The raccoon Procyon lotor is an invasive species inhabiting Europe and its impact on local populations, particularly on endangered species, is not well known. The aim of the study was to determine whether raccoons pose a threat to bats wintering in the Nietoperek nature reserve, one of the largest hibernation sites in Central Europe. In the winter of 2016–2017, 67 raccoon scats were collected in one of the main underground corridors in the reserve. It was confirmed, with the use of molecular methods, that the scats belonged to raccoons. Raccoon prey was identified based on the features of skulls, jaws or hair found in the scats. Analysis of the determinable remains indicates that bats (including Daubenton’s bat/Natterer’s bat/Brandt’s bat M. daubentonii/nattereri/brandtii, Natterer’s bat Myotis nattereri, greater mouse-eared bat Myotis myotis, brown long-eared bat Plecotus auritus) made up the largest percentage of raccoon diet (96%). Remains of other mammal species, lizards Lacerta spp., plant materials and anthropogenic food were also identified in raccoon scats. The results of the research indicate that predation by raccoons can constitute a significant factor in the increasing mortality of bats wintering in Nietoperek.

Expressways act as barriers to animals that block free movement in their habitats, especially when the roads are continuously fenced to prevent collisions between animals and vehicles. Various types of animal passages have been repeatedly studied in terms of their utility, albeit rather less frequently in the suburban environment. We conducted our research in a section of the fenced expressway S3 connecting two closely located cities in western Poland (Lubuskie province). Over the course of one year, we monitored four underpasses intended for small- and medium-sized animals using tracks. The underpasses were inspected weekly. Animal traces most frequently found belonged to roe deerCapreolus capreolus(20.9%), red foxVulpes vulpes(15.1%), wild boarSus scrofa(14%), and domestic dogCanis l. familiaris(12.4%). Surprisingly, the results of our study indicate that underpasses for small and medium mammals are also used by ungulate mammals. The use of the underpasses varied seasonally, being the highest in spring (37.9%) and the lowest in winter (10.4%). Moreover, seasonal differences in the use of passages were related to particular species/groups of animal species. We found that 22% of animals that entered the passage did not completely traverse it. People accounted for 17.1% of all stated traces in the underpasses. Stagnant water in the underpasses reduced the number of predatory mammals and wild boars using the underpasses but did not affect the activity of roe deer. These studies indicate that animal underpasses located in suburban areas are used by many species of animals despite the activity of humans and domesticated mammals.

The European badger plays an important role as a natural factor shaping species diversity in forests. Its extensive setts can be used by many other animals as shelters. Soil perturbations in their setts support plant communities that differ from the matrix landscape. The badger is also an effective seed disperser. We investigated its role as an ecosystem engineer in preserving species diversity and discussed its legal status across Europe. In most European countries (69.3% of the continent), the badger is hunted, sometimes year-round. The hunting season lasting through winter until early spring may have a negative effect on badger populations, especially when cubs are born in February. Although this species is Red Listed in 19 European countries (with categories ranging from LC to EN), the badger is strictly protected by law in 30.7% of its European range. A reduction in badger populations may limit its ecosystem services (seed dispersal, topsoil disturbances, microhabitat creation). Much new data on the importance of badgers in ecosystem engineering has allowed us to reconsider how we manage badger populations.

The setts of the European badger Meles meles can be cohabited during reproductive season by the red fox Vulpes vulpes and raccoon dog Nyctereutes procyonoides. There is no information on the possible impact of both species on the size of badgers’ litter. The aim of the study was to show the influence of cohabitation of the same setts by badger, raccoon dog and fox on the litter size. The research was conducted in 2012–2014 and 2018 in the lowland forests of western Poland. We conducted the survey of setts by direct observations and analysis of photographic material from trap cameras during mid-April–July each year. We recorded 85 badger litters, 18 fox litters, and 15 raccoon dog litters. Average litter size was 1.71 (±0.90), 2.44 (±1.34) and 4.93 (±2.76) litter mates in badgers, foxes and raccoon dogs, respectively for all observed pairs. Badger litter size did not differ between setts used only by badgers including pairs with no cubs (1.66 ± 0.98) and cohabited with foxes (1.90 ± 0.32) or raccoon dogs (1.88 ± 0.81). However, foxes reared even more cubs in setts cohabited with badgers than when badger was absent (2.90 ± 1.37 vs. 1.88 ± 1.13 respectively). In the case of raccoon dogs, there were no differences in the mean number of their cubs in setts with badgers (5.25 ± 2.92) and without badgers (4.57 ± 2.76). The results indicate that the cohabitation of setts by badgers, foxes and raccoon dogs does not affect litter size negatively.