LTREB: Interaction of Below- and Above- Ground Herbivory in Forest Gap Formation:Long-Term Analysis of Underlying Mechanisms and Spatio-temporal Patterns

本研究的总体目的是探讨红松茎、根的植食作用及其相互作用。地下过程和地上过程（如草食过程）之间的相互作用被广泛认为是陆地生态系统的重要组成部分，但对其了解甚少。在红松中，以茎为食的食草动物包括树皮甲虫和其他无聊的昆虫；另一类生物以树根为食。先前的研究结果表明，扎根的甲虫也会把真菌带到新林分的一些树木中。这些生物不会杀死成熟的树木，但它们会干扰茎和根之间物质（水、营养物质、碳）的运输。这种干扰降低了树木抵抗树皮甲虫感染的能力。与此同时，树皮甲虫的侵扰正在增加，真菌通过根部传播，导致树木死亡。随着受感染的树木死亡，不同类型的植物占据了由此产生的空白空间，导致森林植被发生重大变化。本研究的具体目标是：1)研究根的食草性对茎食草动物易感性的影响；2)测量根甲虫、树皮甲虫及其捕食者在树与林之间的运动；3)通过实验确定茎定殖生物、根定殖生物及其捕食者在树木死亡和林窗（开放森林空间）形成中的相对重要性。由于树皮和根茎昆虫对商业和天然林造成重大损失，本研究的结果将有助于森林管理和公共土地管理。这项研究将使人们更好地了解作物多样性在多大程度上可以减少损失。这项研究还将通过强调本科、研究生和研究生各级的跨学科教育来促进科学培训。

The overall purpose of this research is to explore the effects of, and the interactions between, herbivory on stems and herbivory on roots of red pine trees. Interactions between below-ground and above-ground processes such as herbivory are widely recognized as important but are poorly understood components of terrestrial ecosystems. In red pine, the group of herbivores that feeds on stems includes bark beetles and other boring insects; a different group of organisms feeds on tree roots. Previous results suggest that root-colonizing beetles also bring fungi into a few trees in new stands. These organisms do not kill mature trees, but they interfere with transport of materials (water, nutrients, carbon) between stems and roots. This interference reduces trees' ability to resist infection by bark beetles. At the same time that bark beetle infestation is increasing, fungi spread through roots and contribute to tree mortality. As infected trees die, different types of plants colonize the resulting empty space, leading to major vegetational changes in the forest. The specific objectives of the current study are to 1) study the effects that herbivory on roots has on susceptibility to stem herbivores, 2) measure movements of root beetles, bark beetles and their predators among trees and among forests, and 3) conduct experiments to determine the relative importance of stem-colonizing organisms, root-colonizing organisms, and their predators in tree mortality and gap (open forest space) formation. Because bark and root insects cause significant losses in commercial and natural forests, results from this study will aid forest management and public land management. The study will provide a better understanding of the scale at which crop diversity can reduce losses. The research will also contribute to science training by emphasizing interdisciplinary education at the undergraduate, graduate and postgraduate levels.