How beavers help fight wildfires

24 February 2023

Published by: https://weather.com

What might beavers have to do with wildfire mitigation? Quite a lot, as it turns out. I talked about it with Dr. Emily Fairfax, an environmental scientist at California State University-Channel Islands who studies (among other things) how beaver dams impact the landscape around them. Here’s part of our conversation, edited for brevity.

Tell me, what do beavers have to do with wildfires?

Beavers are ecosystem engineers that can rapidly transform simple streams in thriving wetland ecosystems. In doing so, they also massively increase the surface water storage and soil water storage of landscapes.

During wet periods, the earth around beaver ponds fills up with water like a great big sponge. Then during dry periods, the plants that live near beaver ponds can access the stored water in that earthen sponge and stay green and healthy, even if the droughts are long and intense. Because the vegetation around beaver ponds is buffered against drought stress, it is relatively inflammable.

When a wildfire starts, that fire will take the path of least resistance and rapidly burn through dry vegetation. The beaver wetlands and the vegetation within them are quite wet, so fire either skirts around them or stalls, and sometimes blows over them. As a result, beaver complexes stay green while the rest of the landscape burns.

You made a really great stop-motion video that shows how beavers can help with wildfires. What inspired you to do this? What was the response?

I made that stop-motion video because I was in the middle of applying for jobs and I had given my “elevator speech” about my research like 100 times and always found myself wishing I had a visual to go along with it. I had this very vivid mental picture of how beavers can help with wildfires, but just describing it verbally was not having the impact I wanted. I couldn’t find any visuals that got the point across the way I wanted, so I decided to just make my own! I had never made a stop-motion video before, and honestly I thought that maybe the rest of the beaver researchers would think it was cool when I posted it on Twitter, but that was about it. I was really surprised to see how fast it spread online and how many people were watching it and commenting on it. It is still my greatest networking tool. That 45 second felt, hot glue, and construction paper video has resulted in more collaborations, more partnerships, and more interest in my research than any paper or presentation I have given.

What does your research around beavers and wildfires show?

I’ve also looked to see whether this effect persists in megafires (which are increasingly common as climate changes), and in one study I found that 89% of beaver dammed areas served as fire refugia – meaning they didn’t burn, or only had very low intensity burning. Only 60% of riverscapes without beavers were fire refugia, and only 37% of the nearby hillslopes and non-riverine environment were fire refugia. So this beaver-driven fire resistance is a really durable effect – beaver complexes are uniquely and remarkably hard to burn.

What is the current beaver population in the U.S./North America, and how does it compare with historical beaver populations?

The current beaver population is around 10% of the historical population in North America. Prior to the Fur Trade, there were 100-400 million beavers on this continent. Overexploitation during the Fur Trade pushed beavers almost to extinction – their population fell to around 100,000. Today, we estimate that there are 10-40 million beavers here. Some places, like the Rocky Mountains, have seen significant rebound in their beaver populations and many creeks are at or near their beaver capacity. Other places, like most of California for example, still have far fewer beavers than they did historically and a long way to go on recovery.

How might understanding what beavers do help us understand how to better control or survive wildfires?

Climate change is a really big, really complicated challenge we’re facing. There is so much work to do, and honestly it sometimes feels like too much work to do on our own. The fire refugia that beavers create has very real value as fire moves through the landscape. Not only can plants and animals stay safe in these beaver-engineered landscape patches during fast-moving blazes, but the physically complex wetlands also help catch and settle out debris and ash that is being carried in the rivers post-fire.

Further, understanding how beavers engineer their wetlands to be so fire resistant can help inform our own fire management strategies in river corridors. We don’t have to solve all the challenges of climate change on our own – working with nature and ecosystem engineers like beavers can be really powerful.