Separating Species and Functional Group Diversity Effects on Plant Tissue Chemistry and Biomass Production Under Elevated CO2 in a Grassland Ecosystem

Abstract

Our planet is undergoing environmental change at an accelerated rate. Increases in atmospheric CO2 concentrations are increasing global temperatures and biodiversity is being threatened by habitat loss and exploitation. A decrease in tissue nitrogen (N) concentration is a common response of plants when grown under elevated CO2 (eCO2), which can limit other aspects of ecosystem function such as herbivore success and N cycling. Ecosystem responses to eCO2 have been found to differ depending on the number of species present (species diversity) and/or the functional attributes (such as differing photosynthetic pathways or N- fixing ability) of the species present (functional diversity). For example, higher species diversity and functional diversity each independently resulted in increased biomass under eCO2 conditions compared to lower diversity assemblages in a grassland ecosystem.