Ecological and biological aspects of the existence of mole rats (Spalacidae) in the Kuialnik–Bug interfluve

Abstract

The Black Sea steppes and particularly the steppe–field area between the Velykyi Kuyalnyk and Southern Bug rivers, delineated from the north by the valley of the Kodyma River, are a natural arena for the existence of two species of mole rats, which still inhabit fields, virgin steppe areas, ravines and river valleys. The materials of the article are the result of long-term (1989–2023) studies of the steppe biota of this territory, which has an area of 15 559 km2. The habitats of mole rats, found by characteristic molehills, do not allow species differentiation, so all mole rats are provisionally assigned to two species— Spalax leucodon (west of Tiligul) and Spalax zemni (east of Tiligul). The habitats of mole rats are distinguished by stationarity for decades, but the seasonal-stationary manifestation of burrowing activity is unstable—the main share of ‘fresh’ emissions in the fields falls on May–June and October–December. The main reserves of the species are meadow areas of river valleys and ravines, which are not subject to flooding. The highest concentration of mole rats was found in the valleys of Tylihul (from the village of Andriyevo-Ivanove down to the town of Berezivka) and Velykyi Kuyalnyk (from the town of Shiryaevo to the village of Severynivka). In the agricultural landscape, in particular in fields (winter and old ploughing), the locations of mole rats are scattered sporadically, gravitating towards river valleys. Thus, field locations on the eastern outskirts of Odesa essentially extend the Sudlymansko–Kuyalnytsia strip of the subarea to the sea coast. At the same time, the nature and activity of burrowing activities of mole rats has a pronounced stationary-biotopic dependence on the level of their food supply. Thus, the ‘chains’ of soil emissions in winter crops, on old ploughing and rolled up crops of spring crops are always long (36–45 m) and combine 28–60 molehills. Similar ‘chains’ in the natural habitats of river valleys, ravines, along the edges of forest belts and near roads are always short (6–11 m) and each time are represented by only 3–5 molehills. Preservation of the main reserves in river valleys from the threat of further anthropogenic transformation is the main means of protecting mole rats within the Southern Steppe.