Richard - your question is the ever present important one. Perhaps we should be considering human population issues versus always culling the herds of animals because of their encroachment. Birth control is a topic, and in Kenya, your worth with some tribes is the size of your family along with the herd numbers. We continue to punish the animals for healthy reproduction, but no punishment for healthy human reproduction. By punishment, I mean control and of birth rates. 

Outside of this, better and proactive monitoring of animal population growth allows for strategic planning, not reaction based conservation. I sense that herd numbers are allowed to grow because it offers a way to make money perhaps off culling practices. It costs money to relocate animals, far more expensive than culling. However, South Africa may soon find itself in a situation equal to its friends in the northern Range states where dramatic numbers of animals are being lost. It will only be a matter of time. Once herds are decimated in certain areas due to habitat loss, human/conflict, and poaching, the demand for ivory will continue its trek south. If it doesn't, then we need to ask why not.

My belief is that you have to have human population control, innovative land and habitat management, the ability to naturally control birth rates in elephants (which is reversible when appropriate), proactive monitoring of population growth, and strategic agreements between other range states who are losing elephants to perhaps relocate families from areas of surplus to areas of loss. This could enable excellent trade agreements, revenue models surely would be innovative. Much of elephant conservation today is reactive. That needs to change.

At the end of all of this, my opinion is that humans are the source of the problem, not the animals, yet they bear the brunt of the punishment. With no predators in sight for humans, what will we change in our behavior to co-exist effectively?