Species Distribution in Cenofloras of the Cryophytic Steppes and Cushion Plants with the Participation of Stellaria pulvinata Grub. in the Mongolian Altai

The distribution of the vascular plants species occurring in the composition of high mountain communities with the participation of stitchwort polster ( Stellaria pulvinata Grub.) are analyzed. They form a separate altitudinal belt in the altitudinal-zonation range of vegetation and belong to the arid class of zonality types in the central Mongolian Altai (2700–3300 m a.s.l. Baltic System (BS)). The analysis identified cenotically active species in the cenofloras of cryophytic steppes and cryophytes–forb cushion plants, which include distinctive elements of cryo-xerophytic conditions, such as Oxytropis oligantha , O. chionophylla , Saussurea leucophylla , Chamaerhodos altaica, Arenaria meyeri , and Androsace septentrionalis ; montane species confined to the high mountain areas of southern Siberia and central Asia ( Festuca kryloviana and Poa altaica ) and bunchgrasses, which are represented by widely distributed species typical of the steppe ( Festuca lenensis and Koeleria cristata ). Modeling of the spatial distribution revealed that the ecological–cenotic optimum for the majority of species in the region is found outside of the cryophytic steppes and cushion-plant growth area. According to the identified potential distribution ranges of species accompanying Stellaria pulvinata , a close relationship has been established between the vegetation of the central Mongolian Altai high mountains and the mountains of southern Siberia.