Location: Texas

Friday, November 26, 2004

Ancient bison done in by climate, not hunters

Thousands of years before white and Indian hunters drove the buffalo of America's Great Plains to virtual extinction, the ancestors of those lordly animals suffered a similar fate -- but it was major climate change, not hunting, that did them in, says an international research team.

Moving in huge herds, more than 20 million bison roamed the American West before white men arrived. For centuries, the Indians hunted them with bows, arrows and spears for food, clothing and shelter.

But within a few brief years after 1850, the guns of the white men -- and of the Indians -- drove the American buffalo to near extinction. By 1889, naturalists could find only 550 left, giants 6 feet high at their massive shoulders and weighing more than a ton.

In contrast, the extinction of the buffalo's ancestors took thousands of years longer, according to the scientists who analyzed their fossil bones, and it was periodic climate change and the appearance and disappearance of vast ice sheets that virtually wiped out the ancient herds.

A few subspecies of the ancient bison may have survived briefly in the far north, but eventually they all vanished, the scientists believe. However, larger groups farther south survived, and their descendants were the ones that eventually populated the Great Plains.

Okay, sounds reasonable to me. But wait, there's dissent in the ranks.

Extinction by climate change is a controversial idea, and John Alroy, a population biologist at UC Santa Barbara, disagrees strongly with the Oxford- led group, arguing that there is "solid evidence" of large human populations in America by at least 13,400 years ago.

"The climate model makes no sense whatsoever," Alroy insisted in a phone interview. "It's all overkill, and even the early human populations of the region were capable of decimating the large animals that were heading for extinction at the end of the Pleistocene," the geologic period that began about 1.8 million years ago and ended about 11,000 years ago.

Not just bison, but moose and red deer also fell prey in huge numbers to the rapidly growing population of early human hunters, Alroy argues.

"Human population growth and hunting almost invariably leads to a mass extinction," he wrote in an earlier article that, like the current work, was published in the journal Science.

Sounds like your typical leftist agenda to me, i.e. people are bad, hunting is worse, and actually eating what you kill....blechh!!!

But sanity prevails:

But Cooper had a response to Alroy's argument in an e-mail interview:

"We think that for many species, the small population sizes that had been produced by environmental changes were very vulnerable to human hunting," he said. "Basically, humans turned up at exactly the wrong moment -- just when many species were already in deep trouble due to the changes in the environment.

"We wouldn't argue that humans didn't kill the last survivors of many populations and species, but the important point is that these groups had already been dramatically reduced in population size and genetic diversity by climate changes over the preceding 25,000 years. This has major implications for understanding the likely impact of global warming trends -- and they don't paint a pretty picture."

More here.

Stay tuned.


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