Invasive Species

Ginseng in multiflora rose tangle

Non-native plants are continually being introduced into natural ecosystems. These introductions occur by accident, when non-native species hitchhike to the U.S. on ships, planes, cars, or people. Quite frequently, however, non-native species are intentionally introduced. A good example of this is the use of non-native species as ornamentals for lawn and garden beautification. Of all the non-native species in the U.S., a few will demonstrate extreme vigor and competitive ability in their new habitat, and are referred to as invasive species. Famous examples of invasive species include: kudzu, garlic mustard, Japanese honeysuckle, and multiflora rose. The debate is ongoing concerning what characteristics allow particular non-native species to become invasive. Whatever the cause, invasives represent a major threat to native biodiversity in the U.S. due to their ability to outcompete native species. Once established, invasives often form dense, monotypic stands that prevent native re-establishment in the area.

Many invasive species have been found in the ginseng populations that we monitor, including multiflora rose, Japanese barberry and garlic mustard1. Detailed experimental studies of garlic mustard’s effects on ginseng show strong effects on mortality of seedlings, but limited effects on growth of seedlings or established plants2. Much is yet to be learned about the impacts of specific invasive species on native plants, including ginseng.

References

1Wixted and McGraw 2008
2Wixted and McGraw 2010