POPULATION DYNAMICS OF BATS OF THE IVANKIVTSI ADITS (PODILLIA, UKRAINE): RESULTS OF LONG-TERM MONITORING OF WINTER AGGREGATIONS

Visual survey of colonies of hibernating bats is a traditional research method. The data obtained using this method serve as a basis for determining population trends. These data are especially important for protected areas that ensure the protection and conservation of species and their key habitats. The Ivankivtsi adits (IVK-mines) are located in the territory of the Podilski Tovtry National Nature Park (in the protected zone of the national park). The site is a system of adits and mines used for machine mining of sawn limestone. This area is also part of the European Emerald Network. The IVK-mines are listed as a key underground site for the conservation of European bat species. The monitoring of wintering bat communities at the IVK-mines has continued for about 20 years. Surveys are conducted annually, but mostly only the entrance parts of the adits are covered (about 50% of the site’s total area). Every few years, total bat counts are carried out throughout the entire mine system. The previous total bat count at the IVK-mines was conducted in 2009 (15 years ago). In January 2024, a repeated total survey of bats was conducted. According to its results, 5967 bats belonging to 12 species were recorded. Compared to the previous total count, the increase in numbers is about +60%. The dominant species by number is Barbastella barbastellus . The western barbas-telle has been forming a large winter aggregation for


Introduction
The importance of underground hibernacula for the conservation of bats and monitoring their populations is well-recognized.Bat species can be properly protected only if activities are carried out over the entire range of the species and that monitoring is a necessary prerequisite for effective and optimized conservation of bats.Unfortunately, the present state of bat monitoring in Ukraine does not achieve this goal.In Ukraine very run bat monitoring programs that produce robust results.Monitoring programs in place are not assembled into a national database so the information is not processed or the results published.Some programs have been running for over 20 years, but there are no agreements on using the same protocols for data collection and processing and survey methods are not standardized.In addition, no structure able to coordinate a long-term, harmonized bat monitoring programs.
Podolian Uppland (Podillia) belongs to the cave regions of Ukraine.Attempts to monitor winter underground sites are known from the literature [Godlevska 2005].There are large natural caves and artificial underground shelters (limestone mines).Obviously, there are unexplored underground sites.Protected areas in the region monitor and protect bats and their habitats [Vikyrchak 2018[Vikyrchak , 2020;;2021].These activities, although carried out in the same region, are poorly synchronized.In our opinion, a joint program for monitoring bats and their habitats should be implemented to introduce effective conservation management in the region.
Visual counts of the number of hibernating bats colonies have a long tradition.Usually, counts are conducted in the winter (January-February), and the dungeon is surveyed once or several times, depending on its size and accessibility.Parts of the dungeon or its entire territory are surveyed [Pan-European ... 2009].The data obtained serve as the basis for determining population trends.
So, hibernation roosts are particularly useful for surveying numerous species.But, at hibernation sites, the relationships between the number of bats seen and the number of bats present is not always clear because of numerous cracks and crevices in which bats may be hidden from view.It is also important to conduct synchronized accounting, at least in the entire region, which would also improve the quality of the data obtained.Monitoring of winter bat communities at IVK-mine has been going on for about 20 years.A preliminary absolute census of bats at IVK-mine was carried out in 2008-2009 (15 years ago) [Godlevska 2009].Although the results of long-term monitoring show signs of dynamics in the number of species, it becomes clear that modern methods, in particular automatic accounting systems, need to be applied.

