Several animals became extinct about 14,000 years ago. A new study suggested various factors that led to their quick disappearance.
Dramatic Animal Extinction Based on Fossils From La Brea Tar Pits
Downtown Los Angeles was teeming with dire wolves, saber-toothed cats, almost one-ton camels, and 10-foot-long ground sloths some 14,000 years ago. But everything altered in a geologic instant. These enormous beasts had all vanished roughly 13,000 years ago. Large fires were frequent in the chaparral, a dry, shrubby area that had once been lush woods.
The iconic La Brea Tar Pits were the subject of a new study published on Aug. 17 in Science. Natural asphalt from these "tar pits" ensnared a variety of creatures between 50,000 and 10,000 years ago, including hoary bats (Lasiurus cinereus), rainbow trout (Oncorhynchus mykiss), and garter snakes (Thamnophis sirtalis).
The most recent research demonstrates how rapidly the greatest creatures vanished from the La Brea fossil record. The researchers listed 172 specimens from seven extinct species, including the dire wolf (Aenocyon dirus), the ancient bison (Bison antiquus), the saber-toothed cat (Smilodon fatalis), the American lion (Panthera atrox), and Harlan's ground sloth (Paramylodon harlani), as well as the coyote (Canis latrans), which is still alive today. Although the coyote fossils ranged in age from 16,000 to 10,000 years ago, the researchers found that every other species vanished suddenly between 14,000 and 13,000 years ago, with camels and sloths appearing to go extinct a few hundred years before the carnivores.
According to Robin O'Keefe, F., A biologist at Marshall University and a co-author of the study, nobody involved was ready for what they discovered. Coyotes remain left behind, but the megafauna vanishes. And for most of them, it is a dramatic event similar to a "poof."
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Factors That Reported Led to Extinction
O'Keefe and his colleagues examined sediment cores from a nearby lake that contained information on air temperature, salinity, and precipitation to comprehend these creatures' destiny—the 300 years of significant charcoal deposition from wildfires in the lake that started around 13,200 years ago, exactly around the time the megafauna vanished from the tar pits, particularly caught the attention of the researchers.
O'Keefe said they saw the massive pulses of charcoal going into Lake Elsinore all of a sudden, and they were big compared to anything that happened before or after that time, and that convinced them that the fires were a crucial aspect.
Next, the researchers utilized a computer model to determine how fires, climate change, species extinction, and regional human settlement interacted. The result is a considerably more nuanced picture of the extinction than was presented by earlier hypotheses, which frequently assigned a single cause, such as human hunting or climate change, to extinctions.
Instead, O'Keefe contends that humans may have brought the ecosystem to its breaking point by exterminating herbivores, which permitted vegetation growth that served as wildfire fuel when the climate was already drying out and left carnivores without prey.
According to Allison Karp, a Yale University paleoecologist who was not involved in the current research, it is not necessarily the case that large-scale wildfires caused the extinction of megafauna. Human dynamics altered the fire regime, interacting with an arid climate and increasing temperature.
The interaction, along with decreases in herbivore densities, pushed the system nonlinearly and shifted it to another state-one with a lot fewer herbivores, a very different vegetation community, and a much higher fire regime than had been observed previously.
Paleoecologist Jacquelyn Gill of the University of Maine, who was not involved in the new research, expressed little surprise that O'Keefe's team had discovered such a complex answer. According to her, they know that extinction is hardly ever unicausal in contemporary systems. Often, you need to exert some pressure on this demographic. Then, a component of ill luck or another stressor frequently enters, and they frequently witness that.
The similarities between current headlines and the removal of these famous species from southern California against a backdrop of wildfires and climate change, according to O'Keefe, Karp, and Gill, are unsettling.
O'Keefe added that the research shows how two distinct ecosystems changed quickly. He stressed that it's a catastrophe mathematically and claimed that when everything starts to catch fire all around you and the medium of that state transition is fire, you start to wonder whether it's happening again, and that is a reasonable thought to have.
Gill said it's important for them to understand how extinction happened to make better predictions on which species are going next, so they could do the necessary triage and save them.
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