Collaborative Research: Paleoclimate, Paleoenvironment and Other Potential Drivers of Extinction of Mammuthus primigenius, St. Paul Island, Pribilof Islands, Alaska.

该项目将提供关于白令海陆桥南缘海平面上升对古气候、古环境和生物多样性影响的新数据，并有助于更好地理解为什么长毛猛犸象只在该地区的北极岛屿环境中存活到全新世中期。此外，本研究将试图确定阿拉斯加普里比洛夫群岛圣保罗岛上全新世猛犸象种群灭绝的实际时间，并应用这些信息来检验各种关于灭绝的因果假设。来自圣保罗Cagaloq湖的岩心将采集chironomids（水生无脊椎动物）、花粉、嗜粪真菌孢子、植物大化石、木炭、古代DNA和隐藻的样本。手摇鱼头部的氧同位素将提供一个独立的气候记录，可以通过对手摇鱼组合的古生态分析来补充。研究还将测试摇尾虫物种的同位素分馏，以从地下水效应中分离气候信号。通过花粉、孢子和植物大化石重建陆生群落的变化；木炭频率将用于记录火灾事件。对古代DNA的分析将提供传统分析方法未检测到的隐藏植物和动物物种的数据，也可用于分类群到物种的识别。生长在动物粪便上的孢子将被用作猛犸象种群规模的代用品，并记录岛上猛犸象灭绝的时间。古代DNA将作为重要的交叉检查，通过帮助解决这些孢子的具体鉴定，以及通过缺乏猛犸象DNA提供对灭绝时间的独立估计。数字高程、水深数据、海平面曲线和地理信息系统（GIS）技术将用于重建岛屿从孤立到今天的大小。通过使用14c日期和tephras，将获得一个高度受限的Cagaloq记录年表。为了验证猛犸象灭绝的假设，所有的数据都可以进行暂时的比较。本项目将提供2名博士生、1名博士后、1名研究生助理和1名本科生。这项研究的结果将在同行评议的期刊上广泛传播。宾夕法尼亚州立大学的EMS博物馆将用网络组件准备一个关于该项目的成果的展览。此外，一个特别的在线互动展览将允许参与者重建不同大小的岛屿，在岛上居住不同的猛犸象种群，并定义不同的气候和环境因素，以观察这些因素如何影响猛犸象的灭绝。互动式展览将在Neotoma数据库中提供。该小组的成员将在费尔班克斯的阿拉斯加第四纪中心就该项目进行介绍，该中心是促进阿拉斯加第四纪研究和向公众宣传的中心。

This project will provide new data on the paleoclimates, paleoenviroments and the biodiversity impacts of sea level rise on the southern edge of the Bering Land Bridge (BLB), and is intended to facilitate a better understanding of why woolly mammoths survived late into the mid-Holocene only in the environments of Arctic islands of this area. Furthermore, this research will attempt to establish the actual time of extinction of the Holocene mammoth population on St. Paul Island, Pribilof Islands, Alaska, and apply this information to test various proposed causal hypotheses for the extinction.Cores from Cagaloq Lake, St. Paul, will be sampled for chironomids (aquatic invertebrates), pollen, coprophilous fungi spores, plant macrofossils, charcoal, ancient DNA and cryptotephras. Oxygen isotopes from the heads of chironomids will provide an independent climate record that can be supplemented by paleoecological analyses of the chironomid assemblages. Studies will also test chironomid species for isotope fractionation to disentangle climate signals from ground water effects. Terrestrial community changes will be reconstructed from pollen, spores and plant macrofossils; and charcoal frequency will be used to document fire events. Analysis of ancient DNA will provide data on cryptic plant and animal species that have not been detected by traditional methods of analysis, and can also be used to identify taxa to species.Spores that grow on animal dung will be used as proxies for the mammoth population size and to document the time of mammoth extinction on the island. Ancient DNA will serve as an important cross-check by helping to resolve specific identifications of these spores as well as providing an independent estimate the time of extinction by the absence of mammoth DNA.Digital elevations, bathymetric data, sea level curves, and Geographic Information System (GIS) technology will be used to reconstruct island size from the time of its isolation until today. A highly constrained chronology of the Cagaloq record will be achieved by using 14 C dates and tephras. All data can be compared temporally in order to test hypotheses for mammoth extinction. This project will provide opportunities for two PhD students, a postdoctoral fellow, graduate student assistant and undergraduate student. Results of the study will be disseminated widely in peer-reviewed journals. An exhibit on the results of the project will be prepared by the EMS Museum at Penn State University with a web component. In addition, a special on-line, interactive exhibit will allow participants to reconstruct the island at various sizes, populate it with differing mammoth populations and define different climate and environmental factors to observe how each of these components affects mammoth extinction. The interactive exhibit will be available on the Neotoma database. Members of the group will make presentations on the project at the Alaska Quaternary Center in Fairbanks, which serves as a hub for promoting Alaska Quaternary research and outreach to the public.