Image: Public domain.
Humans Not (Completely) to Blame for Woolly Mammoth Demise?
There's always been uncertainty about what caused the extinction of the iconic woolly mammoth. One of the leading hypotheses so far was that humans were a primary cause of their decline because of over-hunting and competition for land, but new research by scientists at Durham University is challenging that view. Could the main culprit actually be... trees?
Image: Wikipedia, Creative Commons.
Climate Change = Ecosystem Change
No, I'm not talking about giant carnivorous trees, but rather the spread of forests over areas that were formerly grasslands because of a global increase in temperatures after the ice age that took place about 21,000 years ago.
The research is part of the most comprehensive study to date of Northern Hemisphere climate and vegetation during and after the height of the last Ice Age, 21,000 years ago. It shows that, over a huge part of the Earth's surface, there was a massive decline in the productivity and extent of grasslands due to climatic warming and the spread of forests.
These habitat changes made grazing much more difficult for large mammals and dramatically reduced the amount of food available for them. [...]
"We believe that the loss of food supplies from productive grasslands was the major contributing factor to the extinction of these mega-mammals."
Of course, we can't be 100% sure what happened so many thousand of years ago. This research is based on fossils and models of how the changing climate would have affected the growth of various plants and trees. But it seems to be the best hypothesis we have so far.
Image: Wikipedia, Public domain.
Lesson to Learn
This doesn't mean that humans didn't have anything to do with the woolly mammoth's extinction. But even if our ancestors hadn't been around, the much diminished food supply over a large surface of the planet probably would have caused a major decline in their population on its own.
This is a cautionary tale about the power of climate change to reshape ecosystems and make them inhospitable to species that hav evolved to depend on them. It's a lesson we need to learn from the past, because if we wait for it to be too obvious in the present, it'll be too late to do much about it.