Researchers at the University of Alberta are tracking some invaders that have already crossed the Alberta border heading into the Northwest Territories and may be making inroads into the Yukon.

Earthworms are damaging boreal forests, researchers say, killing plants by churning up the stratified soil northern boreal plants depend on.

Worms haven't mucked around in northern soil since before the last ice age.

"As you can kind of imagine, earthworms aren't the speediest creatures on the planet so they haven't really had time to move all the way back up to places like Whitehorse and things like that on their own," says Erin Bayne, a professor with the Biological Sciences department at the University of Alberta in Edmonton.

"When earthworms get in, they mix that all up and the plants and animals that actually relied on that structure can be negatively impacted. In fact in Minnesota, what we're seeing is that mixing of the soil layer has essentially resulted in either the local extirpation or potentially even the extinction of a couple of plant species in Minnesota."

Biologists and volunteers are concentrating their search for earthworms near roads, campgrounds and boat launches, because worm cocoons can hitch rides in boats, bait and tackle boxes as well as truck tires.

They have also launched a campaign to educate anglers not to dump their worm bait on land or in water.

Researchers are asking for Northerners to call in any worm sightings along with photographs and locations where worms have been found. You can also download their Worm Tracker data collection app on iTunes.