DISSERTATION RESEARCH: Using Host-Parasite Comparative Phylogeography to Determine the Genetic Consequences of Climate Change for a Montane Faunal Assemblage

本项目利用一种哺乳动物（美洲鼠兔，Ochotona princeps）与其五种肠道寄生虫之间的密切关系，探索气候变化对山地生物的遗传影响。鼠兔对气候非常敏感，它们的种群分布、大小和结构在1.8万年前的最后一次冰川高峰之后随着全球气候变暖而发生了巨大变化。鼠兔的宿主特异性寄生虫在这一时期追踪了它们的宿主，并提供了同一种群历史的独立观点。综合起来，这些观点将有助于解决有关气候对基因流动障碍、种群规模波动和殖民模式的影响等问题。鼠兔和寄生虫将从分布在北美西部山间的40个种群中收集，研究问题将通过检查每个物种范围内的DNA序列变化来解决。鼠兔是高海拔生态系统健康的标志；因此，它们对历史气候变化的响应对预测当前气候变暖的影响具有重要意义。这项研究也是独一无二的，因为它检查了整个宿主-寄生虫组合的遗传变异。目前没有可比的数据集。最后，这项工作正在产生对监测生物多样性至关重要的隐多样性和物种分布数据。初步收集的标本包括至少一种以前不为科学界所知的寄生虫。

This project exploits the close relationship between a mammal (American pika, Ochotona princeps) and five of its intestinal parasites to explore the genetic effects of climate change on montane organisms. Pikas are climate-sensitive, and their population distribution, size, and structure changed dramatically as global climate warmed following the last glacial maximum 18,000 years ago. The host-specific parasites of pikas tracked their hosts throughout this period and provide independent views of the same population history. Combined, these views will help to resolve questions regarding climatic effects on barriers to gene flow, population size fluctuations, and modes of colonization. Pikas and parasites will be collected from 40 populations distributed across North America's intermountain west, and research questions will be addressed by examining DNA sequence variation throughout the range of each species.Pikas are indicators of healthy high-elevation ecosystems; therefore, their responses to historical climatic change have important implications for predicting the effects of current climate warming. This study is also unique in that it examines genetic variation across a full host-parasite assemblage. No comparable data set currently exists. Lastly, this work is yielding data on cryptic diversity and species distributions that are critical for monitoring biological diversity. Preliminary collections include at least one species of parasite previously unknown to science.