European Earthworm Invasion and Deer in Forests
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.
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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.