A pair of beavers in Yellowstone National Park’s Lamar Valley. Photo courtesy of National Park Service / Neal Herbert.
Beavers’ infrastructure slows and stores water in their ponds, canals, and the surrounding soil during wet periods. Because their dams raise water levels, the ground stores water like a sponge. Then, during dry periods the stored water is accessible to riparian vegetation, effectively irrigating the riparian zone and often providing water to flow downstream in the drier months. This greater amount of cool water directly benefits rearing steelhead and trout. Beavers can create and maintain wetlands that are resistant to both seasonal and multiyear droughts by spreading water across the floodplain, essentially creating gaps in combustible vegetation, or firebreaks. These can help slow and limit the destruction of wildfires.
The green strip of vegetation along beaver-made ponds in Baugh Creek near Hailey, Idaho, resisted flames when a wildfire scorched the region in 2018, as shown in this drone image (courtesy of J. Wheaton).
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Beaver-dammed riparian zones have been shown to burn on average three times less than those without beaver (Fairfax and Whittle 2020). For example, the Sharps Fire that scorched over 57,000 acres in south-central Idaho in July 2018 burned a wide swath of a watershed where Idaho Fish and Game had relocated beavers to restore a floodplain. A strip of wet, green vegetation stood untouched along the beavers’ ponds, in the midst of a vast swath of burned forest. Similarly, on the Susie and Maggie Creeks in northeastern Nevada, streamsides near beaver dams were up to 88 percent greener than undammed stream sections when measured from 2013 to 2016 (Fairfax and Small 2018). Even better, beaver ponds helped maintain lush vegetation during the hottest summer months, even during a multiyear drought. |
Studies have been conducted to see if creeks with beaver activity stayed greener than creeks without beavers during wildfires. Across the board, beaver-dammed areas didn’t burn (Fairfax and Small). Areas without beavers averaged three times more damage than those with beavers, and where beavers or rain are absent, plants dry out and become dry fuel for fires.
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In 2021, Oregon endured the third-largest wildfire in its recorded history. The Bootleg Fire tore through the Upper Klamath Basin, an ecologically sensitive area that is home to multiple threatened and endangered species including the northern spotted owl, and two fish — the koptu and c’waam (shortnose sucker and Lost River sucker) — that are culturally vital to the Klamath Tribes. The fire left behind a charred landscape more than twice the size of New York City. Ash from the fire, which burned for more than a month, had clogged formerly pristine tributaries and turned them into black slurries. Thriving trout populations had disappeared, presumably choked to death by waterborne debris particles that deprived the fish of oxygen. |
A huge column of smoke from the Bootleg Fire. National Interagency Fire Center, Fremont-Winema National Forest
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However, amid an otherwise burned-out area along Dixon Creek, a tributary in the Sprague River, roughly five acres of pristine greenery persisted. At the center were roughly eight active beaver dams. Even though the upstream reaches were burned and fish were absent, the water downstream of the beaver ponds was running clear — and trout were thriving. The dams and ponds appeared to have altered the hydrology of the landscape around them, and the beavers had effectively built something that staved off fire-related contamination (Wathen 2021).
Similar dam-driven refuges have been documented from Colorado (Fairfax and Whittle 2020) to California (Schwartz 2021), Idaho (Whitcomb 2022), and Wyoming. Through many studies, it has been shown that, along with deterring the flames themselves, beaver dams and ponds also function as filters for ash and other fire-produced pollutants that enter waterways—thus maintaining water quality for fish, other aquatic animals, and humans — emerging evidence suggests.
Perhaps instead of relying solely on human engineering and management to create and maintain fire‐ resistant landscape patches, we could benefit from beaver’s ecosystem engineering to achieve the same goals at a lower cost. Reconnecting waterways to their floodplains, as beavers do, improves water quality and quantity, supports biodiversity and sensitive species conservation, increases flood, drought and fire resiliency, and bolsters carbon sequestration. Climate-driven disturbances are actively pushing streams into increasingly degraded states, and while the importance of river restoration is clear, beaver-based restoration — for example, strategic coexistence and mimicry — remains an underutilized strategy despite ample data demonstrating its efficacy.
Similar dam-driven refuges have been documented from Colorado (Fairfax and Whittle 2020) to California (Schwartz 2021), Idaho (Whitcomb 2022), and Wyoming. Through many studies, it has been shown that, along with deterring the flames themselves, beaver dams and ponds also function as filters for ash and other fire-produced pollutants that enter waterways—thus maintaining water quality for fish, other aquatic animals, and humans — emerging evidence suggests.
Perhaps instead of relying solely on human engineering and management to create and maintain fire‐ resistant landscape patches, we could benefit from beaver’s ecosystem engineering to achieve the same goals at a lower cost. Reconnecting waterways to their floodplains, as beavers do, improves water quality and quantity, supports biodiversity and sensitive species conservation, increases flood, drought and fire resiliency, and bolsters carbon sequestration. Climate-driven disturbances are actively pushing streams into increasingly degraded states, and while the importance of river restoration is clear, beaver-based restoration — for example, strategic coexistence and mimicry — remains an underutilized strategy despite ample data demonstrating its efficacy.
