DISSERTATION RESEARCH: Shifting climates and stable niches: Assessing the impact of ancient climate cycles on phylogeographic structure within three Andean marsupials

这项研究调查了过去几十万年来冰河时代的极端气候波动如何影响物种的地理分布，遗传结构和多样性。理论表明，波动的气候可能是促进多样化的一种力量。为了更好地了解古代气候波动对物种多样性的具体影响，该项目将重点放在一组生活在南美洲安第斯山脉的有袋动物（Thylamys opossums）上。遗传数据和计算工具将用于对遥远过去发生的事件进行推断。有了这些遗传学证据，关于古代气候变化对物种多样性的影响的假设就可以得到检验。只有少数研究在古代气候波动的背景下研究了安第斯哺乳动物的进化模式，在这项工作之前，没有人考虑过这些因素对Thylamys物种的影响。这个项目是重要的，不同于以往的努力，因为它将明确测试替代进化假说使用多种类型的遗传数据，每个种群的地理分布的生态模型，和复杂的计算工具。完成后，该项目将从多个角度说明气候变化对袋鼠生物多样性的影响。最后，这里考虑的物种生活在一个生物多样性的热点（热带安第斯山脉），和一个清晰的理解，这组的遗传模式可以用来指导本地化的保护策略，这一独特的哺乳动物群体。

This study investigates how extreme climate fluctuations of the Ice Ages over the past several hundred thousand years might have affected the geographic distributions, genetic structure, and diversity of species. Theory suggests that fluctuating climates may have acted as a force promoting diversification. To better understand the specific effects of ancient climate fluctuations on the diversification of species, this project focuses on a group of marsupials (Thylamys opossums) that live in the Andes Mountains of South America. Genetic data and computational tools will be used to make inferences about events that occurred in the distant past. With this genetic evidence in hand, hypotheses concerning the impact of ancient climate change on species diversity can be tested.Only a handful of studies have examined the evolutionary patterns of Andean mammals in the context of ancient climate fluctuations, and prior to this work, none has considered these factors for Thylamys species. This project is significant and distinct from previous efforts because it will explicitly test alternative evolutionary hypotheses using multiple types of genetic data, ecological models of each population's geographic distribution, and sophisticated computational tools. When complete, this project will illustrate from multiple perspectives the impact of climatic shifts on biodiversity in Thylamys. Finally, the species considered here live in a biodiversity hotspot (the Tropical Andes), and a clear understanding of genetic patterns for this group can be used to guide localized conservation strategies for this unique group of mammals.