Just when you were feeling like summer had gotten to that sleepy, not-much-happening stage, we find a glut of beaver news. Yesterday four prime articles dropped and they all deserve our attention but I’ll start at the top and let the others trickle out later. There are beavers again in National Geographic. Sadly not written by Ben Goldfarb, but quoting him. Does that count?
Beavers on the coast are helping salmon bounce back. Here’s how.
This tidally salty wetland might seem a strange place to search for beaver, which are known to settle in freshwater ponds, lakes, rivers, and wetlands throughout North America, but that’s what I had come for. The beavers’ presence is remarkable not just because they’re only typically found inland, but also because their ecosystem engineering is the suspected key to the remarkable Chinook salmon recovery that’s going on here.
These dam-created pools are one of numerous, well-documented ways beavers create advantages for fish. They provide havens during times of drought. They also create slower-water habitats that host many more insect larvae—which feed fish—than fast-moving channels. Beaver lodges offer physical refuge for young fish navigating the predator-rich waters.
Oh this is fun. Having the full force of NGO and its team of graphics specialists turned for the moment like a bright spotlight on the subject of beavers. Promise me you’ll go read the whole thing later, okay?
Got that? Before beaver very few salmon. After beaver very many more salmon. Are you even listening wildlife services?
In near-shore areas, where tides impact the lives of all animals daily or seasonally, low-tide pool habitats created by beaver dams allow juvenile fish to seek refuge from predation, says Greg Hood, a senior research scientist at Washington’s Skagit River System Cooperative, who has researched beavers there. “The pools beavers make are too shallow for diving predators like mergansers and kingfishers and bigger fish. But the pools are too deep for waders like great blue herons, and there’s too much shrub around the margins, so birds with big wings can’t get in there.”
In his research, Hood found that pools created by beaver dams in the tidal marshland channels tripled juvenile Chinook salmon habitat compared to similar marshlands without beavers.
I have a question. How do fish know to avoid predation from birds? What is their thought process? “A big beak comes when the waters deep sometimes and eats my friends so lets go somewhere shallow?” Do fish even know whether water is shallow or deep?
Despite this evidence, there has been resistance to beaver dams in salmon streams, the concern being that they might impede the salmon’s ability to swim upriver—after all, the reason human-made dams have been removed is to help salmon. “Beaver dams are nothing like human-built dams though—they are lower, semi-permeable, and due to their porous construction, fish can go over or around them,” says Ben Goldfarb, author of Eager: The Surprising Secret Life of Beavers and Why They Matter, who points out that beavers and salmon co-evolved in the same ecosystems.
HOORAY! A fine Ben-sert! Nicely done sir. And people who think beavers block salmon don’t do their homework. Everyone knows that.
Beavers have probably continuously lived in environments that are difficult for people to access, says Hood. Beavers in out-of-the-way places were protected from humans and other predators, so they were likely unknown—or forgotten. Hood blames “ecological amnesia” for some of our assumptions about where beavers are “supposed” to live. He found just as many beavers living in the tidal shrub marshlands at the mouth the Skagit River than in other non-tidal rivers.
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Back at the mouth of the Elwha, Shaffer shows me how the beavers here are trying different channel locations and building techniques for their dams, looking for just the right placement in this particular ecosystem. It’s this kind of adaptive flexibility to local environments that led to beaver’s widespread success in North America in the past—and is key to its survival in the future. Because beavers’ building naturally expands entire ecosystems, their triumphs are a boon for other animals too, including those in need of all the help they can get—like Chinook salmon.
Ooh lala. Beavers are adaptive ecological swiss army knives that get the job done. I love this article! And that video. Isn’t it amazing? NG doesn’t allow it to be embedded so I tried a workaround with a new tool. If a team of attorneys come lock me up and throw away the key just remember I tried to spread the beaver gospel.
Now go read the whole thing, and make sure it’s open in all the waiting room coffee tables later this month.
