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Coexisting with Beavers

Beavers are superb engineers — their ability to change the landscape is second only to humans. The dams built by beavers play a key role in the creation of wetland habitats, which in turn prevent erosion, purify water, control flooding, and combat global climate change. Wetlands are also among the most biologically productive natural ecosystems in the world, comparable to tropical rainforests in terms of the diversity of species they support and importance to the health of our planet. Some native peoples, including the Cowlitz and Tulalip tribes, revere the beaver because the ponds and wetlands created by beavers serve as rich habitats for other mammals, fish, turtles, frogs, and ducks and other birds.

Beavers were almost driven to extinction by the early 1900s at the hands of European colonizers, who trapped beavers for their skins. Prior to the arrival of Europeans, there were estimated to be around 60-400 million beavers across the land that became the United States. Today, following population regrowth thanks to a combination of habitat restoration, active reintroduction efforts, and restrictions on trapping practices in some areas, there are thought to be around 10-15 million.


Situations


Beavers cause problems for humans when their dam building blocks or redirects water flow, creating flooding in some areas. This can change landscapes and impact human land use, including farming. Beavers can also damage or even fell trees as they gnaw them to harvest materials for their dams.

Prevention Measures


There are a number of measures that can be taken to discourage beaver damming and/or flooding:

  • Bafflers — Beavers are stimulated to repair breaches in their dams by the sound, feel, and sight of running water. Beaver “bafflers” work by dispersing the flow in such a way that the beavers are not stimulated to plug them up. Bafflers have many different designs and can be constructed of pipe or metal mesh fencing formed into culverts.
  • Deceivers — Beaver “deceivers” are trapezoid-shaped fences built around points of vulnerability such as easily plugged culvert openings. These fences extend outward to create an area large enough to discourage damming.
  • Levelers — Beaver ponds with properly installed and maintained pond “levelers” can also be effective in decreasing flooding. These devices lower the pond below the top of the dam so storm runoff is held back. Beavers will not continue to raise the height of their dam unless there is water flowing over it, so the size of the beaver pond can be controlled to prevent flooding.

Trees can be protected in the following ways:

  • Wire Wraps — Trees can be wrapped with simple cylinders of galvanized, welded wire, placed 6–12 inches out from the trunk and standing about three feet high.
  • Sand and Paint — Mature trees can be painted with exterior latex paint and mason sand mixture. Mix 5oz of sand per quart of paint or 20oz of sand per gallon of paint.
  • Fencing — Since beavers are not good climbers, a three-to four-foot fence can also be a permanent deterrent in large areas where trees are grouped together.


Fun Facts about Beavers


Beavers are North America’s largest rodent and second in size only to the capybara globally.

Beavers’ orange teeth may look like they need a good brush and floss, but they are not stained or damaged. Their teeth are covered with an iron-rich enamel that makes them particularly strong and well suited to the hard use that beavers put them to.

Beavers use their distinctive, paddle-like tails to aid swimming and slap on water to signal danger. Their tails are scaly on the surface and store fat for the beaver to use during times of scarce food.

As they spend so much time in water, the undercoat of a beaver is waterproof. They can also stay underwater for up to eight minutes.

Beavers have adapted to have a second set of eyelids which are translucent. These cover and protect the eye when they are underwater.

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