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冰河时期的极端气候波动如何影响地理分布、遗传结构和物种多样性。理论表明，波动的气候可能起到了促进多样化的作用。为了更好地了解古代气候波动对物种多样化的具体影响，该项目重点研究了生活在南美洲安第斯山脉的一组有袋动物（Thylamys负鼠）。基因数据和计算工具将用于推断发生在遥远过去的事件。有了这些遗传证据，有关古代气候变化对物种多样性影响的假设就可以得到检验。只有少数研究考察了安第斯哺乳动物在古代气候波动背景下的进化模式，在此之前，没有人考虑过百里香类动物的这些因素。这个项目意义重大，不同于以往的努力，因为它将使用多种类型的遗传数据、每个种群地理分布的生态模型和复杂的计算工具，明确地测试替代的进化假设。完成后，该项目将从多个角度说明气候变化对Thylamys生物多样性的影响。最后，这里考虑的物种生活在生物多样性热点地区（热带安第斯山脉），对这一群体遗传模式的清晰理解可以用来指导这一独特哺乳动物群体的局部保护策略。

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.