[Contribution of syntaxonomy to the study of vegetation dynamics].

Of late decades, numerous studies on vegetation dynamics have been carried out and the spectrum of studied objects extended. However, syntaxonomy, while is capable to reveal patterns in vegetation changes, is virtually not used in analysis of succession. Prospects of syntaxonomy application to the study of vegetation dynamics are demonstrated by the example of succession analyses of pasture digression, vegetation changes under influence of recreation, progressive succession at the place of deserted settlements.

[Contribution of the Brown-Blanquet method to the explanation of species richness of the plant communities].

A possibility of estimation of factors of formation of species richness of the plant communities by H-function as a measures of complexity of the phyto-sociological spectrum of communities is proved. The phyto-sociological spectrum reflects contribution of those various syntaxa to the coenofloras that indicate ecotope character and the successional status of communities. Analysis of a wide set of grassy vegetation of the South Ural region (from synanthropic to natural) revealed a linear positive correlation between H-function values and species richness.

[Synanthropic plant communities: models of organization and features of classification].

It is proposed to distinguish between three models of organization in synanthropic plant communities formed under the influence of man: R-modle, communities of segetal weeds in fields of annual crops and at initial stages of restoration successions; R --> CRS-model, serial communities of the later stages of restoration successions; CRS --> S-model, serial communities of allogenic successions under the influence of grazing and other external factors. The higher units of the ecological and faunistic classification (classes and orders) well represent the succession status and the soil and climate conditions under which synanthropic communities are formed. At the same time, the continual character of synanthropic vegetation makes recognition of plant associations inexpedient in some cases.