1. Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa
2. Compton Herbarium, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, South Africa
3. Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag X7, Claremont, Cape Town 7735, South Africa