Friday, August 20, 2010

Humans Said Innocent in Mammoth Extinction

We certainly need a better explanation for the demise of the wooly mammoth than our great hunting skills.  We only have to look at Africa to understand why.  There is plenty of easy game to collect and the big ones are not possible unless you run them off a cliff.  It was never going to make any impact on numbers.

The explanation proffered here is less likely.  One small locale would have been enough to maintain a living population.  These animal were engineered to live in an environment moderated by nearby ice and ice sheets during the summer.

What this means is that the summer had enough warmth to support tundra like environs with a strong growing season in which plenty of over winter fodder was produced. 

The climate was much more volatile and demanding. Perhaps this meant that a range of other competitors for fodder simply could not prosper and that ice age adapted mammals were able to simply prosper deep into the temperate zone we now occupy.

The fact is that our temperate zone biome is not rich and is unable to hold its own in the face of Arctic winters and volatile summer conditions.  A couple of summers without a real growing season would wipe out many species of plant we take for granted.

The tundra gave them those conditions but were simply too poor to retain much of the ice age biome.  Today we have only the Musk Ox surviving because they adapted to moss.

Humans said innocent in mammoth extinction

by Staff Writers

Durham, England (UPI) Aug 18, 2010 

The disappearance of ancient grasslands, not human hunting, may have led to the extinction of animals such as the woolly mammoth, U.K. researchers say.

Scientists at Durham University in England say the new findings challenge accepted theories that humans played a large part in the extinction of woolly mammoths, woolly rhinos and cave lions through hunting, competition for land and pressure on habitats, Science reported Tuesday.

Instead, a massive reduction in grasslands and the spread of forests may have been the primary cause of the decline, they say.

The researchers studied data on climate and vegetation in the Northern Hemisphere during and after the height of the last Ice Age, 21,000 years ago.

Over a huge part of the Earth's surface, they say, there was a massive decline in the productivity and extent of grasslands due to climatic warming and the spread of forests.

"Woolly mammoths retreated to northern Siberia 14,000 years ago whereas they had roamed and munched their way across many parts of Europe, including the U.K., for most of the previous 100,000 years or more," Professor Brain Huntley said.

"The change from productive grasslands across large areas of northern Eurasia, Alaska and Yukon to less productive tundra-like habitats had a huge effect on many species.

"We believe that the loss of food supplies from productive grasslands was the major contributing factor to the extinction of these mega-mammals."

He called the findings "a model for what may happen as a result of rapid climate change over the next century linked to human activity."

"It is food for thought in these times of global warming and human-induced habitat change," he said. "There may well be a lesson to learn."

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