The mass extinction that killed 80% of life on Earth 250 million years ago may not have been quite so disastrous for plants, new fossils hint. Scientists have identified a refuge in China where it seems that plants weathered the planet’s worst die-off.

The end-Permian mass extinction, also known as the “Great Dying,” took place 251.9 million years ago. At that time, the supercontinent Pangea was in the process of breaking up, but all land on Earth was still largely clustered together, with the newly formed continents separated by shallow seas. An enormous eruption from a volcanic system called the Siberian Traps seem to have pushed carbon dioxide levels to extremes: A 2021 study estimated that atmospheric CO2 got as high as 2,500 parts per million (ppm) in this period, compared with current levels of 425 ppm. This caused global warming and ocean acidification, leading to a massive collapse of the ocean ecosystem.

The situation on land is far hazier. Only a handful of places around the world have rock layers containing fossils from land ecosystems at the end of the Permian and beginning of the Triassic.

A new study of one of these spots — located in what is now northeastern China —revealed a refuge where the ecosystem remained relatively healthy despite the Great Dying. In this place, seed-producing gymnosperm forests continued to grow, complemented by spore-producing ferns.”At least in this place, we don’t see mass extinction of plants,” study co-author Wan Yang, a professor of geology and geophysics at the Missouri University of Science and Technology, told Live Science.

The finding, published in the journal Science Advances, adds weight to the idea that the Great Dying was more complicated on land than in the seas, Yang said. A major advantage of this now-desert site is that the rocks include layers of ash that hold tiny crystals called zircons. The zircons include radioactive elements — lead and uranium — that gradually decay, which enables researchers to determine how long it has been since the crystals formed. This means the researchers can more accurately date the rock layers here than they can at other sites.

Some of these layers also hold fossil spores and pollen. These fossils reveal that there wasn’t a massive die-off and repopulation but a slow changeover of species, Yang said. This is consistent with other evidence from Africa and Argentina, where plant populations seemed to have shifted gradually rather than dying off dramatically and then repopulating, said Josefina Bodnar, a paleobotanist at the National University of La Plata in Argentina who was not involved in the research.

Land plants “have a lot of adaptations that allow them to survive this extinction,” Bodnar told Live Science. “For example, [they have] subterranean structures, roots or stems, that can survive perhaps hundreds of years.” Seeds can also persist a long time, she added.