Material and Methods
Despite these difficulties, counting bats in underground sites is widely used as a method of monitoring bats.Although the proportion seen may vary from year to year, it is assumed that over periods of many years this annual variation is smoothed out to reveal underlying trends in numbers.
Bat counts were performed using standard methods [Petrushenko 2002].The peculiarities of underground site such as underground mines were taken into account [Petrushenko 2017].The midwinter was chosen for the survey, the underground mines was inspected in its entirety (except for some minor parts), with special attention paid to the entrance parts, as well as the main corridors with special attention to the side passages (to the first intersection) and dead-end branches.The surveys covered all temperature zones of the dungeon.In order to avoid repeated counts, a detailed map of the underground mines was used, which marked all the corridors passed.
Ivankovetska mines (IVK-mine)1 located on the territory Podilski Tovtry national nature park (protected zone of the national park).IVK-mine represent mines for machine extraction of saw limestone.Mining was started in the late 1950s and carried out in 1960s.This area is a part of the European Emerald Network (UA0000011, 261521, Biogeo regions -CON).As of 2014, 35 underground sites in the territory of Ukraine were included as key territories for protection and preservation of bats in Europe.Among them are IVK-mine [Source: https://www.eurobats.org(https://bit.ly/3dnCEEm)].Underground sites are important for bats.They are used for hibernation, also as maternity colonies, both critical periods during the life cycle.Some species use underground sites for mating (so called swarming).Underground sites as bat roosts are threatened.The main threats human access (disturbance).Even slight disturbance may be fatal for bat populations inhabiting underground sites, so there is a great need to monitor them.Some sites may be occupied by very large numbers of bats (as it is in the IVK-mine), that return year after year, often using the same location in the site.These are the sites that are particularly important.The distribution map of the important bat site distribution is shown in the figure (Map on Fig. 1).

Species list:
Rhinolophidae: Rhinolophus hipposideros, Vespertilionidae: Myotis brandtii, Myotis dasycneme, Myotis daubentonii, Myotis myotis, Myotis mystacinus, Myotis nattereri, Eptesicus serotinus, Barbastella barbastellus, Plecotus auritus.IVK-site (Khmelnytskyi District) includes a big system with a general length of about 11 km and a small separate system of approximately 150 m.There are four gallery entrances in the big system, three of them situated at the same level, with the fourth one higher on the same slope.The shape of the mine field is a roundish polygon -about 500 by 400 m.It includes three connected parts at different altitudes; two of them have open entrances.Due to the original configuration, the biggest part of the system is cooled in the winter and works as a "cold sac" throughout the year.For example, in summer, the inside temperature near the lower entrances was +4... +5°C (outside temperature was +25... +28°C).Mine exploitation was mostly carried out in one bench.The height of drifts is 2.0-3.5 m.After the official closing of the mine, local people conducted illegal limestone extraction (for burning lime) using explosive methods, which was stopped about two years ago.
The mines were inspected on 04-18 January, 2024.An important condition for recording bats in a winter site is the availability of a detailed map.This simplifies bat counts and improves data quality.For identifying bats on drifts' ceiling zooming photo-cameras were used.For measuring air temperature inside digital thermometers with remote sensors (TFA) were used; metering was done at the height of 1 m from a floor.

Results and Discussion
In January 2024, an absolute census of bats in the IVK-mine was carried out.A total of 5967 bats of 12 species were counted.The dominant species by number is Western barbastelle.For latter species one big cluster of (2000) individuals were observed, other barbastelles placed individually or by rare groups in few specimens.The subdominant one is Myotis daubentonii (more than 1000 ind.).By result A broad-scale one winter bat survey in various parts of Belarus in 2020, the dominance of the species was also Barbastella barbastellus -78.5% [Godlevska 2023].

Characteristics of the wintering colony Western barbastelle
For the first time, a large winter aggregation Western barbastelle was detected during a survey in December 2008, with an estimated population of about 500 individuals.According to the results of the first absolute count of bats in key winter habitats in the Podilski Tovtry National Park, in 2009, more than 498 individuals were recorded in IVK-mine [Godlevska et al. 2011].In all subsequent seasons, the number of Barbastella barbastellus wintering in the IVK-mine has been constantly increasing.As of the winter of 2017-2018, the colony number was already more than 1 thousand individuals, and in 2018-2020 it was about 2 thousand individuals [Drebet 2000].Most of them were located in two large groups of 360-424 and more individuals from 2018-2020 (Fig. 3).Others wintered in smaller groups of 50-150 individuals, as well as 10-30 individuals and singly.In addition, over the past few years, there have been more frequent cases of the Western barbastelle being found in various anthropogenic buildings and structures.Thus, the species was found in abandoned basements of private households, as well as in the basement of the ruins of an old manor.

