ScienceDaily (Sep. 1, 2011) — It is widely acknowledged that human beings are largely responsible for the widespread alteration of ecosystems on the planet. A recent study by Dara Seidl and Peter Klepeis of Colgate University in New York traces the ways in which humans are the principal agents of dispersal of exotic earthworms in the forests of Northern America.
http://www.sciencedaily.com/releases/2011/09/110901104930.htm