Accelerated mass extinction in an isolated biota during Late Devonian climate changes.

Area of Science:

• Paleontology
• Evolutionary Biology
• Climate Science

Background:

• Global environmental disturbances, such as climate change, drive extinction risk.
• Geographic isolation limits species' ability to migrate to refugia, increasing extinction vulnerability.
• Inferred thermal tolerance has been a key predictor of extinction during past climate change events.

Purpose of the Study:

• To investigate the intersection of different extinction risk factors in the Appalachian Foreland Basin brachiopod fauna.
• To analyze extinction patterns during the two pulses of the Frasnian-Famennian mass extinction (Late Devonian, ~372 Ma).

Main Methods:

• Analysis of the fossil record, specifically the well-preserved brachiopod fauna from the Appalachian Foreland Basin.
• Assessment of extinction selectivity in relation to climate change (cooling) as a primary kill mechanism.
• Comparison of extinction severity between endemic species and other regions.

Main Results:

• Extinction patterns are consistent with cooling climate change as the main driver.
• The extinction event was relatively mild in this region compared to others, despite a high number of endemic species.
• Vulnerable taxa experienced rapid extinction during the first pulse, rendering the second pulse insignificant for this group.

Conclusions:

• Vulnerable species in geographically isolated biotas face increased extinction risk at the onset of environmental stress.
• Species in other regions may experience elevated extinction risk if environmental stress is repeated or intensified.
• The timing and nature of environmental disturbances significantly influence extinction patterns and vulnerability.