The study of successions is based on the two-level reduction of the plant continuum, at the level of series (combinations of plant communities) and at the level of stages (syntaxa). For this purpose, it is expedient to use the floristic classification of plant communities by the Braun-Blanquet method. Approaches to identification of series and stages of succession and general evaluation of these series are described, including analysis of the dynamics of alpha-diversity and phytosociological spectrum of plant communities and of beta-diversity of a successional series.