This data contains species richness, abundance and functional diversity of arthropod communities per plot from a grassland biodiversity experiment (the Jena Experiment). Functional diversity here is expressed by functional richness (FRic), evenness (FEve) and divergence (FDiv). These three measures give an impression about the niches filled by members of a community and the range, dispersion, and value of organismal traits, whereby traits are measurable features of individuals affecting their performance or fitness (Villéger et al. 2008). For each consumer species we used the following five traits to calculate the above mentioned indices: feeding mode, food/ host specialization, stratum, aerial mobility, body mass.