1. Department of Botany Rhodes University Grahamstown South Africa
2. Biodiversity Risk Management, Department of Forestry, Fisheries and the Environment Pretoria South Africa
3. School for Climate Studies and Global Change Biology Group, Department of Botany & Zoology Stellenbosch University Matieland South Africa
4. Plants, Photosynthesis and Soil, School of Biosciences The University of Sheffield Sheffield UK