Syntaxonomy of tugai forests of the Syrdarya River

A floristic classification of the vegetation of tugai forests in the Syrdarya river basin on the territory of the Republic of Uzbekistan is presented. Poplar (Populus pruinosa) forests are assigned to the class Populetea euphraticae and the order Populetalia euphraticae. A formalized analysis of the Syrdarya and Amudarya tugai communities allowed to identify species that differentiate them. The poplar forests in the Syrdarya valley are characterized by higher species diversity. At the same time, they are less affected by degradation processes associated with soil salinization, which are typical for the lower reaches of the Amudarya River. Based on comparative analysis, a new alliance Galio spirii–Populion pruinosae all. nov. is described, which includes two associations with distributions covering various sections of the Syrdarya valley. The association Poo bulbosae–Populetum pruinosae ass. nov. represents tugai forests in the lower section of the Syrdarya valley and includes the richest communities. Two variants, Imperata cylindrica and Leymus multicaulis, are identified within the association. The association Lycio dasystemi–Populetum pruinosae ass. nov. unites tugai forests of the Fergana intermountain basin characterized by a well-developed shrub layer, often dominated by Lycium dasystemum. Two variants, typica and Clematis orientalis, are distinguished within the association. A prodromus of the vegetation of Central Asian tugai forests has been compiled including one class, one order, three alliances, seven associations, and six variants. The poplar forests of the region require conservation within newly established protected areas.