Arizona
How Arizona’s beavers could be a secret weapon in fire prevention
Arizona biologists relocate beavers to help restore wetlands
Arizona Game and Fish biologists are moving beavers from locations where they can be a nuisance to areas where they can contribute to conservation.
- Beavers are incredible engineers, building dams so they can deter land predators. Their construction helps the land retain water and attract biodiversity around their ponds.
- Beavers help reduce wildfire risk and spread, as the wetlands they manage act as fire breaks and is less flammable.
- Beavers used to populate the North American continent, but trapping in the 1800s drastically curbed their numbers. Today, beavers are often considered pests for tampering with human infrastructure.
Laura Roche understands the imperative of curbing carbon emissions to prevent climate change from supercharging wildfires to “megafire” status. But she’s also aware that such steps won’t solve the problem right away, even if the entire world got their act together on addressing climate change this instant.
“People get tired” just talking about reducing emissions, she said. Even as smoke lingers in the air from the Pocket Megafire that was burning less than 10 miles away, she knows it won’t be a helpful conversation. “But there are other things that can definitely improve the situation,” she added.
Roche, a Cottonwood resident who works in Sedona, has one suggestion in mind: reintroducing beavers.
Beavers are North America’s largest rodents, with a flair for dam building. Their structures create strings of ponds and vital belts of lush vegetation, which can help prevent and mitigate fires in the region, simply because beavers help wetlands stay wet.
Community interest in beavers is stirring among Sedona residents and workers, who have watched warily in recent weeks as the Pocket Fire raged. They’re circulating YouTube videos about the power of these humble animals to terraform landscapes and reduce fire risk in a fire-prone region.
As of July 15, the Pocket Fire has burned 27,400 acres and is 83% contained.
Roche herself has been sharing the science of beavers with government officials in forest planning meetings, customers, customers and friends across the political spectrum.
“I’ve had nothing but positive support for the idea,” she said.
The science seems to check out. Emily Fairfax is a beaver scientist at the University of Minnesota, and also a beaver evangelist.
“You cannot restore streams that were originally made by beavers and shaped by beavers —without also bringing back the beavers,” she said.
How beavers help mitigate wildfires
Beavers are slow creatures that sorely lack in the physical department — but make up for it with their brilliant minds. They build dams to create deep pools, and there they build island dens to deter land predators. They also construct a network of canals along rivers to facilitate forage without leaving the safety of the water. A single beaver family can service a mile-long strip of wetland.
“It’s incredible how large scale their engineering is,” Fairfax said. There’s a joke among her peers about these crafty animals: “If you have a problem, there’s a beaver for that.”
With a dam in the way, surface water, such as storm runoff, has time to seep into the ground, recharging groundwater in the process. The retained moisture encourages plant growth, especially crucial in times of drought. Studies have shown that beaver-managed streams have more abundant vegetation than a landscape without.
Beavers can thrive in all kinds of riparian ecosystems, including drylands. There, the rodents seek out groundwater springs and excavate their ponds to expand storage capacity.
Beaver families have been observed to frolic in the concrete hearts of California’s San Jose, Portland, Denver and even in metro Phoenix. As long as reeds and trees are present as a food source, beavers can make it work, using rocks, trash and whatever they can find as construction material.
Fairfax has found that beaver wetlands are more fire- and drought-resilient than any other kind of riparian zone bereft of beavers. That’s because beavers work incessantly to maintain their dams and ponds.
“It’s life or death for the beaver to have that wetland,” she said. “So every moment of the beaver’s day, it’s like, how do I make sure this place stays wet?”
During a wildfire, the footprint of beavers makes a difference. It’s harder for lightning struck fires to spread on beaver-managed wetlands, as green vegetation is much less fire-prone. The network of rivers and beaver-made canals can act as a fire break to slow the progression of wildfire.
The wet pockets of beaver habitat also provide refuge for animals fleeing from fires. In 2021, the Beckwourth megafire scorched more than 105,000 acres north of California’s Lake Tahoe but spared a web of lush riparian corridors on the floodplain — sites where beavers had dammed and dug and developed before the blaze hit.
Will beaver reintroduction work?
