Rarity Value and Species Extinction: The Anthropogenic Allee Effect

Standard economic theory predicts that exploitation alone is unlikely to result in species extinction because of the escalating costs of finding the last individuals of a declining species.

Researchers argued that the human predisposition to place exaggerated value on rarity fuels disproportionate exploitation of rare species, rendering them even rarer and thus more desirable, ultimately leading them into an extinction vortex.

They presented a simple mathematical model and various empirical examples to show how the value attributed to rarity in some human activities could precipitate the extinction of rare species—a concept that they call the anthropogenic Allee effect.

The alarming finding that human perception of rarity can precipitate species extinction has serious implications for the conservation of species that are rare or that may become so, be they charismatic and emblematic or simply likely to become fashionable for certain activities.

Courchamp F, Angulo E, Rivalan P, Hall RJ, Signoret L, et al. 2006 Rarity Value and Species Extinction: The Anthropogenic Allee Effect. PLoS Biol 4(12): e415. doi:10.1371/journal.pbio.0040415

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