Bat Assemblages Are Shaped by Land Cover Types and Forest Age: A Case Study from Eastern Ukraine

Abstract

Eastern European broadleaved forests north of the 50th degree of latitude serve as a core breeding area for most migratory bat species wintering in Eastern and Central Europe. The southern border of this region has faced an increase in clear-cutting intensity in recent decades. We conducted a standardized mist-netting survey on eleven heterogeneous oak forest plots in order to assess how land cover types and forest age affect abundance, diversity and the breeding of bats. We found that abundance indices and species richness increased from upland plots surrounded by agricultural lands to riverine or waterside plots with high forest cover. Particularly large mature forests older than 90 years positively affected the breeding activity of bats, their abundance indices and overall species richness. Regarding species associations with specific habitats, we found that Myotis brandtii, Nyctalus leisleri and Pipistrellus pygmaeus were mainly found in mature deciduous forest stands, while Plecotus auritus appeared to be the only species tolerating clearcuts and young stands. Forest-dwelling species such as Nyctalus noctula and Pipistrellus nathusii were additionally associated with water habitats. Thus, the combination of mature forests and water sources is essential in shaping Eastern European assemblages of forest bat species.

Do Bats Avoid the Urban Core in the Breeding Season? A Case Study from Temperate Latitudes

“…We employed two indexes to measure bat abundance levels. The first one was the bats per hour index, which was used for the mist-netting results (e.g., [37]). The total number of captured bats in one night (Nm) was divided by the time (hours) of mist-netting (H) (b/h = Nm/H).…”

“…This might be true in the case of an uncovered mist-net set in an open space, and if a mist-netting session only lasts for the first few hours of the night. However, we always followed the protocol of keeping the captured individuals in textile bags near the mist-nets (inter-species and species-specific distress calls lure more individuals from around) and conducted the mist-netting all night long (after midnight, air-hawking bats tend to fly lower) [37]. This approach increases the proportion of air-hawking bats in a sample and provides a better picture of species diversity and relative abundance for each location and habitat type [37].…”

The dataset of bat (Mammalia, Chiroptera) occurrences in Ukraine collected by the Ukrainian Bat Rehabilitation Center (2011-2022)

“…This species is common in the summer-time in Central and North Ukraine (e.g. Gashchak et al (2013) , Vlaschenko et al (2022a) ). For the last twenty-thirty years, N. noctula formed numerous winter aggregations in cities of Central and Eastern Europe, including Ukraine (e.g.…”

Exceptionally Uniform Bat Assemblages across Different Forest Habitats Are Dominated by Single Hyperabundant Generalist Species

“…These species are adapted to these distances through different wing shapes, flight speed, and maneuverability [11], but also echolocation call designs [12]. The strong variation in the structure of forest bat assemblages is also caused by the tree stand age [13,14], level of natural and human-made disturbance [15], proportion of particular tree taxa [16,17], volume of deadwood [18], elevation [15], size of forest patch [19], location within the patch [20], and land cover adjacent to its borders [14]. As the bat faunal size correlates with the availability and diversity of roosts [21], while even closely related and morphologically similar species differ in roost selection [22,23], the structure of bat assemblage foraging in woodlands might be expected to result from the presence or absence of particular roost types, either within the forest or in its close neighborhood.…”