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Abstract Predation shapes communities through consumptive and non‐consumptive effects. In the latter case, prey respond to perceived predation risk through proactive or reactive risk management strategies occurring at different spatial and temporal scales. The predator–prey space race and landscape of fear concepts are useful to better understand how predation risk affects prey behavioral decisions and distribution. We assessed predation risk effects in a terrestrial Arctic community, where the arctic fox is the main predator of ground‐nesting birds. Using high‐frequency GPS data, we estimated a predator activity landscape corresponding to fox space use patterns and validated with an artificial prey experiment that this predator activity landscape correlated with the predation risk landscape. We then investigated the effects of the fox activity landscape on multiple prey species, by assessing the anti‐predator behavior of a main prey (snow goose) actively searched for by foxes, and the nest distribution of several incidental prey species. We first found that snow geese showed a stronger level of nest defense in areas highly used by foxes, possibly responding with a reactive strategy to variation in predation risk. Then, nests of incidental prey reproducing in habitats easily accessed by foxes had a lower probability of occurrence in areas highly used by foxes, suggesting these birds may use a proactive risk management strategy by shifting their distribution away from risky areas. For incidental prey species nesting in microhabitat refuges difficult to access by foxes, probability of nest occurrence was independent of predation risk in the surrounding area, as they avoid risk at a finer spatial scale. By tracking all individuals of the dominant predator species in our study area, we demonstrated the value of using predator space use patterns to infer spatial variation in predation risk. Overall, we highlight the diversity of risk management strategies in prey sharing a common predator, hence refining our understanding of the mechanisms driving species distribution and community structure.

Tularemia is a zoonotic disease found throughout most of the northern hemisphere that may experience range expansion with warming temperatures. Rodents and lagomorphs are reservoirs for the disease, and outbreaks of tularemia often follow peaks in their abundance. As small mammals dominate the diet of arctic foxes (Vulpes lagopus), we determined whether they may serve as sentinels by identifying antibodies in live-captured and harvested foxes from northern Canada. Overall seroprevalence was 2% (CI95 1–2%) in 176 foxes harvested in 2018–2019 compared to 17% (CI95 12–22%) of 230 foxes captured live in 2011–2021. Prevalence was at an all-time high in 2018, following a peak in vole abundance in 2017. Antibodies were identified in fox pups born in 2018 and 2019, suggesting that F. tularensis was actively transmitted during the summers. High precipitation during the summer, increased snow cover and colder temperatures in May, and a higher abundance of voles were all associated with increased seroprevalence in live-captured foxes. Thus, exposure to F. tularensis is largely mediated through climate and rodent populations in the Canadian Arctic, and arctic foxes are useful sentinels for F. tularensis in northern ecosystems. Further studies should investigate whether infection impacts arctic fox survival and reproductive success in the circumpolar North.

This document is a collection of book reviews and short notices from the Journal of the Australian Early Medieval Association. The reviews cover a range of topics, including hagiography, power and authority in late antique and medieval contexts, and animal-human relationships in medieval Iceland. The reviews provide insights into the scholarly contributions of each book and highlight their relevance to specific research areas. The collection offers diverse perspectives and explores various cultural and linguistic contexts, making it a valuable resource for researchers in these fields. [Extracted from the article]

Background: Biologging now allows detailed recording of animal movement, thus informing behavioural ecology in ways unthinkable just a few years ago. In particular, combining GPS and accelerometry allows spatially explicit tracking of various behaviours, including predation events in large terrestrial mammalian predators. Specifically, identification of location clusters resulting from prey handling allows efficient location of killing events. For small predators with short prey handling times, however, identifying predation events through technology remains unresolved. We propose that a promising avenue emerges when specific foraging behaviours generate diagnostic acceleration patterns. One such example is the caching behaviour of the arctic fox (Vulpes lagopus), an active hunting predator strongly relying on food storage when living in proximity to bird colonies. Methods: We equipped 16 Arctic foxes from Bylot Island (Nunavut, Canada) with GPS and accelerometers, yielding 23 fox-summers of movement data. Accelerometers recorded tri-axial acceleration at 50 Hz while we obtained a sample of simultaneous video recordings of fox behaviour. Multiple supervised machine learning algorithms were tested to classify accelerometry data into 4 behaviours: motionless, running, walking and digging, the latter being associated with food caching. Finally, we assessed the spatio-temporal concordance of fox digging and greater snow goose (Anser caerulescens antlanticus) nesting, to test the ecological relevance of our behavioural classification in a well-known study system dominated by top-down trophic interactions. Results: The random forest model yielded the best behavioural classification, with accuracies for each behaviour over 96%. Overall, arctic foxes spent 49% of the time motionless, 34% running, 9% walking, and 8% digging. The probability of digging increased with goose nest density and this result held during both goose egg incubation and brooding periods. Conclusions: Accelerometry combined with GPS allowed us to track across space and time a critical foraging behaviour from a small active hunting predator, informing on spatio-temporal distribution of predation risk in an Arctic vertebrate community. Our study opens new possibilities for assessing the foraging behaviour of terrestrial predators, a key step to disentangle the subtle mechanisms structuring many predator–prey interactions and trophic networks. [ABSTRACT FROM AUTHOR]

