Optimising the offtake of large herbivores from a multi-species community

The Natal Parks Board annually sells hunting licences for the Controlled Hunting Area (CHA) adjacent to the Mkuzi Game Reserve. A management objective is to maximise the revenue obtained from these hunting activities while ensuring that the population of each species is kept above some minimum level. This management problem is formulated as a linear programming problem and solved for the fourteen different species in the CHA. The LP problem is formulated in such a way as to utilise the same data that is the basis for present management decision-making. jective function takes into account that animals are hunted for both meat and trophies. Only a fraction of each population is suitable for trophy hunting and higher prices are usual for such animals. The model considers fourteen species divided according to their food preferences into four groups. There is a carrying capacity constraint which limits the weighted sum of the populations in each of these groups. Further constraints relate to the specific growth rates of each species. timal equilibrium population levels were calculated to serve as goals or targets. However, droughts and other natural phenomena which affect population numbers are frequently encountered at Mkuze. A number of experiments were therefore performed where the populations were set to reduced levels. The optimal control problem which steers the populations towards the target levels in an optimal way was formulated. Some illustrative solutions are presented.