Invasive Earthworms Deplete Key Soil Inorganic Nutrients (Ca, Mg, K, and P) in a Northern Hardwood Forest

Kit Resner, Kyungsoo Yoo, Stephen D. Sebestyen, Anthony Aufdenkampe, Cindy Hale, Amy Lyttle, Alex Blum

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Hardwood forests of the Great Lakes Region have evolved without earthworms since the Last Glacial Maximum, but are now being invaded by exotic earthworms introduced through agriculture, fishing, and logging. These exotic earthworms are known to increase soil mixing, affect soil carbon storage, and dramatically alter soil morphology. Here we show, using an active earthworm invasion chronosequence in a hardwood forest in northern Minnesota, that such disturbances by exotic earthworms profoundly affect inorganic nutrient cycles in soils. Soil nutrient elemental concentrations (Ca, Mg, K, and P) were normalized to biogeochemically inert Zr to quantify their losses and gains. This geochemical normalization revealed that elements were highly enriched in the A horizon of pre-invasion soils, suggesting tight biological recycling of the nutrients. In the early stage of invasion, epi-endogeic earthworm species appeared to have been responsible for further enriching the elements in the A horizon possibly by incorporating leaf organic matter (OM). The arrival of geophagous soil mixing endogeic earthworms, however, was associated with near complete losses of these enrichments, which was related to the loss of OM in soils. Our study highlights that elemental concentrations may not be sufficient to quantify biogeochemical effects of earthworms. The geochemical normalization approach, which has been widely used to study soil formation, may help when determining how invasive soil organisms affect soil elemental cycles. More generally, this approach has potential for much wider use in studies of belowground nutrient dynamics. The results support the existing ecological literature demonstrating that invasive earthworms may ultimately reduce productivity in formerly glaciated forests under climate change.

Original languageEnglish (US)
Pages (from-to)89-102
Number of pages14
Issue number1
StatePublished - Jan 2014

Bibliographical note

Funding Information:
The authors are thankful for the generous support from USDA NRI program to K. Yoo, A.K. Aufdenkmape, and C. Hale. Yoo’s effort was also partly supported by Hatch Fund from Agricultural Experimental Station. We thank Cristina Fernandez, Tyler Nigon, Rebecca D. Knowles, and Andrew Haveles for field assistance, and Jennifer Wang and Justene Davis for lab assistance.

Publisher Copyright:
© 2014, Springer Science+Business Media New York.


  • biological invasion
  • calcium
  • earthworms
  • geochemical mass balance
  • hardwood forest
  • inorganic nutrient cycling
  • magnesium
  • phosphorous
  • potassium


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