Pollen fossils indicate that a mass extinction event is near

Hyperaxion Aug 25, 2020

Analysis of more than 14,000 fossilized pollen samples reveals that North American plant biomes are in danger and may take centuries to recover.

According to researchers at the Georgia Institute of Technology, plant biomes in North America are having a hard time adapting to rapid atmospheric changes, and this could indicate a mass extinction scenario like never seen in the past 13,000 years.

Pollen fossils indicate that a mass extinction event is near
(Credit: Unsplash).

The study, published in the scientific journal Global Change Biology, analyzed 14,189 samples of fossilized pollen taken from 358 places spread across North America to determine the resilience of the local landscape.

The scientists assessed how long fossilized forests and grasslands persisted – a factor known as residence time – and how well they recovered from disturbances like forest fires and deforestation – a factor called recovery.

One of the results showed that landscapes currently have an adaptation capacity as low as that observed at the end of the megafauna extinctions in the Pleistocene (Ice Age) period.

“Though we know that strategies exist to mitigate some of these effects, our findings serve as a dire warning about the vulnerability of natural systems to extinction,” said Yue Wang, the researcher who led the study.

Another important result highlighted the vulnerability of the landscapes: in the last 20 thousand years, forests persisted longer than grassland habitats, although they also took much longer to recover after being destroyed.

Finally, the research found that forests and grasslands change when temperatures are changing rapidly and that they recover more quickly if the ecosystem contains high plant biodiversity.

However, not all biomes recover – only 64% recover their original biome type through a process that can take up to three centuries. In addition, arctic systems are less likely to recover.

“Identifying the tempo and mode of landscape transitions and the drivers of landscape resilience is critical to maintaining natural systems and preserving biodiversity given today’s rapid climate and land use changes,” the authors wrote. “However, resilient landscapes are difficult to recognize on short time scales, as perturbations are challenging to quantify and ecosystem transitions are rare.”

While the effects of climate change and human environmental impacts do not bode well for the future of North America’s plant biomes, there are ways to deal with it, Wang explained. “We know that strategies exist to mitigate some of these effects, such as prioritizing biodiverse regions that can rebound quickly and increasing the connectivity between natural habitats so that species can move in response to warming.”


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