The investigators propose to examine the effect of elevated levels of carbon dioxide and ozone on plant chemical composition and insect performance in common tree and insect species of the midwestern deciduous forest. Experiments will focus on the interaction between carbon dioxide and ozone. Estimates of the effects on insect populations will be made by measuring performance over several generations. The proposed research will provide insights into how elevated carbon dioxide will affect species interactions in forest communities. It will improve understanding of how trophic interactions will be altered and the consequences of such changes for insect populations and tree productivity. As part of a multidisciplinary Free Air Carbon Exchange (FACE) study this work will enhance the development of increasingly realistic models of carbon budgets in terrestrial ecosystems. Understanding the ecological consequences of enriched atmospheric carbon dioxide is of considerable national and international importance, especially as the international community becomes embroiled in debate over emission restrictions. Although increasing concentrations of atmospheric carbon dioxide are anticipated to exert significant impacts on forest ecosystems over the next 50-100 years, little is known about how these changes will affect ecological interactions, and how these in turn will feed back to affect forest structure and function. This work is of critical importance as the United States evaluates the environmental and economic consequences of global environmental change, and implements policies to address such issues. Moreover, this research will enhance our understanding of basic ecological problems such as how resource availability alters chemical composition and carbon partitioning in plants, and the effects of such changes on plant-insect interactions.
