Research Issue

[photo:] Soil respiration measurements in this northern hardwood stand are used to understand the impact of exotic earthworms on forest carbon dynamics.

  • Populations of exotic European earthworms have been expanding into formerly worm-free forests in the north central and northeastern United States.  These earthworms consume the organic horizons of the forest floor, often removing leaf litter within several years of invasion.  This leads to changes in soil carbon, nutrients (e.g. nitrogen and calcium), soil microclimate, hydrology, soil organisms, and plant community assemblages. 

Our Research

Our work is currently focused on characterizing earthworm invasion fronts located in the Huron Mountains in northern Marquette County, MI, where we are studying earthworm communities and ecosystem responses across a range of earthworm species densities in maple and hemlock dominated forest systems. We are characterizing long-term soil temperature and moisture, soil respiration, litter water interception, lysimetry, soil chemistry, litterfall mass and chemistry, soil microbial communities, and earthworm and other invertebrate communities. This information is being used to determine the effects of earthworms on carbon, nutrient and water cycling, and microbial and invertebrate communities across the sites.

Expected Impact

We will elucidate earthworm-induced changes in carbon cycling, nutrient cycling, hydrological budgets, microbial communities, and plant productivity and nutrition. This information will be used to understand the effects of earthworms on ecosystems, and to adapt current forest management practices for sites that have been recently invaded by earthworms. In addition, information on changes in soil carbon will be used to determine the effect of earthworms on the ability of soils to store atmospheric CO2.

Research Results

Potvin, Lynette R.; Lilleskov, Erik A. 2017. Introduced earthworm species exhibited unique patterns of seasonal activity and vertical distribution, and Lumbricus terrestris burrows remained usable for at least 7 years in hardwood and pine stands. Biology and Fertility of Soils. 53(2): 187-198. https://doi.org/10.1007/s00374-016-1173-x.

Yatso, Kassidy N.; Lilleskov, Erik A. 2016. Effects of tree leaf litter, deer fecal pellets, and soil properties on growth of an introduced earthworm (Lumbricus terrestris): Implications for invasion dynamics. Soil Biology & Biochemistry. 94: 181-190. https://doi.org/10.1016/j.soilbio.2015.11.030.

Shartell, Lindsey M.; Lilleskov, Erik A.; Storer, Andrew J. 2013. Predicting exotic earthworm distribution in the northern Great Lakes region. Biological Invasions. 15(8): 1665-1675.

Gailing, Oliver; Hickey, Erin; Lilleskov, Erik; Szlavecz, Katalin; Richter, Klaus; Potthoff, Martin. 2012. Genetic comparisons between North American and European populations of Lumbricus terrestris L. Biochemical Systematics and Ecology. 45: 23-30. https://doi.org/10.1016/j.bse.2012.07.018.

Karberg, N.J.; Lilleskov, E.A. 2008. White-tailed deer (Odocoileus virginianus) fecal pellet decomposition is accelerated by the invasive earthworm Lumbricus terrestris. Biological Invasion. 7 p.

Lilleskov EA, Mattson WJ, Storer AJ. 2008. Divergent biogeography of native and introduced soil macroinvertebrates in North America north of Mexico. Diversity and Distributions 14:893-904.

Research Participants

Principal Investigators

  • Erik Lilleskov, USDA Forest Service- Northern Research Station Research Ecologist

Research Partners

  • Chris Swanston, USDA Forest Service- Northern Research Station Research Ecologist
  • Randy Kolka, USDA Forest Service- Northern Research Station Research Soil Scientist
  • Tom Pypker, Michigan Technological University
  • Andrew Storer, Michigan Technological University


  • Last modified: November 18, 2019