Evolutionary and geographic diversification of plants

点击翻译按钮获取中文摘要

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.********