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Bioenergetic constraints are the ultimate determinant of the timing of reproduction, and seasonal breeding is consequently a widely observed trait. Consistent with this, attention has focused on plasticity in reproductive phenology conceptualized as a response to concomitant advances in the phenology of the environmental energy supply caused by climate change. Few studies, however, have directly compared timing of reproduction with energetic status in free-living wild animals. Here we demonstrate that neither body mass nor adiposity are strong proximate predictors of date of conception in wild reindeer (Rangifer tarandus). Weak coupling between energetic status and the phenology of reproduction accounts for the increasing discrepancy between the phenology of forage (energy supply) and the phenology of reproduction (energy demand) observed across the last 2-4 decades in two populations of this species. The results emphasise that phenological plasticity is not a passive response to changes in energy supply but derives from the way in which environmental factors interact with the core control mechanisms that govern timing. Central in this respect is integration, within the rheostatic centres of the hypothalamus, of information on nutritional status with the circannual life-history calendar.

Herbivores drive shifts in plant species composition by interacting with vegetation through defoliation, trampling and nutrient addition: urine and faeces. As herbivore effects on vegetation accumulate over time, they might spillover to other trophic levels, but how and when this happens is poorly understood. Since it is methodologically demanding to measure biodiversity across spatial gradients, an alternative approach is to assess it through biodiversity indices of vascular plants. We employed the Index of biodiversity relevance developed for Swedish flora which provides an estimated number of organisms associated with a plant species, allowing the quantification of trophic community size. Values from this index were coupled with vegetation data from a network of 96 fenced and paired grazed plots across Fennoscandia. We analysed the role herbivory has on plant richness and diversity, and on the number of organisms that interact with the vegetation according to the index values. We also explored how herbivores influence the competitive effects of tall shrubs on other plants since the dominance of a vegetation type links directly to biodiversity. Plant diversity had no clear response to grazing. Overall vegetation and the vegetation subgroups herbs and non‐fruit shrubs had higher biodiversity index values in fenced plots, indicating a higher number of plant–host interactions. Herb cover was negatively related to shrubs in both treatments but with a faster decline in the absence of herbivores. This study highlights the importance of maintaining herbivore populations in the Arctic to conserve the vegetation structure and biodiversity of the tundra. This method of coupling biodiversity indexes with vegetation data provides complementary information to the plant diversity, especially when methodological or time constraints prevent complete field inventories. [ABSTRACT FROM AUTHOR]

Recent studies of ungulate movement ecology suggest that seasonal movement tactics often vary within a population. The forest‐tundra and forest‐dwelling ecotypes of woodland caribou (Rangifer tarandus caribou) in Ontario, Canada, are traditionally presumed to differ in migratory strategy; however, their potential for facultative migration, the practice of interannual switching between migratory and non‐migratory strategies, has yet to be explored. Understanding facultative migration, and any inherent variation and influences could help improve habitat management. We acquired global positioning system (GPS) telemetry‐based movement data from 109 radio‐collared caribou across the Hudson Bay lowlands between 2009 and 2019. We compared the data with estimates of vegetation density, snow cover, and human disturbance to identify environmental influences associated with the probability and magnitude of migration. We also compared seasonal resource selection between migratory and sedentary individuals. Caribou demonstrated plasticity in migration, with evidence of facultative migration by the forest‐tundra and the forest‐dwelling ecotypes. Variation in migration was likely a combination of local adaptation and acute response to changing environmental factors, particularly snow. Probability and distance of migration were positively correlated with snow, while distance also showed spatial dependency. Plasticity in migration has significant implications in relation to future shifts in climate and should be considered in relevant predictive analyses. [ABSTRACT FROM AUTHOR]

