Capacity of conifer populations for climate adaptation

气候变化正在影响全球许多树种的健康，破坏种群对当地气候的适应，并增加干旱、昆虫和野火造成的死亡率。对于每一代经历高环境变化率的长寿森林树木来说，情况尤其如此。两个世纪以来，森林科学家一直在通过普通的花园实验研究树木种群对历史气候的适应。在过去的二十年里，我一直在研究针叶树对气候的局部适应，首先用表型方法，后来用种群基因组工具。我的长期研究目标是了解进化生态学、人口统计学历史和针叶树种群的当地适应性，并利用这些了解来为保护、再造林和恢复决策提供信息。本研究的目的是利用表型、基因组和模拟方法预测针叶树种群适应或容忍快速变化的气候的能力。范围边缘种群的适应潜力：我的研究小组以前的研究已经描述了气候与来自广泛地理区域的几种针叶树种群的表型或基因型之间的关系，但没有包括对气候变化响应重要的范围边缘种群。我们将对北美西部的弯曲松种群进行采样，重点关注处于或接近边缘的种群，并根据先前发现的与气候或气候相关性状相关的标记对它们进行基因分型。将建立模型来预测这些种群适应新气候的能力。适应干旱：温带针叶树通常是耐旱的，但在北美西部，与干旱有关的死亡率正在增加。我们将分析孟氏伪糖（pseudosuga menziesii）耐旱性的种群变异，并确定与干旱相关的基因组标记。新的实验将描述西部落叶松和白桦种群对干旱的反应。最后，我们将比较孟氏孢子和西方孢子在干旱条件下的基因表达可塑性。适应能力和辅助基因流：我们需要从表征适应状态转向预测应对气候变化的适应潜力。根据繁殖物候、花粉运输距离和风型的重叠程度，对扭曲松种群间适应或不适应基因流动的机会进行建模。利用扭曲松（Pinus contorta）和孟氏伪杉树（pseudosuga menziesii）的基因组和表型数据集来参数化种群模拟模型，并评估不同情景下的适应能力。最后，表型和基因组数据集将用于评估物种局部适应的主要气候驱动因素是否是那些定义物种气候生态位的因素。

Climate change is affecting the health of many tree species globally, disrupting adaptation of populations to local climates, and increasing mortality due to drought, insects and wildfire. This is particularly the case for long-lived forest trees that are experiencing high rates of environmental change per generation. For two centuries, forest scientists have been studying the adaptation of tree populations to historic climates through common garden experiments. For the past two decades, I have been studying local adaptation of conifers to climate, first with phenotypic approaches and later with population genomic tools. My long-term research objective is to understand the evolutionary ecology, demographic history, and local adaptation of conifer populations, and to use that understanding to inform conservation, reforestation and restoration decisions. The goal of this research is to predict the capacity of conifer populations to adapt to or tolerate rapidly changing climates using phenotypic, genomic and simulation approaches. Adaptive potential of range margin populations: My research group's previous studies have characterized relationships between climate and phenotypes or genotypes of populations from broad geographic areas for several conifer species, but have not included range margin populations that are important for climate change responses. We will sample populations of Pinus contorta from throughout western North America, emphasizing populations at or near range margins, and genotype them for previously identified markers associated with climate or climate-related traits. Models will be constructed to predict the capacity of these populations to adapt to new climates. Drought adaptation: Temperate conifers are generally drought hardy, yet drought-related mortality is increasing across western North America. We will analyze population variation in Pseudotsuga menziesii drought tolerance and identify genomic markers associated with drought. New experiments will characterize drought responses of populations of Larix occidentalis and Thuja plicata. Finally, gene expression plasticity in response to drought will be compared in P. menziesii and L. occidentalis. Capacity for adaptation and assisted gene flow: We need to move from characterizing adaptive state to predicting adaptive potential in response to climate change. The opportunity for adaptive or maladaptive gene flow among populations of Pinus contorta will be modelled based on the extent of overlap in reproductive phenology, pollen transport distance, and wind patterns. Genomic and phenotypic datasets for Pinus contorta and Pseudotsuga menziesii will be used to parameterize population simulation models and evaluate the capacity for adaptation under different scenarios. Finally, phenotypic and genomic datasets will be used to assess whether the major climatic drivers of local adaptation within species are those that define species climatic niches for several species.