The structure and state of coenopopulations of the rare species Hedysarum gmelinii Ledeb. (Fabaceae) in different parts of the range

The paper studies the ontogenetic structure features of coenopopulations of a rare representative Hedysarum gmelinii Ledeb. (Fabaceae) on the periphery of the range (the Middle Volga and the Bashkir pre-Urals) and in its central part (the Altai Mountains). The main demographic indicators are determined - the age index and the aging index. Taking demographic indicators into account, the types of coenopopulations were determined according to the «delta-omega» criterion: in the Bashkir pre-Urals they are mostly young, transitional in the Middle Volga region, and mature in the Altai Mountains. In habitats with great moisture in populations, an increase in the proportion of regenerative individuals was noted. Anthropogenic load (mainly in the form of grazing) has a greater impact on the number and density of individuals, but not on the type of ontogenetic spectrum of coenopopulations. The spatial and ontogenetic structure of coenopopulations of H. gmelinii is characterized by a rather high variety of ontogenetic spectra types (and types of populations, respectively) in the European part of the species range. Differences in the demographic parameters of the populations of the Samara and Orenburg Regions from the populations of the Bashkir pre-Urals and the Altai Mountains were revealed, which is associated with the difference in climatic conditions (primarily the degree of moisture). Features of the organization of H. gmelinii populations indicate their greater instability on the border of the range.