DISSERTATION RESEARCH: The role of rapid adaptation in population establishment

进化曾经被认为是在长时间尺度上缓慢发生的，但最近的许多研究发现，快速适应（在人类可观察到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，并可以影响生态相互作用和过程。理论预测，快速适应也可能潜在地影响物种在新栖息地的建立，但几乎没有来自自然系统的证据支持这一点。该项目将研究新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。通过在生态修复现场开展这项工作，该项目不仅可以扩大我们对基本生态过程的了解，而且项目的成果可以应用于更成功的修复。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中发挥关键作用，但在恢复中播种的物种往往无法建立。此外，该项目还包括指导本科生和开发K-12学生的在线教育材料。通过田间试验、互惠移植和温室研究，本项目旨在从几个方面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，足以影响建制，但很少有研究考虑到适应的人口效应。本研究将研究适应对新建立的植物种群的人口统计学影响。其次，本工作旨在确定负责局部适应的选择因子和性状，这方面的研究很少。通过将选择分析与互惠移植实验相结合，本研究将预测进化反应并测试这些预测的进化转变是否实际发生。最后，本研究将通过研究豆科植物与固氮细菌之间的相互作用，以及介导与根瘤菌相互作用的性状如何在不同土壤养分有效性和根瘤菌群落特性的田间环境中进化，来研究微生物互生菌在植物快速适应中的作用。这项工作的结果将阐明快速适应与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.