Woodland caribou (Rangifer tarandus caribou) are declining across much of their distribution in Canada in response to habitat alteration, leading to unsustainable predation, particularly by wolves (Canis lupus). Habitat alteration can benefit the primary prey species of wolves (moose [Alces alces] and deer [Odocoileus spp.]) by creating early seral conditions that contain more of their preferred food types. This increase in primary prey populations results in elevated wolf abundance and heightened predation pressure on caribou. In response to the elevated wolf populations and the risks to caribou, managers have reduced wolf abundance in key areas. Ecological theory suggests that reducing wolf abundance would release moose from the top‐down effects of wolf predation, potentially allowing moose populations to grow. Elevated moose abundance thus has the potential to cause wolf populations to rebound quickly each year following reductions, suggesting a possible link between moose abundance and the number of wolves killed for caribou conservation. To test this idea we used a unique management situation in British Columbia and Alberta, Canada, where lethal wolf removals were annually conducted across specific southern mountain caribou population ranges and, in some places, moose populations were concurrently reduced via liberalized hunting. We used indices of moose abundance and wolf removal data to test the hypothesis that reducing moose populations to a historical abundance target by hunting leads to fewer wolves killed for caribou conservation. After controlling for habitat quality, wolves removed per km2 was 3.2 times lower in areas with reduced moose density ( x ¯ $\bar{x}$ = 1.55 wolves/1,000 km2 ± 0.33 [SE]) than in those without reduced moose density ( x ¯ $\bar{x}$ = 5.02 wolves/1,000 km2 ± 0.52). However, the average number of wolves removed per year decreased under both conditions. After 9 years, there was a 35% reduction in the predicted difference in the annual removal between areas with and without moose reduction. Our results suggest that policies that do not reduce or stabilize moose abundance will result in the removal of more wolves to increase caribou abundance. Like wolf reductions, moose reductions can also be controversial and affect local harvesters. Thus, understanding the consequences of actions that support caribou recovery is essential to supporting evidence‐based policy discussions. [ABSTRACT FROM AUTHOR]

For prey, movement synchrony represents a potent antipredator strategy. Prey, however, must balance the costs and benefits of using conspecifics to mediate risk. Thus, the emergent patterns of risk-driven sociality depend on variation in space and in the predators and prey themselves. We applied the concept of predator–prey habitat domain, the space in which animals acquire food resources, to test the conditions under which individuals synchronize their movements relative to predator and prey habitat domains. We tested the response of movement synchrony of prey to predator–prey domains in two populations of ungulates that vary in their gregariousness and predator community: (i) elk, which are preyed on by wolves; and (ii) caribou, which are preyed on by coyotes and black bears. Prey in both communities responded to cursorial predators by increasing synchrony during seasons of greater predation pressure. Elk moved more synchronously in the wolf habitat domain during winter and caribou moved more synchronously in the coyote habitat domains during spring. In the winter, caribou increased movement synchrony when coyote and caribou domains overlapped. By integrating habitat domains with movement ecology, we provide a compelling argument for social behaviours and collective movement as an antipredator response. This article is part of the theme issue 'The spatial–social interface: A theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]

Site fidelity—the tendency to reuse familiar spaces—is expected to improve fitness. Familiarity with the local environment is particularly crucial when resource demands or predation risk are high. Consequently, site fidelity often peaks during reproduction when energetic costs are high and offspring are vulnerable. For many species, the environment they experience is not solely a function of geography but also of the social environment. Social fidelity, the selection for familiar social environments, could constitute an independent or parallel strategy to spatial fidelity when considering behaviour at the spatial–social interface. Using global positioning system locations from caribou across Newfoundland, we tested whether females selected calving sites based on proximity to familiar conspecifics, in addition to geographical (spatial) fidelity. These strategies were synergistic, not alternative, and correlated across the population but more variable within individuals. We also tested whether either form of fidelity affected reproductive success. We failed to detect an effect of spatial or social fidelity on reproductive success in this population. Nevertheless, given the association between social and spatial fidelity and the demonstrated fitness consequences of site fidelity in other systems, familiar conspecifics and the potential benefits these social partners provide may be an underappreciated component driving site fidelity. This article is part of the theme issue 'The spatial–social interface: a theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]

