Australia has 650 known species of native earthworm that survive in both rich and in nutrient-poor conditions where they may be sensitive to changes in the environment.
[3] Approximately 182 earthworm taxa in twelve families are reported from the United States and Canada, of which sixty (about 33%) are introduced.
When worms decompose that leaf layer, the ecology may shift making the habitat unsurvivable for certain species of trees, ferns and herbs.
[6] Earthworms normally spread slowly, but can be quickly introduced by human activities such as construction earthmoving, plantings, and the release of worms used as fishing bait.
Sightings of the New Zealand flatworm have been mainly localised, but it has spread extensively since its introduction in 1960 through contaminated soil and plant pots.
The Minnesota Department of Natural Resources, in cooperation with local groups, has launched a public education campaign using posters in bait shops and other outreach efforts.