Community stability and selective extinction during the Permian-Triassic mass extinction

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Science  02 Oct 2015:
Vol. 350, Issue 6256, pp. 90-93
DOI: 10.1126/science.aab1371

No precedent

Human activities are creating a mass extinction event. The intensity of this event is unprecedented during human times, but there have been several comparable events during Earth's history. Roopnarine and Angielczyk examined one of the largest, the Permian-Triassic Extinction (see the Perspective by Marshall). The structure and diversity of communities were key predictors of stability through the event. Furthermore, extinctions were not random, with smaller-bodied species being more prone to extinction. This pattern is in direct contradiction to the patterns seen in our current extinction. Thus, the current anthropogenically driven extinction is fundamentally different from previous catastrophic extinctions.

Science, this issue p. 90; see also p. 38


The fossil record contains exemplars of extreme biodiversity crises. Here, we examined the stability of terrestrial paleocommunities from South Africa during Earth's most severe mass extinction, the Permian-Triassic. We show that stability depended critically on functional diversity and patterns of guild interaction, regardless of species richness. Paleocommunities exhibited less transient instability—relative to model communities with alternative community organization—and significantly greater probabilities of being locally stable during the mass extinction. Functional patterns that have evolved during an ecosystem's history support significantly more stable communities than hypothetical alternatives.

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