Collaborative research: Paleobiology and exinction of mammoths in northern Siberia and Wrangel Island

摘要长毛猛犸象（Mammuthus primigenius）在距今约1万年前的西伯利亚大陆和距今仅3700年前的西伯利亚东北海岸弗兰格尔岛灭绝之前，一直是冰河时期动物群的重要成员。这个项目将阐明猛犸象生物学的各个方面，猛犸象灭绝的原因，以及从冰河时代到今天更典型的气候过渡期间环境变化的本质。支持这些进步的新数据来自猛犸象的象牙，这是所有大象近亲的典型的放大门牙，经常从北极永久冻土中发现。猛犸象的象牙是通过一生的过程在象牙基部增加锥形层而形成的。这一过程受到气候、食物资源、行为和生殖历史等复杂相互作用的调节，并因此被记录下来。通过在象牙的多个位置钻取材料岩芯，并分析这些岩芯中各层的结构和组成，我们将收集饮食、气候、健康状况、迁徙运动和生殖史的记录。这提供了一幅关于猛犸象在其一生中如何对环境条件做出反应的详细图景，哪些变化与它们在冰河时代末期活动范围的急剧缩小有关，以及在它们最终灭绝之前发生了哪些变化。该项目将包括密歇根大学和明尼苏达大学的合作项目负责人和研究生，以及俄罗斯和欧洲的合作者，在西伯利亚中北部、西伯利亚东北部和弗兰格尔岛进行实地考察。我们将收集新的标本，现有标本中的样本，并将样本送回国内机构进行分析。分析程序将包括(a)放射性碳定年，将每个标本置于时间和空间背景中；(b)记录生长线，列出生活史的基本框架；(c)氧、碳和氮同位素分析，评估饮食、气候和生理方面；(d)锶同位素分析，评估迁徙运动模式。猛犸象牙是自然历史和环境数据的丰富档案，该项目协调了一系列广泛的方法来提取这些信息并将其应用于多个领域的研究问题。该项目的合作方面支持了欧洲和亚洲的国际合作，猛犸象和猛犸象象牙的戏剧性特征使这项工作吸引了非专业观众，以及对数据感兴趣的古生物学家、生态学家、考古学家和气候建模者。

Collaborative Research: Paleobiology and Extinction of Mammoths in northern Siberia and Wrangel IslandDaniel C. Fisher, Univ. Michigan EAR-0615095David L. Fox, Univ. Minnesota EAR-0615090ABSTRACT Woolly mammoths (Mammuthus primigenius) were important members of Ice Age faunas until the time of their extinction, about 10,000 years ago on the Siberian mainland, and only 3700 years ago on Wrangel Island, off the northeast coast of Siberia. This project will clarify aspects of mammoth biology, the cause of mammoth extinction, and the nature of environmental change during the transition from the Ice Age to climates more typical of today's conditions. The new data that permit these advances come from mammoth tusks, the enlarged incisor teeth typical of all elephant-relatives and frequently recovered from the Arctic permafrost. Mammoth tusks formed through a life-long process of adding cone-shaped layers to the tusk base. This process was modulated by, and thus recorded, complex interactions involving climate, food resources, behavior, and reproductive history. By drilling cores of material from multiple positions along tusks and analyzing the structure and composition of the layers in these cores, we will assemble records of diet, climate, health status, migratory movements, and reproductive history. This yields a detailed picture of how mammoths responded to environmental conditions during their lifetimes, what changes were associated with their dramatic reduction in range, near the end of the Ice Age, and what changes preceded their final extinction. This project will involve fieldwork by University of Michigan and University of Minnesota Co-PIs and graduate students, along with Russian and European collaborators, in north-central Siberia, northeast Siberia, and Wrangel Island. We will collect new specimens, sample specimens in existing collections, and return samples for analysis at our home institutions. Analytical procedures will include (a) radiocarbon dating, to place each specimen in a temporal as well as a spatial context, (b) documentation of growth lines, to lay out the basic framework of life history, (c) oxygen, carbon, and nitrogen isotope analyses, to assess aspects of diet, climate, and physiology, and (d) strontium-isotope analyses to evaluate patterns of migratory movement. Mammoth tusks are a rich archive of natural history and environmental data, and this project coordinates a broad array of approaches for distilling this information and applying it to research questions in multiple fields. Collaborative aspects of this project support international cooperation in Europe and Asia, and the dramatic character of mammoths and mammoth tusks makes this work engaging for non-specialist audiences, in addition to the paleontologists, ecologists, archaeologists and climate modelers interested in the data.