The alliance Onopordion acanthii comprises thermophilous to moderately thermophilous anthropogenic vegetation with a predominance of biennial and perennial plants. Soils are usually dry and developed on loess or hard base-rich bedrock types, but also on anthropogenic substrates such as building rubble in villages, around castle ruins and in waste places. In the course of secondary succession in anthropogenic habitats this vegetation usually develops out of stands of the Atriplicion. Sisymbrion officinalis and Malvion neglectae. Onopordion acanthii is an ancient type of ruderal vegetation, which has probably been common since the Neolithic. It contains many archaeophytes, of which several are endangered species of the Czech flora; there are few neophytes.