, but most plants would struggle to grow in an Alpine habitat without this organism to help facilitate nutrient and water absorption in the environment, as noted in a journal published in Frontiers. The blast from the eruption buried the soil under tephra (volcanic ash and rock), but the digging of the pocket gophers allowed spores from the fungi, as well as beneficial bacteria, to make it to the surface, where they could affect vegetation growth. In 2024, studies analysing this long-term experiment reported that areas influenced by pocket gophers had a better network of fungi 43 years after their introduction compared to similar sites untouched by pocket gophers.
How Burrows rebuilds soil structure
Pocket gophers are a prime example of ‘ecosystem engineers,’ organisms that manipulate their surroundings to benefit others. Pocket gophers create burrows, which provide suitable conditions for other species and also help increase the aeration and infiltration of water in the volcanic soils. The data collected over the years show how even short-term biological intervention can determine a habitat’s structure for almost half a century. Their activity led to the creation of established, intricate plant communities much faster than natural processes.