The light climate at high latitudes, in particular the extended twilight of winter and the reduced diel variation in light level in midsummer and midwinter, potentially constrains visual function and the synchronisation of temporal organisation in polar species. In this paper, we describe the temporal pattern and variation in the spectral composition and brightness of skylight (daylight, twilight, moonlight, starlight, airglow and aurorae) at high latitudes and review photoreception of reindeer/caribou (Rangifer tarandus; ‘Rangifer’) which is one of the few polar resident species for which data are available. Experimental data indicate that the rods of Rangifer may be stimulated by levels of ambient light lower than those occurring during astronomical twilight (solar angle <−18°). Several features of the eyes of Rangifer contribute to their visual capability under extended twilight. These include transmission of UV through the optical media, which enables the animals to exploit the shorter wavelengths characteristic of twilight, and a shift in the peak spectral reflectance of the tapetum lucidum (TL) from around 640 nm in summer to around 450 nm in winter, which increases retinal illumination at short wavelengths. Enhanced sensitivity to short wavelengths is likely to enhance the contrast of some objects and hence the ability of Rangifer to discriminate forage plants and to detect other animals (conspecifics or predators) against a snowy background under low illuminance. There is, nevertheless, currently no evidence of any specific boreal adaptation in their visual system: (i) The eyes of Rangifer, and by inference the area of the dilated pupil, are no larger than expected based on the allometry of eye size in ruminants. (ii) There is no evidence of a change in the spectral sensitivity of photoreceptors associated with detection of UVa. (iii) Transmission of UV through the anterior eye is not unique to Rangifer. (iv) The blue shift in the reflectance of the winter TL appears to be a passive response to prolonged dilation of the pupil and there is no a priori reason not to predict the same response in other large ungulates exposed to low light levels. (v) There is no conclusive evidence of a seasonal shift in absolute retinal sensitivity in Rangifer. (vi) Weak circadian organisation in Rangifer has tentatively been linked to mutations within the circadian molecular clockwork but it remains unclear to what extent this represents a specific adaptation to high latitude. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Animal behaviour is important for prevalence and outbreaks of infectious diseases, for instance by affecting individual interactions. Increasing the knowledge of individual movement patterns can provide better insight into disease prevalence and spread, helping to target efforts to minimise disease outbreaks. Chronic wasting disease (CWD) is a fatal prion disease affecting cervids. CWD is transmitted by animal‐to‐animal contact and through the environment, thus individual variation in space use and social associations may influence disease transmission patterns and infection risk. CWD was detected in Norwegian alpine reindeer Rangifer tarandus tarandus in 2016, and eradication of the infected population was implemented. A 3:1 infection rate between males and females suggests sex‐specific behavioural drivers. We utilised an extensive individual‐based dataset of 149 GPS‐marked wild reindeer to investigate individual variation in movement patterns in terms of inter‐ and intra‐annual home range size and site fidelity, and variation in home range overlap and distances between individuals. We aimed to identify patterns which could indicate higher potential disease risk. Females had larger annual and seasonal home ranges than males, except during calving and rut. Greater home range overlaps and shorter between‐individual distances were found between same‐sex individuals than different‐sex individuals, except during the rut. Accordingly, the rut season stands out with greater male home ranges, greater home range overlap and shorter distances between males and between males and females, which could indicate that this season is critical for disease transmission. Measures to prevent disease spread should lower contact rates, e.g. by reducing the abundance of adult males before they mix with other groups during the rut. This can be achieved for instance by allowing earlier hunt on adult males when they are distributed in small male groups, to reduce the transmission risk and keep disturbance of other individuals low. [ABSTRACT FROM AUTHOR]

