Biological Invasions

, Volume 13, Issue 2, pp 349–358 | Cite as

Spatial variability of an invasive earthworm (Amynthas agrestis) population and potential impacts on soil characteristics and millipedes in the Great Smoky Mountains National Park, USA

  • Bruce A. SnyderEmail author
  • Mac A. CallahamJr.
  • Paul F. Hendrix
Original Paper


European and Asian earthworm invasions are widespread in North America. European earthworms especially are well-known to cause dramatic changes in ecosystems in northern, formerly glaciated portions of the continent, but less is known about the impacts of earthworm invasions in unglaciated areas inhabited by indigenous earthworms. We monitored fluctuations in the spatial extent of an Amynthas agrestis (Megascolecidae) population in the Great Smoky Mountains National Park in eastern Tennessee, USA. Two years of monthly growing-season observations revealed that the distribution of the earthworm population was dynamic, but overall distribution was closely linked to temperature and moisture with dramatic reductions of earthworm numbers associated with very dry conditions. In plots where A. agrestis were more often detected, we measured increased A-horizon soil aggregation and decreased thickness of the Oe/Oa-horizon. However, A. agrestis was not related to A-horizon microbial biomass, A-horizon C:N, Oi-horizon (litter) thickness, or mass of forest floor (O-horizon). Reductions in millipede species richness and density were associated with frequency of A. agrestis presence, possibly due to direct competition for food resources (Oe/Oa material). This evidence for potentially negative interactions between millipedes and A. agrestis suggests that expansion of the non-native earthworm into new habitats in the Park may alter soil physical properties and could pose a threat to native millipede diversity.


Earthworm Amynthas Invasive species Millipede Soil aggregation 



Amynthas invasions in GSMNP were first reported to us by K. Langdon and B. Nichols (National Park Service Inventory & Monitoring) to whom we are grateful for logistical and intellectual support throughout this study. We also acknowledge: NPS volunteer B. Lochbaum for GPS location of our plot arrays; C. Lawson (Western Carolina University, WCU) for surveying plot elevations; J. Craft and S. Ferrell (WCU) for vegetation surveys; T. Maddox and the Odum School of Ecology Analytical Lab for chemical analysis; and the staff of the Great Smoky Mountains National Park and Great Smoky Mountains Institute at Tremont for their enthusiastic assistance. J. Blackmon, W. Duncan, K. Jacobsen, and two anonymous reviewers provided helpful comments on the manuscript. Field collecting would not have been possible without the help of many, many field assistants, who could not all be named here. This research was permitted under study number GRSM-00337 and supported by National Science Foundation grant number 0236276 to the University of Georgia Research Foundation, Inc.


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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Bruce A. Snyder
    • 1
    • 2
    Email author
  • Mac A. CallahamJr.
    • 3
  • Paul F. Hendrix
    • 1
    • 4
  1. 1.Odum School of EcologyUniversity of GeorgiaAthensUSA
  2. 2.Division of BiologyKansas State UniversityManhattanUSA
  3. 3.Center for Forest Disturbance Science, Southern Research StationUSDA Forest ServiceAthensUSA
  4. 4.Department of Crop & Soil ScienceUniversity of GeorgiaAthensUSA

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