Evolutionary and ecological dynamics of a contemporary climate-driven range expansion

人为的气候变化正在改变全球物种的分布。物种范围的这种当代变化可能对整个生态系统产生级联效应。本项目以潮间带猫头鹰帽贝为例，阐明了海洋系统中气候驱动的物种范围变化的机制。在最近的北美太平洋海岸的海洋热浪中，在加利福尼亚北部的北部范围范围内的种群已经扩大，即使在热浪事件结束后仍在继续繁殖。因此，这是一个理想的系统，用于探索物种占据新区域时发生的自然选择动力学。总的来说，该项目加深了对海洋系统中范围变化如何发生的理解，并进一步提高了预测未来物种分布以应对气候变化的能力。该项目通过参与现有的、明显有效的项目，为来自历史上代表性不足的群体的高中生和本科生提供研究经验。研究人员为高级女研究生举办领导力和技能建设研讨会，并与加州科学院、博德加海洋实验室和旧金山探索博物馆合作，吸引公众参与。最后，培养1名博士后和2名研究生。虽然现象学研究表明，与气候相关的范围变化在海洋系统中很常见，但迄今为止，对改变地理分布的气候-生物相互作用的机制研究主要集中在陆地系统。然而，在许多海洋系统中，扩散动力学大不相同，因为洋流可能经常将浮游生物幼虫运送到新的环境制度中。该项目整合了潮间带猫头鹰帽贝（Lottia gigantea）最近范围扩张的详细人口统计观察，以及其范围内差异的生态、表型和基因组测量。具体来说，这项工作1)记录了幼虫和幼鱼性状在范围扩展区域内的表型差异，2)使用全基因组测序来估计整个范围内的基因流动，3)确定了范围扩展区域和时间范围内的基因组选择模式，4)确定了纬度和微地理尺度上表现变化的驱动因素。实时监测这种范围变化的能力，以及该系统对多年跟踪个体的适用性，使研究人员能够在表型和基因组水平上检查新范围边缘条件下选择的影响，并从个体到物种水平对持续环境变化的响应进行衡量。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Anthropogenic climate change is shifting the distributions of species across the globe. Such contemporary shifts in species’ ranges may have cascading effects on entire ecosystems. This project disentangles the mechanisms underlying climate-driven species range shifts in marine systems using the intertidal owl limpet as a case study. During the recent marine heatwaves off the Pacific coast of North America, populations at the northern range limit in northern California have expanded, with ongoing reproduction even after termination of the heatwave events. This is therefore an ideal system to explore the dynamics of natural selection that occur as species occupy new regions. Broadly, this project deepens understanding of how range shifts occur in marine systems and furthers the ability to predict future species distributions in response to climate change. The project provides research experiences for high school and undergraduate students from historically underrepresented groups by engaging with existing, demonstrably-effective programs. The investigators host leadership and skill-building workshops for senior female graduate students and engage the public in partnership with the California Academy of Sciences, Bodega Marine Lab, and San Francisco Exploratorium. Finally, the project provides training for a postdoctoral scholar and two graduate students.Although phenomenological studies suggest that climate-associated range shifts are common in marine systems, to date, mechanistic studies of the climate-organism interactions that alter geographic distributions have largely focused on terrestrial systems. However, dispersal dynamics greatly differ in many marine systems, as currents may frequently transport planktonic larvae into new environmental regimes. This project integrates detailed demographic observations of the recent range expansion of the intertidal owl limpet, Lottia gigantea, with ecological, phenotypic, and genomic measurements of divergence across its range. Specifically, the work 1) documents phenotypic divergence in larval and juvenile traits across the zone of range expansion, 2) uses whole genome sequencing to estimate gene flow across the entire range, 3) identifies genomic patterns of selection across the zone of range expansion and through time, and 4) identifies drivers of variation in performance over latitudinal and microgeographic scales. The ability to monitor this range shift in real time, along with the suitability of this system for tracking individuals across multiple years, allows the investigators to examine the impact of selection in novel range-edge conditions at the phenotypic and genomic levels, and scale from individuals to species-level responses to ongoing environmental change.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.