RUI: Collaborative Research: Trait differentiation and local adaptation to depth within meadows of the foundation seagrass Zostera marina

RUI：合作研究：大叶草码头基础草甸内的性状分化和局部适应深度

• 批准号: 1851432
• 负责人: Cynthia Hays
• 金额: $ 21.71万
• 依托单位: Keene State College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851432&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Trait; differentiation

Understanding how species cope with spatial variation in their environment (e.g. gradients in light and temperature) is necessary for informed management as well as for predicting how they may respond to change. This project will examine how key traits vary with depth in common eelgrass (Zostera marina), one of the most important foundation species in temperate nearshore ecosystems worldwide. The investigators will use a combination of experiments in the field and lab, paired with fine-scale molecular analyses, to determine the genetic and environmental components of seagrass trait variation. This work will provide important information on the microevolutionary mechanisms that allow a foundation species to persist in a variable environment, and thus to drive the ecological function of whole nearshore communities. The Northeastern University graduate and Keene State College (KSC) undergraduate students supported by this project will receive training in state-of-the-art molecular techniques, as well as mentorship and experience in scientific communication and outreach. A significant portion of KSC students are from groups under-represented in science. Key findings of the research will be incorporated into undergraduate courses and outreach programs for high school students from under-represented groups, and presented at local and national meetings of scientists and stakeholders. Local adaptation, the superior performance of "home" versus "foreign" genotypes in a local environment, is a powerful demonstration of how natural selection can overcome gene flow and drift to shape phenotypes to match their environment. The classic test for local adaptation is a reciprocal transplant. However, such experiments often fail to capture critical aspects of the immigration process that may mediate realized gene flow in natural systems. For example, reciprocal transplant experiments typically test local and non-local phenotypes at the same (often adult) life history stage, and at the same abundance or density, which does not mirror how dispersal actually occurs for most species. In real populations, migrants (non-local) often arrive at low numbers compared to residents (local), and relative frequency itself can impact fitness. In particular, rare phenotypes may experience reduced competition for resources, or relative release from specialized pathogens. Such negative frequency dependent selection can reduce fitness differences between migrants and residents due to local adaptation, and magnify effective gene flow, thus maintaining greater within-population genetic diversity. The investigators will combine spatially paired sampling and fine-scale molecular analyses to link seed/seedling trait variation across the depth gradient at six meadows to key factors that may drive these patterns: local environmental conditions, population demography, and gene flow across depths. The team will then experimentally test the outcome of cross-gradient dispersal in an ecologically relevant context, by reciprocally out-planting seeds from different depths and manipulating relative frequency in relation to both adults and other seedling lineages. The possible interaction between local adaptation and frequency-dependence is particularly relevant for Zostera marina, which represents one of the best documented examples of the ecological effects of genetic diversity and identity. Further, a better understanding of seagrass trait differentiation is not simply a matter of academic interest, but critical to successful seagrass restoration and conservation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

了解物种如何应对其环境的空间变化(例如，光和温度的梯度)对于知情的管理以及预测它们可能如何应对变化是必要的。该项目将研究普通鳗草(Zostera Marina)的主要特征如何随深度变化，后者是全球温带近岸生态系统中最重要的基础物种之一。研究人员将结合野外和实验室的实验，结合精细的分子分析，确定海草性状变异的遗传和环境因素。这项工作将提供有关微进化机制的重要信息，使基础物种能够在可变的环境中生存，从而推动整个近岸群落的生态功能。由该项目资助的东北大学毕业生和基恩州立学院(KSC)本科生将接受最先进的分子技术培训，以及科学交流和推广方面的指导和经验。很大一部分KSC学生来自在科学领域代表性不足的群体。这项研究的主要发现将被纳入本科课程和针对代表不足群体的高中生的推广计划，并在地方和国家科学家和利益攸关方会议上展示。本地适应是“本土”与“外来”基因型在当地环境中的优越表现，是自然选择如何克服基因流动和漂移以塑造与其环境相匹配的表型的有力证明。对局部适应的经典测试是相互移植。然而，这样的实验往往无法捕捉到移民过程的关键方面，这些方面可能会调节自然系统中实现的基因流动。例如，相互移植实验通常在相同的生活史阶段(通常是成年)，在相同的丰度或密度下测试当地和非当地的表型，这并不能反映大多数物种的实际扩散情况。在真实人口中，移民(非本地)抵达的人数往往低于居民(本地)，而相对频率本身可能会影响健康。特别是，罕见的表型可能会经历对资源的竞争减少，或者从专门的病原体中相对释放。这种负频率依赖的选择可以缩小由于当地适应而导致的迁徙和居民之间的适应度差异，并放大有效的基因流动，从而保持更大的种群内遗传多样性。研究人员将结合空间配对采样和精细分子分析，将六个草甸的种子/幼苗特征跨深度梯度的变异与可能驱动这些模式的关键因素联系起来：当地环境条件、种群人口统计和跨深度的基因流动。然后，研究小组将在与生态相关的背景下，通过相互从不同深度播种种子并操纵相对于成虫和其他苗种谱系的相对频率，来实验测试交叉梯度传播的结果。当地适应和频率依赖之间可能的相互作用与带状藻特别相关，它是遗传多样性和特性的生态效应的最好记录例子之一。此外，更好地了解海草特征的差异不仅是一个学术兴趣问题，而且对成功的海草恢复和保护至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Intra-Meadow Variation in Seagrass Flowering Phenology Across Depths

不同深度海草开花物候的草甸内变化

• DOI: 10.1007/s12237-020-00814-0
• 发表时间: 2021
• 期刊: Estuaries and Coasts
• 影响因子: 2.7
• 作者: von Staats, Daniel A.;Hanley, Torrance C.;Hays, Cynthia G.;Madden, Sophia R.;Sotka, Erik E.;Hughes, A. Randall
• 通讯作者: Hughes, A. Randall

Local Adaptation in Marine Foundation Species at Microgeographic Scales

• DOI: 10.1086/714821
• 发表时间: 2021-08-01
• 期刊: BIOLOGICAL BULLETIN
• 影响因子: 1.6
• 作者: Hays, C. G.;Hanley, T. C.;Sotka, E. E.
• 通讯作者: Sotka, E. E.