DISSERTATION RESEARCH: The Effects of Gene Flow, Dispersal and Local Adaptation on the Distribution of Silvetia Compressa in the Intertidal Zone

在不断变化的环境中，基因流动可以对抗自然选择并阻止适应;这可能对不同物种在空间中的分布方式产生深远的影响。 拟议的研究将研究基因流的影响，适应和分布，一个强大的环境梯度，使用的Silvetia compressa和它的分布在潮间带作为一个模型系统。 这项工作将包括：（1）映射S所跨越的再现时间梯度; compressa种群和研究如何在这个梯度的遗传结构和人口统计率变化;（2）通过模仿殖民化事件测量扩散距离;（3）评估当地适应的位置在潮间带的相互移植实验;和（4）直接测试的后果，基因流跨越梯度进行控制杂交和出植受精卵到外地。 最近的理论进展表明，基因流动和局部适应可能共同决定物种分布，但对于任何生物，我们目前都不了解这些过程如何在范围的边缘相互作用。 因此，本研究的结果将提供一个关键的实证检验目前的想法之间的拮抗作用的基因流不同的选择性环境。 基因流在维持物种分布中的作用对生态学理论（如理解梯度和斑块景观的生物多样性模式）以及重要的应用问题（如物种入侵和种群对环境变化的反应）都有影响。 这项研究的其他更广泛的影响源于其地理规模，以及参与和培训来自多所大学的本科生的机会。

Gene flow across a changing environment can counter natural selection and prevent adaptation; this may have profound consequences for the way that different species are distributed in space. The proposed research will examine the effects of gene flow on adaptation to, and distribution across, a strong environmental gradient, using the alga Silvetia compressa and its distribution in the intertidal zone as a model system. This work will include (1) mapping the gradient in emersion time spanned by S. compressa populations and examining how genetic structure and demographic rates vary across this gradient; (2) measuring dispersal distance by mimicking colonization events; (3) assessing local adaptation to position in the intertidal zone with reciprocal transplant experiments; and (4) directly testing the consequences of gene flow across the gradient by conducting controlled crosses and outplanting zygotes into the field. Recent theoretical advances have shown that gene flow and local adaptation may jointly determine species distributions, yet for no organism do we currently understand how these processes interact at the edges of a range. Thus the results of this study will provide a key empirical test of current thinking on the antagonistic effects of gene flow among different selective environments. The role of gene flow in the maintenance of species distributions has implications both for ecological theory (e.g. understanding patterns of biodiversity across gradients and patchy landscapes), as well as for important applied problems such as species invasions, and population-level response to environmental change. Additional broader impacts of this study stem from its geographic scale, and the opportunity for involvement and training of undergraduates from multiple universities.