Humans may have caused the mass extinction of species for thousands of years now. And a new World Wildlife Fund (WWF) report says the elimination continues, as humanity has wiped out 60 per of mammals, birds, fish and reptiles since 1970.
The new estimate of the disappearance of wildlife is made in a report by the WWF, involving 59 scientists from across the globe. It said overexploitation and humanity’s growing consumption of food and resources are the main factors to blame for the loss in species.
“Our constantly increasing demands on nature are driving wildlife to extinction. It’s not just elephants, freshwater dolphins and rhinos, but Canadian wildlife too,” said Megan Leslie, WWF-Canada president and CEO, in a release.
This isn’t the first time humans have been at fault for wiping out wildlife on a mass scale. According to Anthony Barnosky, professor of biology at Stanford University, we’ve been “decimating” species for thousands of years now.
“It’s pretty clear that we do have the effect, we have in the past,” he said.
Bye-bye big mammals
Modern humans began to migrate out of Africa to Asia between 60,000 and 80,000 years ago, and then to Australia around 45,000 years ago and finally crossing to North and South America around 15,000 years ago.
And when humans set foot on a new continent, waves of extinctions followed, according to experts.
In an article published in NCBI, the authors argued the timeline of mammal extinctions is closely intertwined to the first human colonization on different continents.
“And direct or indirect human involvement in these events is now widely accepted by most paleontologists,” the authors stated.
In Yuval Noah Harari’s book, Sapiens: A Brief History of Humankind, he argued that homo sapiens were a key cause of the extinction of other human species such as the Neanderthals, along with numerous megafauna (large animals).
The historian said when humans first reached Australia they were met with a “two-metre kangaroo,” “koalas far too big to be cuddly” and “flightless birds twice the size of ostriches.”
And within a few thousand years, virtually all of the giants vanished, he wrote.
He said the same events happened in North And South America. When humans first migrated to the continents, “American fauna 14,000 years ago was far richer than it is today,” Harari wrote.
“The sabre-tooth cats, after flourishing for more than 30 million years, disappeared, and so did the giant ground sloths, oversized lions, native American horses, native American camels, the giant rodents and the mammoths.”
Artwork of the woolly mammoth. This animal lived during the Pleistocene epoch and into the early Holocene, and as such coexisted with humans.
A 2014 article published in the Royal Society argued that the extinction of large mammals was linked to our ancestors.
Large mammals, like the mammoth, were wiped out when humans first arrived because “suddenly introducing a new and effective big-game predator into regions with megafauna naive to human hunting,” the authors stated.
“It doesn’t take a lot to make a species go extinct,” Advait Jukar, a paleontologist from George Mason University, told the Atlantic. “Humans didn’t need to go out and kill every last individual; all you need is a stressed population and just enough hunting pressure to keep the fertility rate [below replacement levels]. Eventually, the population will collapse.”
Of course, experts say the extinction of species cannot be blamed on humans alone. Jessica Theodor from the University of Calgary told the Atlantic that climate change could also have impacted the extinction.
The extinction continues
Barnosky argues that after the large mammal extinction, “things stabilized for around 12,000 years.” But now it’s ramping up again.
From hedgehogs to elephants, rhinos and polar bears, wildlife is in decline, due to the loss of habitats, overexploitation and climate change, the WWF report said.
The report stated that only a quarter of the world’s land area is free from the impacts of human activity and by 2050 that will have fallen to just a 10th.
Species which live in freshwater habitats, such as frogs and river fish, have seen global population falls of 83 per cent. Almost six billion tonnes of fish and invertebrates have been taken from the world’s oceans since 1950. And 90 per cent of the world’s seabirds have fragments of plastic in their stomachs compared to only five per cent in 1960.
The annihilation of wildlife is now an emergency that threatens civilization, the WWF warned. And Barnosky agreed.
“This is a crisis,” he said. “It does not take complicated math to know that if we keep losing 60 per cent of wildlife, it’s not going to be long until there is virtually nothing left.”
Barnosky said that humans are so interconnected to wildlife, that without a functioning ecosystem, we will be left without a world that sustains human health.
“It’s like pulling all the rivets out on an airplane, you pull the last one out and the entire wing will fall off.”
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