LATimes, CSMonitor, New Scientist, NYTimes, etc: Mammoths and other megafauna dwindled for centuries before extinction, taking an ecotone with them
What a wonderful term is “mammoth steppe,” with its evocation of a vanished, northern prairie with vegetation and immense mammals unlike anything today – yet spread widely across the northern hemisphere just a geological blink ago. The terminology has a long history, but is given more meaning, and melancholy, by news this week. I missed tracking this in time for Friday’s email newsletter, but found the research too interesting to just leave unexamined all weekend.
Plenty of news outlets perked up to a paper in Science entitled “Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America.” Its authors, from U. of Wisconsin-Madison mainly, plus colleagues at U. of Wyoming and Fordham, stitch up a detailed tableau of how the mammoths, mastadons, giant sloths, camels, and other great beasts died away – and all inferred from dung fungus and other biological proxies for giant animals and their accompanying plants that were taken from a lake in Indiana and a few places in New York. The analysis concludes that the creatures took their main dive between 14,800 and 13,700 years ago. At the same time vast stretches of grass and brush land converted itself to forest – perhaps because big herbivores weren’t eating the trees anymore.
The point: this millennial-scale die off occurred considerably before when another widely-publicized hypothesis for the extinctions cause, the impact of a small comet somewhere over or near what is now Canada, is supposed to have occurred. That’s a pretty good news hook, even though the impact explanation for the end of mammoths has never quite gone mainstream in the academic community. A better hook, one used by more reporters, is simply that research is startng to pry apart the mystery of the end of the hefty Pleistocene bestiary. No proof of what happened is at hand. But the timing is clearer.
At the Christian Science Monitor Peter N. Spotts zips economically through such points quickly and selects for his first quote one, from an outside authority, who calls the work “elegant” (even with dung spores as exhibit A, it’s elegant!). And he describes nicely the reaction of the research team – which went into it with a limited agenda and would up glimpsing a time when “everything is happening all at once.” Plants and animal in tumult, ice sheets retreating, people showing up, and so on. Climate change, he reports, looks like the big actor (not comets, not spear-chunking hunters. They both would have come after the extinction was basically done).
An unusual twist on the news is at New Scientist. There Jeff Hecht combines the report in Science with some digging into papers and sessions coming up in San Francisco next month at the annual fall meeting of the American Geophysical Union. The AGU is where the comet hypothesis got its first major airing a few years ago. And backers of the impact explanation plan a new round of papers – and expect to encounter plenty of skeptics, Now, reports Hecht, and new paper this week should raise doubters’ eyebrows even more.
Other stories:
- Wired Science – Betsy Mason: Dung Fungus Provides New Evidence in Mammoth Extinction ;
- NYTimes – Nicholas Wade : New Data Shed Light on Large-Animal Extinction ; His lede is different – it stresses that whenever modern peoples came across a landscape of big animals that evolved without people around, the animals tended to get killed off. His implication: N. America, too. But the piece than sketches out how and why, in this case, just maybe H. sapiens is off the hook.
- BBC – Victoria Gill: Dung helps reveal why mammoths died out ;
- Guardian (UK) Ian Sample: Sophisticated hunters not to blame for driving mammoths to extinction ;
- Milwaukee Journal-Sentinel – Mark Johnson: UW scientists creep closer to solving mystery of mammoths’ extinction ;
- NPR – Richard Harris : Fungus Provides Clues to North American Extinctions ; He calls the researchers’ method clever and nifty and adds in some of the other species that went out with the mammoths – beavers big as bears, horses, the American lion, dire wold, and the short-faced bear. One might also add the steppe bison, bigger than our buffalo and with marvelous long horns.
- LiveScience – Jeanna Bryner: Extinction of giant mammals altered landscape ; She muses that the result “could paint a picture of what’s to come if today’s giant plant eaters, such as elephants, disappear.”
Grist for the Mill: U. Wisconsin-Madison Press Release ;
- Charlie Petit
