Hundreds of invasive species established in Ontario

By MPP Toby Barrett

Hundreds of invasive species of plants, animals and marine life have become established in Ontario.

Not all non-native species are invasive. Invasive species are defined as harmful alien species whose introduction or spread threatens the environment, the economy, or society, including human health. Once established, invasive species can be extremely difficult and costly to control and eradicate, and their ecological effects are often irreversible.

Invasive species certainly came to light in Ontario when sea lamprey took advantage of the Welland Canal to gain access to the Great Lakes in the early 1900s. Sea lamprey use a sucker-like mouth and sharp teeth to attach to a fish and suck the blood out of it. Only one in seven fish survive a lamprey attack and trout species are more vulnerable.

Zebra and quagga mussels were the next big invader affecting aquatic ecosystems. Arriving in ship ballast from Europe, these freshwater mussels quickly took over in the Great Lakes, then inland lakes, displacing native mussels. Their numbers were so huge a problem developed with them clogging municipal water intakes. The impact of these mussels started the movement to make society more aware of invasive species.

Many aquatic invasive species followed a similar pattern for becoming established. The Asian carp, which could be the greatest threat facing Ontario’s lakes and rivers, is an exception. The four sub-species of Asian carp were brought to the southern United States in the 1960s and escaped into the wild. Since then they have moved northward along the Mississippi River system.

In some cases, invasive plants spread were intentionally planted in people’s gardens, unaware of the potential of spreading. Purple loosestrife is one example of this. It’s also one of the invasive species eradication success stories. Periwinkle, English ivy and goutweed are also ornamental plants that have become established and invasive.

It’s my hope that phragmites can become the next invasive species control success story. This tall reed grabs hold in wetlands, ditches and any wet spot. It quickly spreads and crowds out native vegetation. This was evident in the marshes of Long Point Bay, where a control effort recently eliminated much of it. For landowners, the Long Point Phragmites Action Alliance has a program available to assist with removal of this invasive.

Garlic mustard is gaining notoriety as it grabs a foothold in woodlots and backyards across southern Ontario. Brought to North America from Europe as an edible herb, it spreads quickly when established.

There is a huge list of other invasive plants, both terrestrial and aquatic, that pose threats: common buckthorn, dog-strangling vine, giant hogweed, hydrilla, water soldier and many more.

Invasive plants aren’t the only threats to our forests. Asian long-horned beetles, emerald ash borer and Dutch elm disease have all brought destruction to our woodlands. Oak wilt, a fungal pathogen, is not yet in Ontario but could wreak havoc if it became established.

Another threat to the province’s forests are wild pigs. These non-native pigs dig in the forest disrupting plants growing on the forest floor.

The most important thing with any invasives is prevention – preventing a non-native plant or animal to establish itself in the province – and individuals can make a difference in this regard.

Toby Barrett is the MPP for Haldimand-Norfolk