The contrast is striking between the beaver wetland in Little Last Chance Creek in California and the surrounding area a year after a forest fire in 2021.
Photo Courtesy of Emily Fairfax.
Photo Courtesy of Emily Fairfax.
In California, a new policy went into effect in June 2023 that encourages landowners and agencies dealing with beaver damage to seek solutions such as putting flow devices in streams or protective wrap on trees before seeking permission from the state to kill the animals. The state is also running pilot projects to relocate beavers to places where they can be more beneficial. Federal and State land managers are acknowledging the utility of having beavers on the landscape, and are working to lower hurdles in permitting that would allow more community-driven projects to preserve more beavers, along with their nature-friendly behaviors.
Hopefully the continued good press and catalog of successful projects will encourage more beaverinspired restoration to support building climate resilience across the landscape. Not every stream will be a good candidate for beaver-based restoration, but we have the tools to know which ones are–and so many are. We need more project proponents to spread the good word! For more information and resources, see the list below.
Hopefully the continued good press and catalog of successful projects will encourage more beaverinspired restoration to support building climate resilience across the landscape. Not every stream will be a good candidate for beaver-based restoration, but we have the tools to know which ones are–and so many are. We need more project proponents to spread the good word! For more information and resources, see the list below.
REFERENCES:
Davee, R., Gosnell, H, and Charnley, S. 2019. Using Beaver Dam Analogues for Fish and Wildlife Recovery on Public and Private Rangelands in Eastern Oregon. https://www.fs.usda.gov/pnw/pubs/pnw_rp612.pdf
Fairfax, E. and Whittle, A. 2020. Smokey the Beaver: beaver‐dammed riparian corridors stay green during wildfire throughout the western United States. Ecological Applications. Published online September 2, 2020. doi: 10.1002/eap.2225.
Fairfax, E, and Small, EE. 2018. Using remote sensing to assess the impact of beaver damming on riparian evapotranspiration in an arid Landscape. Ecohydrology. 11:e1993. https://doi.org/10.1002/eco.1993
Schwartz 2021. Crews work to mitigate Bootleg Fire sediment loading. Klamath Falls Herald & News Dec 1, 20221 Wathen, Gus. (2021). North Fork Sprague River: Bailey Flat Riverscape Restoration. 10.13140/RG.2.2.20929.43368.
Whitcomb 2022. Beaver Dams Help Wildfire-Ravaged Ecosystems Recover Long after Flames Subside - Dams mop up debris that would otherwise kill fish and other downstream wildlife, new observations suggest Scientific American. February 7, 2022.
Wheaton, J.M., et al. Low-Tech Process-Based Restoration of Riverscapes: Design Manual. Technical Report, Utah State University. March 2019. doi: 10.13140/RG.2.2.19590.63049/2.
RESOURCES:
Castro, Janine & Pollock, Michael & Jordan, Chris & Lewallen, Gregory & Woodruff, Kent. 2017. The Beaver Restoration Guidebook Working with Beaver to Restore Streams, Wetlands, and Floodplains. Prepared by US Fish and Wildlife Service North Pacific Landscape Conservation Cooperative.
Davee, R., Gosnell, H, and Charnley, S. 2019. Using Beaver Dam Analogues for Fish and Wildlife Recovery on Public and Private Rangelands in Eastern Oregon. https://www.fs.usda.gov/pnw/pubs/pnw_rp612.pdf
Fairfax, E. and Whittle, A. 2020. Smokey the Beaver: beaver‐dammed riparian corridors stay green during wildfire throughout the western United States. Ecological Applications. Published online September 2, 2020. doi: 10.1002/eap.2225.
Fairfax, E, and Small, EE. 2018. Using remote sensing to assess the impact of beaver damming on riparian evapotranspiration in an arid Landscape. Ecohydrology. 11:e1993. https://doi.org/10.1002/eco.1993
Schwartz 2021. Crews work to mitigate Bootleg Fire sediment loading. Klamath Falls Herald & News Dec 1, 20221 Wathen, Gus. (2021). North Fork Sprague River: Bailey Flat Riverscape Restoration. 10.13140/RG.2.2.20929.43368.
Whitcomb 2022. Beaver Dams Help Wildfire-Ravaged Ecosystems Recover Long after Flames Subside - Dams mop up debris that would otherwise kill fish and other downstream wildlife, new observations suggest Scientific American. February 7, 2022.
Wheaton, J.M., et al. Low-Tech Process-Based Restoration of Riverscapes: Design Manual. Technical Report, Utah State University. March 2019. doi: 10.13140/RG.2.2.19590.63049/2.
RESOURCES:
Castro, Janine & Pollock, Michael & Jordan, Chris & Lewallen, Gregory & Woodruff, Kent. 2017. The Beaver Restoration Guidebook Working with Beaver to Restore Streams, Wetlands, and Floodplains. Prepared by US Fish and Wildlife Service North Pacific Landscape Conservation Cooperative.
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Emily Fairfax produced a stop-motion video to show how beavers and their dams and channels keep water in an area, supporting the surrounding vegetation and helping the area resist wildfires. Beavers and Wildfire: A stop-motion animation by Emily Fairfax. |
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