Collaborative Research: Chronology and Paleoecology of late Quaternary Proboscidean Extinctions in the Great Lakes Region (USA)

职务名称：合作研究：五大湖地区晚第四纪长鼻虫灭绝的年代学和古生态学（美国）Chris Widga 1，Stacey Lengyel 1，Greg Hodgins 2，Jeff Saunders 1，J.道格拉斯沃克31.景观历史计划，伊利诺伊州博物馆，斯普林菲尔德，IL 2。亚利桑那大学-NSF AMS设施，图森，AZ 3。堪萨斯大学地质系，劳伦斯，堪萨斯更新世末期北美哺乳动物35属灭绝的原因引发了长达世纪的激烈争论。争论的焦点是，灭绝的主要驱动力是人类狩猎还是与气候相关的景观变化，其他拟议的灾难性过程对巨型动物种群的影响，还是上述因素的任何组合。不幸的是，区域长鼻怪灭绝时间的模糊性使实际灭绝事件与文化和气候时间表的严格比较变得复杂。这项研究将改善晚第四纪年代学的长鼻兽的proboscidean的proboscidations在五大湖地区通过直接测年的~80猛犸和乳齿象组合从研究领域，在该地区，这些proboscidations出现特别延长。该项目还将通过检查动物饮食的同位素记录（Δ 13 C），季节性（Δ 18 O）和牙齿和骨骼中的流动性（87 Sr/86 Sr），以及个体生活史的骨骼记录（例如，生长速率、病理学）。这些数据集将被用来定义的生态位结构的长鼻动物在过去的50万年的变化，并随后检查的生态位结构的终端更新世长鼻动物在这些长期的模式。这些平行的年代学和古生态学研究将被用来阐明在灭绝之前长鼻目生态位的假定变化的潜在因素，并检查拟议的灭绝过程的相对重要性（例如，人类狩猎，植被变化）在五大湖地区长鼻动物的消失。过时的长鼻虫遗骸，结合个人的生活史，饮食和流动模式的分析，将提供深入了解终端更新世生态系统的五大湖地区的结构，包括拟议的灭绝驱动程序的相对重要性。该项目还具有确定生态阈值的潜力，这些阈值对于在暴露于快速变化的气候条件下维持现代大型哺乳动物种群的生存能力至关重要。

Title: Collaborative Research: Chronology and Paleoecology of late Quaternary Proboscidean Extinctions in the Great Lakes Region (USA)Chris Widga1, Stacey Lengyel1, Greg Hodgins2, Jeff Saunders1, J. Douglas Walker31. Landscape History Program, Illinois State Museum, Springfield, IL2. University of Arizona-NSF AMS Facility, Tucson, AZ3. Department of Geology, University of Kansas, Lawrence, KSThe factors underlying the extinction of 35 genera of North American mammals during the terminal Pleistocene have incited lively debate for over a century. At issue is whether the primary driver of extinctions was human hunting or climate-related landscape changes, the impact of other proposed catastrophic processes on megafaunal populations, or any combination of the above. Unfortunately, ambiguity in the timing of regional proboscidean extinctions has complicated rigorous comparisons of actual extinction events to cultural and climatic timelines. This study will improve the late Quaternary chronology of proboscidean extinctions in the Great Lakes region through direct dating of ~80 mammoth and mastodont assemblages from the study area, a region where these extinctions appear particularly protracted. The project will also refine our understanding of regional evolution in proboscidean ecological niches by examining isotopic records of animal diet (ä13C), seasonality (ä18O), and mobility (87Sr/86Sr) in teeth and bones, as well as skeletal records of individual life histories (e.g., growth rate, pathology). These datasets will be used to define changes in the niche structure of Proboscidea during the last ~50 ka, and to subsequently examine the niche structure of terminal Pleistocene proboscideans in light of these long-term patterns. These parallel chronological and paleoecological studies will be used to elucidate factors underlying presumed changes in proboscidean ecological niches immediately prior to extinction, and to examine the relative importance of proposed extinction processes (e.g., human hunting, vegetation changes) in the disappearance of proboscideans from the Great Lakes region. Dated proboscidean remains, when combined with analyses of individual life histories, diet, and mobility patterns, will offer insight into the structure of terminal Pleistocene ecosystems of the Great Lakes region, including the relative importance of proposed extinction drivers. This project also has the potential to identify ecological thresholds that are important to maintaining the viability of modern large mammal populations when exposed to rapidly changing climate conditions.