Overthe course of the last two centuries, numbers of biological invasions have steadily increased globally. A newly developed mathematical model indicates that trend is likely to continue. Numbers of invasions will increase by 36 percent between 2005 and 2050, with forecasts suggesting that Europe is likely to experience the most biological invasions, followed by Asia, North America, and South America.

Virtually every corner of the world has been affected by invasive species representing a variety of types of animals and plants. Over time, movement of species from one continent may deplete the supply of potentially new invasive species. A Northern Research Station scientist was part of global team of scientists that developed a mathematical model basedon historical records of invasions that accounts for source pools of invasive species in different world regions. The study delivers a first baseline for the assessment of future developments of biological invasions, information that will support decision-making related to containing the spread of alien species. The model predicts that even though the supply of available species will decline, invasions of most types of organisms will continue at high rates in the future. Overall numbers over invasive species were predicted to increase globally by 36percentfrom 2005 to 2050.Particularly high numbers of new invasions were projected for Europe (2,543 new species) followed by temperate Asia (1,597), North America (1,484),and South America (1,391). Especially high numbers of invasions are projected for invertebrates globally. These forecasts provide information about future invasions that inform policies to contain the spread of alien species worldwide.