No saturation in the accumulation of alien species worldwide
Although research on human-mediated exchanges of species has substantially intensified
during the last centuries, we know surprisingly little about temporal dynamics of alien species
accumulations across regions and taxa. Using a novel database of 45,813 first records of
16,926 established alien species, we show that the annual rate of first records worldwide has
increased during the last 200 years, with 37% of all first records reported most recently
(1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the