Objective. To analyze the presence of melanin and to assess the frequency of pigmented pineal glands (PG) in dogs of different age groups. Material and methods. Studies were performed on racoon dogs (Nyctereutes procyonoides Grey), foxes (Vulpes L.), and Arctic foxes (V. lagopus L.). PG pigmentation was assessed visually in immature or juvenile (6–8 months) and mature (1.5–3.5 years) female animals of each species and the proportions (%) of pigmented and nonpigmented glands were determined. The numbers of immature and adult animals of each species were as follows: racoon dogs (n = 4, n = 15), foxes (n = 15, n = 28), and Arctic foxes (n = 4, n = 14, respectively). The morphological characteristics of the PG were studied using histological methods on sections stained with eosin and by the Fontana–Masson method. Results. The PG of the study species showed accumulations of the pigment melanin both at the periphery of the gland and around blood vessels. A high level of variability in gland pigmentation was noted visually, from unpigmented to intensely pigmented. The frequency of pigmented glands was influenced by age and species. In racoon dogs, pigmented PG were seen only in immature individuals (25%), while in foxes only in adults (21.4%). In Arctic foxes, pigmented PG were characteristic of both age groups, though the proportion decreased with age (from 21.4% to 7.1%). Conclusions. Extensive variability was seen in the extent of PG pigmentation in canids. Pigmented PG frequencies were species-specific and age-dependent. [ABSTRACT FROM AUTHOR]

Patterns of local adaptation can emerge in response to the selective pressures diseases exert on host populations as reflected in increased frequencies of respective, advantageous genotypes. Elucidating patterns of local adaptation enhance our understanding of mechanisms of disease spread and the capacity for species to adapt in context of rapidly changing environments such as the Arctic. Arctic rabies is a lethal disease that largely persists in northern climates and overlaps with the distribution of its natural host, arctic fox. Arctic fox populations display little neutral genetic structure across their North American range, whereas phylogenetically unique arctic rabies variants are restricted in their geographic distributions. It remains unknown if arctic rabies variants impose differential selection upon host populations, nor what role different rabies variants play in the maintenance and spread of this disease. Using a targeted, genotyping-by-sequencing assay, we assessed correlations of arctic fox immunogenetic variation with arctic rabies variants to gain further insight into the epidemiology of this disease. Corroborating past research, we found no neutral genetic structure between sampled regions, but did find moderate immunogenetic structuring between foxes predominated by different arctic rabies variants. FST outliers associated with host immunogenetic structure included SNPs within interleukin and Toll-like receptor coding regions (IL12B, IL5, TLR3 and NFKB1); genes known to mediate host responses to rabies. While these data do not necessarily reflect causation, nor a direct link to arctic rabies, the contrasting genetic structure of immunologically associated candidate genes with neutral loci is suggestive of differential selection and patterns of local adaptation in this system. These data are somewhat unexpected given the long-lived nature and dispersal capacities of arctic fox; traits expected to undermine local adaptation. Overall, these data contribute to our understanding of the co-evolutionary relationships between arctic rabies and their primary host and provide data relevant to the management of this disease. [ABSTRACT FROM AUTHOR]

The silver fox and blue fox are economically important fur species and were domesticated by humans from their wild counterparts, the arctic fox and red fox, respectively. Farmed foxes show obvious differences from their wild counterparts, including differences in physiology, body size, energy metabolism, and immunity. However, the molecular mechanisms underlying these differences are presently unclear. In this study, we built transcriptome libraries from multiple pooled tissues for each species of farmed fox, used RNA‐seq to obtain a comprehensive dataset, and performed selection analysis and sequence‐level analyses of orthologous genes to identify the genes that may be influenced by human domestication. More than 153.3, 248.0, 81.6, and 65.8 million clean reads were obtained and assembled into a total of 118,577, 401,520, 79,900, and 186,988 unigenes with an average length range from 521 to 667 bp for AF, BF, RF, and SF, respectively. Selective pressure analysis showed that 11 and 14 positively selected genes were identified, respectively, in the two groups (AF vs. BF and RF vs. SF). Several of these genes were associated with natural immunity (CFI and LRRFIP1), protein synthesis (GOLGA4, CEP19 and SLC35A2), and DNA damage repair (MDC1). Further functional enrichment analyses demonstrated that two positively selected genes (ACO1 and ACAD10) were involved in metabolic process (GO:0008152, p‐value =.032), representing a significant enrichment. Sequence analysis of 117 orthologous genes shared by the two groups showed that the LEMD2, RRBP1, and IGBP1 genes might be affected by artificial selection in farmed foxes, with mutation sites located within sequences that are otherwise highly conserved across most mammals. Our results provide a valuable transcriptomic resource for future genetic studies and improvement in the assisted breeding of foxes and other farmed animals. [ABSTRACT FROM AUTHOR]

