Under these management practices, the abundance of earthworms is enhanced. In addition, increased fertiliser costs, as well as problems of leaching into waterways, has stimulated interest in finding more efficient and safer means of supplying nutrients to plants. The earthworm fauna of agricultural soils in southern Australia is dominated by exotic species, most notably Lumbricidae which have been accidentally introduced from Europe. The main species are Aporrectodea caliginosa, A. trapezoides and A. rosea. The distributions of these species are patchy, probably in part reflecting their unintentional introduction as well as their responses to local environmental conditions.
Dominant species vary between areas and habitat types.
In pasture-cereal rotations in the same regions, A. rosea is the dominant species. They are relatively more common in agricultural soils in Victoria. Several factors may reduce the numbers of native species in agricultural soils. These include tillage, changes in shelter, food type and soil fertility and competition with introduced species. Research has shown that there is a strong positive association between the abundance of introduced earthworm species and rainfall.