Scientists at the universities of Exeter and Cambridge claim their research settles a prolonged debate over whether humankind or climate change was the dominant cause of the demise of massive creatures in the time of the sabretooth tiger, the woolly mammoth, the woolly rhino and the giant armadillo.
Known collectively as megafauna, most of the largest mammals ever to roam the earth were wiped out over the last 80,000 years, and were all extinct by 10,000 years ago.
Lewis Bartlett, of the University of Exeter, led the research…He said cutting-edge statistical analysis had helped solve the mystery almost beyond dispute, concluding that man was the dominant force in wiping out the creatures, although climate change could also have played a lesser role.
The researchers ran thousands of scenarios which mapped the windows of time in which each species is known to have become extinct, and humans are known to have arrived on different continents or islands. This was compared against climate reconstructions for the last 90,000 years.
Examining different regions of the world across these scenarios, they found coincidences of human spread and species extinction which illustrate that man was the main agent causing the demise, with climate change exacerbating the number of extinctions. However, in certain regions of the world — mainly in Asia — they found patterns which patterns were broadly unaccounted for by either of these two drivers, and called for renewed focus on these neglected areas for further study.
Bartlett…said: “As far as we are concerned, this research is the nail in the coffin of this 50-year debate — humans were the dominant cause of the extinction of megafauna. What we don’t know is what it was about these early settlers that caused this demise. Were they killing them for food, was it early use of fire or were they driven out of their habitats? Our analysis doesn’t differentiate, but we can say that it was caused by human activity more than by climate change. It debunks the myth of early humans living in harmony with nature.”
Matches my own subjective, unscientific feelings derived from wandering physically and intellectually through the Colorado Plateau. Not only large species; but, small to medium animals vanished with the arrival of the Athabascan peoples.
Leaving behind bones gnawed by humans.
Eideard 
“Humanity has wiped out 60% of mammals, birds, fish and reptiles since 1970, leading the world’s foremost experts to warn that the annihilation of wildlife is now an emergency that threatens civilization.
The new estimate of the massacre of wildlife is made in a major report produced by WWF and involving 59 scientists from across the globe. It finds that the vast and growing consumption of food and resources by the global population is destroying the web of life, billions of years in the making, upon which human society ultimately depends for clean air, water and everything else.
“We are sleepwalking towards the edge of a cliff” said Mike Barrett, executive director of science and conservation at WWF. “If there was a 60% decline in the human population, that would be equivalent to emptying North America, South America, Africa, Europe, China and Oceania. That is the scale of what we have done.”
“This is far more than just being about losing the wonders of nature, desperately sad though that is,” he said. “This is actually now jeopardising the future of people. Nature is not a ‘nice to have’ – it is our life-support system.” https://www.theguardian.com/environment/2018/oct/30/humanity-wiped-out-animals-since-1970-major-report-finds Tanya Steele, chief executive at WWF, said: “We are the first generation to know we are destroying our planet and the last one that can do anything about it.”