Wed. Nov 29th, 2023
Meet the invaders

Invasive species are among the greatest threats to the survival of Ontario’s native plant and animal life. They are also costly to manage, harmful to international trade and a risk to human health.

Become a fighter against invasive species and help us stop their arrival and spread.

Your training starts now…

the suspects

Invasive Species Center Brochure Click for a closer look

invasive carp

Introduced to the US during the 1970s to control algae, plants and snails in aquaculture, invasive carp escaped into the Mississippi River basin during periods of flooding.

Asian carp jumpingInvasive Carp Jumps: Beware!

Consuming almost 40% of their body weight daily, invasive carp grow rapidly, making them unsuitable prey for natural predators. They compete for food and habitat and carry diseases and parasites.

Four species of invasive carp threaten our waterways:

  • bighead carp
  • black carp
  • The grass carp
  • silver carp

You can find more information about invasive carp here.


Phragmites that grow approximately 10 feet above the head of an adult female

This giant invader can grow up to 5 m tall. His superpower? Displacing native species, such as cattails, due to their large size.

Once established, phragmites can take over an area and strangle biodiversity by reducing resources such as light, space and nutrients.

Asian longhorned beetle

Discovered in 2003 in Ontario, these beetles arrived hidden in packaging materials shipped from Asia. This infestation is under active eradication; where infested and susceptible trees were removed within a radius of 800 m. Surveys are being carried out to ensure that all beetles and infested trees have been detected.

Small beetle, black with white spots, antennae, on a piece of wood.

Asian longhorn beetles attack a wide range of hardwood trees, including maples, poplars, birches and willows, causing habitat and biodiversity loss.

To prevent further damage and avoid huge losses to Ontario’s forestry and maple syrup industries, infested trees and all surrounding trees must be cut and chipped. Signs of an infestation include sap loss, branch dieback, large (2 cm) exit holes, and yellowing leaves.

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Learn more about the Asian longhorned beetle by visiting the Forest Invasives website.

Emerald ash borer

We know that many of our campers take this bad guy personally. The emerald ash borer has been responsible for tree loss at many of Ontario’s favorite campgrounds.

Small green fly-like insect on a green leaf

Small but destructive, these invaders arrived in North America in 2002, hiding in packaging materials.

Port Burwell Emerald Ash Borer RemovalInfected trees removed from Port Burwell camp

The emerald ash borer feeds on the inner bark of Ontario ash trees, reducing their ability to absorb water and nutrients. Infested trees show “D” shaped exit holes, dieback, yellowing leaves and vertical cracks.

Learn more about the emerald ash borer by visiting the Forest Invasives website.

water soldier

This plant, now located on the Trent and Black Rivers in Ontario, arrived from Europe and northwest Asia.

Close-up of a water soldier: hard green grass like a plant coming out of the water

With leaves that can grow up to 40cm long, their power is suffocating other species.

Swamp on a gray day, covered with a green Water Soldier matWater soldier rug. Photo: Ontario Federation of Anglers and Hunters

Water Soldier mats threaten summer recreational activities such as boating, fishing, and swimming. Water Soldier can also alter the chemistry of the surrounding water, harming aquatic organisms.

Use your superpowers to help fight the invaders!

Now that you’ve read our most (un)wanted list, let’s talk about how you can take action:

Report all sightings

If you find a species suspected of being invasive, call the Invasive Species Hotline (1-800-563-7711) or download the EDDMapS Ontario app to report an invader on the spot.

Buy firewood locally

Firewood is a path for forest pests. Invasive insects like the emerald ash borer and the Asian longhorned beetle can travel on firewood and spread to new areas, putting that habitat at risk.

Always buy it where you burn it.

Don’t throw your bait

Boy of 7 or 8 years old, in the middle of the delivery on a sunny day at a lake.

It is illegal to drop bait or throw the bait bucket anywhere near a body of water. Always discard bait at least 30m from shore.

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Throw worms? Many people are surprised to learn that earthworms are invasive species. Throw unused bait in the trash, not on land or water.

Clean, drain, dry

Always inspect your boat when removing it from the water. Zebra and quagga mussels can attach to your boat and be transported to the next body of water you visit. Some aquatic species can survive up to two weeks out of water!

Motor boat docked on the shore on a sunny afternoon

Always drain livewell and bilge water before leaving a body of water.

Check your clothes, boots, and furry friends for stowaways.

Pests and forest seeds can trap clothing, boots, and fur. Do a check before getting in the car.

5 people, including a person in a wheelchair built for trails, and a dog, on a hike on a grassy trail through the woods.

Don’t forget to wash your boots before embarking on your next hike.

What is at stake?

Our environment

Invasive species reduce the diversity of plant and animal species in an environment and can put native species at risk.

Forest landscape, late summer/early autumn, deciduous trees

They do this by “displacing” other species, competing for resources such as light, water and nutrients, transmitting diseases or parasites, or directly taking advantage of native species.

our economy

The costs of controlling and managing invasive species in Canada are estimated to be $34.5 billion per year!

Large barn with a gravel driveway leading up to it.

These invaders negatively impact commerce and any industry that relies on natural resources, including forestry, fishing, and agriculture.

Our people

Invasive species also directly affect human health and well-being. They can threaten livelihoods, businesses and jobs.

Family of three, on a beach, smiling at the camera, on a sunny day with the water behind them

Invasive beetles, such as the Asian longhorned beetle, destroy a city’s urban tree canopy; others destroy building foundations, decrease property values, and degrade swimming and water recreation spaces.

Our culture

Many of Ontario’s most beloved pastimes are threatened by invasive species. Hiking, swimming, fishing and boating are just some of the activities at risk.

Closeup of a bee pollinating a milk weed flower

What’s more, Ontario’s native species are part of our identity. Imagine a province without maple trees or monarch butterflies.

Do you love parks? Help us protect them

Report your sightings and be a conscientious visitor to the parks to help minimize the spread.

Learn about these evil invasives and how you can help exclude them from Ontario parks and protected areas at the Invasive Species Centre.

Do you want to act right now? Share this post on your favorite social media page to help spread the word using the hashtag. #InvSpWk.