Fig. 4
Results from Generalised Dissimilarity Models (GDM) for two of the studied functional traits: carbon isotope signature (δ13C; a–c) and the ratio between leaf carbon and nitrogen concentrations (C:N; d–f), and for each functional trait, rows correspond to mature (Mat), transition (Trn) and expanding (Exp) forest stages, and panels correspond to GDMs performed in each plot (with plot name indicated at the top of the panel). Curves represent the I-spline functions of predictors with significant (solid line; p < 0.05) or marginally significant (dotted line; 0.05 < p < 0.1) effects on divergence in functional traits between individuals. Predictors are as in Fig. 2 (genetic distance is not included due to a lack of significant effects in the selected functional traits). The values of predictors in horizontal axes were scaled to a 0–1 range to show effects from different predictors in the same panel. The maximum height of the I-spline functions can be interpreted as the importance of the predictor, and the slope provides an idea of the range of values of the predictor in which the effect on functional divergence is higher