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The 'Menglina Leddy' lily cultivar was selected from the Lilium longiflorum Thunb. 'White Fox' γ-rays irradiation line. It produces much less pollen than 'White Fox' but has similar morphology traits. In order to reveal the effects of gamma irradiations on the chromosomes, mitosis, and meiosis in 'Menglina Leddy' cells were investigated by fluorescence in situ hybridization using rDNA and telomeric repeat probes. Although both 'Menglina Leddy' and 'White Fox' had 24 chromosomes, a considerable amount of chromosomal breaking and rejoining were detected in the former. A super long and two super small chromosomes appeared in all the 'Menglina Leddy' cells. Meiotic abnormalities occurred at each separation stage. Chromosomes pairing configuration showed that complex recombination had happened in 'Menglina Leddy'. The super long chromosome was a Robertsonian translocation product composed of two non-homologous long arms. The chromosome deletions and recombinations did not affect the main ornamental traits, but allowed it to acquire the characteristic of less pollen. [ABSTRACT FROM AUTHOR]

Background: Muskoxen are important ecosystem components and provide food, economic opportunities, and cultural well-being for Indigenous communities in the Canadian Arctic. Between 2010 and 2021, Erysipelothrix rhusiopathiae was isolated from carcasses of muskoxen, caribou, a seal, and an Arctic fox during multiple large scale mortality events in the Canadian Arctic Archipelago. A single strain ('Arctic clone') of E. rhusiopathiae was associated with the mortalities on Banks, Victoria and Prince Patrick Islands, Northwest Territories and Nunavut, Canada (2010–2017). The objectives of this study were to (i) characterize the genomes of E. rhusiopathiae isolates obtained from more recent muskox mortalities in the Canadian Arctic in 2019 and 2021; (ii) identify and compare common virulence traits associated with the core genome and mobile genetic elements (i.e. pathogenicity islands and prophages) among Arctic clone versus other E. rhusiopathiae genomes; and iii) use pan-genome wide association studies (GWAS) to determine unique genetic contents of the Arctic clone that may encode virulence traits and that could be used for diagnostic purposes. Results: Phylogenetic analyses revealed that the newly sequenced E. rhusiopathiae isolates from Ellesmere Island, Nunavut (2021) also belong to the Arctic clone. Of 17 virulence genes analysed among 28 Arctic clone isolates, four genes – adhesin, rhusiopathiae surface protein-A (rspA), choline binding protein-B (cbpB) and CDP-glycerol glycerophosphotransferase (tagF) – had amino acid sequence variants unique to this clone when compared to 31 other E. rhusiopathiae genomes. These genes encode proteins that facilitate E. rhusiopathiae to attach to the host endothelial cells and form biofilms. GWAS analyses using Scoary found several unique genes to be overrepresented in the Arctic clone. Conclusions: The Arctic clone of E. rhusiopathiae was associated with multiple muskox mortalities spanning over a decade and multiple Arctic islands with distances over 1000 km, highlighting the extent of its spatiotemporal spread. This clone possesses unique gene content, as well as amino acid variants in multiple virulence genes that are distinct from the other closely related E. rhusiopathiae isolates. This study establishes an essential foundation on which to investigate whether these differences are correlated with the apparent virulence of this specific clone through in vitro and in vivo studies. [ABSTRACT FROM AUTHOR]

The Arctic fox (Vulpes lagopus) is a species indigenous to the Arctic and has developed unique lipid metabolism, but the mechanisms remain unclear. Here, the significantly increased body weight of Arctic foxes was consistent with the significantly increased serum very-low-density lipoprotein (VLDL), and the 40% crude fat diet further increased the Arctic fox body weight. The enhanced body weight gain stems primarily from increased subcutaneous adipose tissue accumulation. The adipose triacylglycerol and phosphatidylethanolamine were significantly greater in Arctic foxes. The adipose fatty-acid synthase content was significantly lower in Arctic foxes, highlighting the main role of exogenous fatty-acids in fat accumulation. Considering the same diet, liver-derived fat dominates adipose expansion in Arctic foxes. Liver transcriptome analysis revealed greater fat and VLDL synthesis in Arctic foxes, consistent with the greater VLDL. Glucose homeostasis wasn’t impacted in Arctic foxes. And the free fatty-acids in adipose, which promote insulin resistance, also did not differ between groups. However, the hepatic glycogen was greater in Arctic foxes and transcriptome analysis revealed upregulated glycogen synthesis, improving glucose homeostasis. These results suggest that the superior fat accumulation capacity and distinct characteristics of hepatic and adipose lipid and glucose metabolism facilitate glucose homeostasis and massive fat accumulation in Arctic foxes. [ABSTRACT FROM AUTHOR]

Diseases and parasites are important drivers of population dynamics in wild mammal populations. Small and endangered populations that overlap with larger, reservoir populations are particularly vulnerable to diseases and parasites, especially in ecosystems highly influenced by climate change. Sarcoptic mange, caused by a parasitic mite Sarcoptes scabiei, constitutes a severe threat to many wildlife populations and is today considered a panzootic. The Scandinavian arctic fox Vulpes lagopus is endangered with a fragmented distribution and is threatened by e.g. red fox Vulpes vulpes expansion, prey scarcity and inbreeding depression. Moreover, one of the subpopulations in Scandinavia has suffered from repeated outbreaks of sarcoptic mange during the past decade, most likely spread by red foxes. This was first documented in 2013 and then again 2014, 2017, 2019, 2020 and 2021. We used field inventories and wildlife cameras to follow the development of sarcoptic mange outbreaks in this arctic fox subpopulation with specific focus on disease transmission and consequences for reproductive output. In 2013–2014, we documented visual symptoms of sarcoptic mange in about 30% of the total population. Despite medical treatment, we demonstrate demographic consequences where the number of arctic fox litters plateaued and litter size was reduced after the introduction of S. scabiei. Furthermore, we found indications that mange likely was transmitted by a few arctic foxes travelling between several dens, i.e. ‘super‐spreaders'. This study highlights sarcoptic mange as a severe threat to small populations and can put the persistence of the entire Scandinavian arctic fox population at risk. [ABSTRACT FROM AUTHOR]

