Come on in, the water’s fine!

   Posted by heidi08 On May - 18 - 2017

beaver physAnother block buster from our friends at the science site that should be called “Beaver Phys.org”. This morning the news has also been picked up by plenty of followers including “New Scientist”.  Because beavers are just rock stars like that, you know?

Beaver dams may buffer against temperatures that threaten sensitive species

Both natural and artificial beaver dams may alter stream temperatures which may benefit temperature-sensitive salmonid species, according to a study published May 10, 2017 in the open-access journal PLOS ONE by Nicholas Weber from Eco-Logical Research, Inc., USA, and colleagues.
Beavers are ecosystem engineers, altering stream temperatures by building dams that increase surface water storage and connectivity with groundwater. Some studies suggest that the dams make water warmer and so are detrimental to salmonids, which are sensitive to . Weber and colleagues tracked beaver dams and monitored water temperatures along 34 kilometers of the John Day River in Oregon over eight years. In addition, the team assessed the impact of artificial beaver dams on water temperature along four reaches of Bridge Creek.

Yes beaver dams lower the temperature for sweaty fish. We here at beaver central have been touting this fact for years. Pollock proved it years ago, but now it’s especially even more extra proven. Has any creek been the subject of more study than Bridge Creek? I doubt it.

The researchers found that beaver dams may alter stream temperatures to the benefit of salmonids. Studies suggest that juvenile steelhead salmonids in Bridge Creek experience extreme stress at about 25°C, and the researchers found that maximum daily temperatures in much of the study stream exceed this temperature for much of the summer. However, temperatures rarely exceeded 25°C after the proliferation of beaver dams, likely because they help moderate temperatures both by increasing water storage and encouraging exchange between surface water and groundwater exchange. This fits with the fact that both beavers and salmonids were once more abundant and widely distributed in North America, and suggests that beaver dams could help mitigate the thermal degradation that can threaten sensitive species.

Dr. Weber notes: “Beaver are often considered a keystone species, and their propensity to build dams plays an integral role in maintaining biodiversity and enhancing aquatic processes that benefit an array of aquatic and terrestrial organisms. Recognizing this, beaver relocation efforts and installation of structures designed to mimic the form and function of beaver dams are increasingly being used as effective and cost-efficient approaches for restoration of stream and riparian function. Despite this trend, the notion that beaver dams negatively impact stream habitat remains common, specifically the assumption that beaver dams increase summer stream temperatures to the detriment of cold-water species such as trout and salmon. However, by tracking beaver dam distributions and throughout a high-desert, scientists have demonstrated that beaver dam can actually reduce high stream temperatures by increasing surface water storage and connectivity with cool groundwater. These results suggest that construction of artificial beaver dams and beaver relocation projects could be used to mitigate the impact of human induced thermal degradation that may threaten sensitive cold- species.”

If you need the reference to go look up it’s here. Feel free to notice how many of the names are friends of this website.

Weber N, Bouwes N, Pollock MM, Volk C, Wheaton JM, Wathen G, et al. (2017) Alteration of stream temperature by natural and artificial beaver dams. PLoS ONE 12(5): e0176313. doi.org/10.1371/journal.pone.0176313

Dr. Wheaton wrote yesterday to make sure I saw it, but three beaver readers had beat him to it. Let’s hope all those backwards thinkers in Wisconsin who rip out beaver dams to protect their baby trout read it and at least think, huh??? Maybe they’ll even start to read the research later than the 1970 study they tuck under their pillows at night.

Our Edinburgh professor friend saw this photo last night uploaded on to the California Academy of Sciences page “biographic”  and sent it our way. I knew you’d appreciate it. No sissy GoPro camera for this lovely shot. Read about the sturdy and patient French photographer who got this beautiful shot.
Castor d'Europe; Castor fiber; transporte une branche sous l'eau; BBC 2011

Louis-Marie Preau has been watching beavers in the Loire region of western France for more than 15 years. He’s never forgotten the first time he saw an adult delivering a tasty branch to its family underwater—but it took him four years to successfully capture this intimate scene. Each evening, wearing snorkeling gear and weights, he would lie motionless on the riverbed for two to three hours. Finally, one evening, his patience paid off. Preau had only just plunged into the water and positioned himself when this adult returned with a freshly harvested poplar branch to feed to its three young kits. He was impressed by the beaver’s strength and determination, as it dragged this leafy meal through the water. Saumur, France

 

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