Comparison of natural and re-introduced populations of the steppe marmot (Marmota bobak) in Donetsk Oblast, Ukraine

The paper presents data on distribution and abundance of the steppe marmot in the territory of two northern raions (districts) of Donetsk Oblast — Sloviansk and Lyman. Research was carried out in 2011 to 2020. In total, 284 burrows were recorded belonging to 25 home ranges. The largest marmot settlements in the studied territory comprise up to 29 burrows. The number of burrows on a home range varies from 1 to 29, in average 11.4. The total abundance of the steppe marmot is over 100 animals in Lyman Raion and over 20 individuals in Sloviansk Raion. The marmot population in Sloviansk Raion is re-introduced—370 individuals were released in 1991—, while the population in Lyman Raion is of rather natural origin. The optimal habitats for the steppe marmot are chalk slopes of southern exposure, where its home ranges consist of the highest number of burrows. Permanent inhabited burrows are located in the middle part of the slopes, whereas the vast majority of protective burrows are below the slope and at the bottom of the beams. All settlements are located on the right bank of rivers. The largest marmot settlements are confined to poor Cretaceous and, less frequently, sandy soils with sparse vegetation. The natural marmot population in Lymansky Raion shows a tendency to slow dispersal and population growth, while the abundance of the re-introduced population is much smaller than the number of released animals. The density of the natural population remains low despite the many uninhabited areas suitable for the marmots. Settlements are formed as separate disconnected groups. New marmot settlements are often formed in places of old settlements. Natural populations are more stable compared to re-introduced ones and the density of natural steppe marmot population is also higher. Poaching, especially in Sloviansk Raion, is a major threat to the marmot, as well as the overgrowth of the steppe by shrubs due to decrease in grazing. Marmot settlements on the Cretaceous steppes are almost insensitive to reduced grazing. In Lyman Raion, fires and ploughing of balka slopes, too, negatively affect the species. Development of epizootics is unlikely given the low density of the marmot. The marmot populations can be preserved and can even expand their range in the region if sufficient protection measures are provided.