An important part of the restoration work at our pilot Foodlands Corridor on the sc̓e:ɬxʷəy̓əm (Salmon River) in Langley has involved removing invasive Reed Canary grass (phalaris arundinacea) and replacing it with native species. The new plants will shade out the invasive grass while creating habitat for local wildlife.
“stɑl̓əw̓” is the hən̓q̓əmin̓əm̓ word for the Fraser River. hən̓q̓əmin̓əm̓ is the Downriver dialect of Halkomelem; one of many Indigenous languages spoken across the Fraser Watershed.
Listen to Al Jonsson (Kerr Wood Leidal Associates Ltd.) describe the invasive Reed Canary grass and how it impacts native plants and fish.
Audio Transcript
I’m going to talk about reed canary grass today and why it affects salmon and other aquatic and riparian habitats.
Reed Canary Grass is a very tall growing aggressive grass that was introduced for agricultural reasons. It’s a formidable foe to native plants because it can outgrow almost anything. It grows an incredibly thick root system and puts out chemicals through its roots that suppress the growth of other species.
In the Fraser Valley you’ll find it growing in stream-side areas and wet meadows and you can very often see very lush green growth and in the winter tall remaining stems. It tends to be a problem for fish in particular because it can get so thick that fish cannot swim through it and very often it will deplete oxygen that is critical for them.
When the Rivershed Foodlands Program started looking at sites, it became very apparent that addressing Reed Canary grass and attempting to overgrow it with native species was going to be critical. Along the Salmon River, as you can see in the photo, it has dominated an area to the point of excluding everything else and contributes to the erosion of the bank. On the outside of the bend where there’s a lot of erosion there, the bank was undercutting because in the absence of trees and shrubs with deeper roots there was nothing to support it. Even pieces that are eroded and fall in will tend to grow quite well in the water or wash down and establish colonies elsewhere.
Although we couldn’t eradicate the grass we did a number of measures to mitigate its immediate impact on the river and the fish living in it. This included sloping back the banks, removing that turf layer, aggressively replanting the area with other native species as well as there will be maintenance undertaken to cut back or stomp down the grass to reduce the competition shading.
One of the challenges is that Reed Canary grass thrives in areas of higher nitrogen. That could be from maneuver, that could be from septic runoff or even airborne from the nitrogen oxides drifting into the Fraser Valley from the rest of the Greater Vancouver area.
We’re still working on the best ways to deal with Reed Canary grass and the Foodlands projects will be critical to trying out various solutions. Where we sloped back the banks on the Salmon River and stabilized it with posts and woody debris we’re going to abundantly stake the area with willows and other species to attempt to get a canopy established and shade out the ground before the grass can reestablish. And although there may be some grass growing there in the future, it will not be dominant. With a deeper and more extensive root system provided by willows and trees we should be able to reduce the erosion and actually start to accumulate sediments such that the bank starts to actually grow rather than eroding.
Reed Canary grass (phalaris arundinacea) is an aggressive invasive grass that can alter stream flow, suppress growth of other species, and obstruct salmon migration paths.
The lush green growth of Reed Canary grass tends to be a problem for fish. The thickness of the grass makes it difficult for them to swim through and it depletes critical oxygen in the water.
Ensuring the silt screen sections are properly stitched together to keep the fish out (during bank re-grading)
After sloping back the banks on the sc̓e:ɬxʷəy̓əm (Salmon River), we’ve stabilized it with posts, large woody debris, and cedar branches to mitigate extreme river forces while redepositing sediment to help build back the river edge.
Xéltsepelhp – χeleʔəɬp (willow) whips (pictured) and other species can establish a canopy and shade out the ground before Reed Canary grass can re-establish.
Aerial photo of sc̓e:ɬxʷəy̓əm (Salmon River) in Langley. Reed Canary grass dominated the area, taking up the majority of the riparian zone and contributing to bank erosion.
Capitalized words are Halq’eméylem, lower case words are hən̓q̓əmin̓əm̓. Traditional place and species names provided by knowledge keepers and speakers from the Kwantlen and Katzie Nations.
This restoration work is supported by the Healthy Watersheds Initiative, a program which is funded by the Government of British Columbia and delivered by The Real Estate Foundation of BC in partnership with Watersheds BC.
Additional funding support provided by Dr. Bronner’s.