Search

The striped field mouse (Apodemus agrarius) is expanding in several European countries, but the details of this process are not always documented due to a lack of long-term studies. We conducted an analysis of changes in relative abundances and proportions of A. agrarius in small mammal communities in nine different habitat groups in Lithuania during 1975–2023. We found an increase in the abundance and proportion of A. agrarius, increasing synanthropization of the species, and tolerance to anthropogenization of habitats. Temporal variations in the relative abundance and proportion of species were observed, with lower values in February–July and higher values in September–January. The main finding is a remarkable increase in species presence in the country after the 1990s, with a peak observed in the 2010s–2020s, confirmed by eight local studies. During these decades, it was the third most abundant species, representing 19.8–20.0% of the individuals caught. It is also important to note that A. agrarius has recently been most abundant in commensal habitats (0.029 ± 0.006 individuals/trap day), with the highest species proportion in agricultural areas (24.8 ± 1.8%). There are many indications that the expansion of A. agrarius in Lithuania is becoming invasive. [ABSTRACT FROM AUTHOR]

Because of their wide distribution, short life cycle, rapid reproduction, and sensitivity to the environment, rodents can indicate changes in habitat quality and climate variables. Long-term studies are needed to verify these changes and assumptions about their causes. We analyzed small mammal trapping data in Lithuania, covering the period 1975–2023, with 1821 trapping sites and 57,426 small mammal individuals, with a focus on the bank vole (Clethrionomys glareolus). The aim of this study was to assess temporal changes in the relative abundance and proportion of this species in small mammal communities in relation to their habitats. With 21,736 captured individuals, C. glareolus was a dominant species in the country; its proportion in general was 37.9%, with 60.0% in forests. Open habitats, meadows and agricultural land were characterized by the lowest species proportions. Our main findings were the confirmation of decreasing abundances and proportions of C. glareolus since the 1990s, the absence of cyclical fluctuations in the relative abundances of the species in general and in forest habitats, and the introduction of a south–north cline in species proportions. The status of this temperate and boreal forest species is subject to change, with implications for the diversity of the mid-latitude small mammal community. [ABSTRACT FROM AUTHOR]

The body condition index (BCI) values in small mammals are important in understanding their survival and reproduction. The upper values could be related to the Chitty effect (presence of very heavy individuals), while the minimum ones are little known. In this study, we analyzed extremes of BCI in 12 small mammal species, snap-trapped in Lithuania between 1980 and 2023, with respect to species, animal age, sex, and participation in reproduction. The proportion of small mammals with extreme body condition indices was negligible (1.33% with a BCI < 2 and 0.52% with a BCI > 5) when considering the total number of individuals processed (n = 27,073). When compared to the expected proportions, insectivores and herbivores were overrepresented, while granivores and omnivores were underrepresented among underfit animals. The proportions of granivores and insectivores were higher, while those of omnivores and herbivores were lower than expected in overfit animals. In several species, the proportions of age groups in underfit and overfit individuals differed from that expected. The male–female ratio was not expressed, with the exception of Sorex araneus. The highest proportion of overfit and absence of underfit individuals was found in Micromys minutus. The observation that individuals with the highest body mass are not among those with the highest BCI contributes to the interpretation of the Chitty effect. For the first time in mid-latitudes, we report individuals of very high body mass in three shrew species. [ABSTRACT FROM AUTHOR]

Habitat type and habitat change are very important factors in the body condition of small mammals that inhabit them. The response can be positive, increasing, or the opposite, decreasing body condition. We analyzed outliers of the body condition indices (BCIs) of 12 species trapped in nine different habitats during 1980–2023 in Lithuania, a mid-latitude country. Mixed and fragmented habitats, as well as commensal habitats, could be considered the least suitable for small mammals, based on the highest proportions of underfit and low proportions of best-fit individuals. On the contrary, meadows and disturbed habitats (landfills and cormorant colonies) had the highest proportions of best-fit individuals, while the proportion of under-fit individuals was much lower than expected. We found outliers in the BCI in all species, except for the under-fit harvest mice (Micromys minutus), and in all habitats, though not numerous. The presence of the highest BCI in yellow-necked mice (Apodemus flavicollis) and bank voles (Clethrionomys glareolus) in the disturbed habitats studied and in house mice (Mus musculus) in commensal habitats may be related to the resources provided by these habitats. Our results demonstrate the feasibility of using retrospective small mammal morphometric data to analyze their relationship with habitat. [ABSTRACT FROM AUTHOR]

