title: Fire, hurricane and carbon dioxide: effects on net primary production of a subtropical woodland.
abstract: Disturbance affects most terrestrial ecosystems and has the potential to shape their responses to chronic environmental change. Scrub-oak vegetation regenerating from fire disturbance in subtropical Florida was exposed to experimentally elevated carbon dioxide (CO₂) concentration (+350 μl l(-1)) using open-top chambers for 11 yr, punctuated by hurricane disturbance in year 8. Here, we report the effects of elevated CO₂ on aboveground and belowground net primary productivity (NPP) and nitrogen (N) cycling during this experiment. The stimulation of NPP and N uptake by elevated CO₂ peaked within 2 yr after disturbance by fire and hurricane, when soil nutrient availability was high. The stimulation subsequently declined and disappeared, coincident with low soil nutrient availability and with a CO₂ -induced reduction in the N concentration of oak stems. These findings show that strong growth responses to elevated CO₂ can be transient, are consistent with a progressively limited response to elevated CO₂ interrupted by disturbance, and illustrate the importance of biogeochemical responses to extreme events in modulating ecosystem responses to global environmental change.
authors.affiliation: Department of Biological Sciences and Ecosystem Science & Society Center, Northern Arizona University, Flagstaff, AZ, 86011, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Hungate
authors.affiliation: Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Day
authors.affiliation: Department of Biological Sciences and Ecosystem Science & Society Center, Northern Arizona University, Flagstaff, AZ, 86011, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Dijkstra
authors.affiliation: Department of Biological Sciences and Ecosystem Science & Society Center, Northern Arizona University, Flagstaff, AZ, 86011, USA.|USDA-ARS, Dairy Forage Research Center, 1925 Linden Dr, Madison, WI, 53706, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Duval
authors.affiliation: University of Central Florida, Orlando, FL 32816, USA.
authors.forename: C Ross
authors.initials: CR
authors.lastname: Hinkle
authors.affiliation: Department of Biology, Villanova University, Villanova, PA 19085, USA.
authors.forename: J Adam
authors.initials: JA
authors.lastname: Langley
authors.affiliation: Smithsonian Environmental Research Center, Edgewater, MD 21037, USA.
authors.forename: J Patrick
authors.initials: JP
authors.lastname: Megonigal
authors.affiliation: University of South Florida, Tampa, FL 33620, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Stiling
authors.affiliation: Department of Natural Resources, University of Nevada-Reno, Reno, NV, 89557, USA.
authors.forename: Dale W
authors.initials: DW
authors.lastname: Johnson
authors.affiliation: Smithsonian Environmental Research Center, Edgewater, MD 21037, USA.
authors.forename: Bert G
authors.initials: BG
authors.lastname: Drake
mesh_terms: D001272:Atmosphere; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism*; D055867:Cyclonic Storms; D017753:Ecosystem; D005390:Fires; D005431:Florida; D009584:Nitrogen / Q000378:metabolism*; D058458:Nitrogen Cycle; D018547:Plant Stems / Q000378:metabolism; D029963:Quercus / Q000254:growth & development* / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D014197:Trees / Q000254:growth & development / Q000378:metabolism
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D009584:Nitrogen
keywords: disturbance; elevated CO2; fire; global environmental change; hurricane; net primary productivity (NPP); nitrogen cycling; oak woodland