ARS | Publication request: SIMULATED NITROGEN CONSTRAINTS ON ELEVATED CO2 RESPONSES FOR GRASSLANDS AND FORESTS

Submitted to: Ecological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 2, 2003
Publication Date: July 22, 2003
Citation: PARTON, W., DEL GROSSO, S., OJIMA, D., MOSIER, A.R., MORGAN, J.A. 970-490-82213. ECOLOGICAL SOCIETY OF AMERICA PROCEEDINGS. 2003.

Technical Abstract: There is increasing evidence that the initial positive increases in net plant production (NPP) following step increases in atmospheric CO2 levels are substantially reduced by soil nutrient limitations. This paper will use the Daycent ecosystem model to simulate the short and long term impacts of soil nutrient limitations on grassland and forest system responses to step increases in atmospheric CO2 levels. The Daycent model has been tested using observed data from grassland elevated CO2 experiments in Colorado, California, and Kansas and the Oak Ridge and Duke Forest sites. Model results mostly represent the observed ecosystem response to increasing atmospheric CO2 levels and suggest that the initial increase in NPP following a step increase in atmospheric CO2 levels will be greatly reduced by nutrient limitations after 5 to 10 years for the forest systems, while the elevated CO2 impacts for grasslands are sustained for up to 100 years. The positive impact of increasing atmospheric CO2 levels for grasslands are largest for the short grass steppe and minimal for the annual grassland system. Model results will contrast the short (1 to 5 year) and long term (10 to 20 year) responses of grasslands and forests to elevated CO2 levels and compare observed versus simulated ecosystem responses to experimental data from elevated CO2 and soil nutrient experiments.