The Arctic fox (Vulpes lagopus) is the primary infection reservoir of Arctic rabies, the dynamics of which are poorly understood and subject to significant spatiotemporal variation. Although rabies presence has been documented in the region since the mid-19th century, there is currently no evidence of rabies impacting Arctic fox population size. Under the influence of climate change in a rapidly evolving Arctic ecosystem, alterations in transmission dynamics are predicted, with implications for this species. Concurrently, the World Health Organization leads the United Against Rabies collective in the aim of elimination of dogmediated rabies by 2030, and although efforts have justifiably been directed to tropical regions, elimination will require a good understanding of rabies in the Arctic. Therefore, this review aimed to provide an overview of current Arctic rabies understanding, while identifying the key knowledge gaps. The review covered spatiotemporal trends in rabies populations, population dynamics of the host species, and current theories about Arctic rabies persistence. It is still unclear how Arctic rabies can persist under low host densities, which has led to several hypotheses in recent years. Creation of high animal density "hotspots" caused by heterogenic fox distribution and multispecies congregations in response to food availability, extensive Arctic fox migration patterns, and the potential evolution to a less lethal variant of rabies may all be part of the explanation. Evidence for these theories by using recent genetic and modeling studies was evaluated within the review. There is currently insufficient evidence about the efficacy and feasibility of vaccines against Arctic rabies. Key knowledge gaps need addressing to enable future control campaigns. [ABSTRACT FROM AUTHOR]

Introduction: The drawbacks of using antibiotics as feed additives for blue foxes have gradually become apparent; moreover, thymol has wide-spectrum antimicrobial activity and has the potential to replace antibiotics in various animals. However, there are few reports on the effects of thymol on blue foxes. Methods: This study aimed to investigate the effects of different concentrations of thymol on the growth performance, apparent nutrient digestibility, serum biochemical indicators, intestinal morphology, and gut microbiota of blue foxes. Twenty-four male blue foxes (120 ± 5 d) of similar weight (6.05 ± 0.16 kg) were randomly divided into 4 groups. 0, 100, 200, and 300 mg/kg thymol were added to the basal diets of groups C, L, M, and H, respectively. Results: Compared with those in the C group, the addition of 100 mg/kg thymol to the diet significantly increased organic matter (OM) digestibility, crude protein (CP) digestibility, immunoglobulin (Ig) A, IgM, the VH of the duodenum, the CD of the jejunum, the VH of the ileum, and the VH/CD of the ileum (P < 0.05) and strongly significantly increased IgG (P < 0.01). The addition of 200 mg/kg thymol to the diet increased the VH/CD of the duodenum (P < 0.05). The addition of 300 mg/kg thymol to the diet significantly increased the VH and CD of the jejunum (P < 0.05). The addition of 200 mg/kg and 300 mg/kg thymol to the diets increased the final weight (FW) (P < 0.05). Adding 100 mg/kg thymol significantly increased the levels of interleukin-4 (IL- 4) and catalase (CAT) compared with those in the other groups (P < 0.05). 16S rRNA gene detection revealed that thymol can change the abundances of Bifidobacterium, Fusobacterium, Allobaculum, Streptococcus, Megasphaera, and Lactobacillus in the gut. Conclusion: The addition of thymol to diets can increase the abundance of Bifidobacterium, Fusobacterium, and Allobaculum, which may contribute to improving the growth performance of blue foxes. [ABSTRACT FROM AUTHOR]

Expansion of boreal species into tundra ecosystems is a consequence of climate change and human exploitation that threatens local species through increased predation, competition, and pathogen transmission. Under these circumstances, efficient control of expanding boreal species may be necessary, but the efficiency of such action depends on understanding the ecological influences of expansion. The red fox (Vulpes vulpes) is expanding into the tundra across the Arctic. In Scandinavia, red foxes threaten local tundra species and communities including the endangered Arctic fox (V. lagopus). The ecological dynamics in the tundra are influenced by small rodent cycles (classified into different phases based on seasonal abundance fluctuations), which can affect red fox expansion, distribution, and abundance. We used a 17‐year (2004–2020) dataset from the tundra in Sweden, consisting of raw snow track data, to test how cyclic prey influenced red fox distribution and abundance, and subsequently red fox control. The winter abundance of red fox was influenced by small rodent phase, with higher abundance during high prey availability (i.e., increased number of prey numbers) with no support for a time lag between red fox and small rodent abundance. This suggests that high prey availability attracts red foxes to the tundra and that higher immigration from the boreal zone can be expected in response to increased prey abundances. There was no relationship between red fox control and small rodent availability, but control was influenced by red fox abundance during the previous year, which highlights an opportunistic control strategy. We recommend an adaptive management strategy where authorities include small rodent dynamics in the planning and execution of red fox control. [ABSTRACT FROM AUTHOR]

In the Arctic tundra, predators face recurrent periods of food scarcity and often turn to ungulate carcasses as an alternative food source. As important and localized resource patches, carrion promotes co‐occurrence of different individuals, and its use by predators is likely to be affected by interspecific competition. We studied how interspecific competition and resource availability impact winter use of carrion by Arctic and red foxes in low Arctic Fennoscandia. We predicted that the presence of red foxes limits Arctic foxes' use of carrion, and that competition depends on the availability of other resources. We monitored Arctic and red fox presence at supp lied carrion using camera traps. From 2006 to 2021, between 16 and 20 cameras were active for 2 months in late winter (288 camera‐winters). Using a multi‐species dynamic occupancy model at a week‐to‐week scale, we evaluated the use of carrion by foxes while accounting for the presence of competitors, rodent availability, and supplemental feeding provided to Arctic foxes. Competition affected carrion use by increasing both species' probability to leave occupied carcasses between consecutive weeks. This increase was similar for the two species, suggesting symmetrical avoidance. Increased rodent abundance was associated with a higher probability of colonizing carrion sites for both species. For Arctic foxes, however, this increase was only observed at carcasses unoccupied by red foxes, showing greater avoidance when alternative preys are available. Supplementary feeding increased Arctic foxes' carrion use, regardless of red fox presence. Contrary to expectations, we did not find strong signs of asymmetric competition for carrion in winter, which suggests that interactions for resources at a short time scale are not necessarily aligned with interactions at the scale of the population. In addition, we found that competition for carcasses depends on the availability of other resources, suggesting that interactions between predators depend on the ecological context. [ABSTRACT FROM AUTHOR]

