Sure beavers are good for trout.
But are they good for ALL TROUT? In Every state? And in streams with left-handed fisherman? Well, science demands an answer. You know just because things are proven true over and over doesn’t mean they’ll be proven true again. Right?
Beavers, Trout, and a Changing Climate
Driving through the lush forests of America’s Pacific Northwest, you might spot this bumper sticker: “Beaver taught salmon how to jump.”
Instead, the bumper sticker refers to the fact that North American fish species co-evolved with the continent’s largest rodent. Salmon and trout have adapted to jump over or swim around beaver dams. In return for the extra effort navigating upstream past dammed waterways, native fish benefited from the bountiful food and shelter created by beaver ponds.
Today, though, both furry and finned creatures are facing a new “normal.” Populations of native salmonids and beavers have declined drastically due to human influence. In addition, climate change has further reduced the water quality and flows in headwaters streams where native trout reproduce. As their habitat dwindles, it may mean that fish are in trouble if certain tributaries are blocked by a natural barrier. This has sparked concerns about whether beaver dams are always in the best interest of wild trout.
See climate change might mean we need to kill more beavers! I knew there was a reason for it!
Natural and simulated beaver ponds help slow down the flow of water, providing natural water storage and flood control. The ponds recharge groundwater, which keeps streams running when rain and snowmelt are scarce. It also spreads water across the floodplain so it can grow more green plants that feed terrestrial wildlife and livestock.
Fish get to join the feast, too, since beaver ponds diversify stream habitat and produce more aquatic plants and insects. Plus, the side channels, sloughs, and meanders created by dams add complexity to stream habitats, giving fish more places to hide, rest, or spawn.
Because of these promising ecological results, beaver-related restoration projects have increased markedly over the past ten years. In fact, these projects have become so popular that their implementation has outpaced the science on how more natural and simulated beaver structures are affecting fish and other wildlife.
“We need more research on exactly how beaver ponds impact fish so we can make confident, science-based decisions moving forward,” says Lahr, who worked with Clark Fork Coalition, Lolo National Forest, and The Nature Conservancy to design and instaNotll his study.
Not so fast there Mr. Beaver. Just because your dam makes things better doesn’t mean they make things BETTER, you know? Bring on the abacus and the measuring tape so we’re sure it all still works. Science needs to count things. You know it does.
“On the whole, fish benefit from beavers and their ponds. The trick is to make sure we choose the sites wisely and make sure they benefit the whole aquatic community, including wild trout,” says Ladd Knotek, a fisheries biologist with Montana Fish Wildlife and Parks who helped tailor Lahr’s research project.
See long ago Montana killed most of its wild trout. So they helped the fisherman along by introducing some hatchery trout. But we don’t know about whether hatchery fish can manage beaver dams too. Because they are sissies and Frankensteins. So the science that has been verified a million times in a million different streams better just prove itself all again.
Knotek says that the majority of beaver-related restoration projects are not a problem for native salmonid species. However, Montana only has a few remaining streams where pure (non-hybridized) cutthroat trout, arctic grayling, and bull trout thrive. These strongholds are areas where fisheries biologists worry that new in-stream structures might unintentionally impact native trout populations because these species can no longer adapt easily to habitat changes.
“One hundred years ago, beaver dams weren’t an issue. If a dam was too high or there was no way through, the overall population was fine because the species was widespread. But we don’t have that population resiliency anymore,” explains Knotek.
Good Lord. This is so irritating it makes my head hurt. Well, maybe banging it on the keyboard does that. This article is in the frickin’ NATIONAL WILDLIFE FEDERATION BLOG. If we’re going to broadcast ridiculous drivel from NWF who should anyone even bother to maintain a informative website about beavers?
“We know that beavers add habitat complexity in the stream, which increases the carrying capacity for all fish species. The question is do they disproportionately benefit non-native trout?” says Knote
What about our Frankenstein fish? Are those icky beavers ruining things for them with all their pointy obstructions?
Instead, Lahr wonders whether beaver ponds are able to hold more fish of all species, supporting native and non-native trout equally.
“When you add beavers to the mix, models predict that westslope cutthroat trout persist and have higher growth rates because there’s more food, more plants, more water,” says Lahr.”And that translates upstream as you leave the pond, too.”
“There’s a chance that beavers may create true climate resilience for trout in Montana,” adds Lahr.
YA’ THINK?
Let’s be fair to Andrew Lahr. He may truly believe the radical notion that beavers are GOOD for fish and his thesis chair is so horrified by the outrageous claim that he is making him prove it scale by scale. I supposed you have to at least appear willing to accept disconfirming data to get your dissertation approved anywhere. But honestly, my money’s on the beavers.
Isn’t yours?
