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

这项研究将深入了解物种适应破碎和变暖栖息地的能力，从而为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，生物体要么在原地适应，要么移动以跟踪它们适应的条件。如果没有这些反应，它们可能会在当地灭绝。相对于迁徙，野生种群对环境变化的适应仍然知之甚少。幸运的是，最近发现自然界适应性的遗传技术的发展使评估这种反应变得更加容易。在该项目下建立的合作包括通过杜克森林办公室、北卡罗来纳州中央大学和科学研究和教育网络进行教育推广，该项目将研究陆生蝾螈（Plethodon cinereus）通过适应对当地温度变化作出反应的能力。在北卡罗来纳州的皮埃蒙特，由于开发造成的局部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10至100年时间尺度上的局部变暖，提供了暴露于高温的时间的准实验梯度。蝾螈种群内和种群间的遗传变异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进行评估。结合环境协变量，新的基因型-环境离群值检测分析将用于将基因组数据划分为中性和潜在的适应性变异;这些数据集分别允许测量种群内和种群间的基因流和局部适应性。这些数据的整合使用贝叶斯方法来建模作为地理和环境距离的函数的中性或自适应等位基因频率的协方差。基因流是通过中性遗传标记的地理分离的图论估计的协方差进行评估;局部适应性是根据遗传标记在环境相异性选择下的协方差来衡量的。相对效应大小将确定的情况下，分散补贴或隔离更好地适应基因型，所代表的位置，景观配置或发展的步伐干扰的能力，居民蝾螈跟踪当地气候。

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.