1. School of Agriculture, Earth and Environmental Sciences; Centre for Invasion Biology; University of KwaZulu-Natal; Private Bag X1 Scottsville 3209 South Africa
2. Department of Zoology and Entomology; Centre for Invasion Biology; University of Pretoria; Private Bag X1 Pretoria 0002 South Africa
3. Department of Botany and Zoology; Centre for Invasion Biology; Stellenbosch University; Private Bag X1 Matieland 7602 South Africa
4. Invasive Species Programme; South African National Biodiversity Institute; Kirstenbosch Research Centre; Claremont 7735 South Africa
5. Department of Mathematical Sciences; Centre for Invasion Biology; Stellenbosch University; Private Bag X1 Matieland 7602 South Africa
6. Mathematical and Physical Biosciences; African Institute for Mathematical Sciences; Muizenberg 7945 South Africa
7. Division of Conservation Biology, Vegetation and Landscape Ecology; University of Vienna; Rennweg 14 1030 Vienna Austria
8. School of Agriculture, Earth and Environmental Sciences; University of KwaZulu-Natal; Private Bag X1 Scottsville 3209 South Africa