Big animals crucial for fertility of soils: study 研究︰大型動物對土壤肥力至關重要

Wed, Sep 25, 2013 - Page 10

The mass extinction of large animals in the Pleistocene epoch caused today’s dearth of soil nutrients, scientists said, 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 5-tonne ground sloths, armadillo-like glyptodons the size of a small car, and herds of elephant-like cuvieronius and stegomastodons.

These megafauna, animals weighing more than 44kg, played a key role in fertilizing soil far away from the areas near rivers where they fed — plowing the nutrients they consumed back into circulation through their dung or their decomposing bodies when they died.

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

“Big animals are like the nutrient arteries of the planet and if they go extinct it is like severing these arteries,” co-author Chris Doughty of the University of Oxford’s Environment Change Institute said.(AFP)