As invasive earthworms threaten Canada’s Northern boreal forest, the University of Alberta is leading a collaborative project to gauge the damage.
Earthworms are commonly thought of as helpful additions to gardens and lawns, but according to U of A biologist Erin Bayne, most earthworms are actually not native to Canada and may harm soil organisms and plant communities, as well as affect climate change. Bayne, along with former graduate student Erin Cameron, has been trying to clarify the worms’ impact by leading the Alberta Worm Invasion Project.
Historical accounts of settlers suggest that Europeans introduced the earthworms in the past 100 years — settlers were reportedly surprised by Canada’s lack of earthworms compared to Europe. Now, one of the most likely causes of earthworm introductions to the forest is abandoned fishing bait. Bayne’s research shows that earthworms are most likely to be found at boat launches and nearby roads. Worms were much less likely to be found around distant roads, forests, and remote shorelines, suggesting that vehicles and bait abandonment help the earthworms’ spread.
The Alberta Worm Invasion Project recommends fishers to either store their earthworm fishing bait for next time or to dispose of excess bait in the trash to reduce invasion.
“It may be that Alberta is in the early stages of invasion,” Bayne said. “We haven’t seen what I would call massive negative effects.”
The project works with “citizen scientists” that help the researchers collect more data on earthworm distribution. Citizen-generated research shows that climate change may be helping the worms, Bayne said.
“(The invasive earthworms) are able to survive perhaps more than they could in the past, with winters not as severe as they have once been,” Bayne said.
One of the species Bayne is focusing on is called group Dendrobaena, which includes the species commonly thought of as the typical earthworm. It lives in shallow leaf litter unlike deep-burrowing earthworms, and therefore does not help the ecosystem by mixing the soil. Dendrobaena eat the leaf litter, which can harm native insects and fungi that use dead leaves for food as well as native plants that root in the soil — this can impact the normal food chain in Canada’s boreal forest.
Some of Bayne’s previous research suggests that the invasive worms may be affecting climate change by influencing the amount of carbon released into the atmosphere. While earthworms may be helpful in gardens by cycling soil, they may have larger negative impacts on the northern boreal forest in the future.
Moving forward, Bayne will examine the effect of the Fort McMurray wildfires on the invasive worms.
“If the fire sets (the worms) back maybe that’s one way the boreal forest is a little tougher than other ecosystems,” Bayne said.