Traits of invaded ecosystems? Are my compost worms a threat to New York?
The native worms are not good at competing for some reason.


There's a reason for that. There are no native earthworms in New York.


  Still, before the most recent glaciers there were worms in these regions.


North America has been hammered by multiple glaciations for the last two million years. It wasn't just the areas covered by ice that lost their earthworms. The northern forest, or taiga extended to the Gulf Coast at the peak of the last glaciation. You have to drive to Ontario to see the taiga now. The Great Plains were the mammoth steppe, very cold and very dry. Most of the US is depleted of native earthworms.

Invasive earthworms are your enemy if you like maple syrup. Sugar maples take a couple of years to germinate, and only need a nice pile of duff (leaf detritus that hasn't been consumed by earthworms) in which to do so.