Quantifying the Duration and Impact of Human-Megafauna Overlap in Australia

在美国国家科学基金会考古项目的支持下，吉福德·米勒教授和澳大利亚合作者将在澳大利亚西北部进行实地考察，以确定两种巨型鸟类——已灭绝的巨型鸟Genyornis和现存的澳大利亚鸸鹋（Dromaius）——蛋壳碎片的人类背景。西澳大利亚的野外活动提供了一个独特的机会，可以牢固地建立人类与已灭绝的巨型动物之间的相互作用，并量化人类与巨型动物重叠的持续时间。米勒团队之前的田野调查记录了早期人类使用Genyornis蛋作为食物来源，烹饪，后来在火中燃烧一些蛋壳。这是人类捕食澳大利亚巨型动物的第一个可靠证据。在早期人类居住地点有经验的澳大利亚考古学家将陪同考古队寻找烧焦的蛋壳和人类活动之间的可靠关系。该项目的一个中心目标是应用四种独立的测年方法来确定人类与巨型动物重叠的持续时间；为了实现这一目标，美国和澳大利亚的约会专家组成了一个团队。一项重大创新是开发了一种测量蛋壳中微量铀同位素水平的方案，该方案利用了质谱法的最新发展，大大提高了检测水平。结合这些测量，蛋壳的矿物和有机成分中含有的氧、碳和氮的稳定同位素可以表征气候状况和鸟类的饮食。通过分析早在人类殖民澳大利亚之前到现在生活的鸟类的Dromaius蛋壳，将有可能独立评估气候变化和任何可能发生的饮食变化。这样的数据集可以将与气候变化有关的影响与人类殖民造成的影响区分开来。比较灭绝的Genyornis和共存的Dromaius的饮食喂养策略将有助于理解为什么一种巨型鸟类灭绝了，而另一种适应了同样的压力并存活了下来。澳大利亚的殖民化是世界史前史的一个重要组成部分。更一般地说，了解人类在从未被人类访问过的景观上的殖民足迹，以及人类对陌生环境的适应性是至关重要的。这项研究有可能解决长期存在的争议，即人类是沿着澳大利亚南部的海岸向内陆扩散，还是通过大陆内部扩散。从创始种群开始的分散模式对适应和社会结构都有限制。由于缺乏可靠的测年工具，对早期人类历史上的这些事件进行测年一直受到阻碍。研究的一个关键方面是测试和完善禽蛋壳的U/Th定年。如果成功的话，这个强大的测年工具不仅将重振对澳大利亚早期人类遗址的研究，而且还将对非洲和欧亚大陆的考古研究产生深远的影响，在非洲和欧亚大陆，鸵鸟蛋壳是许多超过14C测年范围的考古遗址的常见元素。这项研究激发了广大公众的想象力。米勒已经推动了相关的电视和大众媒体宣传活动，并将继续这样做。

With support from NSF's Archaeology Program, Prof Gifford Miller and Australian collaborators will conduct fieldwork in NW Australia to define the human context surrounding eggshell fragments from two giant bird species, the extinct megafaunal bird Genyornis, and the extant Australian emu (Dromaius). The Western Australia field campaign offers a unique opportunity to firmly establish the interactions between humans and extinct giant animals, and to quantify the duration of human-megafauna overlap. Previous fieldwork by Miller's team documented early human use of Genyornis eggs as a food source, cooking, and later burning some of the eggshells in their fires. This is the first secure evidence of human predation on the Australian megafauna. Australian archaeologists experienced in early human occupation sites will accompany the team to derive secure relations between the burnt eggshell and human activity.A central goal of this project is to apply four independent dating methods to firmly define the duration of human-megafauna overlap; a team of US and Australian dating experts has been assembled to accomplish this goal. A major innovation is development of a protocol to measure trace levels of uranium isotopes in eggshells, capitalizing on recent developments in mass spectrometry that have greatly improved detection levels. In conjunction with these measurements, the stable isotopes of oxygen, carbon and nitrogen contained in the mineral and organic constituents of the eggshells allow characterization of the status of climate and the birds' diet. By analyzing Dromaius eggshells from birds living long before human colonization of Australia up through the present day it will be possible to evaluate independently changes in both climate and any dietary shifts that may have occurred. Such datasets allow the separation of impacts related to climate change from those due to human colonization. Comparing the dietary feeding strategies of the extinct Genyornis with co-existing Dromaius will help understand why one giant bird became extinct whereas the other adapted to the same stressors and remains extant.The colonization of Australia is an important element in the larger story of World prehistory. More generally, it is essential to understanding the footprint of human colonization of landscapes never before visited by humans, and the adaptability of humans to alien environments. This research has the potential to resolve long-standing disputes whether human dispersal was along the coasts to southern Australia and then inland, or through the continental interior. The dispersal pattern from a founding population provides constraints on both adaptation and social structures. Dating these events in early human history has been hampered by a lack of reliable dating tools. A key aspect of the proposed research is to test and refine U/Th dating of avian eggshell. If successful, the addition of this powerful dating tool will reinvigorate not only the study of early human sites in Australia, but it also will have profound effects in archaeological studies across Africa and Eurasia where ostrich eggshells are common elements of many archaeological sites beyond the range of 14C dating. This research captures the imagination of the general public. Miller has already facilitated related TV and popular media outreach activities, and will continue to do so.