South American Megafauna Extinction: A Test of Synergistic Effects of Climate Change and Human Population Growth in Magnifying Extinction Intensity

EAR 1148181南美洲巨型动物的灭绝：气候变化和人口增长在放大灭绝强度中的协同效应的检验一个为期三年的项目将研究气候变化和人类影响增加之间的反馈效应作为物种灭绝的加剧因素。来自南美洲的丰富的哺乳动物化石记录将用于开发第四纪巨型动物灭绝（QME）的精细年表，以确定人类在该大陆不同地区显著存在和气候突变的时间。这项工作将涉及一个由北美和拉丁美洲第四纪科学家组成的国际小组，他们的研究专长是第四纪古生物学、考古学、古气候学和放射性碳定年，他们将获得、评估和解释约52属灭绝的大型哺乳动物物种的大约150个放射性碳定年的意义。将采用统计方法来评估最年轻的放射性碳年代反映灭绝的真实时间有多接近，并将灭绝强度与气候变化的速度和幅度以及人类在景观上日益增长的存在进行比较。从本质上讲，南美洲将被视为一个重复的自然实验（其他的是类似的，已经从北美、欧洲和澳大利亚获得的时间顺序数据），通过一种新的基于定量的方法，来检验目前关于不同动物压力源之间的协同作用大大提高了灭绝的规模和速度的观点。南美洲是做这项工作的合适地点，因为尽管灭绝的年表不如其他大陆为人所知，但它有最多的大型哺乳动物属灭绝，有充足的古生物学、考古学和古环境数据，并且有美洲最早的智人记录。这个项目对于理解不同因素的组合如何加剧物种灭绝是很重要的，这是当今一个主要的全球性问题。这项研究的结果将用于告知公众以及保护和政策团体如何在当前异常强烈和迅速的全球变化条件下最好地保护生物多样性。它将为高中生和大学生提供教育资源。同行评议的结果将通过大众和决策者可获得的媒体传播。该项目将通过培养博士生、建立国际研究网络和提供将用于未来研究和生物多样性监测工作的基础数据，开发人力资源，促进科学和工程素养的提高。

EAR 1148181SOUTH AMERICAN MEGAFAUNA EXTINCTION: A TEST OF SYNERGISTIC EFFECTS OF CLIMATE CHANGE AND HUMAN POPULATION GROWTH IN MAGNIFYING EXTINCTION INTENSITYA three-year project will study the effects of feedbacks between climate change and increasing human impacts as an intensifier of extinction. The rich record of fossil mammals from South America will be used to develop a refined chronology of Quaternary megafaunal extinction (QME) with respect to the timing of significant human presence and abrupt climate change in different regions of the continent. The work will involve an international team of North American and Latin American Quaternary scientists, with research specialties in Quaternary paleobiology, archaeology, paleoclimatology, and radiocarbon dating, to obtain, evaluate, and interpret the meaning of approximately 150 radiocarbon dates on some 52 genera of extinct large-bodied mammal species. Statistical approaches will be employed to assess how closely the youngest radiocarbon dates reflect the true time of extinction and to compare extinction intensity with rates and magnitudes of climate change and growing human presence on the landscape. In essence, South America will be treated as a replicate natural experiment (the others are similar, already-available chronological data from North America, Europe, and Australia) to test, through a new quantitatively-based approach, current ideas that synergy between different faunal stressors greatly enhances magnitude and rapidity of extinction. South America is the appropriate place to do this because, although the extinction chronology is less well-known than on other continents, it had the greatest number large-bodied mammal genera go extinct, has adequate paleontological, archaeological, and paleoenvironmental data, and has the earliest accepted record of Homo sapiens in the Americas. The project is important in understanding how combinations of different causal agents can intensify extinction of species, which is a major global problem today. Results of this research will be used to inform the general public and conservation and policy communities about how best to conserve biodiversity under current conditions of unusually intense and rapid global change. It will contribute educational resources for high school and undergraduate students. Peer-reviewed results will be communicated through media that will be accessible to general audiences and policy makers. The project will develop human resources and contribute to science and engineering literacy by training Ph.D. students, building international research networks, and contributing fundamental data that will be of use in future research and biodiversity monitoring efforts.