Dynamics of other species number 2009-2024
In addition to characterizing the dominant species, it is important to compare the proportions of other hibernating bat species based on the results of two absolute bat counts of the IVK-mine, which were performed 15 years apart (2009 and 2024).* Some specimens may appear to be Myotis blythii, which cannot be verified in the field due to the use of saving methods of census.
In 2009 was accounted for 2364 individuals of 9 species.The dominant species by number is Myotis daubentonii.Among the species accounted for in 2024, the following were not found -Myotis nattereri, Myotis mystacinus and Plecotus austriacus.These species are usually rare and few in number.In 2024, it was accounted for 5867 individuals of 12 species.The dominant species by number is Barbastella barbastellus.For latter species one big cluster of (about 2000 ind.) individuals were observed, other barbastelles placed individually or by rare groups in few specimens.Not all key sites located on the territory Podilski Tovtry national park show the same trend (growth in numbers).In the GMN-mine, the number of wintering individuals of the greater mouse-eared bat (Myotis myotis) is decreasing.We observe a decrease in the number of wintering Myotis myotis in other key sites (IVK-mine and ATL-cave).This is reflected in the total number of hibernating individuals.In other underground sites (for example, in the key sites of YAC-mine, ATL-cave), the total number of hibernating bat communities is either stable or there is a slight increase in the number of individuals.Only in IVK-mine, the number of hibernating bats increased rapidly.It is clear to us that the overall increase in numbers was primarily due to an increase in the number of one species, the Western Barbastelle.The numbers of other recorded species in 2009 and 2024 do not differ significantly.However, in any case, it is also important to note that the IVK-mine is characterized by some of the best conditions for bats to hibernate.Unlike a number of other underground sites located on the territory Podilski Tovtry national park, the IVK-mine is characterized by the widest range of winter temperatures (from -4-1 to +9-10).Obviously, this affects the diversity of species that overwinter in the mine.
One of the most common and numerous species of bats in the region is the lesser horseshoe bat (Rhinolophus hipposideros).It is dominant in the composition of winter aggregations of bats in cave-type shelters in the Middle Dniester region, with a share of 92.84% [Vikyrchak 2021].Rhinolophus hipposideros at IVK-mine also chooses cave-type areas.The number of individuals hibernating is very dynamic.According to the results of surveys, it can increase or decrease from year to year, even by several hundred individuals.

Problems of species assessment and protection
Studies of European bat hibernation aggregations have shown significant fluctuations in the number of hibernating bats between censuses of several years, indicating that environmental factors that influence hibernation strategies mask real population trends.In addition, climate change is creating opportunities for cold-loving species to hibernate outside of the main roosts, for example, in tree hollows, which makes it difficult to understand and interpret the data obtained from bat censuses.[Kokurewicz et al. 2017].
For example, according to the abiotic environment monitoring data as part of the Chronicle of Nature program Podilski Tovtry national park, in recent years there has been a significant softening of winter, and in 2020, natural winter did not occur at all (Chronicle of Nature...).This factor may affect the results of bat monitoring.

