Photo: Emily Fairfax
Beaver dams may offer wildfire protection to western watersheds, in addition to providing better-known benefits such as groundwater recharge, wetland and habitat creation, and riparian restoration.
A new study by California State University Channel Islands professor Emily Fairfax analyzed satellite-derived vegetation indices of riparian areas and beaver dams mapped via Google Earth. At the same time, Fairfax analyzed data for large (over 30,000 acre) wildfires that had occurred between 2000 and 2018 in California, Wyoming, Colorado, Idaho, and Oregon, and compared the fate of beaver-dammed areas to areas without dams. Fairfax found that riparian corridors within 100 meters of beaver ponds were buffered from wildfires. “In all of them, the beaver ponds made it through the fire and stayed much greener. The beaver-dammed riparian zones were functioning differently,” says Fairfax. While the riparian areas without beaver dams eventually recovered on their own, she says, vegetation in the areas with dams stayed green and did not go through the amount of habitat destruction the other areas did. Fairfax was surprised by the amount of beaver damming and wet meadow development she found in her study. “Those colonies have probably been there for hundreds of years, making it through wildfires. There’s not a chance they haven’t burned in the last 200 years.” With drought and wildfire increasing in the West, she says, this latest finding is yet another reason to welcome beavers back to Bay Area waterways.