DISSERTATION RESEARCH: The role of rapid adaptation in population establishment

进化曾经被认为只在长时间尺度上缓慢发生，但最近的许多研究发现，快速适应（在人类可观察的时间尺度上发生的适应）可以发生在广泛的物种和许多生物系统中，并可能影响生态相互作用和过程。理论预测，快速适应也可能影响物种在新栖息地的建立，但几乎没有自然系统的证据支持这一点。该项目将研究最近建立的植物种群的快速适应，以及共生微生物如何影响植物的快速适应。通过在生态恢复现场进行这项工作，该项目不仅将扩大我们对基本生态过程的理解，而且该项目的结果可以应用于使生态恢复更加成功。这一点很重要，因为退化景观的恢复可以在生物多样性保护方面发挥关键作用，但播种到植被中的物种往往无法建立。此外，该项目还包括对本科生的指导和为K-12学生开发在线教育材料。通过使用田间实验，相互移植和温室研究，该项目旨在以多种方式扩大对快速适应在种群建立中的作用的理解。首先，尽管经验证据表明，进化可能发生得足够快，足以影响建立，很少有研究考虑适应的人口效应。这项研究将研究适应在最近建立的植物种群的人口效应。其次，这项工作的目的是确定选择剂和性状负责当地的适应，很少有研究试图这样做。通过将选择分析与互惠移植实验相结合，这项研究将预测进化反应，并测试这些预测的进化转变是否真的发生了。最后，这项工作将调查微生物互利共生在植物快速适应的作用，通过研究豆科植物和固氮细菌之间的相互作用，以及如何调节与根瘤菌相互作用的性状已经演变为响应不同的土壤养分供应和根瘤菌群落特性的田间环境。这项工作的结果将阐明快速适应和种群建立之间关系的机制。

Evolution was once assumed to only occur slowly over long time scales, but many recent studies have found that rapid adaptation (adaptation that occurs over timescales observable by humans) can occur across a wide range of species and in many biological systems, and can affect ecological interactions and processes. Theory predicts that rapid adaptation can also potentially affect the establishment of species in new habitats, but there is little evidence from natural systems to support this. This project will investigate rapid adaptation in recently established plant populations, as well as how symbiotic microbes might influence plant rapid adaptation. By conducting this work at an ecological restoration site, this project will not only expand our understanding of basic ecological processes, but results of the project can be applied to make restorations more successful. This is important, as the restoration of degraded landscapes can play a critical role in biodiversity conservation, yet species sown into restorations often fail to establish. Additionally, this project includes the mentoring of undergraduate students and development of online educational materials for K-12 students.By using field experiments, reciprocal transplants, and greenhouse studies, this project aims to expand understanding of the role of rapid adaptation in population establishment in several ways. First, although empirical evidence suggests that evolution may occur rapidly enough to influence establishment, few studies consider the demographic effects of adaptation. This study will examine the demographic effects of adaptation in recently established plant populations. Second, this work aims to identify the selective agents and traits responsible for local adaptation, which few studies attempt to do. By combining selection analyses with reciprocal transplant experiments, this study will both predict evolutionary responses and test whether those predicted evolutionary shifts have actually occurred. Finally, this work will investigate the role of microbial mutualists in plant rapid adaptation by examining interactions between legumes and nitrogen-fixing bacteria and how traits mediating interactions with rhizobia have evolved in response to field environments that differ in soil nutrient availability and rhizobium community properties. The results of this work will elucidate the mechanisms underlying the relationship between rapid adaptation and population establishment.