WALRUS - Walrus Adaptability and Long-term Responses; Using multi-proxy data to project Sustainability

太平洋海象（Odobenus rosmarus divergens）是受北极近期环境变化影响的众多物种之一。很多人的注意力都集中在2007年至2012年记录的海冰减少，随之而来的是阿拉斯加和俄罗斯海滩上成千上万只海象的出现，以及大量踩踏致死的不幸后果。此外，据报道，2007年弗兰格尔岛上出现了异常数量的身体状况不佳的海象，其中许多随后死亡。虽然海象被拖走和死亡事件在历史上并不是孤立的事件，但这些过去在阿拉斯加海岸被拖走的事件，与海冰数量减少有关，表明这一种群发生了变化。根据2006年与1990年的调查，海象的数量估计有所减少（2006年为12.9万只，1990年为20万只），而目前的生育率下降数据也令人不安。太平洋海象对阿拉斯加（和北极其他地区）的自给自足的消费者至关重要。尽管从过去40-50年对太平洋海象的深入研究中获得了令人印象深刻的数据，但基于这样一个相对较短的时间跨度的数据，很难实施拟议的共同管理和保护计划，更不用说预测北极生态系统的额外变化对海象和在其上生存的人类的影响了。该项目旨在整合考古学、民族学、生物学和生态学等多个学科，利用DNA、稳定同位素、类固醇和微量元素分析等多种数据来源，确定过去两千年来海象摄食生态、觅食地点和种群遗传学的长期趋势。这一时间段包括了中世纪温暖期和小冰河期等大型气候异常期，从而为科学家们提供了了解海象如何适应压力和变化的可能性。现在的样本将从阿拉斯加的猎人那里获得，历史的样本将从博物馆获得，史前的样本将从考古收藏中获得。每种类型的数据都将成为更好地了解海象以及它们如何适应北极生态系统变化的基石。DNA分析将为种群瓶颈和种群间潜在的适应性差异提供洞见。骨骼胶原蛋白和牙齿生长环层的稳定同位素分析将定义个体随时间的整体摄食生态。微量元素分析将揭示它们的觅食地点、潜在的种群结构以及必需元素和非必需元素随时间的变化。骨类固醇激素（即应激激素）可以描述种群结构和健康随时间的变化，翻译历史录音采访和使用以前的档案研究将揭示过去100年来海象栖息地和摄食习惯的传统知识。

The Pacific walrus (Odobenus rosmarus divergens) is one of many species affected by recent environmental change in the Arctic. Much attention has focused on the loss of sea ice recorded from 2007-2012, the concomitant appearance of thousands of walruses on Alaska's and Russia's beaches, and the unfortunate consequence of large numbers of trampling mortalities. In addition, an unusual number of walruses in poor body condition were reported on Wrangel Island in 2007, many of which subsequently died. While walrus haul-out and mortality events are not historically isolated occurrences, these past haul-outs on Alaska's coasts, associated with reduced sea ice abundance, signify a change to this population. These occurrences are disquieting taken together with a decrease in estimated walrus based on surveys from 2006 versus 1990, (129,000 in 2006 compared to 200,000 in 1990), and current data on reduced fertility. The Pacific walrus is of critical importance to subsistence consumers in Alaska (and other areas of the Arctic). Despite impressive data from in-depth studies of Pacific walruses over the last 40-50 years, it is difficult to implement proposed co-management and conservation plans based on data from such a relatively short time span, much less project the impact of additional changes to the Arctic ecosystem on both walruses and humans subsisting on them.This project aims to integrate several disciplines including archaeology, ethnology, biology, and ecology using diverse sources of data including DNA, stable isotope, steroid, and trace element analysis as well as to ascertain long-term trends of walrus feeding ecology, foraging location, and stock genetics over the last two millenia. This time frame includes large climatic anomalies such as the Medieval Warm and the Little Ice Age, thereby presenting scientists with the possibility of understanding how walruses adapt during times of stress and change. Present-day samples will be obtained from Alaskan subsistence hunters, historic samples will be acquired from museums, and prehistoric samples from archaeological collections. Each type of data will act as a building block to better understand walruses and how they adapt to change in Arctic ecosystems. DNA analysis will provide insights into population bottlenecks and potentially adaptive differentiation between stocks. Stable isotope analysis of bone collagen and growth ring layers of teeth will define overall feeding ecologies of individuals through time. Trace element analysis will reveal foraging locations, potential population structure, and changes of essential and non-essential elements over time. Bone steroid hormones (i.e., stress hormones) can delineate population structure and health over time, and translation of historic taped interviews and use of previously archived studies will reveal traditional knowledge of walrus habitats and feeding habits over the last 100 years.