Plant Biodiversity and Responses to Elevated Carbon Dioxide

Abstract

Insitustudies of communities suggest that the interactions between biodiversity, atmospheric CO2concentration, and C cycling are very complex. Rising CO2will probably act on plant diversity through a number of very indirect pathways; e.g., by altering the relative availability of resources such as water and nutrients thereby altering competitive interactions among plants. Second, changes in plant community structure due to rising CO2concentrations, particularly in highly dynamic systems, may be as or more important in determining biomass responses than the direct effect of elevated CO2. Finally, species loss resulting from global change might reduce productivity as well as responsiveness to elevated CO2, although the response will largely depend on species identity.Over all, simple scenarios invoking a clear and simple biospheric loop between atmospheric CO2and terrestrial biomass due to CO2fertilization need to be abandoned and replaced by an understanding of a complex system involving both biotic and abiotic feed-back loops. Our ability to either manage or predict the relationship between diversity and ecosystem function is still limited.