Biological invaders in a greenhouse world:: will elevated CO2 fuel plant invasions?

Climate change and biological invasions, two of the hottest topics in ecology, both have ecological and societal implications, but they have developed on separate and parallel paths. Both are likely to have global impacts, yet researchers seldom explicitly consider their interaction. We argue that changes in atmospheric concentrations of carbon dioxide (CO2) and subsequent climate change may facilitate biological invasions, both directly and indirectly, and that our research agenda to date has left us poorly prepared to predict the consequences for communities and ecosystems. Forecasting the impact of biological invaders or elevated CO2 is a challenge for ecologists, and it is therefore prudent and timely to investigate the greater challenge, namely predicting the combined effects of invaders and elevated CO2 on native ecological systems.