The main goal of ecological restoration is to facilitate the recovery of disturbed ecosystems into resilient and diverse systems. Working in partnership with the City of Whitehorse we are examining the use of bioengineering techniques and native plants to increase slope stabilization and revegetation on the clay cliffs and pathways margins. At the clay cliffs we are using a bioengineering technique known as modified brush layers. The brush layers are a series of benches built into the cliff with local materials including Willow and Poplar stakes, as well as, soils amended with peat and compost. We have also seeded the top of each bench and pathway margins with local native plants, because they are well suited to the local environment, which is especially advantageous under harsh northern growing conditions. In addition, locally harvested Biological Soil Crusts (BSC), which are communities of mosses, lichens, algae, fungi and nitrogen fixing cyanobacteria, have been applied at the sites.
In this project focussing on ecological restoration in an urban environment, we will address the following objectives: (i) determine the rooting ability of Willow (Salix spp.) and Balsam Poplar Populus balsamifera in the amended silty soil of the Clay Cliff; (ii) evaluate the germination and growth of native plant species, including Slender Wheatgrass (Elymus trachycaulus),Glaucus Bluegrass (Poa glauca), Boreal Sweetvetch Hedysarum boreale, Prickly Rose (Rosa acicularis), Sage (Artemisia norvegica) and Yarrow (Achillea millefolium); (iii) assess the role of Biological Soil Crust (BSC) applied at two different slurry concentrations in facilitating seed germination and seedling establishment; and (vi) determine whether the concentration of the BSC slurry influences BSC establishment and C and N fixation rates of crusts. These objectives will be pursued at three sites downtown Whitehorse: The Clay Cliff, adjacent to the Black Street stairs, where 13 bioengineered modified brush layers have been installed to reduce erosion and two areas along the pathway margins, one near Wood St. and one near Lambert St. Ongoing monitoring throughout the summer (germination rate, establishment of species), as well as, end of season sampling (BSC N and C fixation) will allow us to evaluate our four objectives. Monitoring will continue in the spring and summer of 2015.
Project supervisor: Dr. Katherine Stewart, Adjunct Faculty, Yukon Research Centre, Yukon College
M.Sc. Student: Annie-Claude Letendre, University of Northern British Columbia/Yukon College
City of Whitehorse
With support from Yukon Invasive Species Council
City of Whitehorse
Yukon Research Centre