[1] S African Natl Biodivers Inst, Kirstenbosch Res Ctr, ZA-7735 Claremont, South Africa
[2] Univ Cape Town, Percy Fitzpatrick Inst African Ornithol, ZA-7701 Rondebosch, South Africa
[3] Univ Stellenbosch, Ctr Invas Biol, ZA-7602 Matieland, South Africa
[4] Univ Cape Town, Leslie Hill Inst Plant Conservat, ZA-7701 Rondebosch, South Africa
[5] Ctr Appl Biodivers Sci, Conservat Int, Washington, DC 20036 USA