By Andi Anderson
New research from Michigan’s Upper Peninsula is shedding light on how invasive earthworms are altering forest soil systems. The study, conducted in the Huron Mountains, examined the body size and growth patterns of several invasive earthworm species to better understand their ecological effects.
Scientists found that these non-native worms are reshaping soils, affecting nutrient cycles, and influencing forest biodiversity.
Although earthworms are commonly thought of as beneficial, the U.S. Department of Agriculture notes that most earthworms in North America are actually invasive species, unintentionally introduced during European settlement.
In the Great Lakes region, these species have become especially influential, changing soil composition and speeding up organic matter decomposition.
Researchers from Governors State University in Illinois studied three invasive species and discovered that each one affects the forest ecosystem differently. The largest species, Lumbricus terrestris, causes major physical disturbances in the soil and influences nutrient movement.
The smallest species, Dendrobaena octaedra, plays a role in fine-scale decomposition. The mid-sized species, Aporrectodea longa, disrupts multiple soil layers, combining the impacts of the other two.
Lead researcher Xiaoyong Chen said the study improves understanding of how these species spread and survive. He explained that entirely eliminating invasive earthworms is not realistic, but learning where they live and how they function will help future management efforts.
Chen is currently working with colleagues on a broader earthworm ecology project to expand this research.
Another project collaborator, microbiology professor Tim Gsell, highlighted the consequences of too many invasive worms. He stated, “We always hear about earthworms being good for the soil and productivity for plants, but as it turns out, too many of them actually causes a lot of loss of nutrients like carbon and nitrogen.”
Environmental biology professor John Yunger and Gsell added that invasive worms accelerate decomposition, releasing greenhouse gases and reducing essential nutrients.
Chen noted that “In the UP, around the Huron Mountains, 70% of the land is occupied by invasive earthworms.” Only a small lake-adjacent area remains worm-free.
To collect worms for research, scientists use a mustard-water solution that irritates the worms and forces them to the surface. Gsell explained, “We use a mustard solution to get the earthworms to come to the surface.” This method works for small areas, but not for large-scale removal.
For now, the researchers say they’re focused on addressing the problem by learning as much as they can about invasive worms to inform management efforts.
Photo Credit: gettyimages-sasiistock
Categories: Michigan, Sustainable Agriculture