Predicting plant invasions in an era of global change.

The relationship between plant invasions and global change is complex. Whereas some components of global change, such as rising CO2, usually promote invasion, other components, such as changing temperature and precipitation, can help or hinder plant invasion. Additionally, experimental studies and models suggest that invasive plants often respond unpredictably to multiple components of global change acting in concert. Such variability adds uncertainty to existing risk assessments and other predictive tools. Here, we review current knowledge about relationships between plant invasion and global change, and highlight research needed to improve forecasts of invasion risk. Managers should be prepared for both expansion and contraction of invasive plants due to global change, leading to increased risk or unprecedented opportunities for restoration. 2009 Elsevier Ltd. All rights reserved.