Saturday, August 17, 2013

Big animals crucial for soil fertility

Seed Daily: The mass extinction of large animals in the Pleistocene era caused today's dearth of soil nutrients, scientists said Sunday, and warned of further damage if modern giants like the elephant disappear.

The Pleistocene epoch, which dated from about 2.6 million to 11,700 years ago, saw large animals dubbed megafauna take over domination of the planet from extinct dinosaurs, only to die out en masse themselves.

During their peak, much of the world resembled a modern-day African savannah. South America, for example, was teeming with five-tonne ground sloths, armadillo-like glyptodonts the size of a small car, and herds of elephant-like cuvieronius and stegomastodonts.

These megafauna, animals weighing more than 44 kilograms (97 pounds), played a key role in fertilising soil far away from the areas near rivers where they fed -- ploughing the nutrients they consumed back into circulation through their dung or their decomposing bodies when they died.

Large animals ate much more and travelled further than small ones, and were mainly responsible for long-distance fertilisation, said a study published in the journal Nature Geoscience....

Comparison of the dog-sized weasel Ekorus ekakeran, of what is now Kenya, with the jackal-sized civet, Viverra leakeyi, of what is now South Africa. From the Late Miocene of Africa (C) Stanton F. Fink. Uploaded by Apokryltaros, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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