SEAWA working to maintain riparian areas

By SAMANTHA JOHNSON, Local Journalism Initiative Reporter on August 17, 2022.

reporter@medicinehatnews.com

The South East Alberta Watershed Alliance held a three-hour riparian site tour near Seven Persons at the Yeast Site on Saturday. There were about a dozen people on the tour, including three summer students, who were heading into their last week on the job. Former owner of the land, Dave Yeast – who joined the tour – invited SEAWA onto the land for leafy spurge control several years ago.

Riparian areas are the transition areas between the water body and the upland, with boundaries that are not easily distinguishable. Healthy riparian areas must have woody vegetation along with grasses and other underbrush. The Yeast site was lacking in woody vegetation with an abundance of leafy spurge. Since SEAWA has been doing work at the site, 600 native shrubs have been planted in addition to native grasses.

Until 2018, long-horned cattle grazed the area. Once they were removed, three species grew in abundance.

Along the edge of the water is sandbar willow with an understory of reed canary grass. Both grow densely and aggressively along the water. Carpets of western snowberries can be found at the edges of this thicker growth. Snowberries are a native species but are not very good at controlling reed canary grass or leafy spurge since they grow low to the ground. The goal was to introduce greater diversity in the woody shrub species and to find natural controls for the leafy spurge problem.

Executive director of SEAWA Marilou Montemayor, led the tour and has spearheaded the restoration of this riparian area and supervises its summer students. As only so many formal experiments can be done, the planting of the shrubs was done by trial and error, One such discovery was that planting plugs leads to a 20 per cent survival rate of the shrubs, which increases to 95 per cent when two-year-old potted plants are put into the ground.

Planting native species that will outcompete the leafy spurge was the focus of some of the formal experiments. In six plots there is wolf willow, half with mulch and half without. In another six plots is silver sagebrush, half of the plots were covered with plywood for two years before planting and half weren’t. One difference between the two shrubs is silver sagebrush, which is allelopathic, meaning it tailors the soil environment to its own needs, discouraging other plants from growing next to it. Sagebrush is also drought tolerant and can grow a tap root that extends up to 12 feet deep.

The riparian area covers a one-kilometre stretch along the edge of the creek, and each plant needs to be hand-watered and weeded, a formidable task for Montemayor and her three summer students. Watering in extreme heat must be done twice a week and takes the three students four hours to complete.

Along with 20 green ash trees and some Manitoba maples, woody shrubs that have been planted by SEAWA at this site are: choke cherries, red osier dogwood, wolf willow, sagebrush, golden currants and thorny buffalo. Most of the shrubs have wire protection around them to prevent wildlife from grazing them to the ground, which will be removed when the shrubs get large enough.

“An organism is fit when they survive and start reproducing, either by producing fruit or suckers via rhizomes,” explained Montemayor.

Except for silver sagebrush, which was either transplanted from a donor site or grown from seed, which Montemayor explained was very easy to do, all the shrubs were bought from a nursery. There were a handful of thorny buffalo that had a black rust or smut on it, which led to an in-depth discussion but no resolution as a microscope would be needed to determine what organism was causing it. It was also unknown if the disease came from the nursery or was already at the site.

Along the top of the bank, terraces were created where Japanese brome was growing. The brome was manually weeded out of the terrace plots. In some, silver sagebrush was planted and in others western wheat grass among other prairie grasses. The goal of the plots is to see if native species can outcompete the brome and suppress it.

Overall, the group learned lots and engaged in many side discussions. Those interested in joining a future tour, becoming a member or volunteer, can check out their website at seawa.ca.

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