Status of <i>Astragalus cornutus</i> Pall. populations in the Samara Region

Abstract

This paper examines features of the demographic structure of natural populations of a rare representative of the steppe flora Astragalus cornutus Pall. (Fabaceae). The rarity of the species makes it necessary to include it in the Red Books of the Russian Federation and some steppe regions. In the Samara Region, species populations require additional protection in connection with the peculiarities of biology and ecology, a significant anthropogenic load on communities, and a reduction in the number of habitats. We studied the features of the structure of populations in the Samara Trans-Volga Region. A total of 84 cenopopulations were surveyed, tendencies of population change, features of demographic and spatial structure were revealed. The structure of populations is affected by the ecological and phytocenotic conditions of the environment and anthropogenic factors. The replacement and recovery of individuals in A. cornutus populations is slow. The ontogenetic structure of populations has a fluctuation dynamics. Assessment of the studied geographical populations by L.A. Zhivotovsky efficiency criterion (2001) showed that they are all mature. Specific cenopopulations of A. cornutus are aging (5%) and old (8%). The average density of individuals is about 3 individuals/m. The average effective density is 2,4 individuals/m, the largest - 4,1, the smallest - 1,3. The condition of all studied populations (even in a satisfactory state) on the territory of the Samara Region causes alarm. Populations of the species in the region need additional protection measures.