[Spatial structure of the community of bats (Chiroptera: Vespertilionidae) hibernating in artificial caves of Samarskaya Luka].

Specific features of the spatial distribution and localization of bats have been studied during their hibernation in artificial caves of Samarskaya Luka. The proportion of cave area occupied by bats varies from 70 to 93% in large caves (> 60000 m2), decreasing to 50% in medium-sized caves (10000-60000 m2) and to less than 30% in small caves (< 10000 m2). Approximately 9% of bats choose sites near cave openings, up to 25% prefer central parts, but most bats (about 66%) concentrate in the deepest parts of caves. Among wintering species, higher rates of occurrence and shelter occupancy are characteristic of Plecotus auritus. Myotis daubentonii, and M. mystacinus, whereas M. dasycneme and M. brandtii show the highest degree of aggregation. The optimal temperature range for the wintering of all bat species is 2-4 degrees C. Myotis brandtii, Eptesicus nilssonii, and M. daubentonii prefer to hibernate in open spaces of cave ceilings; M. mystacinus. E. serotinus, and Pl. auritus usually occupy the middle and upper parts of walls; while M. dasycneme and M. nattereri occur mainly in hollows on ceilings.

[Species structure and dynamics of bat communities (Chiroptera: Vespertilionidae) hibernating in artificial caves of Samara Luka].

Long-term data on the composition and absolute and relative abundance of eight bat species hibernating in artificial caves of Samara Luka are considered. About 13,000 hibernating individuals are annually accounted there. The relative abundance of the species decreased in the following order: Myotis brandtii (35%), Plecotus auritus (20%), M. daubentonii (13%), M. mystacinus (13%), Eptesicus nilssonii (8%), M. dasycneme (8%), and M. nattereri (2%). Singular E. serotinus were recorded not every year. The number of hibernating animals in pits was proportional to their size and the number of shelters. Bats used previously chosen shelters and were never found in adjacent caves. The maximum species diversity (H') and evenness (E) were observed in bat communities in medium-sized caves. One of the main factors of increasing abundance of hibernating bats in abandoned pits is their gradual colonization by the animals.