Despite the availability of ever more data on population trends in Arctic waders, we still have limited insight into the factors influencing reproductive success and its resulting contribution to population trajectories. Here, we present data from Zackenberg in high Arctic Greenland that show no changes in timing of egg laying nor clutch size over more than two decades. With variation among species, we found earlier egg laying in seasons with earlier snowmelt, more invertebrates during the pre-laying period, earlier appearance of invertebrates and higher June temperatures. In addition, we found larger clutch sizes with earlier snowmelt, and lower clutch sizes with later nest initiation dates, together with increasing variability in clutch size during the study years in one species. Nest success was lower in late breeding seasons but seemed to increase with season progress, while nest success was much lower during the lasts 18 years of the study period than during the first part of the period. The reason for this could be both increased Arctic fox activity on the tundra and increased researcher activity at nests, which leaves olfactory clues for the foxes. Numbers of juvenile Dunlins produced seem to be negatively correlated with our index of fox activity on the tundra during nesting and fledging, whereas we found no correlations between fox activity and lemming abundance. The effects of severe events in a number of years are described, including a next to non-breeding year in 2018. Our study adds to our understanding that the Arctic is not a homogeneous biome but may show quite different regional patterns of climate change effects. [ABSTRACT FROM AUTHOR]

Measuring fecal glucocorticoid metabolites (fGCMs) is a widely used, non-invasive method for studies of stress in vertebrates. To study physiological responses in wild Arctic foxes (Vulpes lagopus) to perceived stressors such as fluctuating food availability, occurrence of competitors and predators and disturbance from human activities, a species-specific physiological validation of a method to evaluate adrenocortical activity is needed. Here we used 15 captive Arctic foxes (both males and females and juveniles and adults) to investigate fGCM concentrations following ACTH injection (physiological validation), or handling alone and compared them with their respective baseline concentrations prior to the treatments. A 5α-pregnane-3ß,11ß,21-triol-20-one enzyme immunoassay measured significant fGCM increases following both treatments. The time lags to reach peak fGCM values were 9.3 ± 1.3 h and 12.8 ± 1.7 h for ACTH and handling treatment, respectively. Concentrations of fGCMs varied a lot between individuals, but not attributed to sex nor age of the foxes. However, we found a negative relationship between boldness and fGCM concentrations. Faecal glucocorticoid metabolites concentrations did not change significantly over a period of 48 h in samples kept at temperatures reflecting winter and summer means. This would allow the collection of samples up to two days old in the wild regardless of the season. We conclude that our successfully validated method for measuring fGCMs can be used as a non-invasive tool for studies exploring various stressors both in wild and captive Arctic foxes. [ABSTRACT FROM AUTHOR]

Genome-wide association studies provide good opportunities for studying the genetic basis of adaptive traits in wild populations. Yet, previous studies often failed to identify major effect genes. In this study, we used high-density single nucleotide polymorphism and individual fitness data from a wild non-model species. Using a whole-genome approach, we identified the MC1R gene as the sole causal gene underlying Arctic fox Vulpes lagopus fur colour. Further, we showed the adaptive importance of fur colour genotypes through measures of fitness that link ecological and evolutionary processes. We found a tendency for blue foxes that are heterozygous at the fur colour locus to have higher fitness than homozygous white foxes. The effect of genotype on fitness was independent of winter duration but varied with prey availability, with the strongest effect in years of increasing rodent populations. MC1R is located in a genomic region with high gene density, and we discuss the potential for indirect selection through linkage and pleiotropy. Our study shows that whole-genome analyses can be successfully applied to wild species and identify major effect genes underlying adaptive traits. Furthermore, we show how this approach can be used to identify knowledge gaps in our understanding of interactions between ecology and evolution. [ABSTRACT FROM AUTHOR]

Aim: The Arctic is one of the planet's most rapidly warming regions, with trends expected to intensify in the future. Projections of shifts in species distributional ranges under future climate change are thus far lacking for most vertebrate species using the Arctic tundra. Our aim was to assess possible climate‐induced changes in distributional ranges and inter‐specific overlap of an Arctic species assemblage within the world's largest land‐based protected area. Location: During 1979–2013 location data of eight Arctic birds and mammals, Arctic fox (Vulpes lagopus), Arctic hare (Lepus arcticus), Arctic wolf (Canis lupus arctos), muskox (Ovibos moschatus), polar bear (Ursus maritimus), rock ptarmigan (Lagopus muta), snow bunting (Plectrophenax nivalis) and snowy owl (Bubo scandiacus) were collected in the Northeast Greenland National Park. Methods: The maximum entropy (MaxEnt) algorithm and Schoener's D niche overlap index were used to assess shifts and changes in overlap of species‐specific distributions under recent (1979–2013) and future (2061–2080; representative concentration pathways [RCPs] 2.6, 4.5 and 8.5) bioclimatic conditions. Results: Species distributions were projected to shift northward and upwards across all scenarios, and at higher rates than previously reported. Future distributions were also forecasted to become spatially less clustered and to expand in size for all species. Species‐specific shifts in distribution ranges altered inter‐specific overlap, most notably by an increase in overlap under scenario RCP 8.5. Main conclusions: The rapid shifts in distribution ranges detected here underline that climate change impacts are most pronounced in areas with higher levels of warming, leading to accelerated shifts in species' ranges towards the poles. However, the concomitant range expansions we found may suggest that future climatic conditions in north‐east Greenland may not have such a detrimental impact on the distribution of cold‐adapted species as generally expected, at least in the near future. [ABSTRACT FROM AUTHOR]

