Xerothermic vegetation of fallow lands in western Małopolska

In 2005-2011 the occurrence of xerothermic vegetation on fallow lands located on hills near Trzebinia and Jaworzno was studied. The Braun-Blanquet relevés were performed on SE, S and SW slopes. Well-drained brown loamy soils developed on shallow sands on Triassic dolomites, lime-stone and Myślachowice conglomerate dominating at the sites. Investigations were also conducted on amid-field balks and fallow lands where in 2005 moderate agricultural activity was resumed. In general, superficial ploughing has not eliminated plant cover, but only disturbed turf and uncovered soil seed bank of former cultivation weeds.Fields 10-15 years after they had been abandoned, were dominated by the Dauco-Picridetum hieracioidis xerothermic ruderal association, with considerable share of Malva alcea and Verbascum species (V densiflorum, V. lychnitis, V. phlomoides and V. thapsus) in younger fallows. These communities were characterized by occurrence of xerothermic grasslands and warm thickets taxons from Festuco-Brometea and Trifolio-Geranietea sanguinei classes, i.a.: Achillea pannonica, Allium scorodoprasum, Bromus erectus, Centaurea stoebe, Cerinthe minor, Filipendula vulgaris, Fragaria viridis, Gentianella ciliata, Phleum phleoides, Valeriana angustifolia, Veronica spicata, Viola hirta and Thesium linophyllon.Additionally, on ploughed fallows in gaps of turf numerous annual and biennial segetal as well as ruderal species were observed. In many places thermophilous segetal association of Papaveretum argemones developed, in which a significant share of Avena fatua, Camelina microcarpa subsp. sylvestris, Consolida regalis, Lithospermum arvense and Papaver rhoeas was noted in addition to Arabidopsis thaliana, Papaver argemone and Veronica triphyllos.The oldest fallows (20-25 years after abandonment), amid-fields steep slopes and balks were covered by Geranio-Peucedanietum cervariae associations. Their physiognomy was formed by Agrimonia eupatoria, Brachypodium pinnatum and Origanum vulgare, sometimes also by Geranium sanguineum, Peucedanum cervaria and P. oreoselinum. This vegetation was in spatial contact with thermophilous thickets of Berberidion alliance with Cornus sanguinea, Crataegus monogyna, Prunus spinosa, Rhamnus cathartica, and Rosa canina.On xerothermic post-agricultural areas specific stable communities formed by thermophilous species from meadows, ruderals, grasslands and thickets occurred. A new phenomenon of recent years, related to EU benefits - superficial ploughing of fallows, not followed by regular cultivation - favours segetal vegetation. Weeds communities are regressing in Europe as an effect of modern agriculture. Post-agricultural secondary habitats are important elements that should be taken into account in studies of appearance and protection of xerothermic plants.