The aim of the study was to test the performance of a silver wire modified version of the coded telemetric heart rate monitor Polar Vantage NV™ (PVNV) and to measure heart rate (HR) in a group of captive reindeer calves during different behaviour. The technical performance of PVNV HR monitors was tested in cold conditions (-30°C) using a pulse generator and the correlation between generated pulse and PVNV values was high (r = 0.9957). The accuracy was tested by comparing the HR obtained with the PVNV monitor with the standard ECG, and the correlation was significant (r = 0.9965). Both circadian HR and HR related to behavioural pattern were recorded. A circadian rhythm was observed in the HR in reindeer with a minimum during night and early morning hours and maximum at noon and during the afternoon, the average HR of the reindeer calves studied being 42.5 beats/min in February. The behaviour was recorded by focal individual observations and the data was synchronized with the output of the HR monitors. Running differed from all other behavioural categories in HR. Inter-individual differences were seen expressing individual responses to external and internal stimuli. The silver wire modified Polar Vantage NV™ provides a suitable and reliable tool for measuring heart rate in reindeer, also in natural conditions. [ABSTRACT FROM AUTHOR]

Woodland caribou (Rangifer tarandus caribou) are designated as Threatened or Endangered in Canada, with many populations being at risk of extirpation. Approaches for caribou conservation can be both invasive and expensive. For example, maternity penning involves the relocation of pregnant females to a predator‐free fenced enclosure where they are held for 20–22 weeks. This activity greatly reduces the risk of predation for adult females and their dependent calves, but requires the construction, maintenance, and monitoring of a penning facility as well as the risk associated with the capture and transport of adult caribou. With only four maternity pen trials within the last decade, there has been little study of the potential influence of maternity penning on the distribution and habitat use of caribou after release. We used Brownian Bridge Movement Models to examine changes in range fidelity and overall range use of the Klinse‐Za caribou herd in north‐central British Columbia, Canada, following eight years of maternity penning. We generated annual home range utilisation distributions and examined the space use of caribou among years and between penned and unpenned animals, as well as pre‐penning and post‐penning time periods. We found that following penning, caribou shifted distribution to areas near maternity pens and expanded their overall use of range. However, caribou did not shift their distribution relative to the elevation of their mountainous habitats. Our results suggest that caribou can adapt to capture and forced displacement without altering patterns of instinctual or learned habitat use. [ABSTRACT FROM AUTHOR]

Counting growth layers in dentine and/or secondary cementum is widely used for age determination in wild mammals but the underlying seasonal changes in the structure and degree of mineralisation of dental tissue have not been well characterised. We embedded first (m1) and second (m2) mandibular permanent molar teeth from a 12‐year‐old female Svalbard reindeer (Rangifer tarandus platyrhynchus) in PolyMethylMethAcrylate (PMMA), prepared cut and polished surfaces coated with evaporated carbon and used 20 kV back‐scattered electron imaging in a scanning electron microscope (BSE‐SEM) to study aspects of dental tissue structure which depend on the degree of mineralisation at the micron and sub‐micron scale. BSE‐SEM revealed differences between the mineral content of growth layers (annulations) in the secondary cementum and the primary and secondary dentine, the latter, incidentally, still forming at death in m1. Wide bands of less well mineralised tissue formed in the cementum during active appositional phases. Thin, denser bands formed by maturation‐mineralisation of existing tissue when growth slowed in winter. This maturation mimics the processes seen in lamellar bone and articular cartilage. Counter to previous suggestions, there was evidence of substantial resorption and repair of the secondary cementum and of formation of dentine throughout life. Secondary dentine is layered by mineral content like cementum. In the crown, this was mainly tubular dentine with well‐marked interglobular dentine layers. In the lower pulp chamber and root, it was largely without tubules. Substantial non‐mineralised spaces found at the cement‐dentine junction in the root apical regions in m2 represent inclusions of the Hertwig's Epithelial Root Sheath (HERS) or the Epithelial Rests of Malassez (ERM) between the two tissues, a phenomenon which has previously only been identified in Muridae. The anatomical changes which result in the formation of the incremental lines (annulations) in dental tissues of reindeer, identified here for the first time at the micrometre level, are likely to be common across most if not all long‐lived species of mammals living in seasonal environments. [ABSTRACT FROM AUTHOR]

