1. ARC Centre of Excellence for Coral Reef Studies, James Cook Univ.; Townsville QLD 4811 Australia
2. US Geological Survey - Nebraska Cooperative Fish and Wildlife Research Unit, Univ. of Nebraska; Lincoln NE 68583 USA
3. Ezemvelo KZN Wildlife, Ithala Game Reserve; Louwsberg 3150 South Africa
4. Centre for African Ecology, Univ. of Witwatersrand 2050; Johannesburg South Africa
5. Stockholm Resilience Centre, Stockholm Univ.; SE-106 91 Stockholm Sweden
6. School of Natural Resources, Univ. of Nebraska; Lincoln NE 68583 USA