We report predation by an Arctic Fox Alopex lagopus on two seabird species, Atlantic Puffins Fratercula arctica and Leach's Storm Petrels Hydrobates leucorhous, nesting on Bakeapple Island, Little Fogo Islands, Newfoundland, Canada. This event took place in 2022, when a whole-island inspection revealed that fox, facilitated by over-ice invasion, killed at least 139 adult storm petrels and 8 puffin chicks. The fox also dug out 83 storm petrel and 4 puffin burrows. Breeding by seabirds on the island, which harbours some of the northernmost colonies in Newfoundland, was also largely disrupted; we documented extremely low egg and chick production values associated with the fox's presence and activity. We discuss the implications of such events for local seabird populations and the need for long-term monitoring to fully understand the impact of these predation events. [ABSTRACT FROM AUTHOR]

Museum skull specimens from 224 Arctic foxes (Vulpes lagopus) were examined macroscopically using an established protocol for examination of mammalian skull specimens. Foxes were collected from coastal and island regions of Alaska, USA, except for two individuals. Collection years ranged from 1931 to 2016 with most specimens collected during the 1950s and 1960s. The study population comprised more females (n = 134, 59.8%) than males (n = 83, 37.0%) and individuals of unknown sex (n = 7, 3.1%). There were 108 (48.2%) young adults, 115 (51.3%) adults, and one (0.4%) individual of unknown age. A total of 8,891 teeth (94.5%) were available for examination. The most common types of pathology observed were periodontitis (n = 222, 99.1%), dental fractures (n = 175, 78.1%) and attrition/abrasion (n = 198, 88.4%). Periapical lesions (n = 12, 5.3%), temporomandibular joint (TMJ) osteoarthritis (n = 3, 1.3%) and root number variation (n = 5, 2.2%) were less common. Enamel hypoplasia was noted in eight foxes (3.6%), all of which were discovered on St. Matthew Island, Alaska, in 1963. As in other canid species, periodontitis, attrition/abrasion and tooth fractures are common in the Arctic fox, while TMJ pathology is rare. Loss of tooth crown substance probably reflects the influence of diet, interspecific and conspecific aggression and oral trauma due to trapping and hunting methods. The high prevalence of periodontitis is probably also due to the combined effects of diet, genetics and host immune reaction to oral bacteria.

We present the history of research activities at the Bylot Island Field Station of the Centre d’études nordiques, a hotspot of biodiversity in the Canadian Arctic. Intensive wildlife studies started at the station in the late 1980s, initially focussing on greater snow goose ecology and its impacts on the tundra vegetation. Since then, studies have expanded to encompass the whole vertebrate food web and have become one of the most comprehensive ecological monitoring programs in the Canadian Arctic. The main vertebrate species monitored include snow geese, lemmings, shorebirds, avian predators, buntings, and Arctic foxes. Over time, we recorded 66 bird and 10 mammal species, including 51 confirmed breeders. Contributions of the program to the field of ecology are numerous, but our demonstration of the dominant role played by predator–prey interactions in the Arctic food web is especially significant for the understanding of direct and indirect trophic interactions. Our studies provided essential information for management decisions taken to control the overabundant greater snow goose population and supported international efforts to assess the state of Arctic biodiversity. Future directions will reflect the need to deepen our understanding of trophic interactions and the effects of climate change using innovative advanced technologies.

Garbage may cause substantial environmental perturbations, in part because of its consumption by wildlife. Such consumption may have direct health implications for animals and may also influence trophic relationships. Even in pristine Arctic ecosystems, wildlife feeding in marine environments consume garbage in the form of plastic debris transported by ocean currents. We show that Arctic wildlife in pristine terrestrial environments may also ingest garbage or food items derived from abandoned camp sites. We found the remains of a chocolate wrapper and a milk powder bag in two Arctic fox (Vulpes lagopus) scats and a piece of cloth in an Arctic wolf (Canis lupus arctos) scat collected near Nares Strait, northern Greenland, one of the most pristine terrestrial wilderness regions on Earth. Found on Washington Land and associated with long-abandoned camp sites, these three scats were among 657 Arctic fox scats and 92 wolf scats collected as part of a larger study. Our study demonstrates that these two highly opportunistic predators managed to consume garbage despite the almost complete lack of human activity in this High-Arctic region. Our results highlight that abandoned anthropogenic material in the High Arctic may function as a source of garbage for local terrestrial wildlife over extended time periods, and that garbage consumption may become a potential issue if human activity in remote Arctic regions increases.

Thiamine deficiency can result in life‐threatening physiological and neurological complications. While a thiamine‐deficient diet may result in the onset of such symptoms, the presence of thiaminase – an enzyme that breaks down thiamine – is very often the cause. In such instances, thiaminase counteracts the bioavailability and uptake of thiamine, even when food‐thiamine levels are adequate. Here, we report on a case of failed reproduction in seven Arctic fox (Vulpes lagopus) breeding pairs kept at a captive breeding facility, including the presentation of severe thiamine deficiency symptoms in two male foxes. Symptoms included ataxia, obtundation, truncal sway, star‐gazing and visual impairment. Blood tests were inconclusive, yet symptoms resolved following treatment with a series of thiamine hydrochloride injections, thereby verifying the diagnosis. A fish‐dominated feed, which for the first time had been frozen for a prolonged period, was identified as the likely source of thiaminase and subsequent deterioration in the animals' health. Symptoms in the two males arose during the annual mating period. All seven breeding pairs at the captive breeding station failed to reproduce – a phenomenon never recorded during the captive breeding facility's preceding 17‐year operation. Relating our findings to peer‐reviewed literature, the second part of this case report assesses how thiamine deficiency (due to thiaminase activity) likely resulted in subclinical effects that impaired the production of reproduction hormones, and thereby led to a complete breeding failure. While previous work has highlighted the potentially lethal effects of thiamine deficiency in farmed foxes, this is, to our knowledge the first study showing how subclinical effects in both males and females may inhibit reproduction in foxes in general, but specifically Arctic foxes. The findings from our case report are not only relevant for captive breeding facilities, but for the welfare and management of captive carnivorous animals in general. [ABSTRACT FROM AUTHOR]

