Resistance and tolerance of aspen to mammalian herbivores: Costs, benefits and selection in ontogenetic context

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。浏览哺乳动物和树木之间的相互作用在塑造北美森林生态系统中发挥着关键作用。这些相互作用的性质很可能是由植物防御性状，如化学抗性，耐受性和逃避。虽然这些综合防御综合征的作用已被广泛记录的草食性昆虫，相对较少的可比工作已经解决了浏览哺乳动物的影响。各种防御性状的效力的发育限制可能在昆虫和哺乳动物之间不同。最近的工作与白杨（杨树tremuloides）已经证明了强大的发展变化的阻力，并牵连哺乳动物的工具，在塑造表达防御在这个基础树种。该项目将调查白杨针对浏览哺乳动物的多元防御系统（抵抗力、耐受性和逃逸）的成本、效益、发育限制以及生态和进化后果。这项工作将采用一组不同的白杨基因型，生长在共同的花园研究和受到人工和自然浏览，以确定在何种程度上特定的化学化合物赋予防御浏览哺乳动物，评估成本和效益，以及潜在的权衡，阻力，宽容和逃避在多种环境中，并评估在实验种群中浏览对防御性状遗传结构的选择性影响。白杨在北美分布广泛，经济价值高。这项工作应提供新的见解和工具，有关土地管理人员和机构的工作，以保持白杨在整个山间西部下降的环境。这项研究也将有助于培养本科生，研究生和博士后。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Interactions between browsing mammals and trees play key roles in shaping North American forest ecosystems. The nature of these interactions is likely governed by plant defense traits, such as chemical resistance, tolerance, and escape. Although the roles of these integrated defense syndromes have been extensively documented for herbivorous insects, relatively little comparable work has addressed impacts of browsing mammals. Developmental constraints on the efficacy of various defense traits likely differ between insects and mammals. Recent work with aspen (Populus tremuloides) has demonstrated strong developmental variation in resistance, and implicated mammals as instrumental in shaping the expression of defense in this foundation tree species. This project will investigate the costs, benefits, developmental constraints, and ecological and evolutionary consequences of multivariate defense systems (resistance, tolerance and escape) in aspen against browsing mammals. This work will employ a set of diverse aspen genotypes, grown in common garden studies and subjected to artificial and natural browsing, to determine the degree to which specific chemical compounds confer defense against browsing mammals, assess the costs and benefits of, and potential tradeoffs among, resistance, tolerance and escape in multiple environments, and evaluate the selective impact of browsing on the genetic structure of defense traits in an experimental population. Aspen is a widely distributed and economically important species in North America. This work should provide new insights and tools relevant to land managers and agencies working to maintain aspen in environments of decline throughout the Intermountain West. This research will also contribute to the training of undergraduate, graduate and postdoctoral students.