Weedy Advantage

New research shows that two key causes of plant invasion act in concert. They are escape from natural enemies and increases in plant resources. This study shows that fast-growing, weedy exotic species have a double advantage in today's world. Increases in resources enable them to out compete slow-growing plants. An escape from an unusually large number of enemies enables them to out compete even fast-growing native plants.

The research also found that global change is likely to exacerbate invasion by exotic plants. As global change proceeds, continuing increases in resource availability are likely to exacerbate such plant invasions.

Fast-growing weedy species thrive in environments with ample plant resources. And global change increases key plant resources, such as carbon dioxide and soil nitrogen, through increases in the greenhouse gases carbon dioxide and nitrous oxide, respectively.