一万两千年前南美洲大型草食动物的减少导致亚马逊流域的营养物质横向运输的下降，这也可以解释为何今天的亚马逊盆地可用磷元素变得有限，9月《自然—地球科学》上的一项研究给出上述结论。
Christopher Doughty等人利用模型演示了诸如大型树獭和犰狳类雕齿兽一类的远古巨型动物会通过粪便和身体携带的方式将营养物质从高浓度区域带向周边地区。他们通过一系列的计算发现，这些动物的灭绝会伴有地区间营养物质横向运输的显著减少。这种情况在亚马逊盆地是最显著的，减少率最高可达98%，但美洲、欧亚和澳洲地区也普遍存在这种现象。
Tanguy Daufresne在一篇评论文章中称“随着那些对营养物质分布起促进作用的巨型动物的印记逐渐消逝，现在也许是时候追问生物地球化学给全球带来的后果了”。（生物谷 Bioon.com）
生物谷推荐的英文摘要
Nature Geoscience doi:10.1038/ngeo1895
The legacy of the Pleistocene megafauna extinctions on nutrient availability in Amazonia
Christopher E. Doughty, Adam Wolf & Yadvinder Malhi
In the late Pleistocene, 97 genera of large animals went extinct, concentrated in the Americas and Australia1. These extinctions had significant effects on ecosystem structure2, seed dispersal3 and land surface albedo4. However, the impact of this dramatic extinction on ecosystem nutrient biogeochemistry, through the lateral transport of dung and bodies, has never been explored. Here we analyse this process using a novel mathematical framework that analyses this lateral transport as a diffusion-like process, and we demonstrate that large animals play a disproportionately large role in the horizontal transfer of nutrients across landscapes. For example, we estimate that the extinction of the Amazonian megafauna decreased the lateral flux of the limiting nutrient phosphorus by more than 98%, with similar, though less extreme, decreases in all continents outside of Africa. This resulted in strong decreases in phosphorus availability in eastern Amazonia away from fertile floodplains, a decline which may still be ongoing. The current P limitation in the Amazon basin may be partially a relic of an ecosystem without the functional connectivity it once had. We argue that the Pleistocene megafauna extinctions resulted in large and ongoing disruptions to terrestrial biogeochemical cycling at continental scales and increased nutrient heterogeneity globally.
