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索红松树树干上的食草性和根部上的食草性之间的相互作用。草食等地下和地上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，但人们对此知之甚少。在红松中，以树干为食的食草动物包括树皮甲虫和其他令人厌烦的昆虫；另一类生物以树根为食。之前的研究结果表明，根部定植甲虫也会把真菌带到新林分的几棵树上。这些生物不会杀死成熟的树木，但它们会干扰茎和根之间的物质(水、养分、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，树皮甲虫的侵染正在增加，真菌通过树根传播，导致树木死亡。随着受感染的树木死亡，不同类型的植物在由此产生的空地上定居，导致森林中的主要植被变化。本研究的具体目标是：1)研究根部食草性动物对树干食草动物的敏感性；2)测量根甲、树皮甲虫及其捕食者在树木和森林之间的活动；3)进行实验，以确定树干定殖体、根部定殖体及其捕食者在树木死亡和林隙(空地)形成中的相对重要性。由于树皮和根部昆虫会对商品林和天然林造成重大损失，因此这项研究的结果将有助于森林管理和公共土地管理。这项研究将更好地了解作物多样性可以在多大程度上减少损失。这项研究还将通过强调本科生、研究生和研究生层面的跨学科教育，为科学培训做出贡献。

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.