Research shows that invasive earthworms are damaging forest soils and are a menace to species diversity. The problem is most often associated with formerly glaciated regions, where native populations of earthworms are not present. Comparing soil in front of the invaders to post invasion conditions demonstrates that these worms cause soil compaction, reduced soil fertility, and increased erosion. It appears that these invaders are capable of alterations deep enough into the soil profile to result in a change in soil taxonomic classification at the order level. Other concerns are damage to rhizosphere functions, impairing soil carbon sequestration capacity.