Figure 1.
Standardized Principal Components Analysis (PCA; first vs. second axes) of 60 grassland species characterized by 18 functional traits.
Plant traits were measured in species monocultures in the Jena Experiment and derived from the literature. Symbols show species assignment to plant functional groups. For list of variables and abbreviations see Table 2.
Figure 2.
Standardized Principal Components Analysis (PCA) of community-weighted means of trait values (CWM) and functional trait diversity based on Raòs quadratic entropy (FDQ) of experimental grassland communities.
PCA of community-weighted means of trait values (CWM) first vs. second axes (a), second vs. third axes (b), PCA of functional trait diversity (FDQ) first vs. second axes (c), second vs. third axes (d), and PCA of CWM and FDQ in combination first vs. second axes (e), second vs. third axes (f). Community-weighted means of trait values (CWM) and functional trait diversity (FDQ) were calculated for each community based on species biomass proportions in the mixture and functional traits measured in species monocultures in the Jena Experiment and derived from the literature. Symbols show the position of each community sown with different numbers of species. Black arrows show CWM, red arrows show FDQ for each trait.
Figure 3.
Aboveground community biomass, net biodiversity effect, complementarity effect, and selection effect as a function of species richness.
Biomass data were recorded at estimated peak biomass in late May 2006 in the Jena Experiment. Lines show means across all mixtures per species-richness level.
Table 1.
Summary of best statistical models based on different groups of predictor variables (community-weighted means of trait values (CWM) and functional trait diversity (FDQ)) for community biomass, net biodiversity effects, complementarity effects and selection effects.
Table 2.
List of functional traits derived from measurements in monocultures of the Jena Experiment and from the literature.