Global Change Biol. (2015)

Large numbers of plant species now reside in countries outside of their native range. Although global trade has contributed to the spread of alien species, its impact on the precise movements of plants around the globe has remained unclear.

Hanno Seebens, of the University of Oldenburg, Germany, and colleagues developed a numerical model to assess the influence of bilateral trade on the global movement and distribution of alien plants over the past 60 years, using historical trade, biodiversity and climate data. Their present-day predictions of alien species distributions agree well with observations. The greatest flux of invasive species over this period was from Asia to Europe. However, the establishment of alien species lagged the import of commodities by over 20 years.

Extending their model into the future, the researchers note that large increases in invasive species can be expected in emerging economies over the next two decades, particularly in East Asia and South America. Although climate change may modify the number of invasions over this period, the impact is projected to be small compared with the trade-related increases expected.