Legacy effects of long-term CO₂ enrichment on plant biomass recovery from fire seven years after return to ambient CO₂ levels

• Published in: The journal of the Torrey Botanical Society 2019-01, Vol.146 (1), p.1-7
• Main Authors: Bain, John C., Day, Frank P.
• Format: Article
• Language: English
• ISSN: 1095-5674; 1940-0616
• DOI: 10.3159/TORREY-D-17-00044.1

We sought to determine if elevated CO₂ resulted in long-lasting changes to plant structure and function, particularly disturbance response patterns. Minimal legacy effects were observed 1 yr after the termination of a previous long-term experiment; however, those observations were based on 1 yr of data and only focused on fine root growth, herbivory, and arthropod diversity. We examined above-and belowground biomass inside the footprints of chambers from a former long-term elevated CO₂ experiment in a scrub-oak community 7 yr after CO₂ enrichment ceased and 2 yr after fire. Aboveground biomass was 40.6% higher in the previously elevated plots compared with ambient plots, suggesting that there are legacy effects in the form of more rapid aboveground recovery from fire on previously elevated CO₂ plots. Belowground biomass exhibited minimal change since the historic CO₂ enrichment, suggesting that differences were a result of the original treatment. After disturbance, regrowth occurs via sprouting from large belowground structures; thus changes in aboveground recovery are likely due to changes to belowground biomass caused by altered atmospheric CO₂. Elevated CO₂ has significantly affected disturbance recovery patterns in this community. These changes have the potential to alter plant carbon allocation patterns in frequently disturbed systems.