PARENT SESSION
Organized Oral Session 13: Gas exchange and global change in peatlands: From soil to satellite
Organizer(s): J Limpens, G Schaepman, MB Nilsson, and MM Heijmans
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 510b, Level 5, Palais des congrès de Montréal
Global change, biodiversity and ecosystem function: Predictions for Canadian peatlands.
Jouseau, Claire*,1, Naeem, Shahid1, 1 Columbia University, New York
ABSTRACT- In a world of rapidly declining biodiversity, the ability to predict how changes in local or regional species composition will affect the structure and function of ecosystems has emerged as a critical challenge for ecologists. Here we assess the impacts of climate change and enhanced nitrogen deposition on moss species composition, distribution, and abundance in Canadian peatlands and the consequent effects these changes have on the carbon sequestration potential of 365,157 km2. Using a simple diversity-function model, we compare present-day annual carbon accumulation in peatlands with accumulation under three environmental change scenarios: elevated temperature and precipitation, elevated temperature and decreased precipitation, and enhanced nitrogen deposition. Peatlands were classified into 6 categories of bogs and fens each containing between 6 and 14 dominant moss species. Community-level responses to warming, moisture, and nitrogen deposition were determined from species-specific responses gathered from published experimental manipulations. Species contribution to carbon accumulation was inferred from peatland type, position along a hydrologic gradient, and species morphology. For each scenario, individual peatland types responded differently due to changes in species composition, productivity, and total area occupied by the habitat. In the case of elevated temperature and precipitation, at the biome-level, annual carbon accumulation increased due to enhanced moss productivity from an extended growing season and a shift in species composition favoring more productive water-loving species. Elevated temperature and decreased precipitation yielded a decrease in carbon accumulation resulting from a shift towards less-productive more drought-tolerant species and the effect was compounded by a contraction in biome area. Enhanced nitrogen deposition also yielded a decrease in carbon accumulation but strongly favored the development of forested peatlands which offset much of the lost accumulation potential. These results suggest that accurately identifying relevant species functional traits and understanding how these traits directly and indirectly affect ecosystem function is essential in predicting the ecosystem-level consequences of changes in community diversity.
Key words: peatlands, ecosystem function, species traits, global change