1. South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont, South Africa
2. Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
3. Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Rondebosch, South Africa
4. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa