252 million years ago, a mass extinction disrupted life on Earth. Yet, a region in China provided a haven for plants and animals, revealing unexpected resilience.
This discovery, published in
Science Advances, challenges the idea that terrestrial ecosystems suffered total devastation similar to that of the oceans. The Turpan-Hami Basin in Xinjiang hosted lush vegetation and animals, enabling rapid ecological recovery after the crisis.
A) Landscape of a densely populated lake plain by a forest of conifers or seed ferns during the Permian mass extinction, as indicated by the LA assemblages.
B) Lake plain dominated by herbaceous lycopsids, inhabited by the dicynodontoid Turfanodon before the extinction, according to the CR assemblages.
C) Regional vegetation characterized by an abundance of ferns with fewer gymnosperms and seed ferns, located on a lake delta, according to the Ks assemblages. This area was populated by the carnivorous chroniosuchian and the herbivorous Lystrosaurus after the extinction. An ecosystem preserved despite the chaos
The end-Permian extinction, triggered by massive volcanic eruptions in Siberia, caused abrupt global warming, acid rain, and a drastic drop in oxygen levels. These disturbances devastated most terrestrial and marine ecosystems, but some regions, like the Turpan-Hami Basin, escaped the worst. Thanks to a stable and semi-humid local climate, this area became a refuge for life.
Researchers analyzed fossils of pollen, spores, and tree trunks, revealing vegetation dominated at the time by ferns and conifers. These plants thrived continuously before, during, and after the extinction, forming a resilient ecosystem. The extinction rate of plant species in this region was only 21%, far lower than the massive losses observed in the oceans, where over 80% of species disappeared.
The presence of intact tree trunks and fern stems confirms that these fossils originated from the region and were not transported by wind or water. This ecological stability allowed life to persist despite the hostile conditions prevailing elsewhere on the planet. The Turpan-Hami Basin thus became a rare example of resilience in the face of a global crisis.
A rapid ecological recovery
Within 75,000 years after the extinction, the Turpan-Hami Basin region already hosted a diverse fauna, including herbivores like Lystrosaurus and carnivores such as Chroniosuchia. This rapid recovery contrasts with previous estimates, which suggested ecological recovery taking over a million years. The presence of a significant trophic network shows that the ecosystem regained its balance much faster than in other regions of the globe.
The climatic stability and plant richness of the Turpan-Hami Basin played a key role in this resilience. With approximately 1,000 mm (39 inches) of annual rainfall, the region provided a favorable environment for plant growth and animal survival. This abundance of resources allowed migratory species to establish and thrive, accelerating the restoration of local biodiversity.
This discovery highlights the importance of natural refuges for the survival and recovery of ecosystems after global crises. It shows that, even in periods of extreme disturbances, certain areas can serve as sanctuaries, facilitating the return of life and the reconstruction of ecosystems. These refuges could offer valuable lessons for conservation in the face of current environmental challenges.
Article author: Cédric DEPOND