The Tragedy of the Commons and Evolutionarily Stable Strategies (ESS)

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What is the Tragedy of the Commons?

The Tragedy of the Commons is an often encountered issue regarding the management of a fixed limited resource. Basically, given free access, individuals acting in their own self-interest will deplete a shared resource in an attempt to benefit themselves. The classic example of this dilemma, first proposed by the ecologist Garret Hardin, would be cattle ranching in the American West. Without property ownership, public grasslands are quickly depleted as ranchers try to maximize their herds for maximum profit. This overuse is unsustainable and results in the destruction of the resource -- this hurts everyone, especially those who did not contribute to the resource's over exploitation. When grasslands are owned by the ranchers themselves, care is taken to ensure that herd sizes stay smaller and that the land is preserved so that they can all continue to profit.

A more modern example would be the Earth's atmosphere. Since the atmosphere is a public good, a few can profit by freely emitting carbon dioxide at the expense of others. This, however, is a much more complex problem.

In humans, the Tragedy of the Commons can be solved, albeit sometimes painfully, through governance. This typically involves private ownership (as seen in the cattle ranching example), taxation, and by policing misuse of the good (through punishments such as fines or imprisonment).

Tragedy of the Commons and ESS

Competition and conflict between individuals that are acting to maximize their own fitness can result in evolutionarily stable strategies that are exploitative by nature. Natural Selection does not operate for the good of the species, or for the species' continued survival for that matter. It merely selects for the most fit individuals at that particular time and cannot predict and avoid resource depletion. If an ESS comes into play that is particularly exploitative, it can result in "evolutionary suicide", or the extinction of the species due to evolution.

Luckily, according to the biologist Rankin, the reduced fecundity and lower survival caused by increased conflict over scarce resources often keeps a species population low enough to avoid the depletion of the common resource. (Rankin 2007)

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