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Short-circuiting an Invasional Meltdown

Photo of Immature leaves and fruits of the exotic invasive shrub, Chinese privet. James Miller and Ted Bodner, Southern Weed Science SocietyImmature leaves and fruits of the exotic invasive shrub, Chinese privet. James Miller and Ted Bodner, Southern Weed Science SocietySnapshot : Chinese privet is an invasive plant species in flood plain forests of the southeastern U.S., in some cases occupying up to 80 percent of available riparian floodplain forest habitat. Non-native invasive earthworm species are found in the same soils where Chinese privet is abundant. In this study, Forest Service scientists showed that five years after removal of the plant, there were lower numbers of certain invasive earthworm species, and a simultaneous recovery in numbers of native species.

Principal Investigators(s) :
Callaham, Mac 
Research Location : Oconee River watershed in northeast Georgia, various ownerships including Oconee National Forest.
Research Station : Southern Research Station (SRS)
Year : 2014
Highlight ID : 708


When one invasive species promotes the establishment of other invasive species it's called an invasional meltdown. Forest Service scientists observed that soils underlying the invasive plant, Chinese privet, had much higher numbers of non-native invasive earthworms than soils where the plant was not yet established. The scientists conducted an experiment to see what would happen if the Chinese privet was removed, using two different techniques: simply cutting the privet with power saws, or grinding the privet into mulch and leaving the mulch on the soil surface. Five years after the removal of the plant, they found lower numbers of the most abundant non-native earthworm species. Perhaps more importantly, removal of privet appeared to promote the recovery of one North American native earthworm species. When Chinese privet was removed, the level of acidity in soils increased nearly to levels of soils where privet had not yet invaded (soils in the floodplains of southeastern rivers are naturally highly acidic), and the scientists think that these changes in acidity are large enough to be a disadvantage to the invasive species and favorable for the native species. They conclude that the removal of one invasive species can result in the control of another, and thus short-circuits the invasional meltdown that the expansion of Chinese privet causes.

Forest Service Partners

External Partners

  • Oconee National Forest
  • Dr. Paul F. Hendrix, University of Georgia, Odum School of Ecology

Program Areas