The relationship between the body condition of different small mammal species and the habitat they occupy is poorly analyzed. We analyzed the body condition index, BCI, of 18 small mammal species trapped in forest, shrub, wetland, meadow, riparian, mixed and fragmented, disturbed, agricultural, and commensal habitats of Lithuania during the span of 1980–2023. The composition of small mammal communities was habitat-dependent, being richest in meadows, with eighteen species, and poorest in riparian habitats, with nine species. A significant variation in the BCI with respect to habitat was observed in eight small mammal species (Sorex araneus, S. minutus, Apodemus agrarius, A. flavicollis, Clethrionomys glareolus, Alexandromys oeconomus, Microtus agrestis, and M. arvalis). The highest average BCI for most of these species was found in disturbed habitats, with S. minutus and M. arvalis showing the highest BCI in agricultural habitats. The lowest average BCI for most species was found in mixed habitats, while C. glareolus and M. arvalis exhibited the lowest BCI in shrub habitats. In general, species dominating certain habitats did not have the highest BCI. This is the first multi-species, multi-habitat study of body condition in small mammals at mid-latitudes. [ABSTRACT FROM AUTHOR]

Simple Summary: Based on a sample of nearly 30,000 individuals representing 18 small mammal species trapped in Lithuania between 1980 and 2023, we conducted the first multi-species analysis of the Body Condition Index (BCI) of small mammals in middle latitudes. Our analysis compared BCIs between species and examined differences in age groups, gender, and reproductive statuses within each species (seven species had sample sizes with N < 100 individuals). Among the species with the highest average BCI, seven out of eight granivores or omnivores consume animal food occasionally. Two distinct patterns in the BCI were identified during ontogeny, either decreasing or increasing from juvenile to adult, possibly related to differences in their diet. Our results demonstrate that reproductive stress has a negative impact on the BCI of adult females in all analyzed species and nearly all adult males. We observed a rare case of the Chitty effect in two species of shrews, where their high body mass resulted in a very high BCI. Our results help to understand how changing environmental conditions are affecting small mammals. This is the first multi-species approach of body condition at middle latitudes. The body condition index (BCI) is an indicator of both reproductive success and health in small mammals and might help to understand ecological roles of species. We analyzed BCI data from 28,567 individuals trapped in Lithuania between 1980 and 2023. We compared BCIs between species and examined differences in age groups, gender, and reproductive statuses within each species. Seven out of eighteen species had sample sizes with N < 100. In terms of species, we found that seven of the eight species with the highest average BCIs are granivores or omnivores, which can consume animal-based food at least seasonally. The two contrasting (decreasing or increasing) BCI patterns observed during ontogeny can be related to diet differences among juveniles, subadults, and adult animals. Our results demonstrate that reproductive stress has a negative impact on the BCI of adult females in all analyzed species and nearly all adult males. Although the animals with extremely low BCI consisted mostly of shrews, for the first time we found 23 common and pygmy shrews exhibiting the Chitty effect, i.e., a very high body mass resulting in a BCI > 5.0. This is the first multi-species approach of body condition at middle latitudes. The results increase our understanding of how changing environmental conditions are affecting small mammals. [ABSTRACT FROM AUTHOR]

