Are effects of species mixtures on ecosystems predictable based on effects of the component species?
Eviner, Valerie1, Chapin, F. Stuart2, Firestone, Mary1, 1 2 ABSTRACT- It has been well established that plant species can have distinct effects on ecosystem processes, however, when these plants are grown in mixed-species communities, it is often difficult to predict the effects of the community based on the individual effects of the component species. We grew 8 California annual grassland species in monocultures and in 2-species combinations, and evaluated plant composition effects on plant biomass, soil N availability, net N mineralization and nitrification, soil respiration, soil moisture, P availability, microbial P, decomposition, tissue quality, and microbial community composition. Microbial community composition in plant mixtures tended to be dominated by one of the component plant species, while decomposition tended to be an average of the rates of the 2 species in monoculture. The effects of mixtures on other ecosystem processes were an average of the component species, domina
