我国珍珠菜属（报春花科）海拔物种多样性格局及其成因的研究

Elevational variation in species richness is ubiquitous and important, since many biodiversity hotspots are in montane regions. Understanding the underlying cause of the elevational species diversity pattern is one of the fundamental goals of biodiversity research. A large number of classical ecological theories and hypotheses have been developed in the area. Although evolutionary hypotheses on elevational species richness patterns have been proposed very early, it remains unclear since a lack of species level, time-calibrated phylogenetic trees. The elevational gradient from west to east in China is an ideal model for studying the causes of elevational species diversity pattern. However, there are only a small amount of evolutionary studies in the area, which concentrated in animals with a relative small region scale and limited taxa. To our knowledge, evolutionary hypotheses like time-for-speciation and diversification rate hypotheses have not be tested in any plant groups in China. Therefore, it is necessary to carry out the evolutionary studies on the elevational pattern of plant species diversity in China. The genus Lysimachia (Primulaceae) is well suited for studying the evolutionary causes of the elevational diversity pattern, given it distributed widely in elevation and mostly diverse in China. The project plans to use a comprehensive phylogeny of Lysimachia and its elevational data, to answer (a) the elevational pattern of species diversity of Lysimachia; (b) the evolutionary hypothesis of the pattern (time and/or differentiation rate hypothesis); (c) the route of Lysimachia in China; (d) the diversification rates and causes of Lysimachia species at different elevations. This project benefits us to better understand underlying causes of elevational species diversity, and provides theoretical knowledge for the protection and sustainable use of biological resources in the future.

海拔物种多样性分布格局的成因是生物多样性研究的重要内容，已发展出大量生态学的经典理论和假说。虽然相关的进化假说很早已提出，但实例验证却很少。我国自西向东的海拔梯度变化大，是研究海拔物种多样性形成格局的理想载体，但仅有少量相关的进化研究，且集中在动物领域，地理尺度和类群较小。在植物方面的相关研究更是未见报道。因此，开展我国植物海拔物种多样性格局的进化研究十分必要。我国珍珠菜属是海拔物种多样性研究的理想类群。本项目计划利用该类群结合整合系统发育学方法，在横跨我国三大地势梯度的尺度上开展海拔物种多样性的进化研究，重点回答：（a）珍珠菜属的海拔物种多样性格局；（b）该分布格局的进化假说（时间及分化速率假说）；（c）珍珠菜属迁移的路线；（d）不同海拔内珍珠菜属的分化速率及其成因。本项目的开展将有利于我们更好地理解我国海拔物种多样性格局的形成机制，为生物资源保护和可持续利用提供理论基础。

海拔物种多样性分布格局的成因是生物多样性研究的重要内容，已发展出大量生态学的经典理论和假说。我国自西向东的海拔梯度变化大，是研究海拔物种多样性形成格局的理想载体，但在植物方面研究更是未见报道。本研究根据项目书计划，以我国珍珠菜属为研究对象，通过广泛收集我国珍珠菜属植物的标本和文献资料，发现了我国珍珠菜属物种多样性分布不均匀，整体上呈现出南高北低的分布格局；而我国西南部地区和湘西及鄂西南山地是我国珍珠菜属的热点分布区域；采集了大量珍珠菜属标本及遗传材料，利用叶绿体基因组构建了高支持率的珍珠菜属系统发育关系；发现了多个珍珠菜属新种；发现了我国的珍珠菜属植物的海拔多样性梯度分布呈现出中低海拔高物种多样性高而随着海拔增高后物种多样性越低的分布格局；珍珠菜属高海拔地区的分化速率升高但迁入时间越晚的海拔分布形成格局。总之，本项目为我国植物海拔梯度分布格局的形成提供了典型案例。