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

Affiliations
  • 1School of Earth and Environment, University of Leeds, Leeds, UK. a.dunhill@leeds.ac.uk.
  • 2School of Earth and Environment, University of Leeds, Leeds, UK.
  • 3School of Biology, University of Leeds, Leeds, UK.
  • 4School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton, UK.
  • 5Department of Life Sciences, Natural History Museum, London, UK.
  • 6Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA.
  • 7Santa Fe Institute, Santa Fe, NM, USA.
  • 8Leeds Museums and Galleries, Leeds, UK.
  • 9School of Biosciences, Ecology and Evolutionary Biology, University of Sheffield, Sheffield, UK.

Published on:

October 4, 2024

Abstract

Mass extinctions are considered to be quintessential examples of Court Jester drivers of macroevolution, whereby abiotic pressures drive a suite of extinctions leading to huge ecosystem changes across geological timescales. Most research on mass extinctions ignores species interactions and community structure, limiting inference about which and why species go extinct, and how Red Queen processes that link speciation to extinction rates affect the subsequent recovery of biodiversity, structure and function. Here, we apply network reconstruction, secondary extinction modelling and community structure analysis to the Early Toarcian (Lower Jurassic; 183 Ma) Extinction Event and recovery. We find that primary extinctions targeted towards infaunal guilds, which caused secondary extinction cascades to higher trophic levels, reproduce the empirical post-extinction community most accurately. We find that the extinction event caused a switch from a diverse community with high levels of functional redundancy to a less diverse, more densely connected community of generalists. Recovery was characterised by a return to pre-extinction levels of some elements of community structure and function prior to the recovery of biodiversity. Full ecosystem recovery took ~7 million years at which point we see evidence of dramatically increased vertical structure linked to the Mesozoic Marine Revolution and modern marine ecosystem structure.

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