Jumping worms, also known as Amynthas species, are a type of earthworm native to East Asia that is a new invasive in Canada. Unlike the common earthworm you might find in your garden, jumping worms are a serious threat to North American green spaces and forests. Named for their thrashing and "jumping" behaviour when disturbed, these worms devour soil substrate and have no North American predators. Jumping worms rapidly change the structure of soil, causing damage to entire forest ecosystems.
Description:
Color: Typically a dark purplish-grey with a milky-white band at the 14th segment from the head.
Size: Ranges from 4-20 cm, depending on species.
Jumping worms are distinguished by their glossy, smooth bodies and their thrashing, snake-like movement. Unlike other worms, they are very aggressive in consuming organic matter.
Key Effects on Soil:
Jumping worms are destructive to soil and forest substrate, consuming vast amounts of organic matter and breaking down leaves and mulch with alarming speed (Nouri-Aiin & Görres, 2024). This aggressive feeding cycle collapses the natural nutrient cycling process and destroys the soil structure, leading to a depleted substrate where native understory species struggle to survive (Cassin & Kotanen, 2016; Skinner et al., 2018). As a result of their impact, the health of the entire forest is compromised—harming wildlife, birds, insects, and the vital biota connected to the substrate layer (Bal et al., 2018).
When this process leads to the biological replacement of native plants with invasive species that thrive on the high-nitrogen, disrupted soil environment, the ecosystem is termed "collapsed" (Moore et al., 2018). While an invaded forest may appear to have a lush understory at first glance, the presence of largely non-native species is a definitive sign that the original ecosystem has been hijacked and its foundational processes—such as carbon sequestration and natural recruitment—have failed (Lejoly & Quideau, 2023); Chang et al., 2021).
References/Links:
Bal, T. L., Jurgensen, M. F., Richter, D. L., & Storer, A. J. (2018). Evidence of damage from exotic invasive earthworm activity was highly correlated to sugar maple dieback in the Upper Great Lakes region. Biological Invasions, 20(1), 151–164. https://doi.org/10.1007/s10530-017-1523-0
Cassin, C. M., & Kotanen, P. M. (2016). Invasive earthworms as seed predators of temperate forest plants. Biological Invasions, 18(6), 1567–1580. https://doi.org/10.1007/s10530-016-1101-x
Chang, C.-H., Bartz, M. L. C., Brown, G. G., Callaham, M. A., Jr., Cameron, E. K., Dávalos, A., Görres, J. H., Görres, S., & Szlavecz, K. (2021). The second wave of earthworm invasions in North America: Biology, environmental impacts, and prospects for management of invasive species in the family Megascolecidae. Biological Invasions, 23(10), 3291–3322. https://doi.org/10.1007/s10530-021-02598-1
Lejoly, J., Quideau, S. A., & Laganière, J. (2021). Invasive earthworms affect soil morphological features and carbon stocks in boreal forests. Geoderma, 404(Part 1), 115262. https://doi.org/10.1016/j.geoderma.2021.115262
Nouri-Aiin, M., & Görres, J. H. (2024). Invasive earthworms and ecosystem processes in North America.Springer. DOI:10.1007/978-3-031-64510-5_1
Moore, J.-D., Ouimet, R., & Reynolds, J. W. (2018). Exotic Asian pheretimoid earthworms (Amynthas spp., Metaphirespp.): Potential for colonisation of south-eastern Canada and effects on forest ecosystems. Environmental Reviews, 26(1), 113–120. https://doi.org/10.1139/er-2017-0066
Skinner, M., et al. (2018). Do invasive worms threaten Northeast maple forests? The Maple Digest. https://mapleresearch.org/pub/m0218worms/
The second wave of earthworm invasions in North America: biology, environmental impacts, management and control of invasive jumping worms
https://doi.org/10.1007/s10530-021-02598-1
Ontario Invasive Species Awareness Program: Jumping Worms
All about Invasive Jumping Worms
https://conservationhamilton.ca/blog/all-about-invasive-jumping-worms/
