The article presents the review of currently existing views on the problem of phytocoenotic diversity protection in European countries and Russia. The principles and criteria for the identification of rare plant communities in need of protection, used by scientists from different countries are described. The authors had defined already published works of a monographic nature and projects, containing the information on the phytocenotic diversity of Europe in need of protection, and Green Books, published in the Russian Federation. Special attention is paid to the determination process of plant communities. It is noted that nowadays there is no single concept for the creation of Green Books. The phytocenosis protection inventories created in European countries that have a legislative basis, the Russian Green Books include vegetation monitoring data and have no legal basis.

The article provides information about the composition and structure of the Saratov region steppe communities needing protection. The patterns of composition and structure, the main destabilizing factors, the motives for protection are described. Special attention is given to protected plant species, as revised in the second edition of the Red Book of the Saratov region. Description of the community is given in accordance with the main points developed for rare plant communities of the Saratov region passport. For phytocenoses to be protected the following scale of categories and rarity statuses has been adopted: 1 (E) - (exceptional) phytocenoses unique to the area, known from 1-2 points, for which it is expedient to organize specially protected natural territories. 2 (R) - (rare plants communities) truly rare phytocenoses, known for the area from 3-5 points. 3 (H) - (habitat of rare plants species) communities as habitats of rare plant species. 4 (S) - (standart) phytocenoses that are of interest in the context of official decrees for the region, with minimal human-induced disorders and a complex structure. Studied plant species are the regional natural heritage and pose undoubted interest as standards of steppe vegetation, as habitats of protected species of plants and reserve to restore ecosystems destroyed and transformed due to human activities.

In this article the characteristics of plant communities with the participation of Chartolepis intermedia in Saratov left Volga bank region is considered. The information about vegetation composition, structure and rare plants species is provided. The structure of 45 Chartolepis intermedia cenopopulations is revied in five regions. Recommendations to exclude this species from the list of protected plants of Saratov region are given.

The results of ecology-population investigation of Silene cretacea Fisch. ex Spreng in the Saratov region are represented for the first time for the region. The patterns of community organization and population structure are considered.

The detailed results of studying the nature sanctuary «The steppe site near Lopukhovka rural area» vegetation are given in the article. Phytocenosis structure, the territory nature protection status and biocenotic potential of its vegetation are estimated. The characteristics of the rare plant species cenopopulations are given

The article is devoted to the estimation of functional structure and stability vegetation communities in uplandravine habitat in the south part of Volga right bank in Saratov region. A standard distributions of plants species (geometric rows and MacArthur), corresponding to the experimental one, and their comparison with the help of normalized Shannon index were applied. Different groups of stability were established and its ecological interpretation was performed.