Background: Movement links the distribution of habitats with the social environment of animals using those habitats. Despite the links between movement, habitat selection, and socioecology, their integration remains a challenge due to lack of shared vocabulary across fields, methodological gaps, and the implicit (rather than explicit) historical development of theory in the fields of social and spatial ecology. Given these challenges can be addressed, opportunity for further study will provide insight about the links between social, spatial, and movement ecology. Here, our objective was to disentangle the roles of habitat selection and social association as drivers of movement in caribou (Rangifer tarandus). Methods: To accomplish our objective, we modelled the relationship between collective movement and selection of foraging habitats using socially informed integrated step selection function (iSSF). Using iSSF, we modelled the effect of social processes, i.e., nearest neighbour distance and social preference, and movement behaviour on patterns of habitat selection. Results: By unifying social network analysis with iSSF, we identified movement-dependent social association, where individuals took shorter steps in lichen habitat and foraged in close proximity to more familiar individuals. Conclusions: Our study demonstrates that social preference is context-dependent based on habitat selection and foraging behaviour. We therefore surmise that habitat selection and social association are drivers of collective movement, such that movement is the glue between habitat selection and social association. Here, we put these concepts into practice to demonstrate that movement is the glue connecting individual habitat selection to the social environment. [ABSTRACT FROM AUTHOR]

This study investigates the intersection of bioart and posthumanistic perspectives through the innovative use of reindeer by-products, specifically reindeer blood, as a medium for artistic expression. Utilising an Arts-Based Research (ABR) approach, the research investigates the methodological, ethical, and cultural dimensions of integrating waste materials into creative practices. The project repurposes reindeer blood, an often-overlooked by-product of reindeer herding, to provoke ethical discussions on sustainability and cultural sensitivity within the arts. Experiments in the BioARTech laboratory transform reindeer blood into air-dried pigment, which is then incorporated into glassblowing and surface pattern design. These innovative techniques challenge traditional boundaries of artistic materials and prompt deeper reflections on human-nature relationships. Exhibitions across Finland highlight the ethical application of this unique Northern material, highlighting its cultural significance and promoting a reimagining of our interconnectedness with the natural world. Ultimately the study expands the artistic repertoire and advocates for more harmonious and sustainable futures through pioneering bioart practices. [ABSTRACT FROM AUTHOR]

Zoo conditions are unique for reindeer, since domestic reindeer are not kept in captive facilities like cattle. In the zoo, reindeer are usually surrounded by many different animals that they would never encounter naturally. Thus, they might be infected with new helminths. Numerous petting zoos raise concerns about the safety of tactile interactions for human visitors. Our study is the first large-scale one. Qualitative and quantitative fecal analyses were carried out for 233 reindeer distributed over 50 Russian zoos according to the National Standard of the Russian Federation (GOST R 54627-2011) Ruminant animals—Methods of Laboratory Helminthological Diagnostics. Where possible, DNA analyses of helminths were performed targeting internal transcribed spacer region. As a result, F. hepatica, Paramphistomum sp., Moniezia sp. (including M. expansa), gastrointestinal strongylids (including Nematodirus spp.), Dictyocaulus sp., E. rangiferi, Trichuris sp., and Capillaria sp. were found in 106 (45%) zoo reindeer. All these helminths were previously reported in reindeer and pose no direct danger for humans. The intensity of invasions was mostly low. Fecal examination might be considered as an indirect method for mange diagnostics, as Chorioptes and Demodex mites were found in reindeer fecal samples. The latter may represent a novel species of mite specific for reindeer. [ABSTRACT FROM AUTHOR]

