Dissertation Research: Climate change and candidate gene variation in Populus: Impacts on dependent communities and biotic interactions

这项研究将研究气候如何驱动白杨的遗传变异模式，以及这种变异如何影响依赖白杨的生物。利用从亚利桑那州到阿尔伯塔的复制普通花园，将测量不同纬度梯度的树木种群在生长、生存和生长开始和停止时间（森林树木的关键适应特征）方面的遗传变异。由于复制的花园跨越了广泛的气候范围，研究温度和降水如何与遗传变异相互作用，从而影响树木的性状，并确定树木是否适应当地的环境。利用分子工具，气候对影响生长开始和停止时间的特定基因的影响将被量化。这些特征也会强烈影响依赖昆虫的食草动物。因此，还将对以棉杨树为食的昆虫进行调查，以确定树木的遗传变异如何影响依赖生物。这项研究将在五个主要方面具有更广泛的意义。首先，如果树木种群目前已经适应了当地的环境条件，那么未来的气候变化可能会使当地的树木种群不适应环境。因此，需要了解树木的适应模式和遗传变异，以了解气候变化对自然系统的潜在影响。这些信息将有助于资源管理人员在进行恢复项目时，在全国各地的河岸地区很常见。其次，了解遗传变异如何影响物种之间的相互作用是生态学和进化生物学的前沿。这项工作将通过识别对生物群落有影响的潜在特征的基因来扩展这一前沿。第三，研究生的研究将促进科学教育，通过训练本科生助理在现场和实验室技术。第四，本研究将与加拿大和美国的研究人员建立长期的国际合作关系。最后，这笔拨款将启动一项长期的实地实验，这对于充分了解气候变化对生物群落的影响是必要的。

This research will examine how climate drives patterns of genetic variation in cottonwoods and how this variation affects organisms dependent on cottonwood. Using replicated common gardens from Arizona to Alberta, genetically based variation in growth, survival, and timing of growth initiation and cessation (key adaptive traits for forest trees) among tree populations from a latitudinal gradient will be measured. With the replicated gardens spanning a broad climatic range, investigations of how temperature and precipitation interact with genetic variation to influence tree traits and to determine if trees are adapted to their local environments will be conducted. Using molecular tools, climate's effect on specific genes that influence the timing of growth initiation and cessation will be quantified. These traits can also strongly influence dependent insect herbivores. Therefore, surveys of insects feeding on the cottonwood trees, determining how genetic variation in the trees affects dependent organisms will also be conducted.This research will have broader significance in five main ways. First, if tree populations are currently locally adapted to their environmental conditions, future climate change could render populations locally maladapted. Thus, understanding patterns of adaptation and genetic variation in trees is needed to understand the potential impact climate change will have on natural systems. This information will aid resource managers when undertaking restoration projects, common in riparian areas throughout the country. Second, understanding how genetic variation influences interactions among species is a frontier of ecology and evolutionary biology. This work will extend that frontier by identifying genes underlying traits that have consequences for biotic communities. Third, graduate student's research will promote science education by training an undergraduate assistant in field and laboratory techniques. Fourth, this study will establish a long-term international collaboration with researchers in Canada and the United States. Finally, this grant will initiate a long-term field experiment, necessary to fully understand effects of climate change on biotic communities.