Earlier this week, the New York Times had an article on the use of packrat middens as sources of proxy data for climatic reconstruction. These middens have been an important source of data in the western US for decades, but I can't remember seeing another piece on this in the popular press. From the article:
"Packrats, which look like brown squirrels with Dumbo ears, are skilled home builders, and their massive nests, known as middens, can last 10,000 to 20,000 years (though they are not usually inhabited the entire time).
For that reason, the middens serve as time capsules of desert ecology. By analyzing preserved ancient plants and scat from a variety of middens dating back 12,000 years, Dr. Cole recently proved that a miniature ice age known as the Younger Dryas, long thought to have been confined to the North Atlantic, was also felt in the American Southwest.
The analysis demonstrated that after the Younger Dryas, average temperatures in the area climbed about 14 degrees Fahrenheit in just a few hundred years — a precipitous rise that is lending insight into the effects of today’s warming trends on desert ecosystems.
“After the warming period, you notice that fewer tree and shrub species appear in the middens,” Dr. Cole said. “That’s exactly what’s happening in the Southwest now.”
The middens are full of pollen and other plant data and the preserved organics are easily radiocarbon dated. The structures of the middens are cemented together with dried rat urine and picking them apart to gather data is a smelly and unpleasant job - but apparently not bad enough to make the list of the 10 dirtiest jobs in science.
One of the earliest effective practitioners of this form of analysis is Paul Martin author of Twilight of the Mammoths, a book we much admire. Martin was dissertation committee chairman for Steve's brother-in-law, David Adam, and a colleague of a graduate school friend of mine, Steve Emslie.
A review of the ethnographic literature shows that packrack middens sometimes served other purposes for Native Americans.
2 comments:
"temperatures in the area climbed about 14 degrees Fahrenheit in just a few hundred years ": Dear God, how did our wicked ancestors cause that?
I've always cherished Loren Eiseley's fantasy about prying apart a packrat's midden and causing a Beethoven symphony to fall out.
On the other hand I didn't cherish the packrat who stole all my underwear one night, leaving me several half-rotten apples.
Prairie Mary
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