MODELS FOR THE CONTROL OF FERAL WATER-BUFFALO (BUBALUS-BUBALIS) USING CONSTANT LEVELS OF OFFTAKE AND EFFORT

A model of population growth of feral water buffalo is presented and used as a basis for simulating buffalo control exercises. Simulations incorporated annual removal of constant numbers of buffalo, annual allocations of constant amounts of control effort, or continous application of effort until control density had been achieved. The models rely on data from helicopter-based shooting and shooting by shooters on the ground (Bayliss 1986). Approximately 60% of a starting population had to be removed per annum for control to extinction to be achieved within two years. Annual allocations of constant levels of control effort resulted in failure to reach the control target within 150 years, control in about 40 years, or control within the first two years of operation, depending on the level of effort expended. Addition of two helicopters to a team of four helicopters working for 20 days changed the result from no control to control within two years. Optimal allocation of control effort requires continuous application of control measures until the objective has been achieved. Lower levels of effort result in prolonged campaigns that may not achieve desired objectives.