Fish invasions in the world's river systems: when natural processes are blurred by human activities

"Researchers have found that invasions of exotic fish species in rivers and lakes is related closely to high economic growth, higher human population density and nearby urbanised land. This raises serious concerns for the future of many aquatic ecosystems as the rate of global economic expansion continues to rise, predicting an increase in invasive species and, with it, an increase in the extinction of native animals.", in PLoS Biology, v.6(2)(2008)