Spartina densiflora and Spartina patens are two invasive species that plague the water line from Bowser to Little River.
The plants are highly competitive with native vegetation.
“If we let it go to seed and just let it grow, it will completely turn a diverse native habitat into a monoculture of just the single species,” explains Taylor Marriott, Duck’s Unlimited Canada’s Conservation Programs Specialist. “Because it is not native, nothing can eat it so it’s replacing plants that other species can consume and interact with. The Spartina is really good at accumulating soil, just from its structure, so it will raise the elevation of where it grows which changes all the drainage patterns of the coastline and causes flooding. It fills in sediment so the little holes that crabs use also go away.”
Spartina densiflora was first discovered along Vancouver Island in 2005 while Spartina patens has most likely been around since the 1970s.
Two different removal processes have to be used in order to remove the invasive species. Spartina densiflora can be dug out, getting all the roots out of the affected area while Spartina patens has to be treated with a herbicide.
“Spartina densaflora does not reproduce from its roots, so we dig it out and it is less likely to return. The other species over there, Spartina patens does reproduce from its roots so we found digging it out just wasn’t effective because if you leave a little root fragment or rhizome fragment, it regrows. So we use a targeted herbicide treatment.”
Herbicides are only resorted to when digging the invasive plants will not stop the growth or spread of the species.
“We use backpack mounted sprayers that have a set application rate. We are only using 0.75 per cent of the herbicide and that’s a really non-toxic, low toxicity herbicide. People are always concerned because of the media around chemical treatment but this underwent special registration in Canada and was selected because it’s not really toxic.”
The targeted herbicide is carefully applied to the plants only in optimal conditions so as not to affect other native species of plants. The herbicide also has qualities that make it adhere to where it is sprayed.
“(The herbicide) also has a surfactant in it, which is basically the same chemical that is in soap. Once it dries it binds to the plant tissue and it has a dye so we can see exactly where it’s landing. We spray only on the targeted plant within strict environmental conditions. We have a set tide window we have to do and weather and heat windows.”
The efforts of Ducks Unlimited Canada are having a great impact on the reduction of the plant. On the mainland they have seen such a drop that they are concentrating their efforts on the Island instead, opening the period that they spend here by two months.
“We have typically gone over to Vancouver Island in August to October but this year we are starting in June, so it’ll give us a way bigger window.”
When the full treatment is done on the Spartina plants, a reduction of up to 60 per cent can be seen per year. It is dependent on how much the group is able to treat and that comes down to what the weather is like.
In order to target more of the two Spartina species, the public can report findings of it by using the Report Invasive Species phone app. It notifies the province and helps efforts to find where the plant is growing, allowing for a greater reduction in the spread. You can also email pictures to invasive.plants@gov.bc.ca with a location.
