There are no native earthworms in most forests of the Upper Great Lakes Region. Because European earthworms are used as fishing bait, at this time there are many invasion fronts emanating into forests from lakeshores throughout the northwoods of Minnesota, Wisconsin and Michigan. In many cases these fronts are moving through forests with otherwise similar tree canopy and soils, allowing direct comparison of sites with and without earthworms, an experimental setup rarely duplicated elsewhere. In addition we recently started a major research project on jumping worm invasion in MN (Asian earthworm in the genus Amynthas), to examine factors that determine their distribution and establishment, and impacts on soils and native plants.
Selected publications
Frelich, L.E., B. Blossey, E.K. Cameron, A. Davalos, N. Eisenahuer, T. Fahey, O. Ferlian, P. Groffman, E. Larson, S. Loss, J. Maerz, V. Nuzzo, P.B. Reich, K. Yoo. 2019. Side swiped: ecological cascades emanating from earthworm invasion. Frontiers in Ecology and the Environment 17: 502-510, doi:10.1002/fee.2099.
Fisichelli, N.A., L.E. Frelich, P.B. Reich, and N. Eisenhauer. 2013. Linking direct and indirect pathways mediating earthworms, deer, and understory composition in Great Lakes forests. Biological Invasions 15:1057-1066. [doi: 10.1007/s10530-012-0350-6]
Loss, S.R., R. Hueffmeier, C.M. Hale, G.E. Host, G. Sjerven, and L.E. Frelich. 2013. Earthworm invasions in northern hardwoods forests; a rapid assessment method. Natural Areas Journal 33:500-509. [doi: http://dx.doi.org/10.3375/043.033.0103]
Holdsworth, A.R., L.E. Frelich, and P.B. Reich. 2012. Leaf litter disappearance in earthworm-invaded northern hardwood forests: role of tree species and the chemistry and diversity of litter. Ecosystems 15:913-926. [doi: 10.1007/s10021-012-9554-y]
Eisenhauer, N., N.A. Fisichelli, L.E. Frelich, and P.B. Reich. 2012. Interactive effects of global warming and 'global worming' on the germination of native and exotic herbaceous plant species. Oikos 121:1121-1133. [doi: 10.1111/j.1600-0706.2011.19807.x]
Eisenhauer, N., J. Schlaghamersky, P.B. Reich, and L.E. Frelich. 2011. The wave towards a new steady state: effects of earthworm invasion on soil microbial functions. Biological Invasions 13:2191-2196. [doi: 10.1007/s10530-011-0043-4]
Holdsworth, A.R., L.E. Frelich, and P.B. Reich. 2007. Effects of earthworm invasion on plant species richnes in northern hardwood forests. Conservation Biology 21:997-1008.
Holdsworth, A.R., P.B. Reich, and L.E. Frelich. 2007. Regional extent of an ecosystem engineer: earthworm invasion in northern hardwood forests. Ecological Applications 17:1666-1677.
Frelich, L.E., C.M. Hale, S. Scheu, A. Holdsworth, L. Heneghan, P.J. Bohlen, and P.B. Reich. 2006. Earthworm invasion into previously earthworm-free temperate and boreal forests. Biological Invasions 8:1235-1245.
Hale, C.M., L.E. Frelich, and P.B. Reich. 2005. Effects of European earthworm invasion on soil characteristics in northern hardwood forests of Minnesota, USA. Ecosystems 8:911-927.
Hale, C.M., L.E. Frelich, and P.B. Reich. 2005. Exotic European earthworm invasion dynamics in northern hardwood forests of Minnesota, USA. Ecological Applications 15:848-860.
Augustine, D., L.E. Frelich, and P.A. Jordan. 1998. Evidence for development of alternative communities in an ungulate grazing system. Ecological Applications 8:1260-1269.
Augustine, D., and L.E. Frelich. 1998. White-tailed deer impacts on populations of an understory forb in fragmented deciduous forests. Conservation Biology 12:995-1004.
Roots of a sugar maple sapling exposed after invasive earthworms have eaten the forest floor. Photo: Dave Hansen, University of Minnesota.
An earthworm-free maple forest on the Chequamegon-Nicollet National Forest, WI. Photo: Paul Ojanen.
Lumbricus rubellos in yellow birch and sugar maple forest on Isle Royale. Photo: Kalev Jogiste.