August 30, 2022
Invasive Asian jumping worm spotted in Ontario
By Gail Pope

Earthworms are a familiar friend to gardeners and can have a positive impact on soil health through their digestive processes.

Most earthworms are calm creatures that will wiggle around in your hand when held. The Asian jumping worm, however, is not interested in human interaction.

The name ‘jumping worm’ comes from their thrashing movements when disturbed. This type of worm looks like it has had too much caffeine and will do just about anything to get away from you, including dislocating their tail.

You may be thinking: ‘So the worms in my garden have a bit more spunk, what’s the problem with that?’ Well, the answer is that these worms aren’t a problem for your garden, but they are damaging the biodiversity of Ontario forests.

That’s a big job for a small worm, but as an invasive species, Asian jumping worms are able to reproduce in large numbers and survive harsh conditions creating a recipe for destruction.

Origins of the jumping worm

The Asian jumping worm is originally from East-Central Asia. This species has lived in the U.S. since 1800, but has been spotted in parts of Ontario, including Hamilton and Windsor regions in recent years.  

Colin Cassin, an invasive species policy manager at the Invasive Species Centre in Peterborough, Ont., explained the jumping worm invasion.

“They’re really effective hitchhikers,” Cassin said. “We think just the movement of soil is the perfect mechanism for moving these unwanted species around. And they tend to be really effective as they’re not just moving as adults, but sometimes they’re even moving as eggs that would be almost invisible to the naked eye.”

Cassin also explained that most earthworms are considered invasive species, but this one has a particularly detrimental impact on forests.

Good for the garden, not for the forest

When jumping worms invade naturalized areas like forests, the composition of the soil is shifted. These worms love to munch on organic matter that lines the top of the forest floor — exposing tree roots and leaving behind droppings that are very low in nutritional value.

This also alters the amount of nitrogen and carbon dioxide in the soil, leading to fewer organisms and plants that can’t survive in these changed environments.

“When we have plant communities that aren’t as biodiverse, that also has impacts on the kinds of organisms that use those plant communities. An example is the negative impacts on ground nesting birds that would use the forest understory to lay their eggs and unfortunately, they’re just not found in those kinds of habitats anymore,” Cassin said.

Not only that, but Asian jumping worms are known to frantically travel through soil, their quickened pace grinding the earth to almost coffee grounds-like texture. This texture makes soil prone to erosion.

However, Cassin said he likes to emphasize that all earthworms, including the Asian jumping worm, are ‘good for the garden, bad for the forest.’

“So in human-modified environments, and landscaping scenarios in agricultural fields, earthworms generally have really positive impacts. Their tunnels can increase soil porosity, and increase gas exchange happening, they can increase water infiltration to water the roots. They do a lot of great things.”

What can we do?

Cassin explained how these worms are not as harmful to gardens and should be contained to one area as much as possible and identified before taking further action.

“The best thing to do is take a picture of it, and report it to a great website, like, because it helps us confirm if that is that.”

There are over 20 species of earthworms in Canada alone, so it’s always good to check with a professional to identify what type is in your garden.

“When you do come across them, try not to move that contaminated material, soil, plant material, what have you. It’s just, in general, good practice. It’ll help us with Asian jumping worms. It’ll help us with all other invasive species, too.”