Invasive species can take over sensitive ecosystems and upset the balance of plant, insect, bird and other animal life.
In Guelph, ongoing efforts by both city staff and residents help to tackle the spread.
“Invasive plants pose significant challenges to the local ecosystem in Guelph. They can out-compete native species, reduce biodiversity and disrupt habitats for wildlife,” said Dave Beaton, program manager of forestry and sustainable landscapes with the City of Guelph.
“However, locally, we have been met with a number of successes. Our efforts over the last six or seven years in slowly scaling to a still small but significant program, has been successful.”
A priority invasive plant in Guelph is the giant hogweed, originally from Asia. Its sap is dangerous to the skin, and can cause inflammation, burns and possible blindness if it gets in your eyes.
“It’s a major issue in other municipalities, however, the parks team has done considerable work on this, and with residents' help in spotting new outbreaks, we have eliminated this from the city of Guelph,” Beaton said.
“We are still working on one small patch that’s on city-managed property, but with residents helping us spot new patches, we are essentially able to manage our giant hogweed problem."
Dog-strangling vine is a plant that smothers native plants and young trees, reducing habitat for birds and pollinators.
Beaton said this invasive plant has continued to spread slowly, however, the density of outbreaks has been reduced by 80 per cent throughout the city.
“It will continue to need ongoing vigilance and effort by residents and the city to prevent this from dominating the landscape as it does in east Toronto,” he said.
“It takes a very long time to eliminate it because it is so good at spreading.”
There are efforts underway to control the spread of wild parsnip, another problematic invasive species.
“Two years ago, a local resident spotted it, and we were able to get on it right away. We have hope that we can keep that one from getting a foothold in Guelph,” Beaton said.
Buckthorn is another common weed shrub that can dominate sensitive habitats.
“Unfortunately, it has a 50 plus year head start on us and is very common. We have been treating a lot of it to build back our biodiversity," Beaton said.
“The more we do to keep these out of our most sensitive ecological areas, the better we can maintain our ecological spaces.”
Efforts to manage invasive species throughout the city happens at different stages during the year.
“There’s really no point in the year where we are not trying to deal with invasive species. The winter is actually a good time of year to be dealing with Buckthorn,” Beaton said.
“In spring and fall, we might have a lot of rain so that might not be great. But generally, as long as the weather cooperates in any one season, there’s things that we can do to make things better.”
A hired student crew, the Natural Area Stewardship team, works in the spring to fall seasons to help with the management of invasive species.
Last year, the team treated 41 hectares of land at 68 sites in parks and natural areas in Guelph to fight back a variety of different invasive plants.
Guelph residents can take several actions to help manage and remove invasive species, Beaton said. First by learning to identify them and also to verify the plants they purchase for their yards or gardens are not invasive.
“Replace invasive plants in your garden with non-invasive alternatives. Ask your local nursery staff for help in identifying invasive plants or use the Grow Me Instead guide from the Ontario Invasive Plant Council to identify native alternatives for your garden,” Beaton said.
Invasive plants van be reported to the City of Guelph here.
"Sharing photos and giving precise information is key as it is easy to be tricked by lookalikes," Beaton said.
"I’ve probably had 200 reports of giant hogweed, all of which but three were not giant hogweed. But I would much rather have 197 wrong ones, and get the three that are giant hogweed before it spreads.”
When removing invasive species from property, it's also important residents make sure to wear protective clothing for safety and to ensure proper disposal.
Beaton said residents are also invited to join volunteer groups and participate in community events focused on removing invasive species such as the The Park Stewards Program that aims to improve the ecological health of parks and natural areas.
"There’s currently 11 of these groups around the city that are improving the ecological health of parks and natural areas by removing invasive species and planting native plants,” Beaton said.
“They are just a really friendly group of local citizens that are very heavily involved in their local parks."
In April, the city will roll out a new program that will include a tree give-away for residents to plant trees on their own properties.
"This is to build a native canopy that contributes to helping the birds and the wildlife in our area. That is critical in being able to build our canopy and overall ecology," Beaton said.
“Thankfully, there is a resurgence of a lot of native wildlife. It is coming back. A lot of that is traced to the measures that people are doing on their own properties, the work being done by the city, and by all of the community groups that are so active in the City of Guelph.”
