Aridity and hominin environments
Aridity and hominin environments
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DOI：
10.1073/pnas.1700597114
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发表时间：
2017-07-11
影响因子：
11.1
通讯作者：
Cerling, Thure E.
中科院分区：
文献类型：
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作者：
Blumenthal, Scott A.;Levin, Naomi E.;Cerling, Thure E.
干旱化通常被认为是非洲东部上新世-更新世长期生态变化和人类进化的主要驱动力;然而，由于重建陆地古气候的困难，这一假设仍然没有得到充分的验证。我们提出了一个修订后的干旱指数量化水赤字（WD）在陆地环境中使用牙釉质三角洲O-18值，并使用这种方法来解决在过去的440万年在非洲东部的古干旱。我们发现没有长期的趋势，WD，与其他陆地气候指标在Omo-Turkana盆地，和没有关系的古干旱和草食动物的古饮食结构化石收集满足标准WD估计。因此，我们认为，丰富的C-4草和放牧食草动物在非洲东部的上新世和更新世的变化可能已经脱钩干旱。在现代非洲生态系统中，其他因素，如降雨季节性或植物和哺乳动物之间的生态相互作用，可能是重要的理解C-4草和食草动物为主的生物群落的演变。
Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel delta O-18 values, and use this approach to address paleoaridity over the past 4.4 million years in eastern Africa. We find no long-term trend in WD, consistent with other terrestrial climate indicators in the Omo-Turkana Basin, and no relationship between paleoaridity and herbivore paleodiet structure among fossil collections meeting the criteria for WD estimation. Thus, we suggest that changes in the abundance of C-4 grass and grazing herbivores in eastern Africa during the Pliocene and Pleistocene may have been decoupled from aridity. As in modern African ecosystems, other factors, such as rainfall seasonality or ecological interactions among plants and mammals, may be important for understanding the evolution of C-4 grass-and grazer-dominated biomes.