Plant communities with naturalized Elaeagnus angustifolia L. as a new vegetation element in Altai Krai (Southwestern Siberia, Russia)

Elaeagnus angustifolia L. (Russian olive) is a deciduous small tree or large multi-stemmed shrub that becomes invader in different countries all other the world. It is potentially invasive in some regions of Russia. In the beginning of 20th century, it was introduced to the steppe region of Altai Krai (Russia, southwestern Siberia) to prevent wind erosion. During last 20 years, Russian olive starts to create its own natural stands and to influence on native vegetation. This article presents the results of ecocoenotic survey of natural plant communities dominated by Elaeagnus angustifolia L. first described for Siberia and the analysis of their possible syntaxonomic position. The investigation conducted during summer season 2012 in the steppe region of Altai Krai allows revealing one new for Siberia association Elytrigio repentis–Elaeagnetum angustifoliae and no-ranged community Bromopsis inermis–Elaeagnus angustifolia which were included to the Class Nerio–Tamaricetea, to the Order Tamaricetalia ramosissimae. During the study, the following special features of communities have been described: polydominance of herbal layer, anthropogenic and grazing load, variation of the species richness, plant cover and vertical stratification into layers. These peculiarities mostly prove unestablished character of communities, all of them are relatively young (25–30 years). Russian olive shrubberies varies in moisture and saline regime, which connected with their existence in different landforms (lake alluvial plains, gentle slopes of lakes, low lake terraces).