Testing the Refugia Hypothesis in Southeast Alaska Using Paleogenetics and Glacial Chronology

利用古遗传学和冰川年代学检验阿拉斯加东南部的避难所假说

• 批准号: 1854550
• 负责人: Charlotte Lindqvist
• 金额: $ 54.22万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1854550&HistoricalAwards=false
• 关键词: Testing; Refugia; Hypothesis; Southeast; Alaska

Vast ice sheets covered northern North America during the last Ice Age. These ice sheets blocked movements of plants and animals between Asia and the Americas for many thousands of years. Many species died out and others were forced into isolated, ice-free areas (refugia) north and south of the ice sheets. Today?s plants and animals carry the genetic legacy of the Ice Age and this refugial isolation, but it is not completely known how it impacted and shaped the past trajectory of many species and their movements following the retreat of the ice sheets. Yet, such knowledge is important for understanding how plants and animals may respond in the future due to environmental changes. The exact extent and timing of ice coverage is also poorly known, and islands along the northwestern coast of North America are hypothesized to have escaped Ice Age glaciation. This means they could have acted as a unique bottleneck for the passage of plants and animals in the geologic past, and even perhaps that they were an early gateway for the peopling of the Americas. This research is aimed at improving knowledge of a critical region for plant, animal, and even human migration: Southeast Alaska. We are testing the hypothesis that coastal areas in Southeast Alaska escaped ice cover by collecting rock samples that will tell us whether or not landscapes were covered by ice and when they became ice-free. We are studying the DNA preserved in fossil bones from mammals that died thousands of years ago. This research project is providing much needed insights into the history of iconic mammals and their environmental conditions in Southeast Alaska.The westernmost extent and timing of ice cover along the North Pacific Coast during the Last Glacial Maximum is poorly known, leaving unanswered fundamental questions about the impact of climatic change on biotic diversification and postglacial colonization of the Americas. Various lines of evidence point to the existence of a viable, ice-free coastal corridor that may have played an important role for biotic exchange between the Old and New Worlds during the last Ice Age. This project is designed to be the definitive test of the hypothesis in support of coastal refugia. We are taking advantage of cutting-edge technologies in cosmogenic nuclide exposure dating and paleogenetic analyses of an unparalleled fossil collection from caves in SE Alaska to achieve two key objectives: (1) directly determine if SE Alaska provided ice-free refugia for terrestrial mammals during the LGM, and (2) constrain the extent and history of the western Cordilleran Ice Sheet during the LGM. Whether the hypothesis is supported or not, this highly interdisciplinary project will deliver results with high impact and have important implications for many different disciplines spanning the geological, biological, paleontological, and archeological sciences. The results will answer a broad range of key questions about the dynamic glacial conditions of SE Alaska during the Ice Age, biogeographic history of mammal island populations, and the configuration and timing of an available migration corridor for the postglacial peopling of the Americas. This research will (a) provide training opportunities for graduate and undergraduate students, (b) broadly disseminate results and links to associated relevant topics, such as environmental change and human migration, through a website, and (c) organize a workshop in SE Alaska with public and K-12 outreach components to synthesize past and current research and focus on the intersection between research, natural resource management, and the impact of future climate projections on biotic systems across the archipelago.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在上一个冰河时代，巨大的冰盖覆盖了北美北部。数千年来，这些冰盖阻碍了亚洲和美洲之间动植物的移动。许多物种灭绝了，其他物种被迫进入冰原北部和南部孤立的无冰地区（避难所）。今天的植物和动物携带着冰河时代和这种避难隔离的遗传遗产，但人们并不完全清楚它是如何影响和塑造许多物种过去的轨迹及其在冰盖消退后的迁徙的。然而，这些知识对于了解植物和动物未来如何应对环境变化非常重要。冰覆盖的确切范围和时间也鲜为人知，据推测，北美西北海岸的岛屿已经逃脱了冰河时代的冰川作用。这意味着它们可能是地质历史上植物和动物通行的独特瓶颈，甚至可能是美洲人类的早期门户。这项研究旨在提高对植物、动物甚至人类迁徙的关键地区：阿拉斯加东南部的了解。我们正在通过收集岩石样本来测试阿拉斯加东南部沿海地区逃脱冰雪覆盖的假设，这些岩石样本将告诉我们地貌是否被冰覆盖以及何时变得无冰。我们正在研究数千年前死亡的哺乳动物骨骼化石中保存的 DNA。该研究项目为阿拉斯加东南部标志性哺乳动物的历史及其环境条件提供了急需的见解。末次盛冰期期间北太平洋沿岸冰盖最西端的范围和时间人们知之甚少，因此关于阿拉斯加东南部的基本问题尚无答案。气候变化对美洲生物多样性和冰河后殖民化的影响。各种证据表明存在一条可行的、无冰的沿海走廊，它可能在上一个冰河时代期间在新旧世界之间的生物交换中发挥了重要作用。该项目旨在对支持沿海避难所的假设进行最终检验。我们正在利用宇宙成因核素暴露测年和古遗传学分析方面的尖端技术，对阿拉斯加东南部洞穴中无与伦比的化石集合进行分析，以实现两个关键目标：（1）直接确定阿拉斯加东南部是否在（2）限制末次盛冰期西科迪勒拉冰盖的范围和历史。无论该假设是否得到支持，这个高度跨学科的项目都将产生具有重大影响的成果，并对地质、生物、古生物学和考古学等许多不同学科产生重要影响。研究结果将回答一系列广泛的关键问题，包括冰河时代阿拉斯加东南部的动态冰川条件、哺乳动物岛屿种群的生物地理历史，以及美洲冰河后人类可用迁徙走廊的配置和时间安排。这项研究将（a）为研究生和本科生提供培训机会，（b）通过网站广泛传播结果和相关主题的链接，例如环境变化和人类移民，以及（c）在阿拉斯加东南部组织研讨会与公共和 K-12 外展部分相结合，综合过去和当前的研究，重点关注研究、自然资源管理以及未来气候预测对整个群岛生物系统的影响之间的交叉点。该奖项反映了 NSF 的法定使命，并被视为值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。

