Lee Frelich, Ph.D of the University of Minnesota department of Forest Resources has reported on the topic of exotic earthworms. It is true: There are no native earthworms in Minnesota. All our earthworms are exotic. These worms (of European descent) can strip the duff on the forest floor in a single season. The resulting altered ecosystem cannot support native plants. Frelich found that only jack-in-the-pulpit thrived. Instead, nonnative species, which perhaps coexisted with earthworms in Europe, take over. Furthermore, this alteration of the plant species on the forest floor is followed by changes in the mix of other species. That is, the entire forest ecosystem is affected. For those of us who live in the city, this is not much of an issue. The "ecosystem" in our gardens has been so thoroughly corrupted by all our human modifications, including the nonnative plants we grow, that earthworms are the least of our problems. However, in the north woods, the problem is very serious. The worms move too slowly to cause much damage on their own. Unfortunately, we help them along by dumping live fishing worms when we travel up north, when we move plant material (with soil containing worms) from one location to another, or when we dump animal bedding in a new location.

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