Local Adaptation and Evolutionary and Adaptive Genetic Potential of Marginal Populations of Northern Forest Trees under Climate Change

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Climate change has become a prominent driving force of evolution in northern boreal and temperate ecosystems in which trees are normally the dominant keystone species as it is subjecting them to significant evolutionary and adaptive pressures. Impacts of climate change across natural ecosystems are evident from pole-ward shift of many species' range. Thus, populations at the species' range margins are expected to provide the frontiers for adaptation, evolution and range shifts of plants under climate change.These issues have ignited a debate on assisted migration. The potential of marginal populations to adapt and expand to new areas depends upon their local adaptation, genetic make-up and genetic diversity, especially in genes underlying responses and adaption to climate change. Hence, it is critical to understand the genic responses of a species to climate change, genetic basis of local adaptation of marginal populations, and their evolutionary and adaptive genetic potential under climate change in order to develop mitigation measures. Forest trees populations are usually locally adapted but knowledge of genetic architecture of their local adaptation remains elusive.The objectives of my research are to understand genetic characteristics of central and leading-edge and rear-edge marginal populations of eastern white pine (EWP) and its genetic responses to climate change; understand genetic architecture and mechanisms underlying local adaptation of marginal and central populations; and infer evolutionary and adaptive genetic potential of marginal populations under climate change. Eastern white pine provides an ideal model for the proposed research. It is of high ecological and economic importance, widely distributed across a variety of climate and ecological conditions, is a long-lived keystone species of the North American temperate white pine forest ecosystems, has its northern range margins in Canada, and is expected to extend its range northwards under climate change. It is also a target species for assisted migration. EWP populations from its central range and northern and southern range margins will be studied. Genes responsive to climate change conditions will be identified and functionally annotated. Genome-wide scans will be used to determine genetic characteristics of populations, genetic architecture of local adaptation, and evolutionary and adaptive genetic potential of EWP populations.My research will advance our knowledge of genetic responses of forest trees to climate change, local adaptation, conservation value and adaptive genetic potential of marginal populations, vulnerability of rear-edge populations, and evolution of species' range under climate change. It has major significance for long-term adaptation, sustainable management, and conservation of forest resources, and will address mitigation measure issues, such as assisted migration.