Grantee Research Project Results
Impacts of Global Atmospheric Change on Canopy Insect Communities in Northern Deciduous ForestsEPA Grant Number: F5F21887
Title: Impacts of Global Atmospheric Change on Canopy Insect Communities in Northern Deciduous Forests
Investigators: Habeck, Christopher W.
Institution: University of Wisconsin - Madison
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2005 through August 31, 2006
Project Amount: $110,537
RFA: STAR Graduate Fellowships (2005) RFA Text | Recipients Lists
Research Category: Academic Fellowships
The objective of this research is to quantify the individual and combined effects of elevated atmospheric CO2 and O3 concentrations on herbivore communities in northern deciduous forests (aspen, birch and maple).
The impacts of global atmospheric changes on interactions between plants and animals are expected to be significant, but remain unclear. Changes in plant chemical composition under elevated CO2 suggests herbivores are experiencing a decrease in food quality. This project intends to quantify the response of canopy insect communities to changes in aspen, birch and maple chemistry under atmospheric concentrations of CO2 and O3 expected in 2050. The results will increase our understanding of how organisms across trophic levels interactively respond to CO2 and O3 and our ability to predict community (e.g., biodiversity) and ecosystem (e.g., primary production) level responses to on-going global change.
Global atmospheric change is altering plant productivity and phytochemistry. Changing plant chemistry due to an increase in gaseous pollutants (i.e., carbon dioxide and tropospheric ozone) modifies the quality of food to herbivores. Recent studies on herbivore response to greenhouse gas-induced changes in plant chemistry have concentrated primarily on insect-plant interactions under elevated CO2. However, most of this work has been limited to single species responses and of these, only a few studies have investigated the combined effects of CO2 and O3. More importantly, the community-level response of insects to elevated gaseous pollutants is entirely lacking. Herbivorous insects are major contributors to biological diversity and play important roles in forest health and ecosystem function. Information concerning the community-level effects of global atmospheric change on forest ecosystems is critical to quantify current, and predict future consequences of global change on biodiversity and ecosystem processes such as energy flow and nutrient cycling.
Several factors will be measured including species richness, abundance and biomass of insect canopy communities, phytochemistry, and defoliation patterns in forest stands consisting of aspen, birch and maple and fumigated with CO2 and O3 at levels predicted for 2050. This work will be conducted at the Aspen Free Air CO2 Enrichment (FACE) facility near Rhinelander, Wisconsin. Data will be collected periodically throughout the growing season to assess the temporal dynamics of insect community response.
Insect canopy community composition and defoliation patterns should vary among fumigation treatments, tree species, and tree genotypes. Biodiversity is expected to decline under elevated CO2 and O3, whereas plant damage to herbivores is anticipated to increase under those treatments. Also, insect functional groups are expected to vary in their ability to cope with phytochemical changes among treatments, species, and genotype.