Abundance estimation is frequently an objective of conservation and monitoring initiatives for threatened and other managed populations. While abundance estimation via capture–mark–recapture or spatially explicit capture–recapture is now common, such approaches are logistically challenging and expensive for species such as boreal caribou (Rangifer tarandus), which inhabit remote regions, are widely dispersed, and exist at low densities. Fortunately, the recently developed 'close‐kin mark–recapture' (CKMR) framework, which uses the number of kin pairs obtained within a sample to generate an abundance estimate, eliminates the need for multiple sampling events. As a result, some caribou managers are interested in using this method to generate an abundance estimate from a single, non‐invasive sampling event for caribou populations. We conducted a simulation study using realistic boreal caribou demographic rates and population sizes to assess how population size and the proportion of the population surveyed impact the accuracy and precision of single‐survey CKMR‐based abundance estimates. Our results indicated that abundance estimates were biased and highly imprecise when very small proportions of the population were sampled, regardless of the population size. However, the larger the population size, the smaller the required proportion of the population surveyed to generate both accurate and reasonably precise estimates. Additionally, we also present a case study in which we used the CKMR framework to generate annual female abundance estimates for a small caribou population in Jasper National Park, Alberta, Canada, from 2006 to 2015 and compared them to existing published capture–mark–recapture‐based estimates. Both the accuracy and precision of the annual CKMR‐based abundance estimates varied across years and were sensitive to the proportion of pairwise kinship comparisons which yielded a mother–offspring pair. Taken together, our study demonstrates that it is possible to generate CKMR‐based abundance estimates from a single sampling event for small caribou populations, so long as a sufficient sampling intensity can be achieved. [ABSTRACT FROM AUTHOR]

One of the selective advantages of delayed implantation in carnivores is the flexibility to decouple the time between mating and parturition, allowing both to occur when conditions are most favorable. Terrestrial carnivores with delayed implantation have evolved reduced maternal energy expenditure through shorter gestation length, smaller neonates, and smaller litters, with a possible linkage between maternal body condition and time of birth or litter size. Using data on wolverine (Gulo gulo) females and cubs from management removals covering the entire latitudinal gradient of the Scandinavian population in 2001‐2022, I assessed the effect of extrinsic and intrinsic factors on variation in parturition date and litter size. Timing of parturition varied over 2 months, where 90% of the litters were born between 5 February and 11 March, with a birth peak on 23 February. Females living in winter grazing pastures of semi‐domestic reindeer (Rangifer tarandus) gave birth earlier than those outside, and along an elevation gradient parturition date was delayed at higher altitudes. I did not find evidence of an effect of latitude on parturition date. Furthermore, older females had greater odds than younger females of having litters with 3 cubs rather than 1 cub. To minimize the risk of harvesting lactating females, management regulations should implement harvest seasons that extend no longer than the end of January. [ABSTRACT FROM AUTHOR]

Moose (Alces alces) and woodland caribou (Ranger tarandus caribou) are the 2 large prey species for wolves (Canis lupus) in the Nearctic boreal forest in North America. Caribou have declined, with widespread anthropogenic disturbance as the ultimate cause and wolf predation as the proximal cause. To conserve caribou the government of Alberta, Canada initiated a wolf control program to reduce predation rates on caribou populations and contribute to caribou population recovery. Predators play an important role in shaping the structure and function of ecosystems through top‐down forces. We hypothesized that the strongest factors influencing moose occurrences would reflect changes in predation risk before and after the onset of wolf control. We weighed evidence for competing hypothesis by deploying cameras across a highly industrialized landscape in Alberta for 3 years after wolf control (2017–2020), capitalizing on 3 years of existing data before the onset of wolf control (2011–2014). We created generalized linear models representing competing hypotheses about moose response to natural and anthropogenic landscape features before and after wolf control, examining support for each in an information‐theoretic framework. Prior to wolf control, the model containing landscape features providing security cover was best‐supported, but this was scale‐dependent. After wolf control, the model containing landscape features that offer increased forage opportunities was best‐supported. Unexpectedly, the direction of effect was often opposite to predictions, with moose avoiding some features thought to provide security and forage. We demonstrate that lethal predator control affects the spatial distribution of its primary prey species but in ways we do not fully comprehend, highlighting the need for a better understanding of community dynamics following wolf control. [ABSTRACT FROM AUTHOR]