Rabies occurs throughout the Arctic, representing an ongoing public health concern for residents of northern communities. The Arctic fox (Vulpes lagopus) is the main reservoir of the Arctic rabies virus variant, yet little is known about the epidemiology of Arctic rabies, such as the ecological mechanisms driving where and when epizootics in fox populations occur. In this study, we provide the first portrait of the spatio‐temporal spread of rabies across northern Canada. We also explore the impact of seasonal and multiannual dynamics in Arctic fox populations and climatic factors on rabies transmission dynamics. We analysed data on rabies cases collected through passive surveillance systems in the Yukon, Northwest Territories, Nunavut, Nunavik and Labrador from 1953 to 2014. In addition, we analysed a large and unique database of trapped foxes tested for rabies in the Northwest Territories and Nunavut from 1974 to 1984 as part of active surveillance studies. Rabies cases occurred in all Arctic regions of Canada and were relatively synchronous among foxes and dogs (Canis familiaris). This study highlights the spread of Arctic rabies virus variant across northern Canada, with contrasting rabies dynamics between different yet connected areas. Population fluctuations of Arctic fox populations could drive rabies transmission dynamics in a complex way across northern Canada. Furthermore, this study suggests different impacts of climate and sea ice cover on the onset of rabies epizootics in northern Canada. These results lay the groundwork for the development of epidemiological models to better predict the spatio‐temporal dynamics of rabies occurrence in both wild and domestic carnivores, leading to better estimates of human exposure and transmission risk. [ABSTRACT FROM AUTHOR]

The rapidly growing interest for nature-based recreational activities threaten biodiversity values and increases the disturbance caused to wildlife. Several studies have demonstrated spatial and temporal activity shifts of animals in response to human disturbance. However, most studies investigate effects on how animals use an area of high tourism disturbance, such as a tourist resort or hiking trail, and not the effects of human disturbance at a key site for the animal, such as a denning or breeding site. In this study, we use photos from remote camera monitoring of arctic fox (Vulpes lagopus) dens with the aim to investigate the effects of various levels of tourism disturbance on the diurnal activity pattern and vigilance of breeding adult arctic foxes at the den site. We find a temporal shift towards a higher daytime activity at the den in response to high intensity tourism (71 ± 3.9% in disturbed areas compared with 53 ± 6.2% in undisturbed areas), which stands in contrast to an increased nocturnality seen in studies of many other species, including another study of arctic foxes. We suggest that the difference could be explained by the higher cost of avoiding a key site for the animal, as in this study, compared with avoiding a more general human disturbance in an area within the distribution range of the animal, as in most other studies. Increased time spent avoiding the perceived threat of humans could compromise other important activities and have potential negative effects on e.g. hunting or provisioning for the juveniles. Human disturbance focused at a key site, such as a denning or breeding site, can thereby be expected to have larger consequences than what is observed in most studies of disturbance effects on wildlife. Based on observations of both tourists and arctic foxes during close encounters in an area of high intensity tourism, we also find that they both respond behaviorally to each other. The potential for positive or negative feedback mechanisms in such relationships between tourists and wildlife highlights the importance of considering both sides of the complex interaction to find a balance between preserving biodiversity and ensuring continued possibilities for recreation.

Abstract Climate change has different and sometimes divergent effects on terrestrial and marine food webs, and in coastal ecosystems, these effects are tightly interlinked. Responses of opportunistic coastal predators and scavengers to climate change may thus be complex and potentially highly flexible, and can simultaneously serve as indicators of, and have profound impacts on, lower trophic levels. Gaining mechanistic understanding of these responses is therefore important, but often not feasible due to lack of long‐term data from marked individuals. Here, we used a Bayesian integrated population model (IPM) to elucidate the effects of arctic warming and concurrent changes in terrestrial and marine resource availability on population dynamics of the opportunistic arctic fox (Vulpes lagopus) in Svalbard. Joint analysis of four types of data (den survey, age‐at‐harvest, placental scars, mark‐recovery) revealed relatively stable population size and age structure over the last 22 yr (1997–2019) despite rapid environmental change linked to climate warming. This was related to the fact that terrestrial resources (reindeer carcasses, geese) became more abundant while the availability of marine resources (seal pups/carrion) decreased, and was driven by divergent trends in different vital rates (e.g., increased pregnancy rate but decreased pup survival). Balanced contributions of survival vs. reproduction and of immigration vs. local demography further stabilized population size. Our study thus sheds light on the mechanisms underlying population dynamics of opportunistic carnivores exploiting terrestrial and marine resources and suggests that exploitation of resources across different ecosystems can buffer predators against climate change. Additionally, it highlights the large potential of IPMs as tools to understand and predict the effects of environmental change on wildlife populations, even when data on marked individuals are sparse.

