CAREER: Habitat Specialization and the Evolution of Dispersal

该项目评估了生长在加州春天池塘里的一年生草本植物“金矿”的扩散进化，以了解生物扩散特征与其栖息地专业化之间的进化反馈。当环境在空间和时间上发生变化时，生物体依靠扩散来保持在合适的栖息地。生物分散的倾向和传播的距离，受到自然选择所能进化的特性的影响。反过来，分散的成本和收益将取决于生物环境中合适栖息地的可用性和分布。这项工作将为生物体在复杂环境中导航的机制，以及这些机制如何随着时间的推移而变化，作为适应特定栖息地类型的原因和结果，提供重要的见解。在这个环境迅速变化的时代，了解物种扩散的原因尤为重要。在这个时代，许多物种的自然扩散模式受到人类活动的严重改变，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学、数学和工程学的真实研究经验。该项目还将支持一个针对小学生的双语推广计划的发展，该计划通过实地考察和课堂实验来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宣传，并与参与保护、管理和创造春水池生境的机构和组织分享。本研究将使用实验和建模方法来评估生物栖息地的空间和时间变化对扩散的反应。该系统由三种Lasthenia属植物组成，它们共同出现在加州植物区系省的春天池塘景观中。在春湖景观中，沙蚕属植物占据着不同的生境，在影响种子传播倾向和传播距离的性状上表现出广泛的差异。该项目的第一步将是与工程专业学生合作，在风洞中控制风力条件下对Lasthenia的扩散表型进行功能分析。接下来，野外实验将量化在一个共同的春水池景观中占据不同栖息地的三种不同的Lasthenia种群的扩散策略选择。扩散性状变异的环境成分（即扩散可塑性）将通过一系列实验处理进行测量，这些实验处理将在CURE（基于课程的本科研究经验）课程的背景下在受控的温室条件下施加。最后，数学模型将在更广泛的参数值范围内评估Lasthenia的扩散特征和栖息地专业化的联合进化动态。

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.