DLESE description of It Came from Underground

This short Why Files article discusses the effects of the earthworm on the ecology of some northern deciduous forests. In these ecosystems, glaciers extirpated all worms over 10,000 years ago. The forest ecologist interviewed for this article indicated that in northern Minnesota, the worms probably came from fishing bait that was dumped in the woods over several decades. The earthworms rapidly munch decomposing organic matter, or duff, on the forest floor and thus deprive native plants and tree seedlings of a place to germinate and grow. The result is a bare forest floor, lacking most spring flowers and tree seedlings. Vegetation may return, but in some areas the plants that have returned are invasive species, which are causing widespread ecological destruction. At this point, the phenomenon has been seen in many parts of the eastern deciduous forest, which stretches from New England to Minnesota.