Collaborative Research: The Lost Pastures of Alaska's Last Megafauna

合作研究：阿拉斯加最后巨型动物消失的牧场

• 批准号: 2131589
• 负责人: Beth Shapiro
• 金额: $ 29.4万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2131589&HistoricalAwards=false
• 关键词: Collaborative; Research; Lost; Pastures; Alaska

Rapid climate changes are now impacting the animals and plants that live in the Arctic. Learning what happened when climate changed in the past can help predict what could happen over the next 50 years: Which species will become extinct, and why? Is there anything that can be done to protect Arctic species from the impacts of climate change? The goal of this project is to understand what caused the extinctions of giant, ice-age animals like woolly mammoth around the time that the last ice age ended. Some people think they were killed off by people; others say they died because of rapid changes in climate. No one knows for certain, but everyone argues about it. It is not even known when, exactly, these extinctions occurred: Was it 12,000 years ago, or 4000 years ago? This project aims at pin-pointing when the last mammoth, the last steppe bison, and the last tundra lion lived in Alaska. Once it is known for certain when they became extinct, it will be possible to eliminate some of the proposed explanations. For example, it may turn out that herds of mammoths still roamed across Alaska 4000 years ago. Because it is already known that the first people arrived in Alaska around 14,000 years ago, if this project shows that mammoths and people coexisted for 10,000 years, it makes it unlikely that people drove them to extinction. The research proposed here will obtain more precise dates on when the last ice-age mammals lived in Alaska using new methods based on the DNA that is preserved in frozen ground where these animals once lived. All animals (people included) continually shed DNA into the environment in their skin fragments, hair, feces, and urine. Some of these tissue fragments are buried and preserved in the ground. This is especially true in the Arctic where decay is slowed by cold temperatures. The plan is to extract tissue fragments (think: fur and dandruff) from the ground, and then use the DNA it contains to identify which animal species it came from. Next, the soil layer containing this DNA will be dated, and these new dates will be used to test ideas about what caused this species’ extinction. By better understanding the causes of extinctions in the past, the Arctic mammals that still survive can be better protected, species like polar bears, musk oxen, and caribou. A major goal of this study is to educate students and high school teachers about climate change, DNA, and ice-age ecology. A particular effort will be made to involve students who are Alaskan Natives. All data will be shared in archives that everyone has free access to, and new discoveries will be shared through scientific publications, newspaper articles, and public lectures. Arctic ecosystems now lie on the front lines of global change. There is an urgent need to better understand how rapid changes in temperature, sea-ice extent, and land use could impact large-bodied Arctic mammals like musk oxen, polar bears, and caribou. The geological record preserves many examples of what happened to animals and plants when climate changed rapidly during prehistory. Extinctions are of particular interest, because understanding what caused extinctions in the past can help us conserve the planet’s remaining megafauna, many of which are now endangered. A wave of extinctions occurred in the Arctic around the end of the last ice age, 14,000 to 10,000 years ago. This is when most scientists believe that giant ice-age mammals like woolly mammoth, steppe bison, tundra horses, and tundra lions disappeared from mainland Siberia and Alaska; however, no one is sure what caused these extinctions, and many explanations have been proposed. One reason for this debate is that a key piece of information is still missing, namely: When did these species actually go extinct? Unless it is known with precision when an extinction occurred, the various hypotheses about causation cannot be tested. Present understanding of when these extinctions occurred is based on a few hundred radiocarbon dates scattered across the northern continents, and there is a real possibility that the bones of the last woolly mammoth will never be discovered. But now there is a new and better way to detect the presence of now-extinct animals. All animals shed DNA into the environment in their skin fragments, hair, feces, and urine. Some of this DNA is buried and preserved in the ground, especially in the Arctic, where things decay slowly because it is cold. The aim of this project is to extract the ancient DNA of extinct mammals, use it to identify which species it belonged to, and then to date the soil layer where it came from. These new dates can then be used to test ideas about what caused this species’ extinction. In this study, emphasis will be placed on educating students and high school teachers about climate change, DNA, and ice-age ecology. A particular effort will be made to involve students who are Alaskan Natives. All our data will be shared in archives that everyone has free access to, and new discoveries will be shared through scientific publications, international conferences, newspaper articles, and public lectures.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.

