Spring and fall are often busy times for our staff and volunteers undertaking bioengineering projects – w
illows, dogwood, and poplars are dormant, the weather is fair, and the ground is not frozen. Bioengineering is the use of native plant material to stabilize eroding banks or disturbed sites,or to generally “speed up” the natural recovery of degraded sites. TUC uses willows, dogwood, and poplars because they are the native pioneering species that, given the chance, typically recolonize disturbed sites. These plants are deep rooted, helping to hold soil together while also providing shade and leaf litter to streams. As riparian (shoreline) plants, they are also uniquely adapted to disturbance by floods, fire, and beavers, and cuttings can form roots and shoots when well buried in moist soils. “Staking” is perhaps the simplest method of bioengineering and involves planting cuttings from willows and poplars deep into the soil.
Recently, Trout Unlimited Canada and some dedicated volunteers spent a few hours harvesting cuttings from willows and poplars for a riparian enhancement project along Piper Creek, at the Piper Creek Restoration Agriculture Project site in Red Deer, AB. Several hard working student volunteers from Olds College along with project partners from the City of Red Deer, ReThink Red Deer, Cows and Fish, Red Deer River Watershed Alliance, and the Red Deer River Naturalists carefully cut and bundled about 700 live cuttings to be planted along the creek the following week. The bundled cuttings were then left to soak in the creek until the planting workday. While on site, the students and project partners discussed other restoration plans for the site which was historically used for agriculture. These include removal of an old creek crossing that is no longer needed and riparian and upland enhancements to the property, all with the objective of ecological restoration.
A few days before planting the willow and poplar stakes, one of the project partners visited the site and found the local beaver beat us to it and used all of the cuttings to build a series of dams (see image right)! Upon consideration,we were not too concerned by this turn of events. Beavers are nature’s engineers, creating a diversity of habitats that attract a variety of wildlife species and perform valuable ecosystem services like flood and drought control. We are fortunate that at this site, there is little to no risk to property and infrastructure resulting from beaver activity and the area will likely benefit from the additional water-holding capacity behind these beaver dams. Beaver ponds are also great at flooding out invasive weeds and grass species, creating new habitat for sedges, cattails, and other native water-loving plant species.The largest of the dams was built immediately upstream of the culverts and crossing that we intend to remove so this
may also make our restoration efforts easier.
What about the bioengineering project? Thanks to our volunteers, we harvested another 400 cuttings that were planted along the creek, most of which were fenced off to allow them to become established before the beavers get a chance to take them. Although most woody plants regenerate after being cut by beavers, we want to make sure the new cuttings time to establish a good root system to be able to withstand future chewing.
Want to learn more about how to live with and manage beavers? Cows and Fish will be holding a workshop on May 4 in west central Alberta.
Want to learn more about the Piper Creek Restoration Agriculture Project? Visit their website to learn about this and other ReThinkRed Deer projects.
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