Fig. 5

Rarefaction curves of the S. acaulis cushion and open areas a–d, and RII values against median log diameters of cushions e. The rarefaction curves for cushions and open plots were respectively calculated by the randomization method for the north-east facing slope a, the south-east facing slope b, the control site c, and for the flat ground d. The shaded area shows a 95% CI. The vertical dotted lines show the minimum cumulative area among the four sites. RIIs were calculated from the species richness at the minimum cumulative area in the rarefactions, and they were plotted against the median log diameters of the cushions e. The vertical solid line shows 95% CI of RII. The distribution of the log diameter of the cushions is also shown at the top of the graph