Canine circovirus (canineCV) has been found to be associated with vasculitis, hemorrhage, hemorrhagic enteritis, and diarrhea of canines. CanineCV, like other circoviruses, may also be associated with lymphoid depletion and immunosuppression. This circovirus has been detected worldwide in different countries and species. Recombination and mutation events in the canineCV genome have been described, indicating that the virus is continuing to evolve. However, the origin, codon usage patterns, and host adaptation of canineCV remain to be studied. Here, the coding sequences of 93 canineCV sequences available in the GenBank database were used for analysis. The results showed that canineCV sequences could be classified into five genotypes, as confirmed by phylogenetic and principal component analysis (PCA). Maximum clade credibility (MCC) and maximum-likelihood (ML) trees suggested that canineCV originated from bat circovirus. G/T and A/C nucleotide biases were observed in ORF1 and ORF2, respectively, and a low codon usage bias (CUB) was found in canineCV using an effective number of codon (ENC) analysis. Correlation analysis, ENC plot analysis and neutrality plot analysis indicated that the codon usage pattern was mainly shaped by natural selection. Codon adaptation index (CAI) analysis, relative codon deoptimization index (RCDI) analysis, and similarity index (SiD) analysis revealed a better adaption to Vulpes vulpes than to Canis familiaris. Furthermore, a cross-species transmission hypothesis that canineCV may have evolved from bats (origin analysis) and subsequently adapted to wolves, arctic foxes, dogs, and red foxes, was proposed. This study contributes to our understanding of the factors related to canineCV evolution and host adaption. [ABSTRACT FROM AUTHOR]

Indirect effects resulting from species sharing the same enemy can shape spatio‐temporal variations in species occurrence. The strength of such effects remains poorly known in natural communities composed of species from different trophic levels interacting in heterogeneous landscapes. Benefiting from a well‐known arctic vertebrate community and marked spatio‐temporal variations in the density of key prey species, we examined the effects of direct predator‐prey and indirect predator‐mediated effects on species occurrence in the landscape. We found both positive effects of one prey (lemmings), as well as negative indirect effects of another prey (colonial nesting snow geese) on the occurrence of species (ground‐nesting birds) belonging to different guilds and trophic levels but sharing a common predator (arctic fox). However, species using prey refuges available in the landscape were not or less affected by predator‐mediated effects. Similarly, the smallest (a passerine) and the largest and most dangerous species (an owl) for the shared predator were not affected by these effects. Our study provides one of the rare empirical evidence of predator‐mediated effects ascending the food web (i.e. negative indirect effect of an herbivore on avian predators) and underlines how habitat structure and species traits can modulate the strength of indirect effects in natural communities. [ABSTRACT FROM AUTHOR]

The Arctic fox (Vulpes lagopus) is the only fox species occurring in the Arctic and has adapted to its extreme climatic conditions. Currently, the molecular basis of its adaptation to the extreme climate has not been characterized. Here, we applied PacBio sequencing and chromosome structure capture technique to assemble the first V. lagopus genome assembly, which is assembled into chromosome fragments. The genome assembly has a total length of 2.345 Gb with a contig N50 of 31.848 Mb and a scaffold N50 of 131.537 Mb, consisting of 25 pseudochromosomal scaffolds. The V. lagopus genome had approximately 32.33% repeat sequences. In total, 21,278 protein‐coding genes were predicted, of which 99.14% were functionally annotated. Compared with 12 other mammals, V. lagopus was most closely related to V. Vulpes with an estimated divergence time of ~7.1 Ma. The expanded gene families and positively selected genes potentially play roles in the adaptation of V. lagopus to Arctic extreme environment. This high‐quality assembled genome will not only promote future studies of genetic diversity and evolution in foxes and other canids but also provide important resources for conservation of Arctic species. [ABSTRACT FROM AUTHOR]

In this work, our aim is to investigate the impact of a non-Kolmogorov predator-prey-subsidy model incorporating nonlinear prey refuge and the effect of fear with Holling type II functional response. The model arises from the study of a biological system involving arctic foxes (predator), lemmings (prey), and seal carcasses (subsidy). The positivity and asymptotically uniform boundedness of the solutions of the system have been derived. Analytically, we have studied the criteria for the feasibility and stability of different equilibrium points. In addition, we have derived sufficient conditions for the existence of local bifurcations of codimension 1 (transcritical and Hopf bifurcation). It is also observed that there is some time lag between the time of perceiving predator signals through vocal cues and the reduction of prey's birth rate. So, we have analyzed the dynamical behaviour of the delayed predator-prey-subsidy model. Numerical computations have been performed using MATLAB to validate all the analytical findings. Numerically, it has been observed that the predator, prey, and subsidy can always exist at a nonzero subsidy input rate. But, at a high subsidy input rate, the prey population cannot persist and the predator population has a huge growth due to the availability of food sources. [ABSTRACT FROM AUTHOR]

