Louis Theroux reports on the market in big-game hunting in South Africa: you can pay up to $100,000 for the right to kill a rhino.
Commonsense economics says this is the way to conserve wildlife. If a farmer is given ownership rights over the rhinos on his land and the right to charge hunters to kill rhino, he'll take care to breed rhinos and protect them from other hunters. The result will be more rhinos than if rhinos are unowned - because then the tragedy of the commons will ensure they are hunted to extinction.
Sure enough, some economists have indeed found that private ownership is a great way of conserving wildlife.
Sounds simple. But there's a problem. Property rights have to be enforced. As Theroux points out, that means fencing farms in. And that can be expensive. As this paper (pdf) describes, property rights don't arise from nothing - they only exist if the (private) benefits of establishing them outweigh the costs.
Worse, migratory animals can't be enclosed. And as they migrate, they'll be killed. This paper (pdf) describes how this is a problem for wildebeest in the Serengeti. And it was probably the reason why American bison were hunted almost to extinction in the 1880s; it was just impossible to create private property rights in them.
So, property rights are great in theory. But the practice of creating and maintaining them is a little trickier.