That's a good point. How do we know that worms are exotic? Just
because there are areas without worms doesn't mean worms were solely
imported during the colonial times.

I agree that worms can cause erosion in some forest environs but it
seems hard to believe that North America was devoid of worms.

John Savage wrote in message news:030724000112505.24Jul03$rookswood@suburbian. com...
(simy1) writes:
John Savage wrote in message news:030720000111252.20Jul03$rookswood@suburbian. com...
I'd expect to find no earthworms in soil with little humus, such as in
clay regions, or sandy or rocky soil where there is little vegetation
to contribute humus, or soil where there is insufficient moisture.