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The Arctic fox (Vulpes lagopus), occupying tundra habitats with highly variable resource distribution, is a convenient research model for studying the impact of food availability on space use. Previous studies have shown that the Arctic fox home ranges can vary from 4 to 125 km2. In areas with abundant food resources, home range sizes are smaller and overlap increases. It is theoretically assumed that with an excess of resources, territoriality should disappear. We investigated a fox settlement at the Northern fur seal rookery on Bering Island (North Pacific). We used GPS collars to track nine foxes in the summer of 2014 and 2016. GPS locations were recorded at 5-min intervals. In the home range estimation, we used the Brownian bridge movement model. We also calculated home range sizes using 100% minimum convex polygon (MCP100) and 95% fixed kernel methods to compare our results with previous studies. Home ranges were extremely small with an average of 0.5 km2 (range of 0.2–0.9 km2) by Brownian Bridge and 0.7 km2 (0.3–1.4 km2) by MCP100. We revealed no sex differences in home range size but discovered strong differentiation of activity spatial concentration between males and females. We found a surprisingly small overlap between neighboring foxes, reflecting high territoriality. This runs counter to the trend expected with an overabundant food source. We assume that the combination of the super small size of the home ranges and their exclusivity may be a feature of the island fox land tenure system, which prevents inbreeding and deters infanticide. [ABSTRACT FROM AUTHOR]

In the Eastern European Plain, the Desna valley has delivered few gravettian settlements. The group of Pushkari is characterized by final gravettian occupations relied to the Last Glacial Maximum, before the maximum peak. These are the sites of Pushkari I and Pushkari VIII (Pogon). New excavations were conducted for the last decades. In order to highlight the subsistence strategies adopted by humans we proceeded to the zooarchaeological and lithic analyses of these assemblages. In both sites, the faunal spectrum is restricted, mainly composed of Mammuthus primigenius , then Equus sp., R. tarandus , Canis lupus and Vulpes vulpes / Vulpes lagopus. The skeletal preservation and mortality profile of mammoth shows that they were slaughtered and butchered by human groups. Furthermore some bones were gathered, particularly tusks, which are associated to a new dwelling structure, fireplaces and small pits. These are two of the few final Gravettian sites showing a quite developed organization of the camps. Reindeer, horse and canids could also be hunted more punctually for the exploitation of fur, fat, meat and marrow. Moreover we have an important use of bones as fuel, whose mammoth bones. According to the lithic study, this is local flint exploited to produce blades and bladelets, tool-kit contains backed points and rectangles, points of large form and burins, relied to hunting and butchering activities. The Pushkari group shows among the last occupations of the Desna valley by late Gravettian peoples of a specific ethnic group, before that the end of the Last Glacial Maximum peak marks the disappearance of late Gravettian peoples and of human populations between 19 and 16,000 BP. [ABSTRACT FROM AUTHOR]

Reduced fitness through genetic drift and inbreeding is a major threat to small and isolated populations. Although previous studies have generally used genetically verified pedigrees to document effects of inbreeding and gene flow, these often fail to capture the whole inbreeding history of the species. By assembling a draft arctic fox (Vulpes lagopus) genome and resequencing complete genomes of 23 additional foxes born before and after a well‐documented immigration event in Scandinavia, we here look into the genomic consequences of inbreeding and genetic rescue. We found a difference in genome‐wide diversity, with 18% higher heterozygosity and 81% lower FROH in immigrant F1 compared to native individuals. However, more distant descendants of immigrants (F2, F3) did not show the same pattern. We also found that foxes with lower inbreeding had higher probability to survive their first year of life. Our results demonstrate the important link between genetic variation and fitness as well as the transient nature of genetic rescue. Moreover, our results have implications in conservation biology as they demonstrate that inbreeding depression can effectively be detected in the wild by a genomic approach. [ABSTRACT FROM AUTHOR]

Gray foxes (Urocyon cinereoargenteus) are considered a widespread and common species in the southwestern United States, although little is known about their spatial ecology that can inform rabies management strategies. We used data acquired from very high frequency and global positioning system satellite collars on gray foxes in the White Mountains and Pinaleño Mountains of Arizona to assess habitat use, movement patterns, and home range requirements. We present preliminary results from adult gray foxes (n = 3) from a larger study aimed at understanding gray fox space use for zoonotic disease management in the state. Average home range size was 3.78 ± 2.74 km2 (SD) and gray foxes used ponderosa pine forests across both study sites, with individuals also selecting for this vegetation community at the home range scale. El zorro gris (Urocyon cinereoargenteus) se considera una especie común y con gran extensión de distribución en el suroeste de los Estados Unidos, sin embargo, poco se sabe acerca de su ecología espacial que pueda informar sobre estrategias de manejo de la rabia. Utilizamos datos adquiridos por collares satelitales en zorros grises en las montañas Blancas y las montañas Pinaleño de Arizona para evaluar el uso del hábitat, patrones de movimiento y los requerimientos del ámbito hogareño. Presentamos resultados preliminares de zorros grises adultos (n = 3) de un estudio más amplio dirigido a comprender el uso del espacio del zorro gris para el manejo de la enfermedad zoonótica en el estado. El tamaño promedio del ámbito hogareño fue de 3.78 ± 2.74 km2 (DE) y los zorros grises usaron bosques de pino ponderosa en ambos sitios de estudio con individuos seleccionando también esta comunidad de vegetación en la escala del ámbito hogareño. [ABSTRACT FROM AUTHOR]

