From the Asian tiger mosquito in the American South, to the Eurasian zebra mussel in the Great Lakes, to European quackgrass throughout the United States,
invasions of non-native species can disrupt ecosystems, cause havoc with local economies, and even threaten health. To test the relative weight of human versus other ecologic factors on freshwater fish invasions, Fabien Leprieur and colleagues collated species data on over 1,000 river basins throughout the world (collectively draining over 80% of Earth''s land surface), characterizing each species as
native or non-native. In these areas, more than a quarter of species were non-native, and they had higher-than-average
numbers of native species threatened by extinction. There was no correlation between the richness of native species and that of non-natives, at once refuting
biotic acceptance (for which high numbers of
natives predict high numbers of non-natives) and biotic resistance (for which high numbers of natives predict low numbers of non-natives).
More abstracts about the Human Activity, not Ecosystem Characters, Drives Potential Species Invasions