Ecology of Invasive Forest Insects in the Boreal Forest: Role of Plant Resistance and Community Interactions

气候变化对生态系统产生了许多级联影响，近几十年来，已经导致昆虫，鸟类和海洋物种的范围发生了变化。物种分布范围的扩大是一种短期效应，可能对新殖民生态系统的动态产生重大影响。在北美，一个非常令人关注的物种扩张是山松甲虫（MPB）。目前在加拿大西部爆发的MPB已经杀死了数百万公顷的黑松，构成了已知最大的连续森林昆虫流行病。现在人们非常关注它的东向传播，因为在北方和东部松树中没有与宿主相关的障碍。我的研究主要集中在短叶松树的阻力和本地生物和MPB之间的相互作用是否会影响MPB在短叶松森林入侵。我建议调查是否矮槲寄生感染杰克松树改变杰克松抗MPB。寄生植物矮槲寄生是短叶松林中分布最广的树木压力源。槲寄生感染缓慢进展，并随着时间的推移而加剧，导致树木活力降低，死亡可能性增加。活力降低的树木可能为MPB的建立和存活提供机会。我将进行一些实地和室内实验，以了解MPB和矮槲寄生之间的相互作用，并在我的实验中使用成熟和幼年松树。我将专注于植物的化学防御，特别是萜类和酚类化合物，以评估防御机制，影响杰克松种间相互作用的结果，因为化学防御是针叶树对草食动物和真菌的重要机制。深入了解MPB入侵如何影响短叶松森林系统将是本项目的重要贡献。这种理解是重要的，以阐明的一般结构和行为的杰克松系统对MPB，并将是关键的综合治理的杰克松森林中的MPB的发展。

Climate change has many cascading impacts for ecosystems and in recent decades has led to shifts in the ranges of insect, bird, and marine species. Species range expansions are a short run effect that could have large impacts on the dynamics of newly colonized ecosystems. In North America, one species expansion of great concern is that of the mountain pine beetle (MPB). Current outbreaks of the MPB in western Canada have killed lodgepole pine trees over several million hectares, comprising the largest known contiguous forest insect epidemic. Now there is great concern about its eastward spread as there are no host-related impediments in boreal and eastern pines. My research focuses on whether jack pine tree resistance and interactions between native organisms and MPB affect the MPB invasion in the jack pine forest. I proposed to investigate whether dwarf mistletoe infection of jack pine trees alter jack pine resistance to MPB. Dwarf mistletoe, a parasitic plant, is the most wide spread tree stressor in the jack pine forest. Mistletoe infections slowly progress and intensify with time, resulting in reduced tree vigour and increased probability of mortality. Trees with reduced vigor might provide opportunities for MPB establishment and survival. I will conduct a number of field and indoor experiments to understand the interactions between MPB and dwarf mistletoe and use both mature and juvenile pine trees in my experiments. I will focus on plant chemical defenses, particularly terpenoids and phenolic compounds, to evaluate defense mechanisms that influence the outcome of interspecies interaction on jack pine because chemical defenses are important mechanisms for conifers against herbivores and fungi. Developing deeper understandings of how MPB invasion would affect the jack pine forest system will be important contribution of this project. Such understanding is important to elucidate the general structure and behavior of the jack pine system against MPB and will be critical for the development of the integrated pest management of MPB in the jack pine forest.