“The Great Dying” mass extinction was Harsher than others due to major collapse in diversity, study finds

In Earth’s long history, numerous catastrophic mass extinction events have wreaked havoc on ecosystems, with one infamous event annihilating the dinosaurs. However, none were as devastating as “The Great Dying” approximately 252 million years ago, marking the end of the Permian period. A recent study, published in Proceedings of the Royal Society B, delves into the intricate process of life recovery following this mass extinction, contrasting it with two smaller-scale events. This international research effort involved experts from various institutions, including China University of Geosciences, California Academy of Sciences, University of Bristol, Missouri University of Science and Technology, and the Chinese Academy of Sciences. The findings underscore that the end-Permian mass extinction was uniquely brutal, eradicating a staggering 95% of species, thereby shattering ecosystems and necessitating a complete reconstruction of ecological communities.

To explore this phenomenon further, the lead author and researcher, Yuangeng Huang, who is now affiliated with the China University of Geosciences, Wuhan, meticulously reconstructed food webs across 14 different life assemblages spanning the Permian and Triassic periods. These snapshots, extracted from northern China, offer insights into how a specific region on Earth coped with these crises. Huang explains, “By examining fossils and analyzing evidence from their teeth, stomach contents, and excrement, I was able to piece together the intricate relationships between various species. Building an accurate food web is crucial to understanding these ancient ecosystems.”

These food webs consist of plants, mollusks, insects in aquatic habitats, as well as the fish, amphibians, and reptiles that comprise their respective diets. The reptiles ranged from diminutive lizards to massive half-ton herbivores adorned with robust bony scales. Sabre-toothed gorgonopsians, some as formidable as lions with their long canine teeth, roamed the landscapes. When these creatures perished during the end-Permian mass extinction, they left a void, resulting in unbalanced ecosystems for a staggering ten million years. Eventually, during the Triassic period, the first dinosaurs and mammals began to evolve. Initially, these dinosaurs were modest in size, around one meter long, and primarily insect-eaters. However, they rapidly diversified, giving rise to both flesh-eating and plant-eating varieties.

By the end of the Permian, pareiasaurs had become large and armored for self-protection. Other plant-eaters included dicynodonts, preyed on by dinocephalians . This complex ecosystem collapsed during the end-Permian mass extinction event, and only a few dicynodonts survived. Credit: © Xiaochong Guo

Peter Roopnarine, Academy Curator of Geology, states, “Yuangeng Huang spent a year in my lab, applying ecological modeling techniques to dissect ancient food webs and assess their stability. The model perturbs the food web, removing species to test its overall resilience.”

Professor Mike Benton from the University of Bristol points out, “The end-Permian event stood out in two significant ways. Firstly, the decline in diversity was exceptionally severe, whereas the other two mass extinctions were preceded by ecosystems of lower stability. Secondly, it took an exceedingly long time, possibly over 10 million years, for ecosystems to recover, in stark contrast to the swift recoveries observed after the other two crises.”

In essence, scrutinizing these communities, particularly those that successfully rebounded, offers invaluable insights into how present-day species might fare as humanity pushes the planet to its limits.

Professor Zhong-Qiang Chen of the China University of Geosciences, Wuhan, emphasizes the significance of this research, saying, “This is an incredible breakthrough. Previously, we could describe these ancient food webs, but testing their stability was a challenge. The combination of extensive new data from geological formations in North China and advanced computational techniques enables us to delve into these ancient ecosystems in a manner similar to the study of modern food webs.”

Source: California Academy of Sciences

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