There’s an invader creeping over the border from America and taking root in Delta, but conservationists are fighting back.
Armed with customized technology and a blackberry-infused pesticide, teams from the British Columbia Conservation Foundation, co-ordinated by Ducks Unlimited Canada, are continuing their war against invasive spartina this summer.
Spartina Anglica is a cordgrass originating in southern England, and found widely in Washington state, that was first discovered in Canada in 2003. It’s one of four spartina species of concern along B.C.’s coastline, and is currently found growing in the area of Roberts Bank and Boundary Bay in Delta.
These spartinas are considered invasive in B.C. as they destroy the natural ecosystem in places where they grow by altering mudflats, thereby eliminating food sources and habitats for aquatic life and waterfowl.
“There’s a lot of things in a mudflat that are very important for coastal ecology, and [spartina] turns [a mudflat] into this big field of grass,” Matt Christensen, head of conservation at Ducks Unlimited, told Black Press Media.
As the water moves over it with the tidal cycle, the cordgrass slows water down, allowing sediment to drop out and accumulate. This, in turn, alters the hydrology of the land — the movement and distribution of natural water.
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Using a custom app, conservation teams are setting out to map and tag spartina growth along Roberts Bank and Boundary Bay.
Once all of the patches have been located, a team will return with a diluted herbicide formulated specifically to be safe for aquatic life and apply it directly to the cordgrass with a backpack-style sprayer. Though the herbicide isn’t entirely selective and does have capacity to eliminate other vegetation it comes in contact with besides spartina, it is not harmful to any wildlife or waterfowl that may ingest or touch it.
The spray also paints the plants a shade of blue for easy spotting and monitoring later — the colour is added to the herbicide using blackberry juice, Christensen explained.
The process doesn’t end with the spaying, however. Christensen said it can take years before spartina can be deemed eradicated from an area.
“You have to revisit a site [for] six years consecutively with no detection of a plant. So if you have, say, five years of visiting a site and there’s no plants, and then on the sixth year you have a plant, you’ve kind of reset the whole cycle to determine if it can be eradicated,” he said.
Once spartina is successfully expunged, native plants will eventually recolonize the area and it will return to its natural state.
Despite the lengthy and tedious rinse-and-repeat cycle necessary to remove this overbearing plant, Ducks Unlimited’s tracking has shown a 90 per cent decrease in the number of plants from 2016 to 2022.
As well, 10 years ago, 300 hectares of land in B.C. were impacted by invasive spartina growth. That figure is now closer to 100.
Christensen advised that the best way to help get rid of this invasive grass is to volunteer for removal initiatives, but advised against doing any self-led landscaping as spartina can be hard to accurately identify with the untrained eye.
Rather, he said, the best thing to do is be aware and report suspected sightings of cordgrass to groups like Ducks Unlimited for proper evaluation.
editor@northdeltareporter.com
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