A global study published in Ecological Letters shows with hitherto unmatched differentiation the extent to which non-native plants have spread to oceanic and coastal islands over the last 5,000 years. Researchers at the University of Bayreuth and at universities and research institutes in Great Britain, Norway, Austria, Spain, Australia and New Zealand have compiled a dataset covering the vegetation of 29 islands. This was based on analyses of fossil pollen and the current state of research on the classification of plants as native or non-native.