Climate change has different and sometimes divergent effects on terrestrial and marine food webs, and in coastal ecosystems, these effects are tightly interlinked. Responses of opportunistic coastal predators and scavengers to climate change may thus be complex and potentially highly flexible, and can simultaneously serve as indicators of, and have profound impacts on, lower trophic levels. Gaining mechanistic understanding of these responses is therefore important, but often not feasible due to lack of long‐term data from marked individuals. Here, we used a Bayesian integrated population model (IPM) to elucidate the effects of arctic warming and concurrent changes in terrestrial and marine resource availability on population dynamics of the opportunistic arctic fox (Vulpes lagopus) in Svalbard. Joint analysis of four types of data (den survey, age‐at‐harvest, placental scars, mark‐recovery) revealed relatively stable population size and age structure over the last 22 yr (1997–2019) despite rapid environmental change linked to climate warming. This was related to the fact that terrestrial resources (reindeer carcasses, geese) became more abundant while the availability of marine resources (seal pups/carrion) decreased, and was driven by divergent trends in different vital rates (e.g., increased pregnancy rate but decreased pup survival). Balanced contributions of survival vs. reproduction and of immigration vs. local demography further stabilized population size. Our study thus sheds light on the mechanisms underlying population dynamics of opportunistic carnivores exploiting terrestrial and marine resources and suggests that exploitation of resources across different ecosystems can buffer predators against climate change. Additionally, it highlights the large potential of IPMs as tools to understand and predict the effects of environmental change on wildlife populations, even when data on marked individuals are sparse. [ABSTRACT FROM AUTHOR]

Human-wildlife problems often arise when predators kill livestock. This can develop into serious conflicts between traditional pastoralists and other stakeholders, such as government officials and conservationists. In the Yamal Peninsula (Russia), nearly half of the indigenous Nenets people are reindeer herders. They have recently faced many challenges, such as high mortality of reindeer from pasture icing or disease outbreaks. In addition, predation of arctic fox on reindeer calves is perceived as an increasing problem. Here, we use an interdisciplinary approach to study this emerging predation problem. We present here results from semi-structured interviews with indigenous people, as well as from biological monitoring of fox populations. Our field data were obtained in Erkuta, in the south of Yamal and in Sabetta in the north, close to a newly built industrial settlement. We show how different factors may have come together to create a problematic situation. These factors include the abandonment of the fur trade in the 1990s, the building of huge industrial facilities providing possible resource subsidies and the increasing frequency of abnormal weather events leading to weak reindeer, high reindeer mortality and abundant carcasses as resources for predators. We discuss how each of these factors affects the abundance of predators as well as the understanding of the herders. [ABSTRACT FROM AUTHOR]

The article highlights that the zoologist Dr. Benjamin Sharp, Jr., and his assistant, John M. Justice, left the U.S. Revenue Cutter Service's Bear at Unalaska on September 11, 1895, were relieved to take passage on the Alaska Commercial Company's "Dora" bound for Sitka.

The 'third pole' of the world is a fitting metaphor for the Himalayan-Tibetan Plateau, in allusion to its vast frozen terrain, rivalling the Arctic and Antarctic, at high altitude but low latitude. Living Tibetan and arctic mammals share adaptations to freezing temperatures such as long and thick winter fur in arctic muskox and Tibetan yak, and for carnivorans, a more predatory niche. Here, we report, to our knowledge, the first evolutionary link between an Early Pliocene (3.60-5.08 Myr ago) fox, Vulpes qiuzhudingi new species, from the Himalaya (Zanda Basin) and Kunlun Mountain (Kunlun Pass Basin) and the modern arctic fox Vulpes lagopus in the polar region. A highly hypercarnivorous dentition of the new fox bears a striking resemblance to that of V. lagopus and substantially predates the previous oldest records of the arctic fox by 3-4 Myr. The low latitude, high-altitude Tibetan Plateau is separated from the nearest modern arctic fox geographical range by at least 2000 km. The apparent connection between an ancestral high-elevation species and its modern polar descendant is consistent with our 'Out-of-Tibet' hypothesis postulating that high-altitude Tibet was a training ground for cold-environment adaptations well before the start of the Ice Age.

We evaluated skeletal remains of five blue arctic foxes from St. Paul Island, Pribilof Islands, Alaska. All five had been found dead. Cleared skeletal remains were examined visually and by magnification or backlighting where necessary. Pathological features were described and photographed. Results suggested that more than one disorder may have occurred in these foxes, with primary observations being demineralizing and/or proliferation. Most prominently affected were the skull, maxillae, mandibles, pelvis, long bones, and major diarthrodial joints. It was critically important to recognize certain other pathological features that can be observed on many or most fox skeletal remains but are unlikely to relate to conditions that demineralize bone or cause overt bone loss, multifocal loss of joint architecture, or severe multifocal periarticular boney proliferation. The differential diagnosis of canid skeletal demineralizing includes primary and secondary (nutritional or renal) hyperparathyroidism. Boney proliferation has a wider differential spectrum that can include hypervitaminosis A, osteomyelitis, abnormalities related to inbreeding, and environmental toxicosis. In our view, given the lack of soft tissue for histological evaluation and biochemical analysis, a well‐considered differential diagnosis is an appropriate scientific point of conclusion. In the many similar circumstances that would require additional studies for valid definitive diagnosis during life, investigators should review relevant literature and consider the value of well‐structured differential diagnosis, as contrasted with more speculative definitive diagnoses. [ABSTRACT FROM AUTHOR]

