The study, published in PNAS and led by Hanno Seebens from Senckenberg Biodiversity and Climate Research Centre (BiK-F) with participation of Franz Essl at the University of Vienna, and scientists at UCL, analysed a global database of 45,984 records detailing the first invasions of 16,019 established alien species from 1500 until 2005 to investigate the dynamics of how alien species spread worldwide. Between the years 2000 and 2005, one quarter of records are of species that had not previously been found anywhere as an alien, which is a worryingly high proportion.

For plants, mammals, and fishes, the proportion of newly emerging alien species has remained constant during the last 150 years but the total number of alien species has increased.

Seebens, H. et al. (2018): Global rise in emerging alien species results from increased accessibility of new source pools. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1719429115