1. Department of Biology, Duke University, Durham, North Carolina 27708, USAebernhar@duke.edu
2. Corresponding author. Centre for Riverine Landscapes, Griffith University, Queensland, Australia 4111, s.bunn@griffith.edu.au
3. Patrick Center for Environmental Research, Academy of Natural Sciences, Philadelphia, Pennsylvania USA hart@acnatsci.org
4. Ecology and Environmental Science, Umeå University, Swedenbjorn.malmqvist@emg.umu.se
5. Department of Biology, University of Oulu, Finlandtimo.muotka@ymparisto.fi
6. School of Aquatic and Fishery Sciences, University of Washington, Washington, USAnaiman@u.washington.edu
7. Institute of Ecology, University of Georgia, Athens, GeorgiaUSAcpringle@uga.edu
8. Office of History, US Army Corps of Engineers, USAmartin.a.reuss@hq02.usace.army.mil
9. Centre for Invasion Biology, CSIR Division of Water, Environment and Forestry Technology, P.O. Box 320Stellensbosch, 7599, South Africabvwilgen@csir.co.za