A team of scientists from University College Cork (UCC) , the University of Connecticut, and the Natural History Museum of Vienna have uncovered how plants responded to catastrophic climate changes 250 million years ago. Their findings, published in GSA Bulletin, reveal the long, drawn-out process of ecosystem recovery following one of the most extreme periods of warming in Earth's history: the 'End-Permian Event'.
With more than 80% of ocean species wiped out, the end-Permian event was the worst mass extinction of all time. But the impacts of this event for life on land have been elusive. By examining fossil plants and rocks from eastern Australia's Sydney Basin, researchers have pieced together a multi-million-year story of resilience, recovery, and the long-term effects of climate change.
The long, unsteady path to ecosystem recovery
The fossils from these Australian rocks show that conifers, like modern pines, were some of the earliest to colonize the land immediately after the End-Permian catastrophe. But the recovery back to flourishing forests was not smooth sailing.
The researchers discovered that even higher temperatures during the 'Late Smithian Thermal Maximum' caused the collapse of these conifer survivors. In turn, they were replaced by tough, shrubby plants resembling modern clubmosses. This scorching period lasted for about 700,000 years and made life challenging for trees and other large plants.
It wasn't until a significant cooling event—the 'Smithian-Spathian Event'—that large, but unusual plants called 'seed ferns' began to flourish and establish more stable forests. These plants eventually came to dominate Earth's landscapes for millions of years, paving the way for the lush forests during the Mesozoic 'age of dinosaurs'.
So, after millions of years, the forest ecosystems of the Mesozoic came to look like those from before the end-Permian collapse. But crucially, the plant species that made up the new forests were completely different. "The term 'recovery' can be misleading" says Dr Chris Mays, Leader of the Mass Extinction Group at University College Cork, "forests recover eventually, but extinction is forever."
What does this mean for us?
By understanding how ancient plant ecosystems weathered extreme climate swings, researchers hope to learn valuable lessons about how modern plants and ecosystems might cope with today's climate crisis. Ecosystems depend on a fragile balance, with plants as the backbone of land food webs and climate regulation.
"This research highlights how crucial plants are, not just as the base of land food chains, but also as natural carbon sinks that stabilize Earth's climate," explains UCC researcher, Marcos Amores, the study's lead author. "The disruption of these systems can have impacts lasting hundreds of thousands of years, so protecting today's ecosystems is more important than ever."
This deep dive into Earth's distant past reminds us that plants are unsung heroes of life on Earth—then, now, and in the future.
