Assessment of Long-Term Dynamics of the Little Souslik Abundance in the Steppe Plague Foci of the Northern and Northwestern Caspian Sea Region

The review presents the results of a study of the little souslik population, the main carrier of the plague pathogen, in the foci of the Northern and Northwestern Caspian Sea region. The influence of various factors on the abundance dynamics of this species in the Caspian Northwestern and Volga-Ural steppe natural plague foci is considered. The data of the annual density census of little souslik, the rates of species reproduction, and the average monthly air temperature at the weather stations of Elista for the period of 1960–2024 and Kharabali for the period of 1940–2024 are statistically processed and analyzed. It is emphasized that the population dynamics of the species is determined by a whole range of natural and anthropogenic factors. At the same time, in semi-desert conditions, the distribution of air temperature and precipitation by seasons and years is limiting for little souslik. The effect of temperatures in January and February, which provoke the animal to leave the burrows upon awakening from hibernation, is analyzed. It is noted that the main reason for the decrease in the number of the main plague carrier in the clay semi-desert is not absolute winter temperatures, but the alternation of warm and cold periods during these months. Therefore, if the temperatures of January and February are alike, the consequences of an increase in temperature can be of a different nature. The negative effect of an increase in winter temperatures on the physical condition of animals is manifested mainly in those years when January is “warm”, February is “cold” or when warm and cold periods alternate during the month. When warm and cold periods alternate, early awakened rodents die in large numbers due to lack of food and chills.