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Permian-Triassic mass extinction and paleocommunity stability

Ben Creisler

New papers in Science:

Peter D. Roopnarine and Kenneth D. Angielczyk (2015)
Community stability and selective extinction during the
Permian-Triassic mass extinction.
Science 350 (6256):  90-93.
DOI: 10.1126/science.aab1371

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.


Charles R. Marshall (2015)
How stable are food webs during a mass extinction?
Science 350 (6256): 38-39
DOI: 10.1126/science.aad2729

As we confront the reality of the ongoing human-driven mass extinction
(1), attention often focuses on the response of individual species to
environmental change. However, species survival also depends on other
species in the food web: Changing population numbers or extinction of
one species can propagate through the food web to cause further
perturbation or extinction. Although this has long been appreciated
(2), it is hard to test predictions of how food webs of living
ecosystems will be affected by disturbance. The fossil record provides
a window into how past food webs have responded to mass extinction. On
page 90 of this issue, Roopnarine and Angielczyk (3) assess food web
stability of the remarkably well-preserved terrestrial communities of
the Karoo Basin in South Africa across the largest past mass
extinction, the Permian-Triassic event (∼252 million years ago).