A Geobotanical Characterization of Phytocoenoses with Salsola daghestanica (Turcz.) Turcz. on the Arid Slopes of Eastern Caucasus Ridges

Plant phytocoenoses that contain the Salsola daghestanica (Turcz.) Turcz. have been studied in submountain and inner-mountain Dagestan. One hundred and eight flowering plant species have been revealed, including Caragana grandiflora (M. Bieb) DC, a rare species included in the Red Book of Dagestan (2009), several endemic species of the Great Caucasus, such as Matthiola caspica (Busch) Grossh., Salvia canescens C.A. Mey, and Elytrigia gracillima Nevski, Dagestan endemic species Convolvulus ruprechtii Boiss., and Artemisia salsoloides Willd. that are included in the Red Book of the Russian Federation. Salsola daghestanica, a rare endemic species, is included in Salsoletum graminioso-xeroherbosum, Salsoletum graminioso-artemisosum, Caraganetum varioherboso-graminosum, and Caraganetum salsoloso-artemisosum associations that are observed only on the territory of the Eastern Caucasus. The Caraganetum salsoloso-artemisosum association has been described on three sample plots located at the northwestern and eastern slopes (30°–40° steepness) of the Nadyrbek Ridge (outskirts of the Dubki settlement, submountain Dagestan). The shrub layer with a projective cover up to 45% is composed by 12 species with the domination of Salsola daghestanica and Caragana grandiflora. The total projective cover of the grass–dwarf shrub layer reaches 60%. The species abundance is relatively low (40 species) with the domination of Artemisia taurica. The Caraganetum varioherboso-graminosum association was described on the northwestern slope (with a steepness of 40%) of the Nadyrbek Ridge (on the outskirts of the Dubki settlement, submountain Dagestan). The shrub layer (projective cover 29%) is formed by nine species with the domination of Caragana grandiflora (20% occurrence). The herb–dwarf shrub layer is sparse (4–5% projective cover). This layer includes Artemisia taurica, Stipa caragana Trin., Salvia canescens, and Melica transsilvanica Schur.. Plant communities of the Salsoletum graminioso-artemisosum association have been described on the slopes of the Chakulabek Ridge in the vicinity of the Tsudahar village (inner-mountain Dagestan). The sparse (12%) shrub–tree layer consists mainly of the dominant Dagestanian saltwort (projective cover 10%) as well as Colutea orientalis L. and Spiraea hypericifolia L.. The total projective cover of the herb–dwarf shrub layer is 54% and the species abundance is relatively low. Artemisia taurica is the dominant species in relation to the projective cover (50%) and the number of plants. Salsoletum graminioso-xeroherbosum is described on the slopes of the Chonkatau Ridge in the vicinity of the Gubden village (submountain Dagestan). The tree–shrub layer is dominated by S. daghestanica (projective cover 42%). In the herb–dwarf shrub layer, the dominant species with the projective cover values within 3–5% include Artemisia taurica (4%) and representatives of the Poaceae family: Festuca varia Haenke (4%), Elytrigia gracillima (3%), and Stipa daghestanica Grossh. (3%). To conserve plants in situ, it is necessary to create protected areas at the habitats of the studied species. The results on the study of plant communities are presented for the first time and can be used to monitor rare endemic species.