Interactions between native and introduced earthworms

[First paragraphs...]
There are three ways in which one group of animals may interact with another. They may (i) compete for food, (ii) compete for living space, or (iii) prey upon one another.
This paper discusses the taxonomic status and ecological preferences of the native and introduced earthworms and the extent to which they interact in these three ways.
Included in the native earthworms are about 170 species, all belonging to the family Megascolecidae. The introduced earthworms comprise 14 species of the family Lumbricidae and five species of the family Megascolecidae.