CAREER: Habitat Specialization and the Evolution of Dispersal

该项目评估了在加州春季池塘中生长的一年生草本植物“金矿”的扩散演化，以了解生物体的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，生物体依靠扩散保持在合适的栖息地。一个有机体扩散的趋势，以及它将传播的距离，都受到自然选择所能进化的特征的影响。反过来，分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。这项工作将提供重要的洞察机制，生物体导航复杂的环境，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后果。在这个环境迅速变化的时代，了解扩散的原因尤其重要，因为人类活动严重改变了许多物种的自然扩散模式，扩散的生物体在适当生境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。该项目还将支持为小学生制定双语推广计划，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，研究结果将通过在主要野外场地进行的图尔斯导游向公众传达，并与参与春季池塘栖息地保护、管理和创造的机构和组织分享。这项研究将使用实验和建模方法来评估生物栖息地的时空变化如何影响扩散。该系统由三种植物种在属共同出现在春季池景观的加州植物区系省。在不同的生境中，不同的物种在不同的生境中表现出不同的特性，影响种子传播的倾向和距离。该项目的第一步将是在风洞中控制的风条件下，与工程专业的学生合作，对Lasthenia的分散表型进行功能分析。接下来，田间实验将量化三种不同的Lasthenia物种，占据不同的栖息地内一个共同的春季池景观的种群的扩散策略的选择。扩散性状变异的环境成分（即，分散可塑性）将在一系列实验处理中进行测量，这些实验处理将在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进行。最后，数学模型将评估联合进化动力学的分散特性和栖息地专业化在Lasthenia，更一般地在更广泛的参数值范围。

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.