1. Department of Geography, Namur Centre for Complex Systems, and Namur Interdisciplinary Research Group for Sustainability, Faculty of Sciences, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium; and Geography and the Lived Environment, School of GeoSciences, The University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, Scotland
2. Geography and the Lived Environment, School of GeoSciences, The University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, Scotland
3. Department of Geography, University of Louvain, Place Louis Pasteur 3, 1348 Louvain-la-Neuve, Belgium