1. Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
2. Department of Space Science and Applied Physics, Faculty of Science, University of Zimbabwe, MP167, Mt Pleasant, Harare 00263, Zimbabwe
3. Oppenheimer Fellow in Functional Biodiversity, Centre for Functional Biodiversity, School of Life Science, University of Kwazulu-Natal, Pietermaritzburg 3209, South Africa
4. Department of Genetics, School of Genetics, Evolution & Environment, University College, London WC1E 6BT, UK