CAREER: Habitat Specialization and the Evolution of Dispersal

该项目评估了生长在加利福尼亚州春季池塘中的一年生草本植物的扩散进化，以了解生物的扩散特征与其栖息地专门化之间的进化反馈。当生物的环境在空间和时间上发生变化时，它们依靠扩散来保持在合适的栖息地。生物体的分散趋势以及它将旅行的距离，受到自然选择可以进化的特征的影响。反过来，扩散的成本和收益将取决于生物体环境中合适栖息地的可用性和分布。这项工作将为生物在复杂环境中导航的机制提供重要的见解，以及这些机制作为适应特定栖息地类型的原因和结果如何随时间变化。在这个环境迅速变化的时代，了解扩散的原因尤其关键，人类活动严重改变了许多物种的自然扩散模式，分散的生物在适宜栖息地的大小和分布方面经历了前所未有的变化。这项研究将主要在本科课程、高级设计项目和高中实习中进行，为学生提供整合生物、数学和工程的真实研究体验。该项目还将支持为小学生制定双语推广方案，通过实地考察和课堂实验探索植物传播策略的多样性。此外，结果将通过在主要野外地点进行的导游向公众传达，并与参与保护、管理和创造春季池塘栖息地的机构和组织分享。这项研究将使用实验和建模方法来评估扩散如何随着生物体栖息地的时空变化而演变。该系统由三种植物组成，它们共同出现在加州植物区系省的春季池景中。在春季池塘景观中，Lparenia物种占据不同的栖息地，并在影响种子传播倾向和距离的特征上表现出广泛的差异。该项目的第一步将是在风洞中与工程学学生合作，在受控风速条件下对Lparenia的扩散表型进行功能分析。下一步，野外实验将量化在三个不同物种的种群中对扩散策略的选择，这些种群占据着共同的春季水池景观中的不同栖息地。扩散性状变异的环境因素(即扩散可塑性)将通过一系列实验处理进行测量，这些处理将在CURE(基于课程的本科生研究经验)课程的背景下，在受控温室条件下实施。最后，数学模型将评估分布特征和栖息地专门化的联合进化动态，更广泛地说，评估范围更广的参数值。

This project evaluates the evolution of dispersal in annual herbs called 'goldfields' that grow in vernal pools in California, to understand the evolutionary feedbacks between the dispersal traits of organisms and their habitat specialization. Organisms rely on dispersal to remain in suitable habitat when their environments vary in space and time. The tendency for an organism to disperse, and the distance it will travel, is influenced by traits that can evolve by natural selection. In turn, the costs and benefits of dispersing will depend on the availability and distribution of suitable habitat in the organism's environment. This work will provide important insights into the mechanisms by which organisms navigate complex environments, and how these mechanisms change over time as both a cause and consequence of adaptation to specific habitat types. An understanding of the causes of dispersal is particularly critical in this time of rapid environmental change, in which natural dispersal patterns for many species are severely modified by human activities, and dispersing organisms experience unprecedented levels of change in the size and distribution of suitable habitat. This research will be largely conducted in undergraduate courses, senior design projects, and high school internships to provide students with authentic research experiences that integrate biology, mathematics, and engineering. This project also will support the development of a bilingual outreach program for elementary school students that explores the diversity of plant dispersal strategies through field trips and classroom-based experiments. In addition, results will be communicated to the general public through guided tours that take place at the primary field site, and shared with agencies and organizations involved in the conservation, management and creation of vernal pool habitats.This research will use experimental and modeling approaches to evaluate how dispersal evolves in response to spatial and temporal variation in an organism's habitat. The system consists of three plant species in the genus Lasthenia that co-occur in vernal pool landscapes of the California Floristic Province. Lasthenia species occupy different habitats within vernal pool landscapes and exhibit extensive variation in traits that influence seed dispersal propensity and distance. The first step of this project will be to conduct a functional analysis of dispersal phenotypes in Lasthenia under controlled wind conditions in wind tunnels, and in collaboration with engineering students. Next, field experiments will quantify selection on dispersal strategies in populations of three different Lasthenia species that occupy different habitats within a common vernal pool landscape. Environmental components of dispersal trait variation (i.e., dispersal plasticity) will be measured across a range of experimental treatments that will be imposed under controlled greenhouse conditions in the context of CURE (course-based undergraduate research experience) classes. Finally, mathematical models will evaluate the joint evolutionary dynamics of dispersal traits and habitat specialization in Lasthenia, and more generally across a broader range of parameter values.