The Jena Experiment is one of the largest terrestrial biodiversity experiments worldwide and investigates the relationship between plant diversity and ecosystem processes. Plant communities where plant species richness ranges from 1-60 species are established from a species pool of 60 species from Central European Arrhenatherum grasslands, divided into four functional groups. In total research can be carried out on 470 plots. The experimental communities serve as basis to study ecosystem fluxes of carbon and nutrients. There are continuous measurements of meteorological variables on all large plots as well as monitoring of important components of the C, N and P-cycle.