Features of the Organization of Populations of a Rare Species Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult. (Dipsacaceae, Magnoliópsida) in the Trans-Volga and Cis-Urals Regions

Resumo

Abstract—The results of the study of 23 natural cenopopulations of Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult., a rare subendemic species of the Eastern European steppe zone, in the Trans-Volga and Cis-Urals regions (Republic of Bashkortostan, Samara and Orenburg regions) are presented. The indices of the density, age structure, and demographic features of the population have been studied and compared. The total density varies from 2.2 to 10.3 ind./m². The average ontogenetic spectrum of C. uralensis is centered. According to the delta–omega classification, C. uralensis populations are distributed from young to aging. In most populations of that species, restitution and aging indices are very low. The studies suggest that the populations of C. uralensis in the South Urals, Trans-Volga, and Cis-Urals regions are in a satisfactory state. A threat to the species is the disturbance of its habitats due to excessive cattle pasture.