When thick wet snow covers unfrozen ground at the beginning of winter, herders fear the development of a hard, icy bottom snow layer and the appearance of noxious moulds (microfungi) in semi-domesticated reindeer pastures. Such winter onsets were experienced in 2019 and 2021 in the reindeer herding area of Finland, after which significant reindeer losses, along with collapses in calf production and slaughter animals, were encountered. We studied the development of weather and snow conditions in the late autumn and early winter of 2021–2022 and measured snow conditions in March 2022 in 11 reindeer cooperatives. We also collected samples from reindeer winter forage plants for mycotoxin analysis. We found that the weather and snow conditions during the late autumn and early winter of 2021 caused the formation of a hard, icy bottom snow layer and the development of mycotoxins in pastures. Alternariol (AOH) and alternariol monomethyl ether (AME), produced by Alternaria spp., were found in all 33 samples (104–2562, 61–808 µg/kg DM) and zearalenone (ZEN) by Fusarium spp. in 16 samples (14–206 µg/kg). Certain significant correlations in the concentrations of mycotoxins with snow conditions and ground surface temperatures were found. We assume that besides difficult grazing conditions in the winters of 2019–2020 and 2021–2022, the presence of mycotoxins in pastures has contributed to reindeer losses and reduced the body condition, health, and reproduction of reindeer. As onsets of winters become warmer and rainier, the risk of similar pasture conditions in reindeer herding may increase. [ABSTRACT FROM AUTHOR]

Zoo conditions are unique for reindeer, since domestic reindeer are not kept in captive facilities like cattle. In the zoo, reindeer are usually surrounded by many different animals that they would never encounter naturally. Thus, they might be infected with new helminths. Numerous petting zoos raise concerns about the safety of tactile interactions for human visitors. Our study is the first large-scale one. Qualitative and quantitative fecal analyses were carried out for 233 reindeer distributed over 50 Russian zoos according to the National Standard of the Russian Federation (GOST R 54627-2011) Ruminant animals—Methods of Laboratory Helminthological Diagnostics. Where possible, DNA analyses of helminths were performed targeting internal transcribed spacer region. As a result, F. hepatica, Paramphistomum sp., Moniezia sp. (including M. expansa), gastrointestinal strongylids (including Nematodirus spp.), Dictyocaulus sp., E. rangiferi, Trichuris sp., and Capillaria sp. were found in 106 (45%) zoo reindeer. All these helminths were previously reported in reindeer and pose no direct danger for humans. The intensity of invasions was mostly low. Fecal examination might be considered as an indirect method for mange diagnostics, as Chorioptes and Demodex mites were found in reindeer fecal samples. The latter may represent a novel species of mite specific for reindeer.

The range of tularemia, a disease caused by the bacterium Francisella tularensis, may expand alongside climate change in the North. Transmission occurs via biting arthropods, contaminated water sources, infected animal tissues and fluids and even aerosolized bacteria. Little research has been published on F. tularensis in northern Canada. We investigated whether Rangifer (caribou and reindeer) in Canada and Alaska are exposed to F. tularensis, as they provide significant cultural and subsistence value. From 2016 to 2020, 336 serum samples were collected from Rangifer across 17 herds, including captive reindeer in Alaska (n = 30) and wild caribou across Canada (n = 306) during collaring or harvesting efforts. Using a microagglutination test, we detected antibodies against F. tularensis in 7% of captive reindeer (CI95 2–21), 6% of migratory tundra caribou (CI95 4–11) and 10% of mountain woodland caribou (CI95 6–17), with the highest seroprevalence observed in animals from Nunavut (17%) and British Columbia, Canada (18%). Ten of the herds (n = 10/17; 59%) had at least one positive animal. Evidence of exposure to F. tularensis indicates that further studies are needed to characterize sources of transmission for Rangifer species and any potential health effects following infection.

