Distribution of the Noctule Bat (Nyctalus noctula) in Rostov Region and the Problem of Expansion of the Northern Boundary of Its Wintering Area

Abstract

The materials on the distribution of Nyctalus noctula in Rostov Region are given. On the basis of this, the northern border of its winter habitat and the seasonal characteristics of the stay are specified. The presented findings of this species in the south and extreme east of the region, which were made in the summer and in the off season showed that this territory was used both during the migrRegionation period and as summer habitats. In the scientific literature, the expansion of the winter range of this species over the past decades has been noted. Findings of wintering animals in high-rise buildings of cities are considered as confirming facts of expansion. However, the issue regarding the expansion of wintering boundaries remains ambiguous because all these detections are made in the climatic “risk zone.” The results of modeling of the probabilistic area of winter habitats of N. noctula in conditions of natural shelters (hollows of trees) showed that, over the past 70 years, there have been no changes in the boundaries and its northern limits do not correspond to those that were previously indicated. In the east of the European range of this species, the northern boundary of the natural wintering area passes through Rostov Region and ends to the east at the latitude of the city of Astrakhan. The most important bioclimatic factors that determine wintering within such a territory are the average temperature of the driest and the average temperature of the coldest quarters of the year and the minimum temperature of the coldest month. In the regions to the north of this area owing to the severity of winters, the overwintering of animals in natural shelters is unlikely. On the basis of the results obtained, the total wintering area of N. noctula is divided into two zones. The first zone is the territory where wintering is massive and possible in poorly protected natural shelters; the second zone is a territory with a climatic “risk zone,” where only a very small part of population of the species remains, and the spaces protected from external factors in multistory buildings of settlements serve as shelters. Findings of wintering colonies of noctules in the second zone that are located far outside the natural wintering area can obviously be considered as an invasive process, which in migratory bats has an adaptive character and is associated with the development of urbanized landscapes.