Effect of Translocation on Host Diet and Parasite Egg Burden: A Study of the European Bison (Bison bonasus).

For the purpose of nature management and species conservation, European bison (Bison bonasus) are being increasingly reintroduced into nature reserves across Europe. The aim of this study was to investigate European bison's adaptability to new areas through the study of their parasite-EPG (eggs per gram feces) and dietary diversity during twelve months after translocation. We compared the parasite-EPG from introduced European bison in Lille Vildmose, Denmark, with the parasite-EPG from populations from Bornholm, Denmark, and Bialowieza Forest, Poland. From March 2021 to February 2022, fecal samples were collected from three populations. Samples from Lille Vildmose were examined through flotation, sedimentation, the Baermann technique, and nanopore sequencing. Fecal samples from Bornholm and Bialowieza were examined through flotation and sedimentation. Nanopore sequencing of DNA from 63 European bison's fecal samples collected during March-September in Lille Vildmose identified 8 species of nematodes within the digestive tract of the European bison, with Haemonchus contortus being the most frequently observed. In Lille Vildmose, a significantly higher excretion of nematode-EPG was observed during the summer period than in the spring, autumn, and winter. In addition, monthly differences in the excretion of nematode eggs were found, with this being significantly higher in June than in the months during autumn and winter (October-February). Significant differences in the nematode-EPG were only found between the excretion of nematode eggs in Bialowieza Forest when compared to that of Lille Vildmose, with significantly higher excretion in Lille Vildmose (October-November). The results indicate that the development rates for nematodes may be affected by changes in temperature, with increasing temperatures speeding up their development time. Independent of this study design, wildlife vets together with the gamekeepers managing the herd found it necessary to treat the herd with antiparasitics for practical and animal welfare reasons in relation to translocation. Furthermore, 79 plant taxa were identified in the diet of the European bison. The broadest diet was observed in March suggesting that the European bison quickly adapted to their new habitat. The results suggest a seasonal shift in their diet, with this being most apparent from March to April.

Eurasian beaver - A semi-aquatic ecosystem engineer rearranges the assemblage of terrestrial mammals in winter.

There is increasing awareness of the ecosystem engineering services provided by recovering populations of Eurasian beaver. By modifying aquatic environments, this species has a significant, positive influence on biodiversity. Beaver activity affects not only aquatic ecosystems but also terrestrial habitats and organisms. Our study compares and evaluates the species richness and activity of terrestrial mammals in winter at beaver ponds (N = 65) and randomly-selected reference sites along nearby watercourses unmodified by beavers (N = 65) in Poland (central Europe). Mammal assemblages were investigated near pond/watercourse edges, and also at some distance from them. The species richness of mammal and numbers of their tracks were respectively 25% and 33% greater on the beaver than on the reference sites. The higher species richness on beaver sites extended to areas 40-60 m distant from ponds, devoid any signs of beaver activity. Twenty-three mammal species were recorded on beaver sites (mean species richness 3.8 ± 1.6 SD), and 20 on reference ones (3.0 ± 1.5 SD). The numbers of tracks of grey wolf, least weasel and European polecat were higher on beaver than reference sites. Mammal species richness and activity were related to the existence of beaver ponds, but were also correlated with the numbers of snags and coverage of grass, bramble and coniferous saplings in neighbouring terrestrial habitats. Large and small carnivores occurred more frequently and were more active on beaver sites. The frequencies of occurrence of mesocarnivores, mesoherbivores and small herbivores were correlated with habitat characteristics, regardless of whether beavers were present or not. Our results highlight the fact that both pond creation and the habitat changes resulting from the presence of beavers rearrange the occurrence and activity of the terrestrial mammal assemblage.

Blastocystis occurrence and subtype diversity in wild European terrestrial mammals - The case of Bialowieza Primeval Forest (NE Poland).

Blastocystis cf. Blastocystis hominis is the most common unicellular parasite found in human and animal intestines. Little is known about the life cycle, transmission and mechanisms of pathogenesis for this parasite. The aim of this study was to obtain new data on the genetic diversity of Blastocystis in selected species of mammals found in the Bialowieza Primeval Forest (BPF), Poland, the best preserved lowland forest in temperate Europe. 113 faecal samples were collected in the period 2018-2020 from seven species of wild mammals occurring within the Polish part of BPF and its surroundings. Blastocystis was detected by molecular amplification and sequencing the small subunit rRNA gene. The overall prevalence of Blastocystis in animals was 8.9%. A larger number of stool samples (90) were collected from European bison and only for this species was it possible to calculate the prevalence of infection (5.6%). The isolates obtained from European bison were classified as ST1, ST3, ST5, ST7. Blastocystis was also detected in the grey wolf (Canis lupus) (ST5), wild boar (Sus scrofa) (ST5) and red deer (Cervus elaphus) (ST1). In conclusion, for the first time we have demonstrated the presence of Blastocystis in wild European bison. Preliminary studies have shown that Blastocystis is present in at least 4 species of wild mammals in the BPF area and that it exhibits great genetic diversity.

The first case of genetically confirmed sparganosis (Spirometra erinaceieuropaei) in European reptiles.

Sparganosis is a zoonosis caused by the spargana (larvae) of Spirometra sp. (Diphyllobothriidae). Reptiles are particularly important vectors for the transmission of this parasite in Asia; however, their role in sparganosis spread in European wildlife is unrecognized. We investigated the infection of reptiles with Spirometra sp. in NE Poland, where several mammalian hosts have been identified recently and in the past. Of the 59 dead reptiles, plerocercoids were found in two grass snakes (Natrix natrix) from the Bialowieza Primeval Forest (BPF). The Spirometra erinaceieuropaei species was genetically confirmed using the evolutionary conserved nuclear 18S rRNA gene, and then compared to GenBank deposits. The sequences were identical to previously investigated Spirometra sp. found in Eurasian badger and wild boar from BPF. Our finding is the first genetically confirmed record of Spirometra sp. in reptiles in Europe. Since reptiles are often a component of mammalian diet, they can be a source of Spirometra tapeworm infection in European wildlife; however, further studies are needed to investigate the prevalence of infection in reptiles and other non-mammalian hosts.