Submitted to: International Symposium on Earthworm Ecology
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 1998
Publication Date: N/A
Earthworm communities in 7 experimental watersheds at Coshocton, Ohio were monitored twice annually (Spring and Autumn) for 5 years (1990-94). Sampling by formalin extraction was undertaken along a transect running up slope within the small (0.5-0.7 ha) watersheds that were used for row crop production under a variety of tillage practices. Six earthworm species were found of which four, Aporrectodea turgida, A. trapezoides, Lumbricus rubellus, and Octolasion tyrtaeum were present in all watersheds, whereas A. tuberculata and L. terrestris had restricted distributions. In individual watersheds, earthworm density was lowest at 3 m**-2 (Autumn 1991) and highest at 397 m**-2 (Spring 1994), with watershed averages fluctuating between 55 and 247 m**-2 in association with rainfall. Tillage practice and crop type did not have a significant effect on earthworm numbers (p > 0.05). Equally, position along the transect was not significant for all watersheds. In some watersheds, however, more worms were found towards the bottom of the slope following dry periods. Additional sampling during Spring 1994 using a combination of formalin extraction and hand sorting revealed that populations may have been underestimated by as much as 50%, this difference mainly due to the smaller species. The presence of deep burrowing species has a marked effect on rainfall infiltration. Therefore, attempts were made to establish L. terrestris in a watershed where it was previously absent. These proved unsuccessful, even though a number of techniques were used. This indicates that the distribution of earthworms within this system was not simply a factor of colonization ability.