Fig. 6

Number of vascular plant species (all plant species and beech forest species) in the plots of topographic positions in dolines (south-facing slope, bottom, and north-facing slope) covered with different forest age classes (class 1: 5–10-year-old forest stands with mature forest patches, class 2: 40–45-year-old forests, class 3: 60–65-year-old forests, and class 4: more than 90-year-old forests) (mean ± SE). Significant differences (based on the GLMMs with Bonferroni post hoc tests) are indicated by different lowercase (a–c: between the same topographic positions of the different forest age classes, p < 0.05) and upper case (A–C in different colours: between the different topographic positions within a forest age class, p < 0.05) letters, respectively