ROOT VOLE (ALEXANDROMYS OECONOMUS (PALLAS, 1776) OF THE MIDDLE IRTYSH REGION: TAXONOMY, REPRODUCTION, POPULATION DENSITY, POPULATION DYNAMICS AND TULAREMIA INFECTION
Sidorov G.N., Doctor of Biological Sciences, Professor Federal State Budgetary Educational Institution of Higher Education Omsk State Pedagogical University, 644099, Russia, Omsk, Tukhachevsky embankment, 14 FGBNU Scientific Research Institute of Natural Focal Infections, 644080, Russia, Omsk, pr. Mira, 7 e-mail:
g.n.sidorov@mail.ruKassal B.Yu., Candidate of Veterinary Sciences, Associate Professor SBI Russian Geographical Society, Omsk regional branch, 644099 Russia, Omsk, st. Museum, 3. e-mail:
BY.Kassal@mail.ruSidorova D.G., Candidate of Biological Sciences, Associate Professor Federal State Budgetary Educational Institution of Higher Education Omsk State Agrarian University named after. P.A. Stolypina, 644008 Russia Omsk, Institutskaya pl., 1. e-mail:
dashunia_g.s@mail.ruFrom 1962 to 2023, censuses of the root vole and other small mammals were conducted in 32 municipal districts of the Omsk Region. 664,004 traps/day were processed, 54,145 thousand individuals of Micromammalia were caught. Of these: 22 species of mouse-like rodents - 47,843 individuals and 8 species of insectivores - 6,302 individuals. Root voles 7,526 individuals - 13.90% of all Micromammalia; 15.73% of all rodents. The average long-term abundance index of the root vole for 62 years was equal to 1.22 individuals per 100 trap-days or 488 individuals per sq. km. In the Middle Irtysh region, within the boundaries of the Omsk region, two subspecies have been established: Alexandromys (Microtus) oeconomus (Pallas, 1776), larger, long-tailed and darker colored in the steppe and southern and central forest-steppe landscapes, inhabiting poorly watered landscapes and characterized by relatively high fertility. In the taiga and subtaiga, Alexandromys (Microtus) oeconomus hahlovi (Scalon, 1935) are common, smaller, short-tailed rodents with a light fawn color, living in conditions of relatively high humidity with lower fertility than that of the nominal subspecies. The boundary between the subspecies runs along the northern forest-steppe subzone. For the first time, cartograms of the root vole population density for 1975–2023 were compiled. In the years of its average long-term maximum (more than 2000 individuals/km2), average (up to 2000 individuals/km2) and depression (up to 1000 individuals/km2) numbers. Depression of the root vole numbers covers the entire territory of Omsk Oblast at the same time. With an increase in numbers, the population density increases in areas with no or low intensity of agricultural land development. The cyclicity of the dynamics of the abundance of the common vole was revealed in the absence of a correlation between the abundance and the indices of solar activity (W, Wolf numbers) (r=0.01); with periods of water content (r=0.19), and with the water level in water bodies, including open water sources (rivers and lakes) and wetlands (r=0.12). In contrast to the dynamics of the abundance, the population density was associated with water content. For 1975–2023, this dependence was as follows: in the years of population depressions - 19 years (r=0.48); in the years of average abundance - 18 years (r=0.48); in the years of the highest abundance - 12 years (r=0.44). Thus, the population density of the animal increased in accordance with the degree of water content. A total of 18,768 individuals of small mammals were examined for tularemia. The causative agent of tularemia has been identified in 18 species out of 30 species of small mammals in the Omsk region: 10 species of mouse-like rodents, 7 shrews and the common water shrew. In the territory of the Middle Irtysh region, the root vole was a serious natural distributor of the tularemia pathogen among small mammals, especially in years of low water vole numbers and low muskrat numbers.
Keywords: Middle Irtysh region, root vole, systematics, reproduction, population density, population dynamics, tularemia
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