The article provides information on the Cape fox, a small canid species found in sub-Saharan Africa. It discusses a study that analyzed the complete mitochondrial genome of the Cape fox using a method called genome skimming. The study found that the Cape fox is an early diverging lineage within the Vulpes clade and supports the division of Canidae into two major tribes. The findings contribute to our understanding of the genetics and evolutionary history of the Cape fox and other Vulpes species. [Extracted from the article]

Simple Summary: The intestine is an important immune organ of the body in which the gut microbiota plays an important function. Gut microbiota is considered an important "organ" and is receiving increasing attention. This study investigated the diversity of gut microbiota in different intestinal segments of blue foxes, and the similarity between fecal microbiota and gut microbiota in samples taken before and after weaning. The types, distribution characteristics, and patterns of microorganisms in different intestinal segments of blue foxes differed before and after weaning. Except for the rectum, the dominant microbiota of each intestinal segment before and after weaning changed significantly. The fecal microbiota structure of weaned blue foxes cannot represent the exact structural characteristics of the entire gut microbiota but can represent the structural characteristics of the colon and rectum gut microbiota. Intestinal flora plays an important role in maintaining the internal stability and health of the intestine. Currently, intestinal microbes are considered an important "organ" but are mostly ignored by people. This study evaluated the flora structure of each intestinal segment of blue foxes pre-weaning and explored the differences between the fecal flora and intestinal flora structure of each segment after weaning. Samples of intestinal contents from three blue foxes at 45 days of age (before weaning) and intestinal contents and feces samples from at 80 days (after weaning) were collected for 16s rRNA flora analysis. The species and distribution characteristics of microorganisms in different intestinal segments of blue foxes before and after weaning were different. Except for the rectum, the dominant flora of each intestinal segment of blue fox changed significantly after experiencing weaning, and the fecal flora structure of young fox at the weaning stage did not represent the whole intestinal flora structure but was highly similar to that of the colon and rectum. To sum up, the intestinal flora of blue foxes changed systematically before and after weaning. When performing non-invasive experiments, the microflora structure of the colon and rectum of blue foxes can be predicted by collecting fecal samples. [ABSTRACT FROM AUTHOR]

Given the scale, speed, and complexity of recent changes in the Arctic, our understanding of their multiple implications for Arctic biota is still limited. We detail for the first time in the vast Russian Arctic the long-distance movement of an Arctic fox (Vulpes lagopus (Linnaeus, 1758)) tracked with a GPS/iridium collar providing considerably high precision (several meters) and frequency of locations (every 4 h). Revealed diurnal activity patterns of the Arctic fox indicate that it ran greater distances in night hours and shortest in day hours during the most intense movement period. The movement records suggested several attempts to leave the land, as it seemed to encounter open water four times on different parts of Yamal peninsula. The Arctic fox crossed the Ob Bay towards the Gydan peninsula and satellite imagery of discontinuous ice during crossing suggested that it might have stayed on pieces of floating ice. Our observation may support evidence that a reduction in the duration and extent of sea ice could affect the ability of Arctic foxes to cover long distances and thus, in the long term, the connectivity between populations. Similar studies are needed aiming to understand movement ecology of the Arctic foxes in the changing Arctic. [ABSTRACT FROM AUTHOR]

The geographic variability of the shape of the toothrow of the upper cheek was studied in Arctic foxes using the methods of geometric morphometrics. The geographical variability was studied using 288 specimens from 19 localities in North America, Eurasia, and islands of the Pacific and Arctic oceans. A significant monomorphism of the toothrow was demonstrated for all mainland Arctic foxes, as well as Arctic foxes from Greenland and St. Lawrence Island. The Arctic foxes of four Pacific island populations (two Commander and two Pribilof) differ significantly from the mainland Arctic foxes by the shape of the toothrow. At the same time, Arctic foxes of Mednyi Island, Bering Island, and the Pribilof Islands also differ from each other. The Arctic fox from Mednyi Island has the shortest and most widely spaced toothrow, as well as very large teeth. On the contrary, the Arctic fox from the Pribilof Islands has the smallest teeth. Allometry does not play a significant role in the formation of geographic variability in the toothrow in Arctic foxes. A high level of fluctuating asymmetry was detected in Arctic foxes of Mednyi Island and St. George Island as compared with its level in other Arctic fox populations. It is most likely that, for the Arctic fox from Mednyi Island, this is caused by known low genetic diversity of the population due to passage of an extreme population bottleneck in the recent past. It was suggested that the factors of fluctuating asymmetry affecting the Arctic foxes of Mednyi and St. George islands are identical. [ABSTRACT FROM AUTHOR]

Abstract—An analysis of changes in the role of mammals in the infection of humans with hydrophobia in Russia for the period 1534–2017 is presented. Human deaths when dealing with dogs have continually been recorded since the 16th century. The share of dogs in human hydrophobia infection reached 85% from the end of the 19th century to the middle of the 20th century. In the 1960s and 1970s, it decreased to 30–35%, but in the early 21st century, it increased again to 43%. The role of cats in infecting humans has been reliably traced since the late 19th century, and it has increased from 2 to 18% over the last 130 years. The epidemic value of foxes is cyclical. In the late 18th century, fox rabies in Russia was not known. People died from hydrophobia after fox bites in the early 19th century, but since 1825 cases of human hydrophobia due to contacts with foxes were no more recorded. Foxes again started infecting people only from the 1940s. In some years from the 1970s to the 1990s, foxes were the source of hydrophobia in 50–52% cases. In the 21st century, the role of foxes in human infection has decreased to 16%, but the value of that predator in animal infection increased to almost 50%. The wolf has infected people throughout the historical record. Before World War II, the epidemic value of the wolf reached 19%, but since the second half of the 20th century and in the 21st century, the death of people caused by wolf bites has varied within 2–7% cases. The raccoon dog started infecting people after World War II (0.4%). Its epidemic role has slowly increased and reached 11% in the 21st century. The corsak, the badger, the marten, the ferret, and the Arctic Fox rarely infect people, but they have participated in the epidemic process for at least 50 years, while the Arctic Fox has for 100 years. Over the territory of Russia, only two cases of human death have been recorded from hydrophobia after a bat bite, one in 1985 and the other in 2008. Cattle have infected humans throughout the observable past five centuries, but not too often, 0.3–2% cases. Small livestock, horses, and pigs have been extremely rare as an epidemic danger for at least the last 130 years. In Russia, people have never been infected with rabies received from insectivores, while that obtained from rodents has been recorded only three times: two from gophers and one from a squirrel. [ABSTRACT FROM AUTHOR]

