Notorious for chopping down trees, beavers are often seem as synonymous with the dams they build. Using mud and rocks as glue, beavers strategically place branches together to construct a domed lodge over a stream or river. Beavers enter these dens using an underwater passageway, ensuring protection from the outside world and creating an otherwise dry and cozy home for cuddling, mating, and raising their young. Not only are these dams vital to the lives of beavers, but they also drastically impact the surrounding ecosystem, making beavers a keystone species of their environment.
Once a dam is complete, the pace at which the waterway moves is slowed down, and its path altered. This creates an extensive wetland upstream that houses vast amounts of biodiversity, including a multitude of endangered species. A variety of birds nest on the riverbanks, fish like rainbow smelt, steelhead, and salmon thrive in the ponds, and mink, muskrats, and otters forage the bogs. Surrounding vegetation also flourishes. The riparian zone, or area between the river and land, sees an increase of over 33 percent in the number of herbaceous plants near beaver dams. This feeds the surrounding wildlife and humans have used these herbs in cooking and medicine for hundreds of years.
Downstream, water quality is improved as beaver dams act as a natural filtration system, blocking pollutants from further entering the waterway. The decrease in water pressure allows for sediments and nutrients within the surrounding soil to enter, creating clean, mineral-packed drinking water for the entire region. Water stored behind the dam also maintains this important supply by recharging deep aquifers. This provides a safeguard to the surrounding area in dry seasons. When beavers and their dams are present, 160 percent more open water is available in times of drought compared to when they are absent.
With two species, the North American beaver and the Eurasian beaver, life in most of the Northern Hemisphere is impacted by these semi-aquatic rodents. Various cultures around the world celebrate the beaver for their skill and ingenuity. As one of Nature's best engineers, beavers are a great example of how one species can reshape its environment for the benefit of itself while also improving life for all in its shared ecosystem.