Fig. 1

Least square means and residuals in the analysis of plant final dry mass in two plant pots (“Heli”, Helichrysum, and “Arte”, Artemisia). a Lsmeans for the Carpobrotus and native species’ masses. Vertical lines on the left-hand side and right-hand side of the graph show 95% vertical lines means asymptotic confidence intervals for pots containing African and European Carpobrotus respectively. Interval limits outside the comparison areas may lie outside the areas shown in the graphs. Right, summaries of the Table 1 analyses of Carpobrotus and natives’ masses. b Top, two-dimensional representation of the lsmeans in (a). All lsmeans correspond to untransformed data and are drawn to the same scale to ease comparisons. Middle and bottom, bidimensional representations of the residuals in the analysis of Carpobrotus and natives’ masses in pots containing African and European Carpobrotus, respectively. The r squared and the significance of the slope in a regression of natives’ on Carpobrotus’ residuals are shown on the graphs. *, P < 0.05; **, P < 0.01; ***, P < 0.001