Simple Summary: Analysis of 474 human casualties in wildlife–vehicle accidents (WVAs) in Lithuania between 2002 and 2022 revealed that their numbers have been escalating since 2018. Moose were the primary contributors to fatalities and injuries despite their much lower abundance in the country compared to that of roe deer. Temporal patterns showed that most casualties occurred during dusk or dawn in May and September, on weekends, and between 20:00 and 22:00. Spatially, main roads with high traffic density had the highest casualties per unit length. Most casualties occurred after vehicles directly hit an animal with cars and motorcycles being the most vulnerable. The effectiveness of WVA prevention measures was inconclusive with a small percentage of casualties occurring in areas with warning signs or fenced road segments. These findings highlight the need for a critical evaluation of current prevention strategies to reduce human casualties in WVAs. We analyzed 474 human casualties in wildlife–vehicle accidents (WVAs) that occurred between 2002 and 2022 in Lithuania, which is a small northern European country. The study revealed the escalating trend of WVAs, since 2018 surpassing other transport accidents, although the number of casualties per WVA was ca. 100 times lower compared to other transport accidents. Moose was the primary contributor, responsible for 66.7% of fatalities and 47.2% of injuries, despite much lower species abundance compared to roe deer, which is the main species involved in WVAs without human casualties. Temporal patterns highlighted seasonal, daily, and hourly variations, with the majority of casualties occurring during dusk or dawn in May and September, on weekends, and between 20:00 and 22:00. Spatially, main roads with high traffic density exhibited the highest casualties per unit length. Most casualties occurred after hitting an animal directly with cars and motorcycles being most vulnerable vehicles. The effectiveness of WVA prevention measures was inconclusive: 9.5% of fatalities and 1.4% of injuries were registered in the area of the warning sign, and 10.4% of all casualties occurred on fenced road segments. These findings suggest the need for a critical evaluation of the current prevention strategies in reducing human casualties associated with WVAs. [ABSTRACT FROM AUTHOR]

A review of 113 scientific and other publications on the smallest and most abundant deer in Lithuania, the roe deer (Capreolus capreolus), is presented, along with an analysis based on compound annual population growth rates of population numbers, hunting bags, and roadkill. This review covers the species' history in the country from the last glaciation onwards, the changes in numbers from 1934 to 2023, hunting bag changes from 1965 to 2022, roadkill numbers from 2002 to 2022, data on roe deer reproduction, habitat selection, genetic diversity, pathogens, and damage to forest stands. It also provides an overview of species management and selection for trophies. Despite the exponential increase in roe deer numbers since 1990 and the dominance of this species in roadkill, even on urban roads, the number and density of animals and the damage they cause to forest stands are relatively low compared to other European countries. Within the observed period, drops in numbers were related to harsh winters in 1969/1970 and 1995/1996. Poaching, especially coinciding with weakened enforcement during the period of political–economic transition in the early 1990s, has also had a negative impact on population numbers, as have recent increases in the number of large predators. Population growth over the recent period does not correlate with hunting mortality, which has remained stable at an average of 16.9% since 2002. [ABSTRACT FROM AUTHOR]

Simple Summary: Some species of Sarcocystis parasites form cysts in the brains of small mammals. These parasites have been shown in laboratory experiments to be transmitted by Buteo buzzards. However, there is a lack of studies identifying these parasites in natural definitive hosts. In the current investigation, we examined brain tissues of small mammals and small intestines of two buzzard species collected in Lithuania for Sarcocystis spp. Species of Sarcocystis were confirmed using DNA sequence analysis. Of the eleven small mammal species inspected, only bank voles were infected with cysts of Sarcocystis glareoli. The prevalence of this parasite in the brain of vole hosts reached 9.1%. Based on genetic examination, half of the investigated common buzzards were positive for S. glareoli. Furthermore, two Sarcocystis species, including a putative new species, were detected in the small intestines of rough-legged buzzards. Our results indicate that Buteo buzzards play an important role in transmitting rarely studied Sarcocystis parasites forming cysts in the tissues of small mammals. Representatives of the genus Sarcocystis are worldwide distributed apicomplexan parasites characterised by two-host prey-predator relationships. Sarcocystis spp. produce sarcocysts in the muscles and brains of intermediate hosts and develop sporocysts in the intestines of definitive hosts. Two species, Sarcocystis glareoli and Sarcocystis microti, previously assigned to the genus Frenkelia, form cysts in the brains of rodents and are transmitted through the common buzzard (Buteo buteo). In our study, brain samples of 694 small mammals caught in different regions of Lithuania were examined for Sarcocystis spp. Additionally, 10 B. buteo and two rough-legged buzzards (Buteo lagopus) were tested for sporocysts of the analysed parasites. Sarcocystis species were identified based on 28S rRNA sequence comparison. Of the eleven species of small mammals tested, Sarcocystis parasites were observed only in the bank vole (Clethrionomys glareolus). Cysts of S. glareoli were detected in 34 out of 374 C. glareolus (9.1%, 95% CI = 6.4–12.5%). Molecular investigation showed the presence of only S. glareoli in the intestines of 50% of B. buteo. Furthermore, two species, Sarcocystis sp. Rod3 and Sarcocystis sp. Rod4, were confirmed in B. lagopus. Our results demonstrate the need for further studies on Sarcocystis cycling between rodents and birds. [ABSTRACT FROM AUTHOR]

