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陆桥（BLB）南缘的古气候、古环境和海平面上升对生物多样性影响的新数据，并旨在促进更好地了解为什么长毛猛犸象仅在该地区的北极岛屿环境中存活到全新世中期。此外，本研究将尝试建立阿拉斯加Pribilof群岛圣保罗岛全新世猛犸种群灭绝的实际时间，并将此信息应用于测试各种提出的灭绝因果假说。来自圣保罗Cagaloq湖的岩芯将被取样用于摇蚊（水生无脊椎动物）、花粉、粪生真菌孢子、植物宏体化石、木炭、古DNA和隐孢子虫。摇蚊头部的氧同位素将提供一个独立的气候记录，可以通过对摇蚊组合的古生态分析来补充。研究还将测试摇蚊物种的同位素分馏，以从地下水影响中分离气候信号。陆地群落的变化将重建从花粉，孢子和植物宏化石和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无法发现的神秘植物和动物物种的数据，也可用于确定物种的分类群。在动物粪便上生长的孢子将被用作猛犸种群规模的替代物，并记录岛上猛犸灭绝的时间。古DNA将作为一个重要的交叉检查，通过帮助解决这些孢子的具体鉴定，以及提供一个独立的估计灭绝的时间，由于没有猛犸DNA，数字高程，测深数据，海平面曲线，和地理信息系统（GIS）技术将被用来重建岛屿的大小，从时间的隔离，直到今天。一个高度约束的年代Cagaloq记录将实现使用14 C日期和tephras。所有的数据都可以在时间上进行比较，以检验猛犸灭绝的假设。该项目将为两名博士生，一名博士后研究员，研究生助理和本科生提供机会。研究结果将在同行评审的期刊上广泛传播。宾夕法尼亚州立大学的EMS博物馆将准备一个关于该项目成果的展览，其中包括一个网络组件。此外，一个特别的在线互动展览将使参与者能够重建不同大小的岛屿，用不同的猛犸种群填充岛屿，并确定不同的气候和环境因素，以观察这些因素中的每一个如何影响猛犸灭绝。互动展览将在Neotoma数据库上提供。该小组的成员将在位于费尔班克斯的阿拉斯加第四纪中心就该项目作报告，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.