Most animal ecology studies using remote sensing data have assessed how environmental characteristics shape animal abundance, distribution, or behavior. But the increasing availability of high-resolution data offers new opportunities to study how animals, in turn, shape ecosystems at diverse scales. We evaluate the efficacy of using Sentinel-2 satellite imagery to quantify the effects of Arctic fox (Vulpes lagopus) denning activity (nutrient accumulation, bioturbation) on vegetation. Using an imagery-derived metric (NDVI), we compared maximum plant productivity and plant phenology patterns on 84 Arctic fox dens vs. reference sites, i.e., points generated within preferred denning habitat areas (predicted from a habitat selection analysis). We show that high-resolution imagery can be used to measure the effects of Arctic fox denning activity on vegetation. Plant productivity and the rate of green up were both greater on fox dens compared to reference (preferred-habitat) sites. Productivity on reference sites was lower than average productivity on the tundra (i.e., random sites), indicating foxes primarily establish dens in low-productivity areas. Plant productivity on dens was also unrelated to recent occupancy patterns, indicating fox denning activity has long-term legacy effects on plants that last beyond the lifetime of foxes. Our findings support Arctic foxes being classified as ecosystem engineers in low-Arctic tundra ecosystems by converting low-productivity sites into relatively high-productivity sites through their denning activity. We demonstrate the efficacy of using remote sensing technologies to study how predators increase landscape heterogeneity and influence ecosystem dynamics through patch-scale mechanisms, and ultimately advance our understanding of animal functional roles. [ABSTRACT FROM AUTHOR]

Simple Summary: Global warming at the border of Late Pleistocene-Holocene, around ten thousand years ago caused a dramatic rearrangement of habitats in the Northern Hemisphere. Populations of cold-adapted megafauna species, which were spread over large areas of Eurasia, did not survive it. At the same time, small representatives of this mammoth fauna complex survived, including lemmings and arctic fox, but greatly reduced their distribution northward. However, it is uncertain whether species survived by habitat tracking the elusive tundra, or if they came from other places where they survived warming, and local populations died out without leaving descendants. To answer this, we studied ancient DNA from new fossil remains of arctic foxes from caves in the northern and polar Urals. The data received do not show any connectivity between ancient and modern individuals, supporting the hypothesis of local extinction of arctic fox in the region rather than the tracking habitat hypothesis. These findings are important in light of global climate warming expectations. It is predicted that the most severe effects are expected to occur in high-latitude biomes and the results obtained must be kept in mind when planning conservation policy measures. Despite the high level of interest, the population history of arctic foxes during the Late Pleistocene and Holocene remains poorly understood. Here we aimed to fill gaps in the demographic and colonization history of the arctic fox by analyzing new ancient DNA data from fossil specimens aged from 50 to 1 thousand years from the Northern and Polar Urals, historic DNA from museum specimens from the Novaya Zemlya Archipelago and the Taymyr Peninsula and supplementing these data by previously published sequences of recent and extinct arctic foxes from other regions. This dataset was used for reconstruction of a time-calibrated phylogeny and a temporal haplotype network covering four time intervals: Late Pleistocene (ranging from 30 to 13 thousand years bp), Holocene (ranging from 4 to 1 thousand years bp), historical (approximately 150 years), and modern. Our results revealed that Late Pleistocene specimens showed no genetic similarity to either modern or historical specimens, thus supporting the earlier hypothesis on local extinction rather than habitat tracking. [ABSTRACT FROM AUTHOR]

Bird species on islands are strongly impacted by biological invasions, with the Icelandic common eider (Somateria mollissima borealis) being particularly threatened. Down collection by local families in Breiðafjörður, West Iceland, provided long‐term datasets of nests from two archipelagos, covering 95 islands over 123 years and 39 islands over 27 years, respectively. Using these exceptional datasets, we found that the arrival of the invasive semi‐aquatic American mink (Neogale vison) was a more impactful driver of population dynamics than climate. This invasive predator heavily reduced eider nest numbers by ca. 60% in the Brokey archipelago. In contrast, we detected an apparently adaptive response to the return of the native fox in the Purkey archipelago, with dense nests on islands inaccessible to the fox and no apparent impact on eider populations. This difference might be due to the eiders lacking a joint evolutionary history with the mink and therefore lacking appropriate antipredator responses. [ABSTRACT FROM AUTHOR]

The North has experienced unprecedented rates of warming over the past few decades, impacting the survival and development of insects and the pathogens that they carry. Since 2019, Arctic foxes from Canada (Nunavut) have been observed with fur loss inconsistent with natural shedding of fur. Adult lice were collected from Arctic foxes from Nunavut (n = 1) and Svalbard (n = 2; Norway) and were identified as sucking lice (suborder Anoplura). Using conventional PCR targeting the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), lice from Canada and Svalbard were 100% similar (8 pooled samples from Nunavut and 3 pooled samples from Svalbard), indicating that there is potential gene flow between ectoparasites on Scandinavian and North American Arctic fox populations. The cox1 sequences of Arctic fox lice and dog sucking lice (Linognathus setosus) had significant differences (87% identity), suggesting that foxes may harbour a cryptic species that has not previously been recognised. Conventional PCR targeting the gltA gene for Bartonella bacteria amplified DNA from an unknown gammaproteobacteria from two pooled louse samples collected from Svalbard foxes. The amplified sequences were 100% identical to each other but were only 78% like Proteus mirabilis reported in GenBank (CP053614), suggesting that lice on Arctic foxes may carry unique microorganisms that have yet to be described. [ABSTRACT FROM AUTHOR]