Canine circovirus (CanineCV) is a relatively new viral species, belonging to the family Circoviridae, whose pathogenic role is still uncertain. Since its first description in one domestic dog in 2011 from the USA, several reports have been documenting its distribution worldwide. Recently, CanineCV was also detected in wild animals such as wolves, foxes and badgers. In order to investigate the presence and the genetic characteristics of CanineCV in foxes of Arctic and Sub‐Arctic regions, the presence of CanineCV DNA in internal organs (liver and spleen) of 51 arctic foxes (Vulpes lagopus) from Svalbard archipelago and 59 red foxes (Vulpes vulpes) from Northern Norway, sampled from 1996 to 2001 and from 2014 to 2018, respectively, was screened by real‐time PCR. CanineCV was detected in 11/51 arctic foxes and in 10/59 red foxes, backdating the circulation of the virus at least to 1996 in the arctic fox population. The complete genome of 14 identified CanineCV was sequenced and analysed showing an identity higher than 80.8% with the reference strains available to date. According to the species demarcation threshold of 80% genome‐wide nucleotide sequence identity for members of the family Circoviridae provided by International Committee on Taxonomy of Viruses (ICTV), all the CanineCV belong to a single species. Phylogenetic analysis revealed that all the CanineCV were subdivided into five main clusters with one including only CanineCV identified in foxes. Furthermore, CanineCV identified in arctic foxes and red foxes formed two distinct lineages. From these data, we hypothesize that the viral transmission did not occur between the two species of foxes as a consequence of the lack of contact between the two hosts or that the virus acquired mutations in the time elapsed between the samplings. [ABSTRACT FROM AUTHOR]

Genetic rescue can facilitate the recovery of small and isolated populations suffering from inbreeding depression. Long-term effects are however complex, and examples spanning over multiple generations under natural conditions are scarce. The aim of this study was to test for long-term effects of natural genetic rescue in a small population of Scandinavian Arctic foxes (Vulpes lagopus). By combining a genetically verified pedigree covering almost 20 years with a long-term dataset on individual fitness (n = 837 individuals), we found no evidence for elevated fitness in immigrant F2 and F3 compared to native inbred foxes. Population inbreeding levels showed a fluctuating increasing trend and emergence of inbreeding within immigrant lineages shortly after immigration. Between 0–5 and 6–9 years post immigration, the average number of breeding adults decreased by almost 22% and the average proportion of immigrant ancestry rose from 14% to 27%. Y chromosome analysis revealed that 2 out of 3 native male lineages were lost from the gene pool, but all founders represented at the time of immigration were still contributing to the population at the end of the study period through female descendants. The results highlight the complexity of genetic rescue and suggest that beneficial effects can be brief. Continuous gene flow may be needed for small and threatened populations to recover and persist in a longer time perspective. [ABSTRACT FROM AUTHOR]

Selection for crypsis has been recognized as an important ecological driver of animal colouration, whereas the relative importance of thermoregulation is more contentious with mixed empirical support. A potential thermal advantage of darker individuals has been observed in a wide range of animal species. Arctic animals that exhibit colour polymorphisms and undergo seasonal colour moults are interesting study subjects for testing the two alternative hypotheses: demographic performance of different colour morphs might be differentially affected by snow cover with a cryptic advantage for lighter morphs, or conversely by winter temperature with a thermal advantage for darker morphs.In this study, we explored whether camouflage and thermoregulation might explain differences in reproduction and survival between the white and blue colour morphs of the Arctic fox Vulpes lagopus under natural conditions.Juvenile and adult survival, breeding propensity and litter size were measured for 798 captive‐bred and released or wild‐born Arctic foxes monitored during an 11‐year period (2007–2017) in two subpopulations in south‐central Norway. We investigated the proportion of the two colour morphs and compared their demographic performance in relation to spatial variation in duration of snow cover, onset of snow season and winter temperatures.After population re‐establishment, a higher proportion of blue individuals was observed among wild‐born Arctic foxes compared to the proportion of blue foxes released from the captive population. Our field study provides the first evidence for an effect of colour morph on the reproductive performance of Arctic foxes under natural conditions, with a higher breeding propensity of the blue morph compared to the white one. Performance of the two colour morphs was not differentially affected by the climatic variables, except for juvenile survival. Blue morph juveniles showed a tendency for higher survival under colder winter temperatures but lower survival under warmer temperatures compared to white morph juveniles.Overall, our findings do not consistently support predictions of the camouflage or the thermoregulation hypotheses. The higher success of blue foxes suggests an advantage of the dark morph not directly related to disruptive selection by crypsis or thermoregulation. Our results rather point to physiological adaptations and behavioural traits not necessarily connected to thermoregulation, such as stress response, immune function, sexual behaviour and aggressiveness. Our findings highlight the need to explore the potential role of genetic linkage or pleiotropy in influencing the fitness of white and blue Arctic foxes as well as other species with colour polymorphisms. [ABSTRACT FROM AUTHOR]