Rarely in the discussion of invasive species are earthworms mentioned. However, they are not native to North America, and especially not in areas affected by the Ice Age which probably destroyed them in this region. The common night crawler was introduced through European settlements, perhaps through Jamestown. Mann, 2007, pp 34-6 They move slowly, but their use as bait by a highly mobile America in the 20th century has established them in the northern forest. They eat the leaf litter, upon which seedlings depend. It is still unclear the full impact they may have on the forest, but it very likely will be, and is, significant.
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