Ontario adds 10 new plants and animals to its invasive species list

The Ontario government is adding 10 new plants and animals to its registry of invasive species. In December 2023, the province’s Ministry of Natural Resources and Forestry reported that several species would enter the Ontario Invasive Species Act as of the new year. The aquatic plants, fish, trees, and mammals were added in an attempt to “help prevent, control and reduce their spread,” the MNRF says.

Colin Cassin is the policy manager for the Invasive Species Centre. He says these additions are crucial for preventing trade, one of the main ways “ecologically devastating” species are brought into new environments. “It’s really about giving us the ability to restrict their sale,” he says. “This helps give us some legislative tools to prevent actions and activities like that.”

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Invasive species that are illegal to trade, sell, breed, or import are considered “prohibited.” Cassin says prohibited species are more likely to have little or no presence in the province—the classification is meant to stop them from entering in the first place.

One such example is nutria (pictured), a rodent native to South America that has yet to be identified in Ontario. The species was brought to North American farms in the late 1800s to be bred for pelt, but when the pelt’s price declined in the early 1940s, farmers released their nutria into the wild. They have since been found chewing holes through the plant layers of U.S. wetlands, causing damage to nearby infrastructure.

“It has negative impacts on how stable a shoreline is,” Cassin says. “We’ve heard from our partners in the States about infrastructure concerns, especially from Louisiana, about bridges being right beside those nutria habitats.”

Cassin says other invasive species added to the registry are “restricted”, meaning they’re illegal to release in the province, or to bring into provincial parks and conservation areas. Restricted species are more likely to already be considered “widely established.”

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For example, the marbled crayfish, which was found in Burlington, Ont., in 2023, is as detrimental as nutria. The crayfish eat through wetland plant layers and outcompetes other animals for food, putting native crayfish at risk. More worrying? This species is the only crayfish in a restricted group of crayfish with the ability to self-clone, Cassin says. “It doesn’t need to find a partner. That’s a really unique advantage. That makes it a strong invasive species.”

Another restricted species, tree-in-heaven, has a small population in southwestern Ontario. According to Cassin, this tree aids in the reproduction of the spotted lanternfly, an invasive pest not yet in Canada that feeds on grapes and hops. “There’s been reports in Pennsylvania of small wineries having financial difficulties, and even shutting down due to spotted lantern fly,” he says. “There are potential impacts on wineries and the craft brewery industry in Ontario. It’s a high priority.”To help prevent the spread of invasive species, Cassin recommends cleaning, draining, and drying watercraft when moving boats over land and between bodies of water. Ontario residents can also take photos of invasive species they spot and submit them to EDDMapS.