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

点击翻译按钮获取中文摘要

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.