I spotted this piece by conservationist Dr Ian Player yesterday on the rhino poaching issue.
Daily News

Rhino species in Africa have undergone a precipitous decline in the last century. Cunningham and Berger[1] note that around 1900 there were perhaps 100,000 black rhinos in Africa. By 1960 it was 60,000. By the 80s it was extinct in Sudan, Ethiopia and Somalia. The continent had 3,500 left. In 1993, Zimbabwe revised down its extimated population of 2000 animals (1991) to 250.

While white rhinos have done a little better, Southern Africa is undergoing a resurgent poaching problem. In 2010, 333 rhinos were killed. By September this year 285 have already been killed.

Like many other charismatic species (like tigers), decades-old efforts to deter poaching have failed. This has prompted Player to suggest we should start debating the legal trade issue again. This is a brave step to take, as often in the conservation-world, suggesting we debate the feasibility of market-policies against poachers, means the person is in favour of carte blanche open-trade.

The reality is we have a policy based entirely around law-enforcement that is failing. And we have people refuse to debate whether legal trade could deter poaching. Again, I don't know whether the trade mechanism Player suggests (using horns from rhinos that have died naturally) will be effective.

What concerns me more is that so many conservationists refuse to debate these issues. Poaching syndicates have become sophisticated, violent, international criminal organisations. They're branched out into other markets. Rangers risk their lives to try to stop poachers. Yet so many people have decided that trade somehow will fuel demand or that Asian consumers base their purchase decision on whether Western conservationists approve of the market. There are some good reasons why trade could fail. But there are a lot of bad reasons that have become part of conservationist-folklore that do need better scrutiny.

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[1] Cunningham, C. and Berger, J. (1997). Horn of Darkness: Rhinos on the Edge. Oxford University Press, New York, Oxford.