MEGAFIRES BE DAMMED: CAN BEAVER-CREATED FIRE REFUGIA PERSIST THROUGH EXTREME WILDFIRE EVENTS? (Invited Presentation)

Megafires, defined here as fires with burn areas greater than 100,000 acres, are partially the result of increasingly short wet seasons coupled with hotter, drier summers, year after year. Though megafires historically are rare, they have become increasingly common in recent years. Three megafires - the Cameron Peak Fire, the Mullen Fire, and the East Troublesome Fire - happened in rapid succession in Colorado and Wyoming this past autumn. These megafires pose unique challenges – they have explosively fast rates of spread, generate their own self-sustaining weather systems, and can easily cause secondary ignitions in the surrounding landscape via ember spotting and lightning strikes from pyroculumus clouds. Managing fires of this size and intensity while preserving sensitive riparian ecosystems is a landscape-scale challenge. Beaver activity has been previously shown to keep riparian vegetation green and lush during both droughts and small to medium-sized wildfires. Whether or not this effect persists in megafires has not been previously studied. We use Sentinel-2 remote sensing data (false color 8,4,3; false color 12,11,4; and NDVI) to characterize fire spread and burn patterns in and around beaver-dammed riparian zones within the Cameron Peak, Mullen, and East Troublesome megafires. Our analyses suggest that beaver-created fire refugia can persist through megafires, and that the degree of fire protection is typically greater in 1) active beaver areas, 2) in beaver complexes with multiple dams in close proximity, and/or 3) where extensive beaver damming has created an anastomosing channel. This work demonstrates that beaver-based stream restoration is a viable climate adaptation strategy in the western United States.