PARENT SESSION
Poster Session # 21: Biogeography, Biodiversity, Populations, and Genetics.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
How does plant competition mediate the interactive effects of CO2, temperature, and soil water availability?
Engel, E. Cayenne*,1, Weltzin, Jake 1, 1 University of Tennessee, Knoxville, TN
ABSTRACT- Global climate change (due to increasing atmospheric CO2 concentration, increased average global temperature and changing precipitation regimes) may drastically affect plant community and ecosystem functions. However, investigations of the interacting factors are rarely attempted. A long term ecological experiment at Oak Ridge National Environmental Research Park was assembled to investigate the interactive effects of predicted global climate change on an old-field plant community. This project, OCCAM (old-field community climate and atmospheric manipulation,) utilizes open-top chambers with experimental plant communities constructed of seven common old-field species, including C3 and C4 grasses, forbs, and legumes to assess the implications of global climate change factors. We assessed plant community level effects of CO2, temperature, and soil water availability as measured through changes in productivity and species composition. In addition we examined how species interactions may control the response of the community. Pairwise competition experiments determined the effects of whole-plant interactions and were used to separate and identify the role of interactions between aboveground components (i.e. light interference) and belowground interactions (e.g. root competition.) Results from the competitive assessments are compared with treatments in OCCAM and are used to inform the interpretation of species and community level response within the experiment. Investigations of the species specific interactions within these communities allow us to evaluate the ramifications of abiotic effects on this system and make inferences toward expected patterns of community development.
Key words: competition, global climate change