Understanding the spatial and temporal patterns of animal road mortality is important for planning protective measures and raising driver awareness. In our study of Lithuania, spanning from 2002 to 2022, we examined these patterns based on road types and categorized them by working days, weekends, and long weekends, predicting the potential impact of transitioning to a four-day working week. We found that road type explains 22–50% of the variability in roadkill numbers for moose, red deer, wild boar, and roe deer. The highest occurrences were on main roads, while regional roads had the fewest incidents. The overall number of roadkills, especially those involving ungulates, was highest on weekends, followed by workdays, with the least on long weekends. However, these variations lacked statistical significance, and their effect size was small. We also observed a trend of increased roadkill numbers on the day before, the first day, notably on All Saints Day, or the last day of long weekends. In this context, with the introduction of a four-day work week, we are only expecting the highest roadkill numbers to move from Friday to Thursday. [ABSTRACT FROM AUTHOR]

Simple Summary: The tundra vole's (Alexandromys oeconomus) distribution in Lithuania has been documented for 70 years, yet its genetic diversity remains unexplored. We analyzed vole samples from northern and western sites in Lithuania, using mtDNA sequence analysis. Despite landscape barriers, our phylogenetic analyses placed Lithuanian voles in the Central European phylogroup, suggesting an origin from northeastern Poland. Genetic diversity in Lithuanian A. oeconomus at the mtDNA loci was low compared to other European samples, revealing distinctions from Poland and Northern Europe. Genetic divergence among western and northern Lithuanian samples, coupled with low variability, provides novel insights into species phylogeography and the influence of barriers on colonization dynamics. The distribution and spread of the tundra vole (Alexandromys oeconomus) in Lithuania have been documented over the last 70 years, but the genetic diversity of the species has not been studied. In this study, we examined A. oeconomus trapped in three sites in northern and western Lithuania using mtDNA sequence analysis of the cytb and control region. The western and northern sites are separated by anthropogenic landscape barriers. The western site is subject to regular spring flooding. Phylogenetic analyses of the studied individuals placed them in the Central European phylogroup, suggesting that Lithuanian A. oeconomus originated from northeastern Poland. In Lithuania, the genetic diversity of A. oeconomus at both mtDNA loci was relatively low (Hd < 0.6, π < 0.002) compared to that found in other European samples (Hd = 0.833–0.958; π = 0.00402–0.01552). Individuals analyzed in Lithuania were genetically different from samples collected in Poland and Northern Europe (ΦST > 0.15, p < 0.05). The genetic divergence between the western and northern samples of A. oeconomus in Lithuania, together with the low genetic variability among the voles studied, provides new insights into the phylogeography of the species and the influence of barriers on the colonization of the country. [ABSTRACT FROM AUTHOR]

This editorial discusses the abundance and dynamics of small mammals and their predators. Small mammals, such as rodents and insectivores, play important roles in ecosystems, including seed dispersal and serving as prey for larger carnivores. However, they are often considered pests in human-dominated environments. The editorial introduces a special issue that includes 10 papers on this topic, with studies conducted in European countries, New Zealand, and Chile. The papers cover a range of topics, including the effects of alien species, pest control in agroecosystems, historical trends in small mammal populations, and the activity of small mammals in response to predation risk. The editorial highlights the unintended consequences of human actions, such as the introduction of predators to control small mammal populations, and the need for new management strategies for conservation. [Extracted from the article]

