Collaborative Research: Evolutionary responses to environmental change at range limits: adaptation, migration and population size at the core, margin and trailing edge

生物学家缺乏对气候变化与物种丰度、连通性和从物种范围中心到边缘的局部适应变化之间的相互作用的普遍理解。到21世纪末，北美大部分温带和北部地区的气温预计将上升3-5摄氏度，导致许多物种的种群面临超出目前容忍范围的气候条件。数学模型预测，对环境变化的响应进化可能在很大程度上取决于种群距离其活动范围的边缘有多近，但从经验上看，对这种环境变化的反应如何在物种分布的空间上发生变化，特别是在活动范围限制附近，人们知之甚少。本研究以北美东部一种具有重要生态和经济价值的森林树种--红云杉(Picea Rubens)为研究对象，研究活动范围限制对环境变化响应的影响。该项目解决了最主要的问题：由环境变化驱动的范围限制的变化如何影响物种分布的适应、迁徙和种群规模？解决这一问题促进了我们对范围限制适应和限制物种分布的过程的科学理解。此外，这项工作解决了一个紧迫的应用问题，即环境变化将如何影响位于边缘环境中的自然和人工管理的生态系统的生产力。其他更广泛的影响包括评估东部针叶林中面临局部灭绝风险的基础树种的南部种群的保护状况。结果将与从事森林保护和管理工作的不同利益攸关方分享，并将与当地人口脆弱性评估和知情缓解工作的设计相结合。农村社区的当地公民将通过公共科普活动参与进来。该奖项还将用于培训两名博士后研究人员、一名研究生和许多本科生研究人员在进化生态学、植物生理学和环境变化科学方面的研究。这项研究的实验方法将利用物种分布建模来跟踪过去11,000年来红杉的历史活动范围，并预测不同地点接近变化范围限制。这些预测将通过采样保存在沉积物中的云杉化石花粉，并利用古生态学和种群遗传学的最新进展来测量植物水分利用效率、有效种群规模和随时间变化的连接性，从而与经历环境变化的种群的大小、连通性和生态生理变化相关。这项研究还将把生态基因组学的最新技术与新的空间建模方法结合起来，以预测在北美预计气候变暖的情景下，局部适应将如何随着范围限制的接近而变化。

Biologists lack a general understanding of the interaction between changes in climate and variation in abundance, connectivity, and local adaptation from the center to the edge of species' ranges. By the end of the 21st century, temperatures are predicted to rise 3-5 degrees C across much of temperate and boreal North America, causing populations of many species to face climate conditions beyond their current tolerances. Mathematical models predict that evolution in response to environmental change can depend critically on how close populations are located to the edge of their range, yet little is known empirically about how responses to this environmental change vary spatially across a species' distribution, especially near range limits. This research uses an ecologically and economically important forest tree in eastern North America, red spruce (Picea rubens), to study the effects of range limits on responses to environmental change. The project addresses the overarching question: how do shifting range limits driven by environmental change affect adaptation, migration, and population size across a species' distribution? Addressing this problem advances our scientific understanding of adaptation at range limits and the processes that constrain species distributions. In addition, this work addresses a pressing applied problem of how environmental change will affect the productivity of natural and human-managed ecosystems located in marginal environments. Additional broader impacts include assessing the conservation status of southern populations of a foundation tree species in eastern coniferous forests at risk of local extinction. The results will be shared with diverse stakeholders working on forest conservation and management, and will be integrated with assessments of local population vulnerability and the design of informed mitigation efforts. Local citizens in rural communities will be engaged through public science outreach. This award will also serve to train two postdoctoral researchers, one graduate student, and numerous undergraduate researchers in evolutionary ecology, plant physiology, and environmental change science.The experimental approach of the research will leverage species distribution modeling to track historical range movements in red spruce over the last 11,000 years, and predict proximity to the shifting range limit for different locales. These predictions will then be related to the changing size, connectivity, and ecophysiology of populations experiencing environmental change by sampling fossil spruce pollen preserved in sediment and using recent advances at the interface of paleoecology and population genetics to measure plant water use efficiency, effective population size, and connectivity through time. The research will also couple the latest techniques in ecological genomics with novel spatial modeling approaches to predict how local adaptation will vary with proximity to the range limit under scenarios of projected climate warming in North America.