The “Beaver Patrol” in Juneau understands how beavers are important to salmon. It was started by our friends Bob Armstrong and Mary Willson years ago. But obviously beaver beliefs are still forming and changing up there, because the forest service isn’t so sure about them. The reporter still thinks they live in the dam, and even one of their volunteers needs to look up the word “Destructive” in the dictionary, I think.
Coho habitat destroyed by beaver dam dismantler
Last summer was a great year for coho salmon returns to Dredge Creek. Unfortunately, salmon redds in the creek below Dredge Lake have been negatively impacted by someone it appears was trying to help them, says the Beaver Patrol.
The “Beaver Patrol” is a group of volunteer Juneau naturalists and concerned citizens who have been working in the Dredge Creek and Dredge Lake area — U.S. Forest Service Land — for about five years. They and the Forest Service manage the dams and have improved salmon habitat in the stream, said member Chuck Caldwell.
Another factor helping Dredge Creek’s coho rearing? Beavers.
Caldwell had taken note of three different redds — nests of pebbles where salmon deposit their eggs — just above a beaver dam. A fourth was outside the main channel and needed a nearby dam to maintain its water depth. The destruction of the dam lowered the water and this winter that area froze, he said.
“He was tearing (the dams) out once or twice a week. Clearly he just hated beavers. He also wanted to dig in the stream to make a nice, deep channel. He dug through two of the redds,” Caldwell said.
The digging and the dismantling of the dams destroyed all the salmon redds he had observed in that area, Caldwell said.
In the first half of November, Beaver Patrol member Jos Bakker ran into and confronted the man when he was in the process of destroying a dam. The man doesn’t appear to have come back after that, but the damage was already done, Caldwell said.
The Beaver Patrol emphasizes beavers’ positive impact on salmon rearing.
“If you look back a couple of decades, people used to think that if you got the dams out, the fish could move back easier,” Caldwell said. “That’s not the limiting factor in the coho population. The limiting factor is having a habitat the juvenile cohos can live in.”
“By and large, it’s a safe bet that beaver dams do provide excellent coho rearing habitat,” Schneider said. “They can cause major problems for adult cohos to access fish habitat, and that’s probably what gets most folks in the public tempted to tear out dams. It has to be a fine balance, like anything else … In a normal setting, you would have these major flood events on occasion. It would rearrange them and keep them in check. You’re not going to get that in Dredge. On top of that, there are not normal predator levels that you would find in a normal wild setting.”
Dams’ impact on adult salmon in a setting like Dredge is something about which the Beaver Patrol and the Forest Service are not in complete agreement. Member Mary Willson says 90 percent of the time beavers are actually helpful to coho populations. Schneider disagrees.
When he and the cub scouts notch the dens, they use specific techniques and tools to ensure muddy debris doesn’t end up covering redds.
Beaver management does require a balance, Miller said.
It’s one of those interesting situations,” he said. “It’s true that habitat is being created, but at the same time, beavers are very destructive.”
In areas where beavers might create an aesthetic issue, the patrol has put a cloth around the trees that will keep the beavers from gnawing them, Miller said.
In my old days back before my time as a psychologist we used to call that “they’re good, they’re bad, they’re really good, they’re really bad” kind of messaging ‘schizophrenogenic’. Meaning if it kind of makes you crazy. Of course now they no longer think schizophrenia is caused by parenting BUT I would argue the term still applies to beavers. Just look at the dedication of folks in a very small area on both sides of the fence. Bob Armstrong even got the forest service to bring out Mike Callahan to talk about flow devices in 2009, but they never let him install one. The breadth of understanding of beaver benefits there is razor thin. But still a lot thicker than some places.
Here’s what Michael Pollock said to me in our podcast interview. “Does some particular beaver dam ever prevent some particular salmon from getting over at some particular time? Sure. But that’s asking the wrong question”.
Beaver dams are doing so much good for so many salmon it balances out.
Here’s my own unscientific variation: “Do people ever get hit by ambulances? Of course they do. Does that mean we shouldn’t have ambulances? Absolutely not.”