Simple Summary: We examined traffic accidents involving wildlife and domestic animals in Lithuanian urban areas from 2007 to 2022. We analyzed the proportions of wild and domestic animals in roadkill, annual trends, the dominant species involved, and monthly changes during the COVID-19 periods of mobility restrictions. During the study period, the number of roadkills increased exponentially, with roe deer (Capreolus capreolus) being the most numerous species. The proportion of domestic animals, 12.2% of the total roadkill in urban areas, significantly exceeded that on non-urban main, national, and regional roads in the country, these being 3.8%, 3.6%, and 4.3%, respectively. During the 2020 and 2021 COVID-19 restrictions, there was a significant increase in the number of accidents involving animals in cities, which again normalized after the lockdowns. Thus, mobility restrictions had only a temporary effect. The increase in animal-related accidents, even when there were fewer people on the roads, suggests that new ways of protecting animals in cities might be required, at least through improving driver awareness on the issue. We investigated roadkills in urban areas in Lithuania from 2007 to 2022, including two periods with COVID-19 restrictions on people's movement. We analyzed the proportions of wild and domestic animals in roadkill, annual trends, the predominant species involved, and monthly changes during the restrictions. Urban roads were characterized by a low species diversity of roadkilled mammals, with roe deer (Capreolus capreolus) dominating. Total numbers increased exponentially during the study period. The proportion of domestic animals, 12.2%, significantly exceeded that on non-urban roads in the country. The proportion of domestic animals decreased from over 40% in 2007–2009 to 3.7–5.4% in 2020–2022, while the proportion of wild mammals increased from 36.1–39.6% to 89.9–90.6%, respectively. During the periods of COVID-19 restrictions, the number of roadkills in urban areas was significantly higher than expected based on long-term trends. Compared to 2019, the number of roadkilled roe deer in 2020–2021 almost doubled from 700 to 1281–1325 individuals. These anthropause effects were, however, temporary. The imbalance between the roadkill number and transport intensity might require new mitigation strategies to sustain mammal populations in urban areas, at least through improving driver awareness on the issue. [ABSTRACT FROM AUTHOR]

The Eurasian harvest mouse (Micromys minutus) is a tiny rodent of the Palearctic and Indomalayan regions, with a distinct regional species status in Europe and irregularly varying local numbers. We analysed the population of M. minutus in Lithuania (Northern Europe) based on trapping data from 1975 to 2022 and owl pellet data from 1986 to 2009. Based on both datasets, the proportion of this species in the small mammal community was similar, 1.13% and 0.62%, respectively. The proportions have remained stable across all decades. Relative abundance was 1.19 ± 0.19 individuals per 1000 trap days, stable over the long term and across the country. Irregular fluctuations in abundance were observed in some of the sites surveyed. The highest average RA was recorded in open sedge habitats, meadows and marshes. The absolute highest RA was 88 individuals per 1000 trap days in floodplain meadows after a major flood. Although the negative impact of habitat anthropogenisation has been confirmed, M. minutus does not require special conservation measures in Lithuania. [ABSTRACT FROM AUTHOR]

Simple Summary: The impact of COVID-19-related human and vehicular mobility restrictions on the number of roadkills of wild mammals, and roe deer in particular, was assessed in Lithuania. Notably, there was a marked decrease in roadkill incidents on main, national and regional roads, particularly in April–May 2020 (the beginning of lockdown period I) and November–December 2020 (the beginning of lockdown period II). During these months, collisions with mammals on the A14 main road were reduced by 75–90%. However, there was a significant increase in the number of roadkills in urban areas, resulting in the total number of mammal–vehicle and roe deer–vehicle collisions in 2020 and 2021 being higher than expected based on long-term trends. However, after restrictions were eased, collision numbers with wildlife on the main, national and regional roads increased again and became higher than expected. The impact of COVID-19 restrictions on human and vehicular mobility on the number of roadkills of wild mammals, and roe deer in particular, was assessed in Lithuania. We statistically analyzed the distribution of all mammals and roe deer (Capreolus capreolus) as the most abundant species annually from 2002 to 2022 and monthly from 2020 to 2021, including during the two restriction periods. Notably, there was a marked decrease in roadkill incidents on main, national and regional roads, particularly in April–May 2020 (the beginning of lockdown period I) and November–December 2020 (the beginning of lockdown period II), 5.1–20.8% and 33.6–54.4%, respectively. During these months, collisions with mammals on the A14 main road were reduced by 75–90%. However, there was a significant increase in the number of roadkills in urban areas, resulting in the total number of mammal–vehicle and roe deer–vehicle collisions in 2020 and 2021 being higher than expected based on long-term trends. However, after restrictions were eased, collision numbers with wildlife on the main, national and regional roads increased again and became higher than expected. [ABSTRACT FROM AUTHOR]

