When you see an invasive plant monoculture developing – a forest understory carpeted with invasive garlic mustard for example – you can get
discouraged and think that native plants have no chance. A recent study offers some encouraging news. A University of Georgia researcher, Richard Lankau, found that native clearweed plants (Pilea pumila) have evolved resistance to invasive garlic mustard (Alliaria petiolata).
For some time, scientists have studied garlic mustard and its ability to suppress native species in an invaded community with biochemical weapons not present in North American ecosystems. Cantor et al. 2006. For example, garlic mustard emits allelochemicals into the soil that suppress fungi that help native plants extract nutrients from the soil. The University of Georgia study indicates that native clearweed has developed resistance to these allelochemicals in areas where garlic mustard and clearweed have coexisted for a long time. A fuller explanation of the study appears in UGA Today.