Fig. 5. Relationship between species richness differentiated according to the presence of (A) legumes or (C) grasses, or functional group richness differentiated according to the presence of (B) legumes or (D) grasses, and volume-weighted mean (vwm) concentrations of total dissolved N (TDN) in spring 2003. Data are presented as mean ± standard error. Note that there is no 60-species mixture without legumes.