The raccoon dog (Nyctereutes procyonoides Gray, 1834) is an invasive mammal widespread in northern, eastern, and central Europe, where it damages biodiversity and carries a wide range of pathogens. Surveys of this species in Lithuania ceased before 2000, so there is a lack of scientific information on its distribution and relative abundance. In 2019–2022, we carried out a nationwide recording of raccoon dogs using camera traps (101 sites, sampling effort of 15,563 trapping days). The species was found at 64 sites (63.4% of the sites surveyed), with an average relative shooting frequency of 4.30 photographs per 100 days. The frequency of raccoon dogs was higher at camera sites where lynx (Lynx lynx Linnaeus, 1758) or wolves (Canis lupus Linnaeus, 1758) were recorded compared to sites where predators were absent (7.95 vs. 3.21 photos/100 days, p < 0.05). The highest raccoon dog activity (69.5% of records) was observed at night and at temperatures between −3 and +5 °C. Below −15 °C, animals were not active, while above 25 °C, there was very little activity. Diurnal activity (36.1% of daytime records in April–June) increased during estrus, gestation, and rearing of pups. We conclude that wide-scale camera trapping is a suitable method for raccoon dog surveys. [ABSTRACT FROM AUTHOR]

Simple Summary: Small mammals not only play an important role in ecosystems, but they also can transmit a wide range of pathogens to humans and domestic animals. The data on protozoan Sarcocystis parasites in orchard-dwelling small mammals are still scarce. Members of the genus Sarcocystis form sarcocysts in the muscles of intermediate hosts and develop sporocysts in the intestines of definitive hosts. In the present study, 679 muscle samples of small mammals, collected in commercial orchards and berry plantations in Lithuania, were screened for Sarcocystis parasites via DNA analysis. The prevalence of Sarcocystis spp. was low as only nine pooled muscle samples were found to contain the parasites examined. Four species were identified in the examined small mammals, including two potentially new Sarcocystis species that were detected in the muscles of voles. The phylogenetic results suggested that birds and mammals are the definitive hosts of the Sarcocystis spp. identified in the current study. Small mammals are an important group of wildlife that can transmit pathogens to humans and animals. There is a lack of comprehensive studies on the protozoan parasites of the genus Sarcocystis in agricultural areas. The aim of the current research was to evaluate the prevalence of Sarcocystis spp., and to identify the parasite species found in the skeletal muscles of rodents and insectivores from commercial orchards. A total of 679 muscle samples from small mammals, mainly rodents (n = 674), belonging to eight species were examined. Muscle samples were pooled into groups, then digested, and the presence of the Sarcocystis species was confirmed by molecular methods. The examined parasites were determined in five rodent species, Apodemus agrarius, A. flavicollis, Clethrionomys glareolus, Microtus arvalis, and M. oeconomus. The prevalence of Sarcocystis spp. was low: 2.23% in voles and 0.79% in mice. Based on a sequence comparison of cox1 and 28S rDNA, four species were identified: S. myodes, Sarcocystis cf. strixi, Sarcocystis sp. Rod1, and Sarcocystis sp. Rod2. This is the first report of S. myodes in A. agrarius, A. flavicollis, and M. arvalis. The identified species were most closely related to Sarcocystis spp., and were transmitted by predatory mammals and birds. Future studies are needed to describe the species morphologically, as well as to define the host spectrum and to evaluate their possible pathogenicity. [ABSTRACT FROM AUTHOR]

Cervid roadkill, including moose, red deer and roe deer, can pose a risk to drivers and are frequently registered. However, the roadkill influence on overall cervid populations is not fully known, especially by roadkill that are not officially registered. The aim of this study was to assess the impact of cervid roadkill on population abundance, evaluating (i) the proportion of ungulate–vehicle collisions not registered by official bodies, (ii) the number of roadkill in relation to hunted animals and (iii) the proportion of roadkill that occurs in forest habitat. The number of unreported roadkill was calculated based on a roadkill index assessed during 3815 registration sessions on main and national roads in Lithuania from 2002–2022. During this period, 373 moose, 712 red deer and 9179 roe deer roadkill were unreported, correlating to 13.8%, 95.8% and 31.1% of those registered by the Traffic Supervision Service. In conclusion, 39.5%, 17.5% and 20.1% of roadkill were registered on roads through forests. Moose roadkill amounted to a figure corresponding to 10% of those hunted, with the same figure for red deer being 1.8%, neither adding much mortality. At 16.5%–16.6%, the figure for roe deer might be important. [ABSTRACT FROM AUTHOR]

