Earthworms may not be our friends in North America

This is an interesting read about earthworms impact on forests.

http://blog.cleveland.com/metro/2009/09/spread_of_european_earthworms.html

it is dependent on where in north america you are. I looked into it for the forest I live in and we have so many natural predators that they do not pose any problem here. when I moved here there was no worms of any sort that I could find. now I do vermicompost so I occasionally find some in the garden but I have yet to see them outside the garden area in the actual forest here.