Systematics, biogeography and evolution of northern floras

系统学的一个中心目标是确定形成跨越空间和时间的多样性的过程。北部植物群提供了这样做的有趣机会，因为它们已经经历了过去气候变化最剧烈的一些时期。我的长期研究目标是发现、分类和保护北方植物令人敬畏的生物多样性，并确定负责产生和维持这种多样性的过程。为了实现这一目标，我将侧重于三个短期目标，这三个目标将从三个进化尺度阐明过去气候变化对北方植物区系演变的影响：宏观进化(目标1)、微观进化(目标2)和生态(目标3)。目标1是量化历史气候变化对化石记录中最丰富的植物科之一莎草科(&gt；1000化石)多样性和进化的影响。我们将首先建立一个文献报道的所有化石的综合数据库，并通过几何形态计量分析(BSC1)重新评估它们的分类亲缘关系。由此产生的被子植物化石数据集将具有前所未有的大小和质量，从而能够高分辨率地分析过去1亿年来植物多样性动态、生物地理学、生态位进化和水果进化，跨越莎草科(MSc 1)的进化历史。目标2是开发莎草科的第一批基因组资源，并利用它们来确定气候如何影响杂交和导入的频率。两个苔草基因组将从实验杂交中以低成本组装到染色体规模(PHD 1)，这将允许基于导入基因组块的长度来估计古代导入事件的时间和强度。我们还将扩展我们以前对莎草科寄主-寄生虫相互作用的研究，利用优先寄生杂交种的炭疽菌目真菌作为代理来推断深层杂交的频率(MSC 2)。目标3将是加快对淡水潮汐植物群的分类研究，这是一个丰富但受到威胁的北美特有植物中心。通过对该植物区系特有的两个莎草科(BSc 2，MSc 3)和一个菊科(PHD 2)谱系的平行分类和种群基因组研究，我们将发现共同的遗传多样性格局，可用于优先保护最不同的种群和地区。然后，我们将汇集淡水潮汐植物群(约100种；BSC 3)中所有分类群的完整分布数据库，以测试面积、气候条件和河口之间的距离如何影响特有性、丰富度、系统发育多样性和种群遗传多样性(PHD 2)。这种结合的方法将使我们能够发现大规模的历史和生态过程，这些过程在从基因到物种和整个群落的所有生物复杂性水平上塑造了多样性。

A central aim of systematics is to identify the processes that shape diversity across space and time. Northern floras offer interesting opportunities to do so, as they have been through some of the most intense periods of past climate change. My long term research goal is to discover, classify and protect the awe-inspiring biodiversity of northern plants, and to identify the processes responsible for generating and maintaining this diversity. Towards this goal, I will focus on three short-term objectives that will shed light on the impact of past climate change on evolution of northern floras at three evolutionary scales: macro-evolutionary (Objective 1), micro-evolutionary (Objective 2), and ecological (Objective 3). Objective 1 is to quantify the influence of historical climate change on the diversity and evolution of one of the most abundant plant families in the fossil record, Cyperaceae (>1000 fossils). We will first compile a comprehensive database of all fossils reported in the literature, and re-assess their taxonomic affinities through geometric morphometric analysis (BSc 1). The resulting fossil dataset will be of unprecedented size and quality in angiosperms, enabling high-resolution analysis of plant diversification dynamics, biogeography, niche evolution and fruit evolution throughout the last 100 million years that span the evolutionary history of Cyperaceae (MSc 1). Objective 2 is to develop the first genomic resources for Cyperaceae, and to use them to determine how climate influences the frequency of hybridization and introgression. Two Carex genomes will be assembled to chromosome-scale (PhD 1) at low cost from an experimental hybrid, which will allow estimation of the timing and intensity of ancient introgression events, based on the lengths of introgressed genomic blocks. We will also expand on our previous investigations of host-parasite interactions in Cyperaceae by utilizing Anthracoidea fungi, which preferentially parasitize hybrids, as a proxy to infer the frequency of hybridization in deep time (Msc 2). Objective 3 will be to accelerate taxonomic research on the Freshwater Tidal Flora, a rich but threatened North American centre of endemism. Through parallel taxonomic and population genomic studies of two Cyperaceae (BSc 2, MSc 3) and one Asteraceae (PhD 2) lineage endemic to this Flora, we will discover shared patterns of genetic diversity that can be used to prioritize conservation on the most distinct populations and areas. We will then assemble a complete distribution database of all taxa occurring in the Freshwater Tidal Flora (c. 100 species; BSc 3) to test how area, climatic conditions and distance between estuaries affect endemicity, richness, phylogenetic diversity, and population genetic diversity (PhD 2). This combined approach will allow us to discover large-scale historical and ecological processes that shape diversity at all levels of biological complexity, from genes to species and whole communities.