In 1980, a magnitude 5.1 earthquake accompanied by an avalanche flipped the switch on Mount St Helens, a volcano in the western USA. With the pressure removed from the magma below, the volcano erupted, destroying 350km2 of forest and killing 57 people. But three years later, in 1983, scientists put two wild gophers in a small, fenced enclosure on the volcanic plain. They then left them to dig for 24 hours before removing them. According to a new study, those two little rodents have caused benefits to the mountain ecosystem that could still be seen decades later.
