Athens, Ga. Invasive species such as kudzu, privet and garlic mustard can devastate ecosystems, and, until now, scientists had little reason to believe that native plants could mount a successful defense.
A new University of Georgia study shows that some native clearweed plants have evolved resistance to invasive garlic mustard plantsand that the invasive plants appear to be waging a counterattack. The study, published in the early edition of the journal Proceedings of the National Academy of Sciences, is thought to provide the first evidence of coevolution between native and invasive plant species.
"The implications of this study are encouraging because they show that the native plants aren't taking this invasion lying down," said study author Richard Lankau, assistant professor of plant biology in the UGA Franklin College of Arts and Sciences. "It suggests that if you were to take a longer viewa timescale of centuriesthat exotic species could become integrated into their communities in a way that is less problematic for the natives."
Garlic mustard (Alliaria petiolata) was introduced to the U.S. from Europe roughly 150 years ago first in New York and Virginia and then to the Chicago area. The noxious plant continues to spread rapidly throughout the Northeast, Midwest and Southeast. "It's a pretty well-hated plant," Lankau said, because it can form dense carpets in forest understories and, even after being physically removed from an area, can reestablish itself within a year.
Much of the plant's success is a result of the chemical warfare it wages with a compound known as sinigrin, which kills fungi that help native plants extract nutrients from the soil. The chemical is relatively new to North America, and this novelty gives garlic mustard a huge competitive advantage.
Through a series of greenhouse and field experiments conducted over three years in five states, Lankau has shown that invasive garl
|Contact: Richard Lankau|
University of Georgia