Stefan Krause, School of Geography, Earth and Environmental Science, University of Birmingham, UK and LEHNA — Laboratoire d’Ecologie des Hydrosystèmes Naturels et Anthropisés, Universitè Claude Bernard Lyon 1, France. David M. Hannah, School of Geography, Earth and Environmental Science, University of Birmingham, UK. Nancy B. Grimm, School of Life Sciences, Arizona State University, Tempe, USA.