A new association with Patzkea paniculata on serpentine substrates at low elevations in the western Alps (Italy)

Patzkea paniculata usually dominates grassland communities in the subalpine and alpine belts. The analysis of a unique vegetation community found at low altitudes growing on serpentinitic substrates in the North-Western Alps (Italy) dominated by P. paniculata, is hereby presented. These communities are substantially different from already described alpine communities, framed in the alliance Festucion variae (class Caricetea curvulae, order Festucetalia spadiceae) and typical of higher elevations. Syntaxonomic and ecological investigations were performed to provide a correct phytosociological framework for these grasslands. The new association Potentillo albae-Patzkeetum paniculatae ass. nova is here described, with two different variants, one co-dominated by Bromopsis erecta and the second with co-dominance of Molinia arundinacea. It is a secondary grassland of arid environments attributable to the alliance Bromion erecti (class Festuco valesiacae-Brometea erecti), and characterized by the presence of numerous species, both rare and typical of serpentinitic substrates.