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United States Department of Agriculture

Agricultural Research Service

Title: Population Dynamics of Ambient and Altered Earthworm Communities in Row-Crop Agroecosystems in the Midwestern United States

item Shuster, W - (POST-DOC) USEPA-NRMRL
item Subler, S - PACIFIC-GARDEN
item Shipitalo, Martin

Submitted to: International Symposium on Earthworm Ecology
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2002
Publication Date: N/A

Technical Abstract: Although earthworm communities are known to influence agroecosystem processes, there are relatively few studies addressing earthworm population dynamics under cropping systems, especially in systems where earthworm populations were intentionally altered. We assessed ambient and altered earthworm communities in chisel (CS) and ridge-till (CSW) agroecosystems in nsouth-central Ohio (USA) from fall 1994 to fall 1997. Earthworm communities were altered with spring and fall additions of predominantly deep-burrowing anecic species at a rate of 100 individuals per square meter; ambient plots had no discernable populations of anecic species. We assessed populations semi-annually using a combination of handsorting and formalin expulsion, and evaluated abundance of the predominant species from epigeic (Lumbricus rubellus Hoff.), endogeic (Octolasion tyrtaeum Savigny), and anecic (L. terrestris Linnaeus) ecological groups. Repeated-measures analysis indicated that increases in anecic populations due to additions o individuals were small (7 ind. per square meter) compared to the size of the additions. In the earthworm addition treatments, establishment of anecic species was apparently at the expense of epigeic species, which declined four and two-fold in CS and CSW systems, respectively. Although populations of endogeic species were slightly greater in CSW than CS systems, these species were not affected by the earthworm additions. Results suggest that earthworm populations in these agroecosystems are related to disturbance regimes and resource distribution, and are affected by competitive interactions between different functional groups.

Last Modified: 4/19/2015
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