CANADA’S MOST-UNWANTED LIST
Here’s a list of some of the top “species of interest” that have invaded Canada according to Gail Wallin and Barry Gibbs, co-chairs of the Canadian Council on Invasive species.
Giant hogweed: This was introduced as an ornamental garden plant but it has escaped and taken over roadsides in many parts of Canada. It may cause skin burns if touched.
Knotweed: Widespread across Canada, its roots have damages foundations, roads and bridges.
Knapweed: This purple-flowered weed was imported into North America more than a century ago and has since established itself in fields, forests and prairies, out-competing native species and reducing the amount of forage available for wildlife and livestock.
Zebra mussels: Widespread in waterways in Eastern Canada as far west as Manitoba, these bivalves change the freshwater ecology, stripping nutrients from the ecosystem and clogging up water intakes.
Emerald ash borer: This Asian native has killed millions of ash trees in Ontario. While they travel slowly on their own, they are dispersed by people moving firewood, logs and lumber.
Asian longhorn beetle: This forest pest introduced in the 1990s has no natural North American enemies. It kills all broadleaf trees but prefers native maples.
Feral pigs: Also known as wild boars, these Eurasian natives have escaped from farms where they were raised as meat animals. Known to be aggressive, they also destroy cropland and natural habitat because they tear up the ground while looking for food. They are also prolific in the wild: It is believed there are more than a million feral pigs in Saskatchewan. They have also be sighted in Ontario, including rural areas east of Ottawa.
Flowering rush: This pond plant, which produces a pink flower, was introduced as an aquatic ornamental. When it establishes itself on natural shorelines, this plan forms dense stands that interfere with recreation, crowd out native plants and harm fish and wildlife. Saltcedar: This native of Asia has been sold as an ornamental small tree or shrub for many decades. It produces a leaf litter that increases the salinity of the soil, discouraging native plant species. European fire ant: Found across Canada, this species lives colonies and is known for its painful bite. Colonies are hard to destroy once established. Asian carp: Several species of Asian carp have been found in North America, including the St. Lawrence River. They multiply quickly and displace native fish species, presenting a danger to sport and commercial fisheries. Northern snakehead: Also known as the “frankenfish,” this toothy predator native to Asia has been found in several U.S. states. It was likely dumped into ponds, lakes and rivers from fish markets or pet shops. It been called the “walking fish” for its ability to travel on land for short distances by wiggling forward. It can survive out of water for up to four days.