Monday, 13 September 2010

Cooperation to save species

In a recent paper Frank and Sarkar apply game theory to enhance conservation efforts. Their examples include the wild dogs in South Africa, red grouse and raptors in Britain and the conservation of coral reefs near the Philippenes. I find the application thrilling, though the game theory is not completely correct.
In the case of the wild dogs, the example best developped, the game is between conservationists, who initiated a reintroduction programme for wild dogs in a national park, and the local herders, who fear attacks on their live stock. Presently conservationists make great efforts to increase wild dog populations, while the locals kill the animals that leave the national park. Remarkably, if both changed their actions, the number of wild dogs would be about the same (so the herders would not suffer more), but it would be a lot less costly for the conservationists. We have a prisoners' dilemma, with room for cooperation. The authors do not mention cooperative games or the core, but they practically suggest core outcomes in a TU-game to solve the conflict: the conservationists should spend their money on supporting farmers, who would then appreciate the wild dogs more.

I find the second story less inspiring, but the third problem is also interesting - unfortunately with less good news. Here the problem is in the coral reefs near the Philippines that are suffering from overfishing and in particular from fishing with explosives. While this technique is illegal, it is a more efficient technology. While conservationists are naturally unhappy with these developments, the conflict is a common pool resource problem among the fishermen. Yet again, this problem can be seen as a multiplayer prisoners' dilemma, where cooperation could yield a much better payoff for all, while each individual has an incentive to continue overfishing. Frank and Sarkar suggest that there is a tipping point at the level of cooperation: under this fishermen suffer (especially those cooperating), above it, the situation becomes more efficient, although here the defectors will still benefit more. What they do not study is the stability of such a situation. This is a pity, especially given that Funaki and Yamato (1999) have studied the very same problem in detail (to which I added some additional insights for special cases (Kóczy, 2002)).

Frank DM, Sarkar S (2010) Group Decisions in Biodiversity Conservation: Implications from Game Theory. PLoS ONE 5(5): e10688. doi:10.1371/journal.pone.0010688

Funaki Y, Yamato, T (1999)  The Core of an Economy with a Common Pool Resource: A partition function form approach. International Journal of Game Theory 28, 157-171. doi: 10.1007/s001820050010

Kóczy LÁ (2002) A Note on Funaki and Yamato's Tragedy of the Commons, Centre for Economic Studies Discussion Paper 02/17, Catholic University Leuven, Belgium

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