Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America
Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America
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DOI：
10.1126/science.1179504
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发表时间：
2009-11-20
期刊：
影响因子：
56.9
通讯作者：
Robinson, Guy S.
中科院分区：
文献类型：
--
作者：
Gill, Jacquelyn L.;Williams, John W.;Robinson, Guy S.
虽然北美大型动物群的灭绝和新植物群落的形成是最后一次冰川消融的众所周知的特征，但这些现象之间的因果关系尚不清楚。利用来自印第安纳州阿普尔曼湖和几个纽约遗址的粪便真菌Sporormiella和其他古生态指标，我们确定，大型动物群落的衰退密切早于强化的火灾制度和没有现代类似物的植物群落的发展。Keystone巨型食草动物的丧失可能因此改变了生态系统的结构和功能，因为适口的硬木从食草压力中释放出来，并通过燃料积累。大型动物群的数量从14,800年前崩溃到13,700年前，远在最终灭绝之前和博林-阿勒罗德暖期。人类的影响仍然是可信的，但这种下降早于年轻的仙女座降温和被认为发生在12,900年前的外星撞击事件。
Although the North American megafaunal extinctions and the formation of novel plant communities are well-known features of the last deglaciation, the causal relationships between these phenomena are unclear. Using the dung fungus Sporormiella and other paleoecological proxies from Appleman Lake, Indiana, and several New York sites, we established that the megafaunal decline closely preceded enhanced fire regimes and the development of plant communities that have no modern analogs. The loss of keystone megaherbivores may thus have altered ecosystem structure and function by the release of palatable hardwoods from herbivory pressure and by fuel accumulation. Megafaunal populations collapsed from 14,800 to 13,700 years ago, well before the final extinctions and during the Bolling-Allerod warm period. Human impacts remain plausible, but the decline predates Younger Dryas cooling and the extraterrestrial impact event proposed to have occurred 12,900 years ago.