Roadkill and other impacts of roads on wildlife create pressures on society and the environment, requiring the implementation of mitigation measures in response. Due to various natural and anthropogenic causes, the locations of wildlife–vehicle collisions are not stable in time and space. The identification of urban and wildlife corridor intersections can help anchor collision locations along high-risk road sections. Urban and wildlife corridors and their intersections were identified in a case study of Lithuania using a landscape connectivity identification method based on circuit theory. A strong relationship was found between the numbers of urban–wildlife corridor intersections and the numbers of wildlife–vehicle collisions. Short road sections were characterised by the number of urban–wildlife corridor intersections, mammal–vehicle collisions, and the presence of fencing. Multi-criteria analyses identified the road sections where wildlife fencing is, simultaneously, the longest, and the number of mammal–vehicle collisions and the number of urban–wildlife corridor intersections are highest. The results show that identifying wildlife and urban corridor intersections can reinforce locations for permanent roadkill mitigation measures. The identification of crossing structure type and location within shortlisted road sections and evaluation of their efficiencies remain the challenges for field research. [ABSTRACT FROM AUTHOR]

Simple Summary: Between 2018 and 2022, we surveyed small mammals at 23 sites in Lithuania—meadows, commercial orchards and berry farms, kitchen gardens, homesteads and farms—with the aim to assess the proportion of shrews in the community and their diet using stable isotope analysis. We found that in these natural, agricultural, and commensal habitats, common (Sorex araneus) and pygmy (Sorex minutus) shrews were under-represented—having a proportion of 3.1%, less than a half that of the long-term average in the country. The diet of these two species was similar in both agricultural and commensal habitats. On farms and in orchards with intensive farming, there were no catches of shrews. Contamination by plant protection products and a lack of invertebrates, which are the main food of shrews, may be factors limiting their numbers in the agriculturally managed habitats. Two species of water shrews, Neomys fodiens and Neomys anomalus, were found for the first time in homesteads, including in outbuildings, and their diet requires further investigation. Shrews are a less studied group of small mammals than rodents. Between 2018 and 2022, we surveyed 23 sites in Lithuania, including natural and anthropogenic habitats, with the aim to assess the proportion of Soricidae in small mammal communities and their diet based on stable isotope analysis. The average representation of Soricidae was 3.1%, about half the long-term average in other habitats in the country. The highest proportions were in meadows and farmsteads, at 4.9% and 5.0% respectively. Shrews were not trapped on farms or in young orchards, and their relative abundance was very low in intensively managed orchards (0.006 individuals per 100 trap days). Neomys fodiens and N. anomalus were unexpectedly found in homesteads, including in outbuildings. Sorex araneus and S. minutus had similar diets. The trophic carbon/nitrogen discrimination factor between invertebrates and shrew hair was 2.74‰/3.98‰ for S. araneus, 1.90‰/3.78‰ for S. minutus in the orchards. The diet of N. fodiens and N. anomalus at the homesteads requires further investigation. We propose that the under-abundance of shrews may be due to contamination by plant protection products and a lack of invertebrates under intensive agricultural practices. [ABSTRACT FROM AUTHOR]

Fruit and berry farms are anthropogenic habitats still inhabited by small mammals, though their presence is constantly affected by agricultural activities. Based on trapping data from 2018–2022, we analyzed the abundance and population structure of the dominant rodent species to assess changes in gender and age ratios by year and habitat, the annual and seasonal dynamics of relative abundance, and the relationship between breeding parameters and abundance. The relative abundance of the dominant species, common vole, yellow-necked mouse, striped field mouse, and bank vole, and their proportion in the investigated community varied according to year, season, and habitat. No outbreaks were recorded during the study period. The abundance of the striped field mouse exhibited a downward trend independently of habitat, while the abundance and proportions of the other three species were habitat-dependent. There was no consistent pattern between litter size and relative abundance in the same or following years. Given the ongoing conflict between biodiversity conservation in Europe and agriculture, the results contribute to a better understanding of the functioning and viability of rodent populations in fruit farms and may be used in agroecology and sustainable farming. [ABSTRACT FROM AUTHOR]

