New research published in Nature Earth Science reveals that climate change 201 million years ago transformed Europe into a fern-savannah landscape, leading to frequent wildfires. Explore the study here.

“Ferns are incredibly resilient plants that have survived multiple crises throughout Earth’s history, with some species adapting to extreme environments. They exemplify true survival instincts,” said Dr. Bas van de Schootbrugge, a researcher at Utrecht University.

“Certain ferns can quickly colonize disturbed areas, and the occurrence of wildfires can further stimulate their expansion.”

“Although ferns burn above ground, their underground root systems allow rapid regrowth, often overshadowing other plant species.”

“This ecological phenomenon may have significantly impacted the duration of the fern spike period, estimated to last between 40,000 to 300,000 years.”

In their study, scientists examined fossil deposits dating back to the end-Triassic mass extinction from drill cores located in Germany, Luxembourg, Denmark, and the United Kingdom.

The researchers compiled a record of historical wildfire activities by analyzing the abundance of fossilized charcoal and organic molecules known as polycyclic aromatic hydrocarbons (PAHs) formed during wildfires.

When combined with pollen and spore records, these proxy indicators revealed significant wildfire activity correlating with extinction events and pteridophyte expansion.

However, care must be taken with charcoal records, as larger pieces can fragment into smaller ones during sampling.

Similarly, PAHs generated during wildfires may not be accurately captured in the vicinity of the fire and might not be preserved.

“Our study’s novelty stemmed from analyzing color variations in organic microfossils,” Dr. van de Schootbrugge explained.

“We employed an affordable technique to quantify the ‘darkness’ of fossil pollen and spores, which we termed the palynomorph darkness index.”

“Typically, when organic microfossils are buried in sediments, their color changes due to pressure and temperature alterations.”

“As sediments undergo deeper burial, the temperature increases, causing the trapped organic matter to darken over time. However, we observed a unique pattern.” In the deepest, oldest core samples, pollen and spores showed lighter colors but became very dark brown during the extinction period, reverting to bright yellow thereafter.”

“This phenomenon puzzled us, as it occurred simultaneously across all four cores. Given their diverse geological histories, it seemed unlikely that sediment burial alone could explain it.”

The authors generated 15,000 measurements from both pollen and spores observed before, during, and after the end-Triassic mass extinction.

By comparing tree pollen with fern spores, they eliminated plant group-specific biological effects.

“All plant groups exhibited the same darkening effect, indicating it was likely due to an external factor,” Dr. van de Schootbrugge noted.

“When we compared color changes in microfossils to other indicators of fire, we found that this ‘dark zone’ represented an extended period of intense wildfires during the fern proliferation interval.”

This darkening correlated precisely with key extinction events and a surge in charcoal and PAH levels.

The remarkable increase of ferns during this major extinction was driven by factors like deforestation, soil erosion, greenhouse warming, and wildfires.

“As ferns dehydrate, their thick mats become perfect fuel for igniting large wildfires,” Dr. van de Schootbrugge added.

“Invasive and pioneering fern species contributed to the establishment of widespread fern savannahs, acting as ‘fire ladders’ while outcompeting other vegetation.”

“Consequently, ferns ultimately enhanced fire intensity, leading to recurring massive wildfires. It was a chaotic time in Earth’s history.”

“This serves as a reminder that climate change, deforestation, and opportunistic species can create the perfect conditions for ecological disasters.”

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“TP Horror et al. Continental-scale fern savannah wildfires during greenhouse warming at the end of the Triassic.” Nature Earth Science, published online July 21, 2026. doi: 10.1038/s41561-026-02048-4