Indirect interactions are widespread among prey species that share a common predator, but the underlying mechanisms driving these interactions are often unclear, and our ability to predict their outcome is limited.Changes in behavioural traits that impact predator space use could be a key proximal mechanism mediating indirect interactions, but there is little empirical evidence of the causes and consequences of such behavioural‐numerical response in multispecies systems.Here, we investigate the complex ecological relationships between seven prey species sharing a common predator. We used a path analysis approach on a comprehensive 9‐year data set simultaneously tracking predator space use, prey densities and prey mortality rate on key species of a simplified Arctic food web.We show that high availability of a clumped and spatially predictable prey (goose eggs) leads to a twofold reduction in predator (arctic fox) home range size, which increases local predator density and strongly decreases nest survival of an incidental prey (American golden plover). On the contrary, a scattered cyclic prey with potentially lower spatial predictability (lemming) had a weaker effect on fox space use and an overall positive impact on the survival of incidental prey.These contrasting effects underline the importance of studying behavioural responses of predators in multiprey systems and to explicitly integrate behavioural‐numerical responses in multispecies predator–prey models. [ABSTRACT FROM AUTHOR]

This paper discusses the distribution of terrestrial vertebrates in the northeastern part of the Kanin Peninsula (67°50′47″ N, 46°20′40″ E) based on the results of their census conducted in July 2021. In total, 1 amphibian species, 1 reptile species, 57 bird species, and 6 mammal species have been recorded. The following bird species have been recorded in the tundra zone of the Kanin Peninsula for the first time: tufted duck (Aythya fuligula L.), common eider (Somateria mollissima L.), pallid harrier (Circus macrourus S.G. Gmelin), and common sandpiper (Actitis hypoleucos L.). A distinct feature of the vertebrate fauna inhabiting this region located in the low-growing dwarf-birch tundra belt is the presence of boreal species, including common frog (Rana temporaria L.), viviparous lizard (Zootoca vivipara Lichtenstein), tufted duck, common goldeneye (Bucephala clangula L.), Eurasian crane (Grus grus L.), common sandpiper, brown bear (Ursus arctos L.), and European elk (Alces alces L). So far, this is the northernmost known habitat of the viviparous lizard. The following factors are favorable for the presence of boreal species in this area: its location on the southern slope of the plateaulike Kanin Kamen Ridge and ruggedness of its relief, including deep river valleys with well-heated slopes protected from winds. It is established that the spatial density of the Arctic fox (Alopex lagopus L.) brood burrows has decreased ten times when compared with the 1940–1950s due to the activation of cryogenic processes in permafrost that destroy the burrows dug by this predator in loose soils. [ABSTRACT FROM AUTHOR]

Demographic consequences of rapid environmental change and extreme climatic events (ECEs) can cascade across trophic levels with evolutionary implications that have rarely been explored. Here, we show how an ECE in high Arctic Svalbard triggered a trophic chain reaction, directly or indirectly affecting the demography of both overwintering and migratory vertebrates, ultimately inducing a shift in density-dependent phenotypic selection in migratory geese. A record-breaking rain-on-snow event and ice-locked pastures led to reindeer mass starvation and a population crash, followed by a period of low mortality and population recovery. This caused lagged, long-lasting reductions in reindeer carrion numbers and resultant low abundances of Arctic foxes, a scavenger on reindeer and predator of migratory birds. The associated decrease in Arctic fox predation of goose offspring allowed for a rapid increase in barnacle goose densities. As expected according to r- and K-selection theory, the goose body condition (affecting reproduction and post-fledging survival) maximising Malthusian fitness increased with this shift in population density. Thus, the winter ECE acting on reindeer and their scavenger, the Arctic fox, indirectly selected for higher body condition in migratory geese. This high Arctic study provides rare empirical evidence of links between ECEs, community dynamics and evolution, with implications for our understanding of indirect eco-evolutionary impacts of global change. [ABSTRACT FROM AUTHOR]

To gain better insight into the cascading impact of warming-induced changes in the physical landscape on biodiversity, it is crucial to establish stronger links between abiotic and ecological processes governing species distribution. Abiotic processes shaping the physical characteristics of the environment could significantly influence predator movements in the landscape and ultimately affect biodiversity through interspecific interactions. In the Arctic tundra, the main terrestrial predator (Arctic fox) avoids patches of wetlands composed of ponds with islets that can act as refuges for prey. Little is known about the geomorphological processes generating islets selected by prey species. Our study aimed to identify i) the physical characteristics of islets selected by Arctic-nesting birds and ii) the geomorphological processes generating islets available in the landscape. Over two breeding seasons, we determined the occurrence of nesting birds (Glaucous gull, Cackling goose, Red-throated loon) on islets (N=396) found over a 150 km2 area on Bylot Island (Nunavut, Canada). Occupied islets were located further away from the shore (10.6 m ± 7.3 vs 7.4 m ± 6.8) and surrounded by deeper water (33.6 cm ± 10.6 vs 28.1 cm ± 11.5). As expected, all three bird species selected islets less accessible to Arctic foxes, with nesting occurrence increasing (linearly or nonlinearly) with distance to shore and/or water depth around islets. Based on high-resolution satellite image and field observations, we found that ice-wedge polygon degradation generated the majority of islets (71 %) found in the landscape. Those islets were on average farther from the shore and surrounded by deeper water than those generated by other processes. As polygon degradation is projected to accelerate in response to warming, new refuges will likely emerge in the Arctic landscape, but current refuges could also disappear. Changes in the rate of polygon degradation may thus affect Arctic tundra biodiversity by altering predator-prey interactions. [ABSTRACT FROM AUTHOR]

The long-term dynamics of predator populations may be driven by fluctuations in resource availability and reflect ecosystem changes such as those induced by climate change. The Icelandic Arctic fox (Vulpes lagopus) population has known major fluctuations in size since the 1950s. Using stable isotopes analysis of bone collagen over a long-time series (1979–2018), we aimed at identifying the main resources used by Icelandic Arctic foxes during periods of growth and decline to assess if the variations in their population size are linked to fluctuations in the availability of resources. We hypothesized that (1) the decline in Seabird abundance was responsible for the decrease in the fox population; and (2) that the growth in the fox population combined to fluctuations in main resources would lead to an increase in intra-specific competition, ultimately leading to variations in their isotopic niches at the population scale. The isotopic composition of Arctic fox bones differed clearly between inland and coast. Stable isotopes mixing models suggested that marine resources and rock ptarmigans were the most important food source and highlighted a rather stable diet in coastal habitats compared to inland habitats where more fluctuations in dietary composition were observed. Coastal foxes had a broader niche than inland foxes, and there was more variation in niche size in the inland habitat. Our results tend to confirm that a general decline in seabird populations drove the decline in Arctic foxes, especially in coastal habitats. For the inland foxes, our results suggest that the lack of marine resources might have led to an increased use of ptarmigans especially during the most recent period. [ABSTRACT FROM AUTHOR]

