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: 2131691
• 负责人: Daniel Mann
• 金额: $ 69.02万
• 依托单位: University of Alaska Fairbanks Campus
• 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=2131691&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.

现在，气候变化的快速变化正在影响生活在北极的动物和植物。学习过去的气候变化时发生的事情可以帮助预测未来50年中可能发生的事情：哪些物种将灭绝，为什么？是否可以采取任何措施保护北极物种免受气候变化的影响？该项目的目的是了解是什么原因导致了巨型冰镇动物的扩展，例如上一个冰河时代结束的时间。有人认为他们被人杀死了。其他人说，他们死于气候迅速变化。没有人知道，但是每个人都在争论。甚至还不知道这些扩展是什么时候发生的：是12，000年前还是4000年前？该项目旨在当上一篇猛mm象，最后一根草原和最后一头苔原狮居住在阿拉斯加时。一旦确定何时灭绝，就可以消除一些拟议的解释。例如，可能事实证明，她的猛mm象在4000年前仍在阿拉斯加漫游。因为众所周知，大约14，000年前的第一批人到达了阿拉斯加，所以如果这个项目表明猛mm象和人们共存了10，000年，那么人们就不太可能开车将他们驱使他们扩展。此处提出的研究将获得更精确的日期，以使用基于将这些动物曾经居住的冷冻地面保存在冷冻地面中的DNA使用新方法居住在阿拉斯加的最后一个冰期哺乳动物。所有动物（包括人）在皮肤碎片，头发，粪便和尿液中不断将DNA脱落到环境中。这些组织碎片中的一些是在地面建造和保存的。在北极的衰变会因寒冷的温度而变慢，这尤其如此。该计划是从地面提取组织碎片（思考：毛皮和头皮屑），然后使用其中包含的DNA来确定其来自哪种动物物种。接下来，将使用包含此DNA的土壤层进行日期，这些新日期将用于测试有关该物种扩展的原因。通过更好地了解过去延伸的原因，仍然可以更好地保护北极哺乳动物，例如北极熊，麝香牛和驯鹿。这项研究的主要目标是教育学生和高中老师有关气候变化，DNA和冰期生态学的知识。将要付出特殊的努力，使其成为阿拉斯加原住民的学生。所有数据都将在每个人都可以免费访问的档案中共享，并且新发现将通过科学出版物，报纸文章和公开讲座共享。北极生态系统现在位于全球变化的前线。迫切需要更好地了解温度，海冰范围和土地使用的迅速变化可能会影响大型北极哺乳动物，例如肌肉牛，北极熊和驯鹿。地质记录保留了许多例子，说明在史前期间气候迅速变化时动物和植物发生了什么。灭绝是特别感兴趣的，因为了解过去导致扩展的原因可以帮助我们保护地球剩余的大型巨型，其中许多人现在濒临灭绝。在最后一个冰河时代结束时，北极发生了一波扩展，14,000至10，000年前。这是大多数科学家认为，像羊毛猛mm象，草原野牛，苔原马和苔原狮子等巨型冰哺乳动物从西伯利亚大陆和阿拉斯加消失了。但是，没有人确定是什么原因引起了这些扩展，并且已经提出了许多解释。这场辩论的原因之一是，仍然缺少关键信息：这些物种何时灭绝？除非在发生扩展时精确地知道，否则无法测试有关原因的各种假设。目前对这些扩展发生的何时发生的理解是基于散布在北大陆的几百个放射性碳末日，而真正的羊毛骨头实际上永远不会被发现。但是现在有一种新的，更好的方法来检测现已灭绝的动物的存在。所有动物在皮肤碎片，头发，粪便和尿液中都将DNA浸入环境中。其中一些DNA被埋葬并保存在地面上，尤其是在北极，由于寒冷，情况缓慢腐烂。该项目的目的是提取灭绝的哺乳动物的古老DNA，使用它来识别其属于哪种物种，然后迄今为止其来自的土壤层。然后，这些新日期可以用于测试有关该物种扩展的原因的想法。在这项研究中，将重点放在教育学生和高中老师有关气候变化，DNA和冰上年龄的生态学方面。将要付出特殊的努力，使其成为阿拉斯加原住民的学生。我们所有的数据都将在每个人都可以自由访问的档案中共享，并且将通过科学出版物，国际会议，报纸文章和公开演讲共享新发现。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响来评估的珍贵的支​​持。