TL;DR: water from beaver ponds is spread around the landscape in little channels the beavers dig. The pond water slowly seeps into the soil, keeping it wet and plants green. When wildfires come through, the beaver wetlands are too wet to burn. Can’t start a campfire with soggy sticks. Beavers = Firefighters.
Publication: Fairfax, E. and Whittle, A. (2020), Smokey the Beaver: beaver‐dammed riparian corridors stay green during wildfire throughout the western USA. Ecol Appl. Accepted Author Manuscript. doi:10.1002/eap.2225
Beavers and Wildfire: The Conceptual Model
Beavers build dams, dig channels, and change small streams into broad wetland areas. This keeps plants green and lush, even during periods of drought. When a fire ignites, that green vegetation near the beaver ponds will be more difficult to burn than other nearby dry vegetation. The fire will often take the path of least resistance and burn through the dry vegetation away from beaver ponds instead of smoldering through the wet vegetation near beaver ponds.
Beavers and Wildfire: The Verdant Refuge
These beaver-assisted green patches in the landscape can act as a refuge for animals that may be physically unable to escape a wildfire, including fish, frogs, birds, small mammals, grazers, etc. While other portions of the landscape burn, the area around beaver ponds remains relatively unaffected – the perfect place to hunker down and wait out the fire.
Beavers and Wildfire: The Results
This was observed throughout the western USA – specifically in fires in California, Colorado, Idaho, Oregon, and Wyoming. Overall, riparian zones with beaver activity were three times less affected by wildfires compared to riparian zone without beaver activity. In short, places with beavers stayed green. Places without beavers? Not so much.