Correct material identification is considered essential when documenting museum objects. This study examines the morphology of mammal hair and records the geographical use of common species in Inuit fur clothing collected by the National Museum of Denmark (NMD) from c. 1830–1940 in the Bering Strait region, Alaska, Arctic Canada, and Greenland. Through hair microscopy, the purpose is to test whether original identifications are correct to assess the origin of unique Inuit garments. By means of transmitted light microscopy (TLM) of stained, 1 µm thick cross-sectioned hairs and undyed, longitudinally mounted hairs, the research reveals that specific morphological structures are characteristic of the common native reindeer/caribou, musk ox, members of the seal family, domestic dog, wolf, Arctic fox, polar bear, and wolverine. Rarer animals (hare, lynx, otter, etc.) are not part of this study because of limitations in the collection. Hairs from seal species are difficult to distinguish from one another. Hairs from dog and wolf are distinguishable but have relatively similar morphology. Therefore, to confirm identification, supplementary analyses are required. The hair microscopy technique was used on 49 garments in NMD's collections, and the results were compared to the original macroscopic species identification. The study revealed that the latter method is often erroneous when it comes to dog/wolf and wolverine fur. [ABSTRACT FROM AUTHOR]

Between 24 June and 1 September 2023, highly pathogenic avian influenza (HPAI) A(H5) outbreaks were reported in domestic (25) and wild (482) birds across 21 countries in Europe. Most of these outbreaks appeared to be clustered along coastlines with only few HPAI virus detections inland. In poultry, all HPAI outbreaks were primary and sporadic with most of them occurring in the United Kingdom. In wild birds, colony‐breeding seabirds continued to be most heavily affected, but an increasing number of HPAI virus detections in waterfowl is expected in the coming weeks. The current epidemic in wild birds has already surpassed the one of the previous epidemiological year in terms of total number of HPAI virus detections. As regards mammals, A(H5N1) virus was identified in 26 fur animal farms in Finland. Affected species included American mink, red and Arctic fox, and common raccoon dog. The most likely source of introduction was contact with gulls. Wild mammals continued to be affected worldwide, mostly red foxes and different seal species. Since the last report and as of 28 September 2023, two A(H5N1) clade 2.3.4.4b virus detections in humans have been reported by the United Kingdom, and three human infections with A(H5N6) and two with A(H9N2) were reported from China, respectively. No human infection related to the avian influenza detections in animals on fur farms in Finland or in cats in Poland have been reported, and human infections with avian influenza remain a rare event. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA. The risk of infection remains low to moderate for occupationally or otherwise exposed people to infected birds or mammals (wild or domesticated); this assessment covers different situations that depend on the level of exposure. [ABSTRACT FROM AUTHOR]

Background: Range expansion of species, a major consequence of climate changes, may alter communities substantially due to competition between expanding and native species. Methods: We first quantified size differences between an expanding habitat generalist, the red fox (Vulpes vulpes), and a circumpolar habitat specialist, the Arctic foxes (Vulpes lagopus), at the edge of the Arctic, where climate-related changes occur rapidly, to predict the likelihood of the larger competitor escalating interference to intraguild killing. We then used satellite telemetry to evaluate competition in a heterogeneous landscape by examining space use early during the foxes' reproductive period, when resource scarcity, increased-food requirements and spatial constraints likely exacerbate the potential for interference. We used time-LoCoH to quantify space and habitat use, and Minta's index to quantify spatio-temporal interactions between neighbors. Results: Our morphometric comparison involving 236 foxes found that the potential for escalated interference between these species was high due to intermediate size difference. However, our results from 17 collared foxes suggested that expanding and native competitors may coexist when expanding species occur at low densities. Low home-range overlap between neighbors suggested territoriality and substantial exploitation competition for space. No obvious differential use of areas shared by heterospecific neighbors suggested low interference. If anything, intraspecific competition between red foxes may be stronger than interspecific competition. Red and Arctic foxes used habitat differentially, with near-exclusive use of forest patches by red foxes and marine habitats by Arctic foxes. Conclusion: Heterogeneous landscapes may relax interspecific competition between expanding and native species, allowing exclusive use of some resources. Furthermore, the scarcity of habitats favored by expanding species may emphasize intraspecific competition between newcomers over interspecific competition, thus creating the potential for self-limitation of expanding populations. Dominant expanding competitors may benefit from interference, but usually lack adaptations to abiotic conditions at their expansion front, favoring rear-edge subordinate species in exploitation competition. However, due to ongoing climate change, systems are usually not at equilibrium. A spread of habitats and resources favorable to expanding species may promote higher densities of antagonistically dominant newcomers, which may lead to extirpation of native species. [ABSTRACT FROM AUTHOR]

Mesocestoides canislagopodis is a common parasite of the arctic fox (Vulpes lagopus) in Iceland. In the past, household dogs (Canis familiaris) and cats (Felis catus) were also reported in Iceland to be infected. Recently, scolices of a non-maturing Mesocestoides sp. were detected in the intestines of the gyrfalcon (Falco rusticolus), and tetrathyridia were isolated in the body cavity of rock ptarmigan (Lagopus muta) and subsequently described. All stages were confirmed, using both morphological and molecular methods, to belong to the same species, M. canislagopodis. In the present study, post-mortem examination of wood mice (Apodemus sylvaticus), sampled in autumn 2014 on a farm in Northeast Iceland, revealed the presence of tetrathyridia in the peritoneal cavity and in the liver. Most tetrathyridia in the peritoneal cavity were free, but some were encapsulated in a thin connective tissue stroma and loosely attached to the inner organs. They appear as whitish, heart-shaped, flattened, unsegmented bodies with a slightly pointed posterior end. In the liver, tetrathyridia were seen as pale-tanned nodules embedded in the parenchyma. Comparative molecular analysis, both at the generic level (D1 domain LSU ribosomal DNA), and at the specific level (cytochrome c oxidase subunit I (cox1) and 12S mitochondrial DNA), revealed that the tetrathyridia belonged to M. canislagopodis. A. sylvaticus represents a new second intermediate host record in Iceland, and the first description of a rodent as intermediate host for this species, thus participating in the life cycle of the parasite. [ABSTRACT FROM AUTHOR]

