Unintended Consequences meet Tragedy of the Commons

A decade ago, the saiga antelope seemed so secure that conservationists
fighting to save the rhino from poaching suggested using saiga horn in
traditional Chinese medicines as a substitute for rhino horn.

Research commissioned by WWF at the Chinese University of Hong Kong in the
late 1980s found it to be as effective as rhino horn in fighting fevers, and in
1991 WWF began a campaign in Hong Kong to publicise it as an alternative. The
following year, the UN Environment Programme appointed WWF ecologist Esmond
Bradley Martin as its "special envoy" to persuade pharmacists across Asia to
adopt saiga horn (New Scientist print edition, 9 March 1991 and 3 October
1992).

And the result?

In 1993, over a million saiga antelopes roamed the steppes of Russia and
Kazakhstan. Today, fewer than 30,000 remain, most of them females. So many males
have been shot for their horns, which are exported to China to be used in
traditional fever cures, that the antelope may not be able to recover
unaided.

The tragedy here is that diversion would have been a good idea had the WWF understood some economics – for diversion to work you must divert to a privately owned resource. 

Hat tip to MetaFilter.