The alliance Calamagrostion arundinaceae includes species-rich subalpine grasslands dominated by the tussock-forming grass Calamagrostis arundinacea usually occurring on steep south-facing slopes having a pronounced snow cover in winter. Compared with other habitats above the timberline, such slopes are relatively warm both in summer due to insolation and in winter due to the protective effect of snow. This vegetation type is typically developed in glacial cirques of the Hercynian mountain ranges of Central Europe, but has also been reported from the Carpathians and the Urals.