Hong Yang1, Julian R Thompson2, Roger J Flower2. 1. CEES, Department of Biosciences, University of Oslo, Blindern, 0316 Oslo, Norway. Wetland Research Unit/Environmental Change Research Centre, UCL Department of Geography, University College London, London, WC1E 6BT, UK. hongyanghy@gmail.com. 2. Wetland Research Unit/Environmental Change Research Centre, UCL Department of Geography, University College London, London, WC1E 6BT, UK.