Ben Goldfarb, NATIONAL GEOGRAPHIC
The American West is ablaze with fires fueled by climate change and a century of misguided fire suppression. In California, wildfire has blackened more than three million acres; in Oregon, a once-in-a-generation crisis has forced half a million people to flee their homes. All the while, one of our most valuable firefighting allies has remained overlooked: The beaver.
A new study concludes that, by building dams, forming ponds, and digging canals, beavers irrigate vast stream corridors and create fireproof refuges in which plants and animals can shelter. In some cases, the rodents’ engineering can even stop fire in its tracks.
“It doesn’t matter if there’s a wildfire right next door,” says study leader Emily Fairfax, an ecohydrologist at California State University Channel Islands. “Beaver-dammed areas are green and happy and healthy-looking.”
For decades, scientists have recognized that the North American beaver, Castor canadensis, provides a litany of ecological benefits throughout its range from northern Mexico to Alaska. Beaver ponds and wetlands have been shown to filter out water pollution, support salmon, sequester carbon, and attenuate floods. Researchers have long suspected that these paddle-tailed architects offer yet another crucial service: slowing the spread of wildfire.
“It’s really not complicated: water doesn’t burn,” says Joe Wheaton, a geomorphologist at Utah State University. After the Sharps Fire charred 65,000 acres in Idaho in 2018, for instance, Wheaton stumbled upon a lush pocket of green glistening within the burn zone—a beaver wetland that had withstood the flames. Yet no scientist had ever rigorously studied the phenomenon.