1. Ecosystem Management Program, Centre for Sustainable Resources, Department of Wildlife and Aquatic Resources, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
2. Department of Crops and Soil Sciences, Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
3. Ecoexist Project, Maun, Botswana
4. Ecology and Conservation Biology, Texas A & M University, College Station, Texas, USA