The Capacity of Populations to Respond to Climate Change

气候变化有可能在全球范围内重塑生物多样性的格局。尽管人们普遍认识到这些担忧，但研究人员仍在试图回答核心问题：人口是否有能力应对气候变化，还是会灭绝？由于温度对这些生物的生物学有许多影响，预计的温度升高可能对异温物种（那些依赖外部热源来控制体温的物种）尤其具有挑战性。热性能定义了个体体温与适合度之间的关系，可以作为了解变温物种当前地理分布的框架，并预测物种对气候变化的脆弱性。我的研究项目将专门评估热带和温带鱼类心肺系统的热性能及其对气候变化的响应能力。预计鱼类的心肺系统与健康密切相关，其在热应激下的衰竭可能是影响种群生存能力的主要因素。我的实验室将详细研究个体在其一生中暴露于高温下的反应（“表型可塑性”）和种群在进化过程中潜在的遗传反应（“适应潜力”）。我的实验室还将通过研究心脏形态和线粒体效率对心脏功能崩溃的最高温度限制的贡献，来了解热性能变化的机制基础。通过微观实验，我们将为热性能性状与适合度之间的假设关系提供关键测试，从而表征作用于这些性状的选择强度。我将进一步监测多代高温下热性能性状的演变，测量适应潜力和表型可塑性的变化，并使用基因组学方法确定与适应相关的特定候选基因。这些数据将填补我们对热性能理解的空白，并对建立基于气候变化情景的种群和物种灭绝风险预测模型至关重要。我的实验室将继续与政府的决策者合作，将这些数据和预测纳入政策，特别是在鲑鱼的管理方面，鲑鱼对加拿大人来说是经济和社会上重要的鱼类。因此，我的研究项目将解决气候变化研究的前沿问题，并将提供一个培训环境，使我的学生能够在包括学术界、政府和工业界在内的不同部门找到工作。

Climate change has the potential to reshape patterns of biodiversity on a global scale. Despite widespread recognition of these concerns, researchers are still trying to answer the central question: do populations have the capacity to respond to climate change or will they go extinct? Projected temperature increases are likely to be especially challenging for ectothermic species – those that rely on external heat sources to control body temperature – because of the many effects that temperature has on the biology of these organisms. Thermal performance defines the relationship between an individual’s body temperature and fitness, and can be used as a framework for understanding the current geographical distributions of ectothermic species, and to predict the vulnerability of species to climate change. My research program will specifically assess the thermal performance of the cardiorespiratory system and its capacity to respond to climate change in both tropical and temperate fishes. The cardiorespiratory system is expected to be tightly linked to fitness in fishes, and its failure under heat stress may be a leading factor affecting population viability. My lab will detail both the responses of individuals exposed to higher temperatures during their lifetime (“phenotypic plasticity”) and the potential genetic responses of populations over evolutionary time (“adaptive potential”). My lab will also work to understand the mechanistic basis of variation in thermal performance by studying the contributions of heart morphology and mitochondrial efficiency to the upper temperature limits at which heart function collapses. Using experimental microcosms, we will provide a critical test of the hypothesized relationship between thermal performance traits and fitness, and thereby characterize the strength of selection acting on these traits. I will further monitor the evolution of thermal performance traits at elevated temperatures for multiple generations, measuring changes in adaptive potential and phenotypic plasticity and using a genomics approach to identify specific candidate genes associated with adaptation. These data will address gaps in our understanding of thermal performance, and are critical to construct predictive models of population and species extinction risk based on climate change scenarios. My lab will continue to work with decision-makers in government to incorporate these data and predictions into policy, particularly around the management of salmon, which are economically and socially important fishes to Canadians. My research program will thus address questions at the forefront of climate change research, and will provide a training environment that will allow my students to find employment in diverse sectors including academics, government and industry.