Study: Recovery from human-caused biodiversity declines to take millions of years

Study: Recovery from human-caused biodiversity declines to take millions of years
It took at least 12 million years for biodiversity levels to recover in the wake of the asteroid impact that killed off the dinosaurs -- and researchers say recovering from losses caused by humanity could take even longer. Photo by Pixabay/CC

May 21 (UPI) -- Imperiled by climate change, deforestation, hunting, pollution and other human-caused disruptions, Earth's biodiversity continues to decline across the globe.

To estimate how long it might take for the planet's biota to recover, scientists analyzed the pace of speciation in the wake of the extinction event that killed off the dinosaurs 66 million years ago.


The analysis, published Friday in the journal Communications Earth and Environment, suggests that even if humans disappeared tomorrow, it will take several million years for the planet's biodiversity to recover.

Though dinosaurs were the only major animal group to be wiped out completely, the asteroid impact responsible for the Cretaceous-Paleogene extinction event also put a dent in the diversity of mammals, reptiles, insects and more.

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In total, scientists estimate the event extinguished more than three-fourths of all species on Earth.

To quantify the losses precipitated by the extinction event, as well as the rate of recovery in its aftermath, researchers focused on freshwater biota.

More specifically, scientists analyzed 3,387 fossil and living snail species living in Europe over past 200 million years.

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The dataset allowed researchers to estimate the rates at which species disappear and new species emerge.


Though the analysis showed freshwater biota losses during the Cretaceous-Paleogene extinction event were greater than previously estimated, the rate of biodiversity decline is dwarfed by today's losses.

Using modern data on extinctions among freshwater species, scientists estimated that by 2120, nearly a third of all freshwater species will have disappeared.

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"Losing species entails changes in species communities and, in the long run, this affects entire ecosystems," lead study author Thomas Neubauer said in a press release.

"We rely on functioning freshwater environments to sustain human health, nutrition and fresh water supply," said Neubauer, a postdoctoral researcher at the Naturalis Biodiversity Center in the Netherlands.

The asteroid impact that killed the dinosaurs lasted a matter of seconds, but the climatic and ecological impacts were long lasting.

The latest fossil analysis suggests extinction rates remained elevated for nearly 5 million years. It was 12 million years before biodiversity levels recovered and ecological balance was restored.

The destructive activities of humans remain ongoing, the researchers point out.

"Even if our impact on the world's biota stops today, the extinction rate will likely stay high for an extended period of time," Neubauer said.

"Considering that the current biodiversity crisis advances much faster than the mass extinction event 66 million years ago, the recovery period may be even longer. Despite our short existence on Earth, we have assured that the effects of our actions will outlast us by millions of years," Neubauer said.


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