Beavers ruled North America for 7.5 million years, in numbers up to 200 million strong. Up to a billion beaver dams peppered the landscape. Pretty much every river on the continent had resident beavers, except for predator-plied places such as the Everglades, where there are alligators.
Fur trapping in the 1820s nearly caused beavers to go extinct. Today, only 10% of their historic population are found in waterways.
In Arizona, beavers are still widely distributed across the state, but in scant numbers. Reintroduction programs have helped sustain their populations, though their abundance is still far from their heyday.
Along the San Pedro River, also historically called Beaver River, reside an estimated 38 beavers. Arizona Game and Fish Department experts have been relocating beavers here since 1999. But the San Pedro’s beaver count is still declining, likely due to drought that has strained water levels, drying up their moated homes and suppressing cottonwood regeneration.
In the age of drought and megafires, Fairfax thinks beavers should be part of government agencies’ tools for managing fires. One rainy season is all it takes for reintroduced beavers to bring fire suppression and mitigation effects into their new home.
Can beavers make a dent on Arizona’s fire-prone landscape? Potentially, said Northern Arizona University community ecologist Stefan Sommer, especially along the riparian corridors where they den. But these strips make up just 0.5% of Arizona’s diverse landscapes. Moreover, 90% of the state’s surface waters have been wrangled into pipes and concrete canals, which are far from the ideal habitat of beavers.
But Sommer says beavers have the greatest promise for reducing flood risk in burn scars. Beaver dams and the riparian vegetation around them can act as sponges to hold back runoff after heavy rains.
Post-fire or no, other flood-frequent areas have already benefited from beavers. The Greenford Tube station in West London used to flood after every storm. But since beavers built a dam upstream three years ago, flooding no longer occurs.
Beavers’ dam-building bent isn’t broadly beloved. The industrious architects often plug up culverts, which can flood human infrastructure nearby.
As nature’s engineers, beavers bend rivers to their will, not unlike humans. For this reason, beavers are still considered nuisance animals. Beaver presence can interfere with the well-laid plans and long-term goals of human engineers who too want to work rivers to their own vision.
For all the benefits of bringing back beavers, reintroduction isn’t straightforward either. Beavers need to be moved with their entire family, as estranged individuals can die from depression.
The antics of beavers have garnered them fans — they’re known to be playful and prone to getting the zoomies. But their personalities need to be managed to prevent human habituation, Fairfax said. Beavers easily form bonds with humans, which complicates reintroduction success.
Ideally, work must be done in advance to make sure reintroduced beavers have all the resources they need to thrive. The process of planting willow and cottonwoods, the favorite snacks of beavers, can take years before denuded rivers become conducive enough for beavers to move in. Constructing analog dams helps beavers settle in, too, as it tricks them into thinking that other beavers have been there before.
Arizona’s translocation programs are geared toward removal from areas of human-animal conflict. According to the Arizona Game and Fish Department, none of these projects and any future ones are specifically intended for fire mitigation, which the agency considers a secondary benefit.
“We do not utilize beavers … as our federal and state foresters have more effective tools in their toolbelt for management of the forested woodlands of Arizona,” wrote Shawn Lowery, the agency’s supervisor of habitat restoration and mitigation, in an email.
With the double whammy of wildfires and drought around the West, the movement to reinstate the beaver onto rivers is growing. In the southern Sierras in California, the Tule River Tribe has been leading the efforts of returning beavers to their reservation to help retain water. In Nevada and Utah, restored beavers have fashioned lush oases in the middle of the desert.
Beavers aren’t a silver bullet to the West’s fire and water woes, and it’s possible their vast impact of the landscape might not be enough to turn the tide against climate-change-fueled disasters, Sommer said.
Nevertheless, beaver reintroduction is pretty low-risk compared to the destructive scale of natural hazards that humans contend with.
“Let (beavers) do their thing, and if it works, great,” Fairfax said. “If it doesn’t, oh well, now you have biodiversity, carbon sequestration and all the other benefits.”
Back in Sedona, Rowe has been a long-time advocate for repopulating beavers in the watershed, though it still hasn’t translated into concrete action from government officials. Rowe hopes that the recent Pocket Fire will finally persuade land managers to reconsider, before the next wildfire arrives.
Shi En Kim covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to shien.kim@arizonarepublic.com.
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