Table 3 . Characteristics of TWINSPAN sample groups (A – G) and sample-group devoid of vegetation (H): (a) Classification statistics and vegetation variables; (b). Environmental variables. Data for variables are mean values ( ± standard error where applicable). Per variable, means sharing a superscript letter in common do not significantly differ (p <0.05: ANOVA with Tukey’s post-hoc mean separation test (vegetation height; total PAH), or Kruskal-Wallis tests (all other variables): tests only applied for individual PAHs where at least one TWINSPAN group mean value exceeded 20.0 µg kg-1 soil dry weight). Variables were log10-transformed where necessary to normalize the data. Values for total PAH content are the sum of all component PAHs measured. Units for PAHs (see Methods for abbreviations): µg kg-1 soil or plant tissue dry weight. For further information see caption to Table 1.