快速的气候变化正在影响生活在北极的动植物，了解过去气候变化时发生的情况有助于预测未来 50 年可能发生的情况：哪些物种将灭绝，为什么？可以采取哪些措施来保护北极物种免受气候变化的影响？该项目的目标是了解上一个冰河时代结束时，导致猛犸象等巨型冰河动物灭绝的原因。被别人杀掉了；没有人确切知道它们是因为气候变化而死亡的，但每个人甚至都不知道这些灭绝发生在 12,000 年前，还是 4000 年前？确定最后一只猛犸象、最后一只草原野牛和最后一只苔原狮子生活在阿拉斯加的时间 一旦确定它们灭绝的时间，就有可能消除一些提出的解释。例如，事实可能是，4000 年前，成群的猛犸象仍然在阿拉斯加漫游，因为众所周知，第一批人类在大约 14,000 年前抵达阿拉斯加，如果这个项目表明猛犸象和人类共存了 10,000 年，那么它就可以证明。人类不太可能导致它们灭绝，这里提出的研究将利用基于保存的 DNA 的新方法，获得关于阿拉斯加最后一批哺乳动物生活时间的更精确日期。在这些动物曾经生活过的冰冻土地上，所有动物（包括人类）都不断地将 DNA 通过其皮肤碎片、毛发、粪便和尿液排放到环境中，其中一些组织碎片被埋藏并保存在地下。在北极，寒冷的温度会减缓腐烂速度，计划是从地下提取组织碎片（例如：皮毛和头皮屑），然后使用其中包含的 DNA 来识别它来自哪种动物物种。含有该 DNA 的样本将被标明日期，并且这些新的日期将用于测试导致该物种灭绝的原因，通过更好地了解过去灭绝的原因，仍然可以生存的北极哺乳动物，如北极熊、麝牛和驯鹿等物种可以得到更好的保护。这项研究的一个主要目标是对学生和高中教师进行有关气候变化、DNA 和冰河时代生态学的教育，并将特别努力让阿拉斯加原住民的学生参与其中。所有数据都将在每个人的档案中共享。可以免费访问，并且有新的北极生态系统现在处于全球变化的前沿，我们迫切需要更好地了解温度、海冰范围和土地利用的快速变化。地质记录保存了许多史前时期气候快速变化时动物和植物发生的情况特别令人感兴趣，因为了解导致灭绝的原因。过去的历史可以帮助我们保护地球上剩余的巨型动物，其中许多现在已濒临灭绝，大约在 14,000 至 10,000 年前的最后一个冰河时代结束时，北极发生了一次灭绝浪潮。长毛猛犸象、草原野牛、苔原马和苔原狮子等老年哺乳动物从西伯利亚大陆和阿拉斯加消失了；然而，没有人确定是什么导致了这些灭绝；引起这场争论的一个原因是，仍然缺少一条关键信息，即：这些物种实际上是什么时候灭绝的？除非准确地知道灭绝发生的时间，否则关于因果关系的各种假设都无法成立。目前对这些灭绝发生时间的了解是基于散布在北部大陆的数百个放射性碳测年数据，最后一只猛犸象的骨头很可能永远不会被发现，但现在有一种新的更好的方法来发现。检测到的存在所有动物都会通过皮肤碎片、毛发、粪便和尿液将 DNA 排放到环境中，其中一些 DNA 被埋藏并保存在地下，尤其是在北极，那里的东西由于寒冷而缓慢腐烂。该项目的目的是提取已灭绝哺乳动物的古代 DNA，用它来识别它属于哪个物种，然后确定它来自的土壤层，然后可以使用这些新的日期来测试造成这种现象的原因。在这项研究中，强调了这个物种的灭绝。我们将致力于对学生和高中教师进行有关气候变化、DNA 和冰河时代生态学的教育，并将特别努力让阿拉斯加原住民学生参与其中。我们的所有数据都将在每个人都可以免费访问的档案中共享。 ，新发现将通过科学出版物、国际会议、报纸文章和公开讲座来分享。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Deep-time paleogenomics and the limits of DNA survival

深时古基因组学和 DNA 生存的极限

• DOI: 10.1126/science.adh7943
• 发表时间: 2023-10-06
• 期刊: Science
• 影响因子: 56.9
• 作者: Dalen, Love;Heintzman, Peter D.;Kapp, Joshua D.
• 通讯作者: Kapp, Joshua D.