How Did They Get to Ontario?
Jumping worms were introduced to North America through the global movement of soil and plant materials. In the past, soil movement was not regulated at all, and it is under-regulated today. Today, they spread primarily through large commercial horticulture and landscaping supply chains that move mulch, compost, and potted plants over long distances (Chang et al., 2021). Gardeners are usually the first to notice their presence, and play an essential role in detecting, reporting, learning about and managing their impacts at the local level (University of Wisconsin–Madison Master Gardener Program, 2017). Jumping worms are native to Asia, where they are widespread, and related species have been present in North America since the early 20th century, although their ecological impacts and rapid expansion have only been widely recognized in recent decades (Chang et al., 2021). In many regions, they appeared stable or rare for years before suddenly becoming widespread—a pattern typical of invasive species once key thresholds are crossed (Coutts et al., 2018).
This expansion is especially significant in northern, post-glacial landscapes, where earthworms were historically absent and soils developed without them (Bohlen et al., 2004). In these ecosystems, jumping worms can rapidly alter soil structure, consume leaf litter, and disrupt the forest floor in ways that have cascading effects on plants, fungi, and wildlife (Frelich et al., 2006). As they continue to move north, their impacts are expected to be more pronounced, transforming ecosystems that are particularly sensitive to soil change (Lejoly, 2021). As they are rapid detritivores, their appetite for the "duff" layer of Canada's northern boreal forest and in particular the carbon sink of the northern peatlands requires significant scrutiny (Natural Resources Canada, 2021).
Jumping worms are not native to North America. Their spread is driven by the widespread movement of soil, plants, and mulch through regional and global supply chains, along with construction and landscaping activities and the unintentional transport of soil on boots, equipment, and vehicle tires.
The first sightings of jumping worms in Ontario date back to the early 2000s. They are believed to have been introduced accidentally through the transportation of contaminated soil and horticultural materials. Once introduced, jumping worms can quickly establish themselves in a new environment.
They are detritivores that thrive in post-glacial areas where no native earthworms have ever existed and with warming climate, their season for reproduction is lengthened, so that in areas where there appeared to be few, there is now a discernible presence.
References/Links:
Bohlen et al., (2004) U.S. Environmental Protection Agency. (Reference details (HERO ID: 2468641). Health & Environmental Research Online (HERO). https://hero.epa.gov/hero/index.cfm/reference/details/reference_id/2468641
CBC News: Earthworm Problem in Ontario https://www.cbc.ca/news/canada/toronto/jumping-worms-toronto-spread-1.6863841
Coutts, S. R., Helmstedt, K. J., Bennett, J. R., & Roura-Pascual, N. (2018). Invasion lags: The stories we tell ourselves and our inability to infer process from pattern. Diversity and Distributions, 24(2), 244–251. https://doi.org/10.1111/ddi.12669
Frelich, L. E., Hale, C. M., Scheu, S., Holdsworth, A. R., Heneghan, L., Bohlen, P. J., & Reich, P. B. (2006). Earthworm invasion into previously earthworm-free temperate and boreal forests. Biological Invasions, 8(6), 1235–1245. https://doi.org/10.1007/s10530-006-9019-3
Herrick, B. M. (2017). Research update: Jumping worms and sleeping cocoons. University of Wisconsin–Madison Arboretum. https://arboretum.wisc.edu/news/arboretum-news/research-update-jumping-worms-and-sleeping-cocoons/
Lejoly, J., Quideau, S., & Laganière, J. (2021). Invasive earthworms affect soil morphological features and carbon stocks in boreal forests. Geoderma, 404, 115262. https://doi.org/10.1016/j.geoderma.2021.115262
Natural Resources Canada. (2021). Earthworms, a threat to Canada’s boreal forest? https://natural-resources.canada.ca/simply-science/earthworms-threat-canadas-boreal-forest/23961
New film: My Forest Has Worms, New England Forests by Ecologist Robert Asselin
https://www.youtube.com/watch?v=5xvkIDs3zQk
"Non-native earthworms: Entering the second wave of invasion" webinar with Dr. Michael McTavish https://www.youtube.com/watch?v=iqXFVWzXSsI
Ontario Master Gardeners: Jumping Worms Introduction https://haltonmastergardeners.com/2022/04/15/invasive-jumping-worms-information-for-home-gardeners/
Pheretimoid jumping worms confirmed to be in Ontario; can destroy topsoil https://www.cleannorth.org/2021/10/06/pheretimoid-jumping-worms-confirmed-to-be-in-ontario-can-destroy-topsoil
