FOR IMMEDIATE RELEASE
16 April 2025
The Geological Society of America
Release No. 25-05
Contact: Katie Busser
+1-303-357-1044
kbusser@geosociety.org

New Fossil Evidence from Australia Reveals How Earth's Worst Mass Extinction Reshaped Life on Land

Boulder, Colo., USA: Around 250 million years ago, Earth experienced its most severe mass extinction event. Over 80% of marine animals became extinct, but the impact of this event on terrestrial ecosystems is less understood—until now. New findings published in GSA Bulletin unveil how this extinction impacted plant communities and shaped their recovery. “We’ve developed this new model that could explain what happened on the terrestrial side of things after this great mass extinction,” says lead author and Ph.D. student Marco Amores.

The international team of researchers from University College Cork (Ireland), the University of Connecticut (USA), and the Natural History Museum of Vienna (Austria) conducted their investigation in the Sydney Basin of eastern Australia, studying the fossilized plants and pollens recorded in the sediment. Unlike previous studies that relied on piecing together data from multiple locations, the Sydney Basin provides a continuous record of continental change. “This work has really tied it all together in a much longer timeframe than anyone’s ever done before, and it's one basin over the whole time frame, which is quite exciting” says co-author Chis Mays. Because all findings come from one place rather than a patchwork of sites, there are fewer uncertainties, allowing for more reliable interpretations of past ecological changes.

Their results found that plant life recovered fairly rapidly after the extinction, with conifers spreading across the landscape. However, climatic changes following the extinction made these communities unstable and caused frequent compositional changes. “We found that there was extreme warming happening, even after this big mass extinction, and extreme cooling happened after that [warming],” says Amores, noting that these changes had a big impact on the plant life. Conifers were unable to thrive in the warmer temperatures, a period known as the Late Smithian Thermal Maximum, and were replaced by shrub-like plants. The following period of cooling, or the Smithian-Spathian Event, caused another plant life transition. Large seed ferns flourished in these conditions and became the dominant vegetation throughout the remainder of the Mesozoic. In total, it took over 1.7 m.y. for the ecosystem to recover and stabilize. “The plants really are telling us the full story of what happened on land,” says Mays, but the team has plans to expand the project by investigating how terrestrial animals responded to these changes.

Although this study focused on the past, it demonstrates how climatic changes can cause long term ecosystem disruptions, providing insights on how modern ecosystems might change with our current climate crisis. It is no coincidence that every major extinction event is associated with rapidly changing temperatures. “Warming the temperature by X number of degrees is a tried and tested way to kill a lot of animals and plants,” says Mays. “Life does recover after a couple million years, but the impacts we feel today will affect us very thoroughly,” adds Amores. Mays concludes, “the idea of recovery might seem like a light at the end of the tunnel, but it’s not like the same plants and animals will come back once they’re extinct. If we want to hang on to the plants and animals [currently] around, we want to make sure we prevent their loss rather than waiting for them to recover.” Research like this demonstrates how the past is the key to the future, and will help us preserve the ecosystems we inhabit.

See University College Cork's news release. 

FEATURED ARTICLE
Age-controlled south polar floral trends show a staggered Early Triassic gymnosperm recovery following the end-Permian event
Marcos Amores, Tracy D. Frank, Christopher R. Fielding, Michael T. Hren, and Chris Mays
Contact: Marco Amores, University College Cork, mamores@ucc.ie

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About the Geological Society of America

The Geological Society of America (GSA) is a global professional society with more than 17,000 members across over 100 countries. As a leading voice for the geosciences, GSA advances the understanding of Earth's dynamic processes and fosters collaboration among scientists, educators, and policymakers. GSA publishes Geology, the top-ranked geoscience journal, along with a diverse portfolio of scholarly journals, books, and conference proceedings—several of which rank among Amazon’s top 100 best-selling geology titles.

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