Dynamics of the Steppe Marmot Populations under Protection Regime in the Southern CIS-Urals

Abstract

This paper presents data on the current state of the population and long-term dynamics of the steppe marmot (Marmota bobak Müller, 1776) population in the Burtinskaya Steppe Site of the Orenburg State Nature Reserve (Orenburg Region, Belyaevsky District). The studies were conducted in the periods 1998–2001 and 2021–2022, and archival data on the steppe marmot census of the reserve were also used. The influence of air temperature and precipitation on the number of marmots, population growth, and brood size was analyzed. Over the entire observation period, three peaks were identified in the dynamics of the steppe marmot population. The first two peaks in numbers in 2000 and 2009 were approximately equal to each other (395–401 individuals); the third, significantly smaller peak (187 individuals) was observed in 2017, and in 2019 the number of marmots reached the minimum for the entire observation period—81 individuals. In 2022, the total number of marmots almost doubled and amounted to 179 individuals. Fluctuations in numbers occurred due to changes in both the number of families and the number of individuals and the composition of families. The maximum number of adult marmots exceeded the minimum by 3.2 times, while the number of yearlings was 28.3 times higher. The population growth was below 40% for half of the observation period, and the average brood size was 2.3 ± 0.16 individuals. A negative correlation was found between the number of marmots and air temperature, and a positive correlation was found between the number of marmots and the amount of precipitation. The combined effect of fires and droughts has a negative impact on the food supply of marmots, which often leads to an almost twofold decrease in numbers the year after the fire.