Alien species in communities of strongly saline soils of southeastern Russia (classes Thero-Salicornietea Tx. in Tx. et Oberd. 1958 and Salicornietea fruticosae Br.-Bl. et Tx. ex A. De bol`os y Vayreda 1950)

The article presents information for the territory of the south-eastern part of Russia on the invasion of alien species into communities of 2 classes of vegetation of salted ecotopes - Thero-Salicornietea Tx. in Tx. et Oberd. 1958 and Salicornietea fruticosae Br.-Bl. et Tx. ex A. de Bolís y Vayreda 1950, common on soils with a high degree of salinization. A list of alien species and the associations where they are registered is given. On the basis of the indicators of species abundance and constancy the universes participation in formation of the associations is assessed, as well as the geography of the communities with the presence of alien species and the ecological peculiarities of their localization sites are characterized. As a result of the study, in the communities of the classes Thero-Salicornietea and Salicornietea fruticosae in the territory of southeast Russia a small number of alien species from different families were found - namely, 2: Atriplex tatarica L. (Chenopodiaceae) and Descurainia sophia (L.) Webb. (Brassicaceae Burnett). Both species are archaeophytes of Iranian-Turan origin, xenophytes, epecophytes. The associations with alien species introduced there are also few - only 5 units. The proportion of such species in the cenoflora of these associations is small (about a tenth). Atriplex tatarica is noted in all associations we consider, and Descurainia sophia - only in the class Salicornietea fruticosae units. The former species more often meets in the Salicornietea fruticosae associations (where its constancy increases up to II-III points), and the latter one in the class associations can be both rare and constant species (constancy is I or IV). Both species in all communities are characterized by a small presence (abundance does not exceed 1 point). All this suggests that the alien species do not have a significant impact on transformation of the cenoses. Geographically, introduction of the 2 named species into the classes Thero-Salicornietea and Salicornietea fruticosae cenoses is noted only within the Caspian lowland territory (including the Volga-river delta and the Volga-Akhtuba floodplain). Atriplex tatarica - euhalophyte of European part of Russia - meets most often and geographically widely in the communities.