System and scope of species protection
The national system and scope of protection of bat species are defined by environmental legislation.In Ukraine, all species of bats are included in the List of animal species listed in the Red Data Book of Ukraine (fauna) (Order of the Ministry of Environmental Protection and Natural Resources of Ukraine No. 29 of January 19, 2021).Out of 28 species, 1 species is extinct (EX) (Miniopterus schreibersii), 8 species -Myotis bechsteinii, Myotis nattereri, Myotis emarginatus, Myotis dasycneme, Myotis alcathoe, Barbastella barbastellus, Nyctalus lasiopterus, Hypsugo savii -near threatened (NT), all other 19 species have the status of Vulnerable (VU).Protected areas play an important role in the species protection system.
Bats have some level of protection in each European country, although the details of this protection and the degree of compliance with environmental legislation vary greatly.In the European Union, the protection of bats and their habitats (including breeding, hibernation and resting places) is ensured by Council Directive 92/43/EC on the conservation of natural habitats and wild fauna and flora.All species of bats are listed in Annex IV -«Species of Animals and Plants of Community Interest and in Need of Strict Protection», and some of them are also listed in Annex II, which also requires the creation of Special Areas of Conservation (SACs).Member States are obliged to incorporate these requirements into their national legislation, which is in line with Directive 92/43/EC.Many European countries are also signatories to the Bern Convention, which requires strict protection measures for species listed in Appendix II.This applies to all bats, except for the pipistrelle (Pipistrellus pipistrellus), which is listed in Appendix III.
As a follow-up to Appendices I and II, the Berne Convention's Standing Committee approved Resolution No. 6 «On the List of Species in Need of Special Measures for their Conservation» with a new version of the Appendix approved in 2011.
The Podilski Tovtry national park is a member of the Emerald Network of Europe, which is analogous to the Natura2000 network in the EU.As a site of the Emerald Network (Podilski Tovtry national nature park -UA0000011), it provides protection and conservation of 6 species of bats: Barbastella barbastellus, Myotis bechsteinii, Myotis blythii, Myotis dasycneme, Myotis myotis, Rhinolophus hipposideros.These species are also included in Annex II of the Bern Convention.All 6 species of bats of the highest conservation interest within Natura2000 and requiring special measures for their conservation (according to BC Resolution 6) are represented in the IVK-mine.The IVK-mine, as a habitat for six bat species of the highest conservation status within the Emerald Network, is a strong candidate for designation as a Special Area of Conservation (SAC) once Ukraine transitions to the Natura 2000 network.With these species requiring specific conservation measures under Bern Convention Resolution 6, the IVK-mine could become a key site in the SAC network, supporting Ukraine's commitments to biodiversity protection in line with European nature conservation standards.
According to the IUCN, only Myotis myotis is characterized by stable population size, while the other 5 species are in decline.The loss or degradation of habitats (winter and summer habitats) is a common major threat to all these species.The multifunctional designation of national parks poses some threats to the conservation of these species, which are sensitive to habitat degradation.Accordingly, the inclusion of underground bat habitats in tourist routes has a negative impact on the conservation of Myotis myotis and M. blythii populations.Since Myotis dasycneme has a rather low population density, any threats to its habitats are critical.
The conservation of species such as Myotis bechsteinii and Barbastella barbastellus also depends on the state of management of forest habitats, in particular the presence of old mature forests and old trees, and this should be taken into account when planning sanitary measures in the forests of the national park, especially where key winter habitats of bats are present.
The Bechstein's bat is one of the rarest bat species in Europe in general and a difficult object of study.Acoustic methods do not allow for reliable recognition of this species, and it is found in winter roosts irregularly, mostly alone in the national park (ATL-cave system, IVK-mine, GMN-mine, YAC-mine).The peculiarity of this species is its actual settling near the wintering grounds.Their peak activity occurs from mid-August to mid-September, and in early September, the first individuals begin to hibernate.In April, the majority of Myotis bechsteinii leave the wintering grounds [Wright et al. 2017] and apparently move to forests near underground sites.
The Western barbastelle population requires the development of separate effective and longterm conservation measures and their inclusion in the management plan of the national park.Current conservation practices for Barbastella barbastellus in Europe are based on the establishment of a protected area around each known mother colony.The proposed areas of the zones are based on radio telemetry studies and vary from a radius of 2-7 km.Effective conservation measures in the national park will focus on preserving and restoring areas of forest that support a diverse species and age structure of trees.Following this approach, in 2023, the national park prepared a scientific justification for the creation of a special protection zone for the protection and conservation of bats.An important step in ensuring the long-term protection and conservation of the key habitat, the IVKmine, will be the change of functional zoning in 2023 and the transfer of 12.2 hectares of the area around the mine to the national park's protected area.
An important step towards improving the understanding of trends in species numbers will be the transition to more modern and high-quality methods of researching winter aggregations of bats and monitoring their winter sites.
Until recently, there was no qualitative method for verifying the results of «usual» visual counts of bats in winter sites.However, the use of automatic light barrier systems installed in openings (entrances) of underground cavities has significantly expanded the understanding of the number of bats in winter roosts.Automatic systems often demonstrate significant differences in the results of accounting.For example, the highest discrepancy between visual and automatic counts is a 60-fold difference (60 and 3500 individuals, respectively) in the Hörre shale mine (Germany).Such facts emphasize the importance of using modern methods to achieve realistic results and assess the importance of underground cavities for bat conservation.
Despite the alleged protection of winter sites by their location in a protected area of national importance, there is still a potential threat of deterioration of wintering conditions from the factor of disturbance due to the development of recreational and tourist activities in the national park.Every year, national parks are increasingly forced to look for additional sources of funding to carry out their activities, including conservation measures.Different types of dungeons are interesting objects for visitors to nature conservation institutions.Given the trends in the development of recreational activities in the region and the importance of the IVK-mine as a key bat habitat in the region, we recommend not to «open» the mine for mass tourism in order to preserve the bat population and their important habitat.

Table 1 .
Species abundance during absolute counts in 2009 and 2024