Illustration: Mark Garrison
“The mouths of the Elwha, Snohomish, and Skagit rivers in Washington State provide important saltwater habitat for beavers, salmon, and other estuarine species,” says the radio show Living on Earth.
One of the main reasons I like writing a blog is that I like to learn new things and to have something interesting to think about. I save up promising links, sometimes just because the headline looks interesting. Later, when I actually work on the post, it’s such a treat to read the whole story!
When I saw that there was such a thing as saltwater beavers, I thought, Really? This is a keeper!
From the radio show Living on Earth: “Until recently, biologists assumed that beavers occupied freshwater ecosystems only. But scientists are now studying beavers living in brackish water and how they help restore degraded estuaries and provide crucial habitat for salmon, waterfowl, and many other species. Journalist Ben Goldfarb speaks with Host Bobby Bascomb.
“BASCOMB: The eager beaver is an extremely effective engineer of its environment. Beaver dams hold back water that can be a nuisance to homeowners, but they create a complex system of ponds and wetlands that are a haven for numerous plant and animal species. …
“Scientists recently discovered that beavers are also happy to live in the brackish mix of fresh and salt water in coastal areas. And just as they help restore freshwater ecosystems, beavers could also hold the key to restoring damaged coastal wetlands. Journalist Ben Goldfarb wrote about saltwater beavers for Hakai Magazine. …
“Ben, how surprised were you to find out that there are saltwater beavers? …
“GOLDFARB: It was definitely surprising. … It’s just really within the last several years, thanks in large part to this guy, Greg Hood, a scientist who works in the Skagit river in Washington, that we’ve begun to understand that [beavers are] living full-time in these intertidal estuaries. …
“BASCOMB: You actually went to visit one of those beaver lodges on this Snohomish river in Puget Sound. Can you describe that? …
“GOLDFARB: It’s kind of this huge saltmarsh that’s scored with these little freshwater channels that freshwater comes down in. But then when the tide comes up twice a day, those freshwater channels are completely submerged, they’re inundated. So it’s this really dynamic ecosystem with the tides are just going in and out all the time. And beavers are actually building in there. So they’ll build these dams that when the tide comes up, the dams are actually completely submerged under water, you could kayak over the top of one of these dams and have no idea that they were beavers building there. And then when the tide goes out again those dams suddenly reemerge. …
[It’s] almost like the beavers are anticipating these tidal fluctuations and are accounting for them in their construction, and in this really sophisticated way. …
“BASCOMB: How do their dams in these intertidal areas affect the ecosystem around them? …
“GOLDFARB: What Greg found is that [these beaver construction sites] are hugely important for juvenile salmon, especially. You know when the tide goes out, those fish would get flushed out into these estuaries where they’re really at risk of being preyed upon by larger fish, by birds. … Baby salmon were three times more abundant in these beaver pools than in other habitat. …
“BASCOMB: Wow. So, they really serve a critical function. I mean, everybody likes salmon, right? The bears, the whales, people. …
“GOLDFARB: We saw this past year just how badly the southern resident killer whales are doing, the orcas in Puget Sound, and they’re essentially starving because there’s just not enough salmon. …
“BASCOMB: It’s all connected. Now, you write about how beaver ponds can help restore degraded coastal wetlands. And there’s clear evidence for that in removal of dams on the Elwha River in Washington State. …
“GOLDFARB: Two enormous dams had basically been there since the ’20s, I think, just trapping enormous amounts of sediment and blocking salmon runs. … A few years ago the government actually bought those dams and — thanks to pressure from native tribes — removed the dams, and opened up this huge amount of spawning habitat for salmon, so now salmon are swimming up river, past the former dam sites.
“[But] the river mouth had been starved of sediment for so long that it basically just flowed straight into the ocean. There was no real estuary there. … Beavers are really going into town in there. And by creating burrows and canals and dams, they’re just creating this amazing habitat complexity. They’re just opening up lots and lots of little spaces for all kinds of salmon and trout and other fish to live in.”
More here.
Photo: Becky Matsubara, Flickr
Because they build dams that shape the very environments in which they live, beavers are a classic example of a “keystone species.”
Suzanne's Mom's Blog 
I’ve never heard of saltwater beavers nor considered that beavers may want to stray into saltwater. Interesting!
The report said that they had been known to travel across saltwater to a new home — on an island, say. But scientists only recently realized that they were staying put.
Wowsah! Never heard of beavers living in salt water. A neat thing to learn.
I’m fascinated by the image of beaver homes being deep under water during high tide so you’d never notice them if you passed over in a kayak. It feels like something that would only happen in Narnia.
Yes, Narnia!