beginning in 1500, with the associated movement of people 
and goods, and industrialization from 1850 resulted in the 
transport and introduction of alien species and were 
historically important. Increases in global trade since 1950 
have resulted in unprecedentedly high and increasing 
27SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
A GLOBAL DISTRIBUTION OF ESTABLISHED ALIEN SPECIES 