DISSERTATION RESEARCH: Assessing adaptative capacity in response to climate change: terrestrial salamanders in an urban heat island mesocosm

这项研究将为物种适应零散和变暖的栖息地的能力提供洞察力，从而为在气候变化下保护生物多样性最有效的行动提供信息。面对不断变化的气候，生物体要么原地适应，要么迁徙以跟踪它们适应的条件。在缺乏这些反应的情况下，它们可能会在当地灭绝。相对于运动，野生种群对环境变化的适应仍然知之甚少。幸运的是，最近用于检测自然界适应的基因技术的发展使评估这种反应变得更容易。在该项目下建立的合作包括通过杜克森林办公室、北卡罗来纳中央大学以及科学研究和教育网络进行教育推广。该项目将研究陆生火蜥蜴(Plethodon Cinereus)通过适应来应对当地温度变化的能力。在北卡罗来纳州的皮埃蒙特，由于开发而产生的当地热岛提供了比天然森林温暖得多的栖息地。这一发展历史导致了从10年到100年的时间尺度上的局部变暖，在暴露在高温下的时间上提供了一个准实验梯度。将使用减少代表性的下一代基因组测序方法在全基因组范围内评估火蜥蜴种群内和种群之间的遗传变异。结合环境协变量，新的基因-环境异常值检测分析将被用于将基因组数据划分为中性和潜在的适应性变异；这些数据集允许分别测量种群内和种群之间的基因流动和局部适应。这些数据的整合使用贝叶斯方法，将中性或适应性等位基因频率的协方差建模为地理和环境距离的函数。基因流通过地理分离的图论估计上的中性遗传标记的协方差来评估；局部适应根据环境差异选择下的遗传标记的协方差来衡量。相对影响大小将确定分散补贴或隔离适应较好的基因类型的情况，如景观配置或发展速度干扰居民火蜥蜴跟踪当地气候的能力的地点。

This research will provide insights into the capacity of species to adapt to fragmented and warming habitats, and so inform actions that will be most effective in conserving biodiversity under climate change. Faced with changing climate, organisms either adapt in place or move to track conditions that they are adapted to. In the absence of these responses, they may go locally extinct. Relative to movement, adaptation in response to environmental change remains poorly understood in wild populations. Fortunately the recent development of genetic techniques for detecting adaptation in nature has made it easier to evaluate this response. Collaborations established under this project include educational outreach through the Duke Forest Office, North Carolina Central University, and the Scientific Research and Education Network.This project will study the capacity of a terrestrial salamander (Plethodon cinereus) to respond to local variability in temperature via adaptation. In the Piedmont of North Carolina, local heat islands resulting from development provide habitats that are substantially warmer than natural forests. This history of development has resulted in local warming over timescales ranging from 10 to 100 years, providing a quasi-experimental gradient in exposure time to elevated temperatures. Genetic variation within and among salamander populations will be assessed at a genome-wide scale using reduced representation, next-generation genomic sequencing methods. In combination with environmental covariates, novel genotype-environment outlier detection analyses will be used to partition genomic data into neutral and potentially adaptive variation; these data sets allow for the measurement of gene flow within and between populations and local adaptation, respectively. Integration of these data uses a Bayesian approach for modeling the covariance in neutral or adaptive allele frequencies as functions of geographic and environmental distances. Gene flow is assessed via covariance of neutral genetic markers on graph-theoretic estimates of geographic separation; local adaptation is measured in terms of covariance of genetic markers under selection on environmental dissimilarity. Relative effect sizes will identify instances of dispersal subsidy or isolation of better-adapted genotypes, as represented by locations where landscape configuration or the pace of development interferes with the ability of the resident salamanders to track local climate.