Open steppes dominated by alpha grass (Stipa tenacissima L.) constitute one of the most representative ecosystems of the semi-arid zones of Eastern Mediterranean Basin (Iberian Peninsula North of Africa).These formations have been intimately tied to human activities since 4,000 years ago. Alpha grass steppes show a high degree of variability in composition and structure. Ecosystem functioning is strongly related to the spatial pattern of alpha grass tussocks, as well as with the cover of sprouting shrubs. Alpha grass is an anemocorous species that is able to reproduce both sexually and clonally, showing masting in the production of flowers and seeds. This species exhibits efficient morpho-structural and physiological adaptations to cope with abiotic stress alloweing a successful colonization of adverse semi-arid Mediterranean environments. Soils beneath alpha grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands". These promote the establishment and growth of vascular plants, mosses and lichens. Advances in our knowledge on the composition and functioning of alpha grass steppes are being incorporated into management.