Extinction cascades, community collapse, and recovery across a Mesozoic hyperthermal event

Area of Science:

• Paleontology
• Macroevolutionary biology
• Ecosystem dynamics

Background:

• Mass extinctions are key drivers of macroevolution, yet research often overlooks species interactions and community structure.
• Understanding extinction causes and Red Queen dynamics is crucial for inferring biodiversity recovery patterns.

Purpose of the Study:

• To analyze the Early Toarcian (Lower Jurassic) Extinction Event and subsequent recovery using network and community structure analysis.
• To investigate the role of species interactions and secondary extinctions in shaping post-extinction ecosystems.

Main Methods:

• Network reconstruction
• Secondary extinction modeling
• Community structure analysis
• Applied to the Early Toarcian (183 Ma) Extinction Event

Main Results:

• Primary extinctions of infaunal guilds triggered secondary extinction cascades to higher trophic levels.
• The extinction event shifted communities from diverse and redundant to less diverse and more connected generalist assemblages.
• Ecosystem function and structure partially recovered before biodiversity, with full recovery taking ~7 million years.

Conclusions:

• Species interactions and secondary extinctions significantly influenced the Early Toarcian mass extinction's impact and recovery.
• Ecosystem recovery dynamics involve complex changes in community structure and function preceding full biodiversity restoration.
• The event preceded increased vertical structure, linking to the Mesozoic Marine Revolution and modern marine ecosystems.