[1] Univ Stellenbosch, Dept Conservat Ecol & Entomol, ZA-7602 Matieland, South Africa
[2] Univ Cape Town, Dept Bot, Leslie Hill Inst Plant Conservat, ZA-7701 Rondebosch, South Africa
[3] Gobabeb Training & Res Ctr, Walvis Bay, Namibia
[4] Univ Hamburg, Biozentrum Klein Flottbeck & Bot Garten, D-22609 Hamburg, Germany