Dissertation Research: Testing Phylogeographic Hypotheses of Holocene Plant Migration and Endemism in the Solidago simplex Species Complex

古生态证据表明，更新世冰川造成了北美各地植被的大范围变化，但个别植物物种如何应对这些反复的冰川循环在很大程度上仍未得到研究。该项目将研究广泛存在的北美单叶一枝黄花物种复合体是如何应对最近的冰期的。对叶绿体DNA序列数据的分析将被用来1)描述和评估北美单纯性草本植物范围内遗传多样性的结构，以及2)检验长期存在的假设，即一些广泛分布的物种在北美避难所西部的冰川中幸存下来，并在全新世期间迁移到大陆东部冰川地区。这项研究将是第一批考察整个北美范围内草本植物物种生物地理格局和冰川历史的分子系统地理学研究之一。这项工作所产生的信息将为我们提供对1)植物物种如何响应历史气候变化以及2)更新世冰川旋回如何影响种群分化和物种形成的更精细的理解。这些信息可以为现有物种如何应对未来的气候变化提供宝贵的洞察力，因此可以大大有助于当前的栖息地和物种保护工作。

Paleoecological evidence indicates that Pleistocene glaciations caused broad scale changes in vegetation across North America, but how individual plant species responded to these repeated cycles of glaciation remains largely unstudied. This project will examine how the widespread, North American, Solidago simplex species complex responded to the most recent period of glaciation. Analyses of chloroplast DNA sequence data will be used to 1) describe and assess the structuring of genetic diversity across the range of S. simplex in North America and 2) test the long-standing hypothesis that some widespread species survived glaciation in western North American refugia and migrated to eastern, glaciated regions of the continent more recently during the Holocene.This study will be one of the first molecular phylogeographic studies to examine the biogeographic patterns and glacial history of an herbaceous plant species across the entirety of its North American range. The information generated by this work will provide us with more refined understandings of 1) how plant species responded to historical climate change and 2) how Pleistocene glacial cycles affected population differentiation and speciation. This information can provide valuable insight into how extant species may respond to future climate change and can therefore significantly aid current habitat and species conservation efforts.