Elevated atmospheric CO2affects structure of a model regenerating longleaf pine community

Differences in plant morphology, physiology, life form, and symbiotic relationships can generate differences in species responses to CO2‐enrichment, which can alter competitive interactions, thus affecting community structure and function. Here, we present data from a two‐year study, examining the species and community responses to elevated [CO2] of a model regenerating longleaf pine community. The model community was constructed from an assemblage of early successional forest species representing major functional guilds within a typical longleaf pine–wiregrass community: (1) a C3evergreen conifer (Pinus palustris); (2) a C4bunch grass (Aristida stricta); (3) a C3broadleaf tree (Quercus margaretta); (4) a C3perennial herbaceous legume (Crotalaria rotundifolia); and (5) a C3herbaceous perennial (Asclepias tuberosa). After 2 years, CO2‐enriched plots had 109% greater above‐ground biomass than ambient plots, mainly due to a 117% increase in pine biomass. Community structure was altered by CO2enrichment;CrotalariaandAsclepiashad higher mortality and less biomass in high‐CO2plots, suggesting that not all species will perform well as global [CO2] rises. Our data suggest that longleaf pine communities as a whole will perform well in a future higher CO2world, but some species may fall prey to altered competitive interactions for light and soil moisture.