Buck teeth, flat tails, and engineering—OH MY! The American Beaver (Castor canadensis) is commonly known for its continuously growing front teeth and ability to chew down entire trees, but here at Reed College, it is seen as the king of the canyon! As any righteous king, it dutifully manages and cares for the entire Reed lake!
Before Reed College was established in 1908, this lake was formed by a beaver dam that blocked water flowing from Crystal Springs Creek. When the canyon restoration project started in 1999, the dam and the beavers were almost removed, but we now understand that they are a vital part of this ecosystem for many reasons. Although chewing down trees may seem counter-productive, they play a very important role in the ecosystem. By weaving fallen trees, sticks, and mud together, they create dams that can change the canyon’s water flow. These dams can change the rough turbidity of the river waters and provide homes for a large variety of canyon plants and animals! Many of the logs you see lying in the lake were felled by “nature’s architects” to create structures that support other species. These trees not only provide above water level nesting sites for local ducks and waterfowl but also slowly decompose over time, allowing their nutrients to re-enter the water-ecosystem and enrich the soil and silt at the bottom. Maintaining Reed’s beaver population has also helped restore this ecosystem in another way. In the late 1800s, fur trapping was such a lucrative business in the Pacific Northwest that trappers imported nutria to breed on fur farms. Native to South America, nutria could be bred for a lower cost than beavers but their pelts could be sold for the same price. Believing that the two species would fill the same ecological niche, local agencies released nutria into the wild in the hopes that they would manage ground cover and trim vegetation. Unlike beaver, however, the invasive nutria proved to be highly destructive by digging burrows under vegetation and chewing at root systems. We have seen over the past few years that as beavers become more active in the canyon the nutria population decreases. Much of what the canyon restoration team has done here at Reed to help restore the canyon, we have done in imitation of what the beavers do naturally! |
Works Cited:
- Cover photo: Zac Perry, "beaver.jpg" Reed College Digital Archives. https://rdc.reed.edu/i/ffd3d54c-41b9-4468-b04e-50ca39aa6ff3
- Lam, C. 2020. Canyon Column 2: Introduction of a Restoration Strategy in 1999. Reed College Quest.
- Reed College Canyon Collection, Photo Archive: reed.edu/c/canyon/home/
- Sheffels, T. and M. Sytsma. 2007. Report on Nutria Management and Research in the Pacific Northwest. Pp.1-57.