Variation in categorical variables describing the bedrock type, its pH and age for each species cluster.

Values in bold are significantly different from those for the pooled data (p<0.05, χ2 test). Abbreviations for age classes: HoloSedi-holocene sediments; PostHist-postglacial, historic, younger than AD 871; PostPreHist-postglacial, prehistoric, older than AD 871; TertPleist-Tertiary and Pleistocene, older 11000 years; UppPleist-Upper Pleistocene, younger than 0.8 m.y.; UppLowPleist-Upper Pliocene and Lower Pleistocene, 0.8–3.3 m.y.; UppTerti-Upper Tertiary, older than 3.3 m.y.; Ind–Indefinite.