Beavers: Eco Engineers and Services
Have you noticed any beaver dams and ponds in your area recently? Beavers are often vilified for plugging up culverts and constructing dams that flood cropland, roads, and the like. And of course, they draw our ire when they drop or girdle our trees. So, it is no surprise that beavers are often shot or trapped, and dams and lodges destroyed. But in many cases, beaver activity can be quite beneficial.
There is an old saying that whiskey is for drinking and water is for fighting over. And particularly in the western states in a seemingly warmer and drier climate, some scientists are beginning to see beaver activity as important to our ability to adapt to a changing climate. Beaver ponds can store a lot of water on the land, at no cost. And those ponds can mitigate the effects of heavy rains and flooding, and recharge ground water, as well as serve as an important source of water (and forage) for livestock and wildlife.
Beaver activity may also result in important benefits related to changes in hydrology. The pond helps sediments settle out of the water, which increases water quality. As the pond fills in with nutrient rich sediments, it may form a “beaver meadow” which spreads the slowly moving water through a much larger area “sub-irrigating” the plants growing there. One study estimated the economic return of beaver ponds may be $1,000 or more per acre per year in benefits relating to ecosystem services such as sediment retention, flood control, water quality, and wetland habitat enhancement, and recreation.
Beaver activity, mainly associated with the ponds behind dams, has also been credited with a variety of desirable changes in the local ecosystem including increased aquatic habitat, increased plant, fish, and bird diversity and abundance, and habitat for big game such as deer and elk. Beaver ponds also generally support greater numbers of ducks, geese, reptiles, and amphibians compared to the free-flowing streams. Plus, the felling of adjacent trees may help rejuvenate stands of aspen and willow which provide important food and cover for a wide variety of animals.
So, when we see signs of beaver activity, perhaps we should give greater consideration to how we can put them to work for us. If all goes well, we could gain some important benefits… at no cost!