项目成果

Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska

古代熊为阿拉斯加东南部更新世冰河时代的避难所提供了见解

• DOI: 10.1111/mec.16960
• 发表时间: 2023-04
• 期刊: Molecular Ecology
• 影响因子: 4.9
• 作者: da Silva Coelho, Flavio Augusto;Gill, Stephanie;Tomlin, Crystal M.;Papavassiliou, Marilena;Farley, Sean D.;Cook, Joseph A.;Sonsthagen, Sarah A.;Sage, George K.;Heaton, Timothy H.;Talbot, Sandra L.;et al
• 通讯作者: et al

New constraints on the last deglaciation of the Cordilleran Ice Sheet in coastal Southeast Alaska

阿拉斯加东南沿海科迪勒拉冰盖末次消融的新限制

• DOI: 10.1017/qua.2020.32
• 发表时间: 2020-07
• 期刊: Quaternary Research
• 影响因子: 2.3
• 作者: Lesnek, Alia J.;Briner, Jason P.;Baichtal, James F.;Lyles, Alex S.
• 通讯作者: Lyles, Alex S.

A cosmogenic nuclide chronology of Cordilleran Ice Sheet configuration during the Last Glacial Maximum in the northern Alexander Archipelago, Alaska.

阿拉斯加亚历山大群岛北部末次盛冰期科迪勒拉冰盖结构的宇宙成因核素年代学。

• DOI: 10.5194/gchron-4-191-2022.
• 发表时间: 2022-04
• 期刊: Geochronology
• 作者: Walcott, C.K.;Briner, J.P.;Baichtal, J.F.;Lesnek, A.J.;Licciardi, J.M.
• 通讯作者: Licciardi, J.M.

A paleogenome from a Holocene individual supports genetic continuity in Southeast Alaska

来自全新世个体的古基因组支持阿拉斯加东南部的遗传连续性

• DOI: 10.1016/j.isci.2023.106581
• 发表时间: 2023-05-19
• 期刊: iScience
• 影响因子: 5.8
• 作者: Aqil, Alber;Gill, Stephanie;Gokcumen, Omer;Malhi, Ripan S.;Reese, Esther Aaltseen;Smith, Jane L.;Heaton, Timothy T.;Lindqvist, Charlotte
• 通讯作者: Lindqvist, Charlotte

Insights into bear evolution from a Pleistocene polar bear genome

从更新世北极熊基因组洞察熊的进化

• DOI: 10.1101/2021.12.11.472228
• 发表时间: 2021-12-12
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: T. Lan;K. Leppälä;Crystal M. Tomlin;S. Talbot;G. K. Sage;S. Farley;R. Shideler;L. Bachmann;Ø. Wiig;V. Albert;J. Salojärvi;T. Mailund;Daniela I. Drautz;S. Schuster;L. Herrera;C. Lindqvist
• 通讯作者: C. Lindqvist