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

人为气候变化正在改变地球仪的物种分布。物种分布范围的这种当代变化可能对整个生态系统产生级联效应。本计画以潮间猫头鹰帽贝为例，探讨海洋系统中气候变化导致物种分布范围改变的机制。在最近北美太平洋沿岸的海洋热浪期间，北方加州的北方范围界限的种群已经扩大，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来探索物种占领新区域时发生的自然选择的动态。总的来说，该项目加深了对海洋系统中范围变化的理解，并提高了预测未来物种分布以应对气候变化的能力。该项目通过与现有的，明显有效的计划参与历史上代表性不足的群体的高中和本科生提供研究经验。研究人员为高年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弗朗西斯科探索馆合作，吸引公众参与。最后，该项目为一名博士后学者和两名研究生提供了培训，虽然现象学研究表明，与气候有关的范围变化在海洋系统中很常见，但迄今为止，气候-生物相互作用改变地理分布的机制研究主要集中在陆地系统。然而，在许多海洋系统中，扩散动力学有很大的不同，因为海流可能经常将浮游幼虫运送到新的环境中。该项目整合了详细的人口统计学观察最近的范围扩大的潮间带猫头鹰帽贝，Lottia flutea，与生态，表型和基因组测量的分歧在其范围内。具体来说，这项工作1）记录了整个范围扩展区的幼虫和幼虫性状的表型差异，2）使用全基因组测序来估计整个范围的基因流，3）确定了整个范围扩展区和时间的选择基因组模式，以及4）确定了纬度和微地理尺度上性能变化的驱动因素。在真实的时间内监测这种范围变化的能力，沿着该系统在多年内跟踪个体的适用性，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，从个体到物种该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

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.