Experimental confirmation of ecosystem model predictions comparing transient and equilibrium plant responses to elevated atmospheric CO2

Ecosystem models predict that short-term responses to elevated atmospheric CO2 may differ substantially from the "real" long-term responses expected a t equilibrium. Experimental validation of these model predictions is diffic ult as the data available are from short-term studies that do not include b iogeochemical feedbacks typical of long-term exposure. Using a reciprocal t ransplant design at a natural CO2 spring, we generated combinations of atmo spheric and soil conditions that represented both short- and long-term elev ated CO2 conditions. Plant responses were significantly different between t hese treatments, confirming model predictions that there is not a simple re lationship between transient and equilibrium responses to elevated CO2.