Just in time for the graphic I was working on yesterday, I didn’t know our buddy Ben Dittbrenner was working at NorthEastern. Good for him, and good for the lucky environmental students in his class. For now appreciate an awesome article from News@Northeastern by Khalida Sarwari
They’re cute. They’re furry. And they’re the unsung heroes of wildfire protection efforts.
From California to Washington, the West Coast is experiencing a fire season unlike any other on record. Since August, climate change-fueled wildfires have scorched more than five million acres across the three states, taking dozens of lives, destroying thousands of buildings, and making the air unbearable for millions of people.
Benjamin Dittbrenner, an associate teaching professor in the Marine and Environmental Sciences department at Northeastern, says wetlands and beavers are an important part of the fire protection puzzle. Beaver ponds and wetlands have been shown to filter out water pollution, sequester carbon, and attenuate floods.
But perhaps a lesser-known fact about the tiny rodents is that they play a key role in creating fireproof shelters for plants and animals. And by building dams, forming ponds, and digging canals, these architects of the natural world irrigate stream corridors that help slow the spread of wildfire.
Ben! My goodness, looking all professor-y, Does that mean we have good beaver researchers on both coasts now? Gosh, I’m so old I can remember when he was working for public works and squeezed in with us at the lunch table so he could hear everything Mike Callahan had to say about flow devices at the beaver conference.
He’s come a long way baby.
One of Dittbrenner’s techniques involved relocating beavers to streams from areas where they were at risk for entrapment. As the critters went to work building dams in their new habitats, Dittbrenner evaluated the transformation of the streams into a wetland complex—multiple wetlands that share adjacent streamside land.
“Wetlands are definitely an endangered or threatened land type,” Dittbrenner says. “There are a ton of existing wetland regulations, but human encroachment is really the biggest threat to that.”
Dittbrenner traces the degradation of streams and the disappearance of natural dams to the fur trade in the 1600s, which at the time centered on the beaver. Prior to the arrival of the European settlers in North America, he says, beavers existed in nearly every stream system, and dams could be found in abundance. As the beaver population was nearly extirpated because of heavy trapping, the dams disappeared, too.
“As those beaver dams degraded and disappeared, those [wetland] systems became much simpler,” Dittbrenner says. “A lot of the wetlands that were there were gone. A lot of the sediment that was there that was doing things like pollution attenuation was gone. And the flood storage capacity was gone.”
Nicely done Ben. Now we are getting fire skills preached from both sides of the country! Let’s hope it catches on and becomes part of our conversation about how to cope with this going forward.
The resulting decrease in water availability for surrounding plants leads to forest stress, says Dittbrenner.
“[The trees] become more prone to insect infestation,” says Dittbrenner, explaining that forest pests contribute to the fires prevalent on the West Coast. The dams also enable water to back up, producing pockets of both deep and shallow waters as well as rocky, sandy, and muddy habitats for birds, fish, mammals, amphibians, and reptiles, Dittbrenner says. As such, he says, the number of interactions between these species is higher.
“Beavers are modifying the environment to create their preferred habitat—we call them ecosystem engineers,” he says. “In doing so, they provide all of this traditional habitat for other species, and all of these additional potential ecosystem services for people as well.”
An excellent point. Althought I’m thinking you maybe should at least mention Emily’s work. Maybe you did and the reporter just didn’t write it down, but this issue would hardly be in the limelight without her right?
“As we have these big fires, much of the vegetation in the forest (such as trees) is basically gone,” he says. “And it creates ash and underlying soil easily migrates when there’s precipitation. When there’s a big storm, all that ash and soil will wash—sometimes quickly—down in streams and fill up some of those streams.”
The ash and sediment cover salmon egg nests, he says, causing the eggs to suffocate because they can’t get enough oxygen. The absence of trees—which help slow down river and overland flow—leads to an uncontrolled surge of water following rainfall and increasing stream flows, which puts added stress on man-made infrastructure, such as bridges and wastewater treatment plants, Dittbrenner says.
You know looking at the great photo by Joe Wheaton I don’t think that beaver dams burned. Which means they stuck around and helped catch all that erosion and soil runoff. Just another service amount their many provided.
And not just aquatic species, he says, but trees lose water as well. The stress makes them more prone to disease and insect infestation. This systemic stress creates what Dittbrenner calls a “positive feedback mechanism” that often results in environmental disasters.
“If there’s a fire, those trees might already be dried out; some might be dead,” he says. “And that standing fuel load allows for increased forest fire prevalence.”
Research shows that healthy streams promote aquatic life and nurture surrounding lands. Dittbrenner’s work provides clues to how beaver ecosystems and wetlands fit into that equation—and contribute to wildfire protection and recovery.
Well, those are good clues to have. It’s great to see this discussed more broadly, and I hope Ben gets lots of interested undergrads to help him carry on the work. In the mean time here’s the graphic I worked on yesterday. Feel free to share.
