Evolutionary and geographic diversification of plants

我使用分子和其他工具来检测植物的遗传变异模式，重建它们的地理历史，并检查导致这些模式的进化过程。这项工作侧重于两个相关领域，涉及植物多样化的不同方面。 其中一个重点是植物的地理历史和景观遗传学，特别是北极高山物种，其环境特别容易受到快速气候变暖的影响。遗传变异的地理模式表明了过去的迁徙路径，揭示了避难所的位置，并显示了植物如何对过去的气候变化做出反应。为了预测植物对环境变化的反应，我们需要了解这些历史模式，并结合植物适应不断变化的条件的过程。在与国际组织的合作下，我研究了北极高山物种在整个范围内的遗传变异，重点是南部高海拔种群的遗传多样性。此外，我评估了局部和广泛物种对的种群遗传结构，以确定地理范围较小或生活在受威胁或支离破碎的生境中的植物物种的脆弱性。 第二个焦点是杂交，现在被认为是植物进化的关键过程。我研究了它对植物谱系的持久性和多样性的贡献。杂交会影响种群的遗传变异性和适应能力，而且(特别是与多倍体结合时)往往会导致物种形成。我研究具有复杂变异模式的植物群体，以确定杂交在它们进化中的作用。了解杂交和其他进化过程如何形成变异模式，对于评估植物如何适应环境和对栖息地变化做出反应至关重要。 将空间视角与对进化机制的更好理解相结合，提供了对物种历史的全面看法。我将利用从这些研究中获得的信息，结合生态和自然历史知识，完善对植物物种将如何受到环境变化影响的预测。这项工作将有助于在当今快速变化的世界中更好地管理和保护植物多样性。

I use molecular and other tools to detect patterns of genetic variation in plants, reconstruct their geographic history, and examine evolutionary processes leading to these patterns. This work focuses on two related areas addressing different aspects of plant diversification. One focus is the geographical history and landscape genetics of plants, especially arctic-alpine species whose environments are particularly subject to rapid climate warming. Geographic patterns of genetic variation indicate the pathways of past migration, reveal the locations of refugial habitats, and show how plants have responded to past climatic shifts. To predict plant responses to environmental change, we need to understand these historical patterns in combination with the processes by which plants can adjust to changing conditions. In collaboration with international groups, I examine genetic variation in arctic-alpine species throughout their ranges with emphasis on the genetic diversity of southern high-elevation populations. In addition, I evaluate the population genetic structure of localized and widespread species pairs in order to identify the vulnerabilities of plant species that have small geographic ranges or live in threatened or fragmented habitats. The second focus is hybridization, now acknowledged as a key process in plant evolution. I study its contribution to the persistence and diversification of plant lineages. Hybridization influences the genetic variability and adaptive capacity of populations, and (especially in combination with polyploidy) can often lead to speciation. I examine plant groups with complex patterns of variation to identify the role of hybridization in their evolution. Understanding how hybridization and other evolutionary processes shape patterns of variation is critical to evaluating how plants can adapt to their environments and respond to habitat change. Combining a spatial perspective with a better understanding of evolutionary mechanisms provides a comprehensive view of the history of species. I will use information gained from these studies, in combination with ecological and natural history knowledge, to refine predictions of how plant species will be impacted by altered environments. This work will contribute to better management and conservation of plant diversity in today’s rapidly changing world.