Cormorant colonies are often viewed negatively by fishermen and foresters due to their extremely high impact on aquatic and terrestrial ecosystems. In forests, the habitats of nesting territories are destroyed, with concomitant impacts on the animal communities. In 2011–2022, investigating three colonies of Great Cormorants (Phalacrocorax carbo), we aimed to test whether their effect on small mammals depends on colony size. In the largest colony in Lithuania, a low species richness, lower diversity and relative abundance, as well as poorer body conditions of the most abundant species was found in the nesting zone. However, once the cormorants left the nesting site, all the parameters recovered. Two small colonies had a positive impact, with higher species richness in the territory of the colony (seven and ten species), diversity (H = 1.56 and 1.49), and relative abundance (27.00 ± 2.32 and 25.29 ± 2.91 ind. per 100 trap days) compared with the control habitat (three and eight species; H = 1.65 and 0.99; 12.58 ± 1.54 and 8.29 ± 1.05 ind./100 trap-days). We conclude that up to a certain colony size, cormorant pressure is a driver of habitat succession and has similar effects on the small mammal community as other successions in disturbed habitats. [ABSTRACT FROM AUTHOR]

The house mouse (Mus musculus) is a most extensively distributed omnivorous rodent species, usually living in close association with humans. Its diet includes various vegetable matter, insects and any available human food. For the first time, we assessed the dietary niche of this species by the isotopic (δ15N and δ13C) compositions of animal hair samples in the gradient of habitats, ranging from natural to fully commensal. The main factors explaining the differences in the isotopic niche of the mice, being the proxy of their diet, were the season and the source of available food. Influence of the habitat was weak, while gender, age, body mass and body condition had no influence on the diet differences. We found that M. musculus dietary niches overlap between different habitats if mice have access to human food. Niches diverge when mice forage outdoors on natural food compared to farms where livestock feed is available. Compared to omnivorous bank vole (Clethrionomys glareolus) living synoptically, M. musculus has much wider dietary niche and consumes more foods of animal origin. Variability of the diet increases the ecological plasticity of this strongly commensal species and, together with behavioural and reproductive adaptability, allows irresistibly occupy various environments. [ABSTRACT FROM AUTHOR]

The genus Bartonella contains facultative Gram-negative intracellular bacteria from the family Bartonellaceae that can cause diseases in humans and animals. Various Bartonella species have been detected in rodents' ectoparasites, such as fleas, ticks, mites, and lice. However, the role of laelapid mites (Mesostigmata: Laelapidae) as carriers of Bartonella spp. needs to be confirmed. We aimed to investigate the presence of Bartonella spp. in laelapid mites collected from small rodents in Lithuania using real-time PCR targeting the transfer-messenger RNA/tmRNA (ssrA) gene and to characterize Bartonella strains using nested PCR and sequence analysis of the 16S-23S rRNA intergenic transcribed spacer region (ITS). A total of 271 laelapid mites of five species (Laelaps agilis, Haemogamasus nidi, Eulaelaps stabularis, Myonyssus gigas, and Hyperlaelaps microti) were collected from five rodent species (Apodemus flavicollis, Apodemus agrarius, Clethrionomys glareolus, Micromys minutus, and Microtus oeconomus) during 2015--2016. Bartonella DNA was detected in three mite species L. agilis, M. gigas, and Hg. nidi with an overall prevalence of 11.4%. Sequence analysis of the 16S-23S rRNA ITS region revealed the presence of Bartonella taylorii in L. agilis, Hg. nidi, and M. gigas, and Bartonella grahamii in L. agilis. Our results suggest that laelapid mites are involved in the maintenance of rodent-associated Bartonella spp. in nature. To the best of the authors' knowledge, this is the first study to demonstrate the presence of Bartonella spp. DNA in laelapid mites from small rodents. [ABSTRACT FROM AUTHOR]

Materials from this study confirm that, despite Lithuania being considered part of the Northern Zone for selecting relevant small mammal species in higher tier risk assessments, the small mammal community structure is more closely related to that of central or eastern Europe. Conversely, larger colony sizes with high breeding numbers have negative impacts on the small mammal community, such as lower species richness, diversity, and relative abundance, as well as poorer body condition index among individual small mammals. Consequently, in Lithuania, the common vole dominates in both orchards and natural habitats, making it the most relevant small mammal species for higher tier risk assessment. [Extracted from the article]