The ecological benefits of “eager beavers”

The trivia question used to say, “what is the only constructed feature not built by man which is visible from space?” The answer used to be the Great Barrier Reef off the coast of Australia, which was constructed by coral.

Well, now there are two answers to that trivia question, because the world’s largest beaver dam can also be seen from space. Located in a remote section of Wood Buffalo National Park in northern Alberta, the 2,790 foot long beaver dam is estimated to have been (and still is) under construction by several generations of beavers since the 1970s and is twice as long as Hoover Dam. It replaced a 2,145 foot long beaver dam in Three Forks, Montana as the world’s longest.

Image c/o BNPS.co.uk and Google Earth

While many of us find beavers to be amazing engineers, their construction projects also bring about important ecological benefits. Below, is a list from the Beaver Dam Information Site, of many of the environmental benefits derived from beaver dams.

  • Nullify the “ditching effect” on water tables caused by deepening river and stream channels.
  • Reduce channel scouring and stream bank erosion.
  • Mitigate erosion.
  • Reduce sediment loading in streams and rivers.
  • Develop new wetlands.
  • Increase biodiversity including a better environment for fish and waterfowl.
  • Create a more stable water supply for wildlife, and vegetation.
  • Provide more cold water springs charging rivers and lakes.
  • Improve groundwater recharge and the elevation of the water table.
  • Allow a longer land water retention time in water cycle since subsurface flow is slower than stream and river flow.
  • Assist with flood mitigation due to increased ground water holding capacity.
  • Reduce stream flow rate variations and stream charge during drought cycles.
  • Form natural lakes and ponds, and maintain of existing ponds.
  • When the dam sites ultimately silt in, they create natural fertile beaver meadows form.
  • Improve canoeing and kayaking by stilling and deepening waters.
North Carolina State University identifies a number of similar benefits to the previous list above, but also breaks down the benefits into those derived from active and abandoned beaver ponds. For active beaver ponds:
  • Improve downstream water quality.
  • Provide watering holes for agricultural and wildlife needs.
  • Supply important breeding areas for amphibians and fish.
  • Provide diverse wetland habitats.
  • Furnish feeding, brood rearing and resting areas for waterfowl.
  • Encourage many reptile, bat, amphibian, fish and bird species.
For abandoned beaver ponds:
  • Furnish snags for cavity-nesters and insectivores.
  • Fallen logs supply cover for reptiles and amphibians.
  • Provide essential edges and forest openings.
  • Supply diverse moist-soil habitats within bottomland forests.
  • Create productive bottomland forests.
  • Provide foraging and nesting areas for bats, songbirds, owls, and hawks.

Thankfully, beavers have made a successful come back from the near brink of extinction. Without their eager and vast engineering expertise, many other forms of wildlife (including humans) would have suffered from their absence.

Segment of longest beaver dam in Wood Buffalo N.P. c/o Billy Wilson, BNPS.co.uk

This entry was posted in Canada, Environment, Nature, Wildlife and tagged , , , . Bookmark the permalink.

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