Egg predation is the primary cause of nest failure for tundra nesting birds. Taverner's Cackling Geese (Branta hutchinsii taverneri) breeding on the North Slope of Alaska have increased approximately 5-fold over the last 25 years and are now one of the most encountered waterbird species breeding at our study site on the coastal plain of Arctic National Wildlife Refuge. This rapid population growth may offer a new food resource for egg predators, impacting predator populations, which in turn could have cascading effects for other tundra nesting bird species, many of which are declining. To determine how the population growth of geese may affect the nest-predator community, and to establish a baseline of predators as the area is impacted by climate change and development, we used digital time-lapse cameras to record predation events at Cackling Goose nests. We determined fate for 52 nests in 2017, 2019, and 2021, of which 20 were depredated. The most frequent predator differed each year. Red foxes (Vulpes vulpes) were responsible for 89% of depredations in 2017 and wolverines (Gulo gulo) for 67% in 2019, and those species only depredated nests in those single years. In contrast, Arctic foxes (Vulpes lagopus) were responsible for nest failure in all years, but did not exceed 40% of total depredations in any year. Golden Eagles (Aquila chrysaetos) were an unexpected egg predator, depredating 2 nests. Our results were notably different than work on other Arctic goose species, where Arctic foxes were the primary predator. The inter-annual variability of egg predators at this Arctic Refuge study site provides insights into complex predator–prey interactions on the Arctic Coastal Plain. La depredación de huevos es la causa primaria del fracaso de nido para aves que anidan en la tundra. El ganso Branta hutchinsii taverneri, que se reproduce en la pendiente Norte de Alaska ha quintuplicado su presencia en los últimos 25 años y ahora es una de las especies acuáticas en reproducción más observadas en nuestro sitio de estudio en la planicie costera del Arctic National Wildlife Refuge. Este crecimiento poblacional acelerado puede ofrecer una nueva fuente de alimentación para depredadores de huevos, impactando las poblaciones de depredadores, que podría tener efectos en cascada en otras especies de aves que anidan en la tundra, muchas en declive. Para determinar cómo el crecimiento poblacional de gansos puede afectar la comunidad de depredadores de nidos y establecer una línea base de depredadores en un área que es impactada por el cambio climático y el desarrollo, usamos cámaras digitales con temporizador automático para registrar eventos de depredación en nidos de ganso Branta hutchinsii. Determinamos el destino de 52 nidos en 2017, 2019 y 2021, de los cuales 20 fueron depredados. El depredador más frecuente varió cada año. Los zorros rojos (Vulpes vulpes) fueron responsables del 89% de las depredaciones en el 2017, mientras que los glotones (Gulo gulo) lo fueron del 67% en el 2019, y esas especies solo depredaron nidos en esos años. En contraste, el zorro artico (Vulpes lagopus) fue responsable de fracaso de anidación durante todos los años, pero su cuota de depredación no excedió el 40% en ninguno de los años. El águila real (Aquila chrysaetos) fue un depredador inesperado, depredando 2 nidos. Nuestros resultados fueron notablemente diferentes que otros estudios con otras especies de gansos silvestres del Artico, donde los zorros articos fueron los depredadores primarios. La variación interanual de depredadores de huevos en este sitio de estudio en el Refugio Artico proporciona información en interacciones complejas depredador-presa en la Planicie Costera Artica. Palabras clave: cámaras para vida silvestre, depredador de huevos, ganso Branta hutchinsii taverneri, gansos de anidación artica, Planicie Costera Artica. [ABSTRACT FROM AUTHOR]

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Introduction: Animal trade favors the spreading of emerging canine adenovirus 1 (CAdV-1) in mink. Because the 100K protein is not exposed to the viral surface at any stage, it can be used to differentiate the vaccine from wild virus infection. However, no related research has been conducted. This study aimed to find evidence of CAdV-1 in mink and predict the character of the 100K protein in the current circulating CAdV-1 strain of mink. Method: In this experiment, the identification of CAdV-1, the phylogenetic tree, homology, and bioinformatics analysis of 100K were conducted. Results: The results showed that the CAdV-1 was identified in the mink and that its Fiber was located in a separate branch. It was closely related to strains isolated from Norwegian Arctic fox and Red fox. 100K was located in a separate branch, which had the closest genetic relationship with skunks, porcupines, raccoons, and hedgehogs and a far genetic relationship with the strains in dogs. 100K protein is an unstable and hydrophobic protein. It had evidence of selective pressure and recombination, 1 glycosylation site, 48 phosphorylation sites, 60 dominant B cell epitopes, and 9 peptides of MHC-I and MHC-II. Its subcellular localization was mainly in the endoplasmic reticulum and mitochondria. The binding sites of 100K proteins were DBP proteins and 33K proteins. Discussion: The stains in the mink were different from fox. The exploration of its genomic characteristics will provide us with a deeper understanding of the prevention of canine adenovirus. [ABSTRACT FROM AUTHOR]

The strength of indirect biotic interactions is difficult to quantify in the wild and can alter community composition. To investigate whether the presence of a prey species affects the population growth rate of another prey species, we quantified predator-mediated interaction strength using a multi-prey mechanistic model of predation and a population matrix model. Models were parametrized using behavioural, demographic and experimental data from a vertebrate community that includes the arctic fox (Vulpes lagopus), a predator feeding on lemmings and eggs of various species such as sandpipers and geese. We show that the positive effects of the goose colony on sandpiper nesting success (due to reduction of search time for sandpiper nests) were outweighed by the negative effect of an increase in fox density. The fox numerical response was driven by changes in home range size. As a result, the net interaction from the presence of geese was negative and could lead to local exclusion of sandpipers. Our study provides a rare empirically based model that integrates mechanistic multi-species functional responses and behavioural processes underlying the predator numerical response. This is an important step forward in our ability to quantify the consequences of predation for community structure and dynamics. [ABSTRACT FROM AUTHOR]