Ecosystems

, Volume 7, Issue 1, pp 45–54

Exotic Earthworm Invasion and Microbial Biomass in Temperate Forest Soils

  • Peter M. Groffman
  • Patrick J. Bohlen
  • Melany C. Fisk
  • Timothy J. Fahey
Article

DOI: 10.1007/s10021-003-0129-9

Cite this article as:
Groffman, P., Bohlen, P., Fisk, M. et al. Ecosystems (2004) 7: 45. doi:10.1007/s10021-003-0129-9

Abstract

Invasion of north temperate forest soils by exotic earthworms has the potential to alter microbial biomass and activity over large areas of North America. We measured the distribution and activity of microbial biomass in forest stands invaded by earthworms and in adjacent stands lacking earthworms in sugar maple-dominated forests in two locations in New York State, USA: one with a history of cultivation and thin organic surface soil horizons (forest floors) and the other with no history of cultivation and a thick (3–5 cm) forest floor. Earthworm invasion greatly reduced pools of microbial biomass in the forest floor and increased pools in the mineral soil. Enrichment of the mineral soil was much more marked at the site with thick forest floors. The increase in microbial biomass carbon (C) and nitrogen (N) in the mineral soil at this site was larger than the decrease in the forest floor, resulting in a net increase in total soil profile microbial biomass in the invaded plots. There was an increase in respiration in the mineral soil at both sites, which is consistent with a movement of organic matter and microbial biomass into the mineral soil. However, N-cycle processes (mineralization and nitrification) did not increase along with respiration. It is likely that the earthworm-induced input of C into the mineral soil created a microbial “sink” for N, preventing an increase in net mineralization and nitrification and conserving N in the soil profile.

Keywords

nitrogen cyclingnitrogen mineralizationnitrificationrespiration

Copyright information

© Springer-Verlag New York, Inc. 2004

Authors and Affiliations

  • Peter M. Groffman
    • 1
  • Patrick J. Bohlen
    • 2
  • Melany C. Fisk
    • 3
  • Timothy J. Fahey
    • 3
  1. 1.Institute of Ecosystem Studies, Box AB, Millbrook, New York 12545USA
  2. 2.Archbold Biological Station, Lake Placid, Florida 33852USA
  3. 3.Department of Natural Resources, Cornell University, Ithaca, New York 14853USA