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We see a lot of "rock dams" in the headwaters this time of year, and remove as many as we find, but keeping up with humans can be difficult. The Beavers do a much better job and there's plenty of science that points to the benefits for healthy populations of most wildlife, importantly our Wild salmonids in the Yakima.

Here's a link to the Facebook page for more discussion and information.


http://wdfw.wa.gov/conservation/drought/graphics/let_them_pass_small_rev.pdf

Support your local beavers!
 

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Question...

So human 'rock dams' are illegal and should be removed. I get that.

In my experience beaver built dams can do a much better job at blocking flows than human built ones since they use rocks, mud, sticks etc. But beaver built rock dams are okay? :confused:
 

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There's certainly a huge difference is ecosystems, Patagonia and the PNW are quite different. The local biospheres are very different. Beavers do good work when they create wetlands in higher elevation streams but they don't do any favors in lower warmer areas. In the driftless area of Wisconsin beavers can create problems, removing bank woody structure/shade and making a dam with it. Likely a problem in Montana too.

Beaver dams definitely create fish passage issues in the PNW but the huge variability of the climate generally takes beaver dams out more frequently. The longer a dam exists the more sealed and problematic it becomes. Beaver dams are good when they are destroyed and rebuilt every few years, otherwise they become a problem.
 

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Well, yeah, take beavers and put them on a different continent, and there are problems. Gee, who'd a thunk it?

Beaver ponds are great nurseries for juvenile fish, especially coho. This includes habitat such as the Puget lowlands. Beaver dams encourage aquifer recharge which helps maintain stream flows during dry periods. They attenuate flooding during big precipitation events by creating flood storage and flood desynchronization. This reduces scour and bedload mobilization. Remember that salmon and beavers evolved together as part of the same ecosystem. Most of the issues with beaver dams are the result of them being in places that are inconvenient for infrastructure. Do they sometimes block fish passage? Yes, but in these limited cases, it's temporary, and it is very rare to find a beaver dam that blocks fish at all flows at all times, year after year after year.

In dry areas, like east of the Cascades, beaver dams raise the water table and encourage growth of riparian vegetation. This is also good for fish, because it means more productive habitat.
 

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Beavers are awesome creatures that help sustain and revitalize streams. Healthy streams are quite often those that flood their banks in the spring instead gushing by. Had a speaker at out local CCC explain this including efforts to transplant these critters to a nearby stream to hopefully undue years of human, habitat destruction.

Maybe a little more bio mimicry from "us",
 
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In the driftless area of Wisconsin beavers can create lot's of problems, removing bank woody structure/shade and making a dam with it. Likely a problem in Montana too.
They sure can be. Unless controlled naturally or otherwise the buck tooth wonders can damage fragile ecosystems in short order. Neighbors have eliminated a dozen so far within a half mile stretch on a small creek, and there are still more to deal with. PNW streams can be very different from many streams in MT.
 

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They sure can be. Unless controlled naturally or otherwise the buck tooth wonders can damage fragile ecosystems in short order. We've eliminated a dozen so far within a half mile stretch on a small creek, and there are still more to deal with. PNW streams can be very different from many streams in MT.
Please consider donating future beavers to the Mid Columbia Fisheries beaver restoration program.

Thanks!:)
 

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They sure can be. Unless controlled naturally or otherwise the buck tooth wonders can damage fragile ecosystems in short order. We've eliminated a dozen so far within a half mile stretch on a small creek, and there are still more to deal with. PNW streams can be very different from many streams in MT.
No offense intended but I'm curious about your small creek habitat and if the beavers are native to Dillon area (I assume they are since I saw evidence of many of them in May of this and last year) and your small creek. Are you removing "native" beavers to enhance a fishery or property for development or, as suggested, they're harming the ecosystem of this creek?

I will completely agree with your first post about Patagonia since they are non-native and invasive. Here in my home town property owners and the electric utility are dealing with invasive non-native red squirrels. I HATE the damn tree rats; they steal walnuts from my tree and they cause utility outages (usually that particular tree rat is fried).

Beavers are quite the wanderers; I spent 28 years working on the mid-Columbia. Beavers use the Columbia to look for new lodgings and were quite adept. So good luck with your controlled removal.
 

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Just read an article that a stealth bomber costs 3.4 billion and over 3 million a month to maintenance. But we can't afford to relocate wildlife as opposed to "eliminating" them.

Perhaps some more communication between all wildlife agencies to send beavers to the many watersheds where they are needed is in order.
 

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Back to the original topic; that is the problem with man-made rock dams.

There is a significant difference between those dams and those made by beavers. Beaver dams tend to be in low gradient and smallish streams which at least here in PNW that are typically used by resident trout, anadromous coastal cutthroat and coho. While this time of year those dams may be impassable the migratory fish typically found in those habitats return during the fall and winter taking advantage of significant flow events to gain access past those temporal barriers. The man-made rock dams tend to be in more open river channels and lower downstream. At times those dams become impassable unfortunately some of the fish species attempting to migrate over those barriers (Chinook, bull trout, etc.) due so during periods of lower flows restricting their ability to by pass those barriers.

I have seen a number of cases where those man-made rock dams where indeed significant barriers. I recall an instance in late September on a bull trout stream where several dozen adult fish were holding in the pooling downstream one of those dams with several fish with their nose against the rocks. There was several miles of prime bull trout habitat upstream that was vacant of adult bulls. I took the time to roll a couple boulders out of the dam opening a passage way on my upstream. A hour later several bulls have moved pass that dam and others were lined up immediately below the "passage way". A week later following a cold snap the bulls were actively spawning upstream of that dam.

Curt
 

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I've been a fan, and to a limited extent, scholar of the natural history observations that Lewis and Clark and their crew made during their trip across the western US in 2004-2006. When I give talks on the subject, I like to use a quote from Lewis about beavers and then ask the audience where they think the observations were made.
Here's the quote (his misspellings, not mine):

Lewis, July 24, 1805 -- "we saw many beaver and some otter today; the former dam up the small channels of the river between the islands and compell the river in these parts to make other channels; which as soon as it has effected that which was stoped by the beaver becomes dry and is filled up with mud sand gravel and driftwood. the beaver is then compelled to seek another spot …

this anamal in that way I believe to be very instrumental in adding to the number of islands with which we find the river crouded."

Where? On the Missouri river near present day Helena, Montana!!!
 

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A big fan of the Lewis and Clark expedition as well.

When Lewis and Clark made their famous trek over two hundred years ago there were adequate numbers of natural predators to keep beaver populations in balance. Not many wolves, coyotes, mountain lions, and bears roaming the river bottoms these days. Not in my neck of the woods anyway.
 
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