Plot reporting the number of articles and fitted linear regression obtained using the following search strings in Google Scholar at the end of October 2019: In red: “negative * of alien species “ OR “negative * of non-native species “ OR “negative * of exotic species” OR “costs of alien species “ OR “costs of non-native species “ OR “costs of exotic species”; In green: “positive * of alien species “ OR “positive * of non-native species “ OR “positive * of exotic species” OR “benefits of alien species “ OR “benefits of non-native species “ OR “benefits of exotic species”.