Means and standard errors of selected soil properties calculated for the C (control) and I (invasion) plots within the Y (yellow dune) and G (grey dune) sites. Where a significant site type × plot type interaction was found (see Table 2), the differences between plot types were examined separately for the two types of sites (using Tukey’s test) and marked with asterisks (*** p < 0.001, * p < 0.05). In the remaining cases, inequality signs were used to indicate significant main effects.