Abstract Chronic wasting disease (CWD), a prion disease affecting cervids, has been known in North America (NA) since the 1960s and emerged in Norway in 2016. Surveillance and studies have revealed that there are different forms of CWD in Fennoscandia: contagious CWD in Norwegian reindeer and sporadic CWD in moose and red deer. Experimental studies have demonstrated that NA CWD prions can infect various species, but thus far, there have been no reports of natural transmission to non-cervid species. In vitro and laboratory animal studies of the Norwegian CWD strains suggest that these strains are different from the NA strains. In this work, we describe the intracerebral transmission of reindeer CWD to six scrapie-susceptible sheep. Detection methods included immunohistochemistry (IHC), western blot (WB), enzyme-linked immunosorbent assay (ELISA), real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA). In the brain, grey matter vacuolation was limited, while all sheep exhibited vacuolation of the white matter. IHC and WB conventional detection techniques failed to detect prions; however, positive seeding activity with the RT-QuIC and PMCA amplification techniques was observed in the central nervous system of all but one sheep. Prions were robustly amplified in the lymph nodes of all animals, mainly by RT-QuIC. Additionally, two lymph nodes were positive by WB, and one was positive by ELISA. These findings suggest that sheep can propagate reindeer CWD prions after intracerebral inoculation, resulting in an unusual disease phenotype and prion distribution with a low amount of detectable prions.

We investigated Alongshan virus infection in reindeer in northeastern China. We found that 4.8% of the animals were viral RNA–positive, 33.3% tested positive for IgG, and 19.1% displayed neutralizing antibodies. These findings suggest reindeer could serve as sentinel animal species for the epidemiologic surveillance of Alongshan virus infection.

Reindeer husbandry takes a leading position in the agricultural sector of the Russian Federation Arctic zone. The purpose of the research is to analyze the science-based assurance of the freedom from highly dangerous infectious diseases in reindeer herds of the Arctic zone. It has been established that diseases such as anthrax, brucellosis, footrot, rabies are still relevant for the reindeer husbandry and can cause not only significant economic damage, but also diseases in humans. The analysis of the archival data and literary sources, as well as own research data lead to the following conclusions: the greatest risk of anthrax occurrence and spread is posed by old carcass sites; to eradicate brucellosis, vaccination of animals along with the general disease control measures is necessary; in case of footrot, special attention should be paid to the control of blood-sucking insects and warble flies; to prevent rabies in reindeer herds, it is important to avoid contacts between deer and wild carnivores and consider emergency vaccination. Undoubtedly, the eradication and prevention of the above-mentioned infectious diseases requires constant epidemiological surveillance, including its element – monitoring, with all necessary special management, animal health measures. There is an obvious need for constant surveillance of infectious diseases in the Arctic zone of the Russian Federation using GIS technologies. It is important to pay special attention to the generation of special information layers related to disease characteristics, including deer herd migration routes, sites where anthrax outbreaks were recorded, and the location of disease-infected facilities.

Animals interact with nutrient cycles by consuming and depositing nutrients, interactions studied separately in nutritional ecology and zoogeochemistry. Recent theoretical work bridges these disciplines, highlighting that animal‐driven nutrient recycling could be crucial in helping animals meet their nutritional needs. When animals exhibit site fidelity, they consistently deposit nutrients, potentially improving vegetation quality. We investigated this potential feedback by analysing changes in forage nitrogen stocks following simulated caribou calving. We found that forage nitrogen stocks increased after 2 weeks and remained elevated after 1 year, a change due to increased forage quality, not quantity. We also developed a nutrient budget within calving grounds, demonstrating that natal fluid and calf carcasses contribute substantial nitrogen subsidies. We, thus, highlight a positive zoogeochemical feedback whereby nutrients deposited during calving become bioavailable during lactation and provide evidence that site fidelity creates a biogeochemical boomerang in which animals deposit nutrients that can be reused later. [ABSTRACT FROM AUTHOR]

Some acoustic parameters of animal vocalisations have been shown to reliably indicate male quality and play a role in mate and rival assessment. Reindeer possess a peculiar vocal tract anatomy involving a laryngeal air sac which probably acts as an additional filter, making it a candidate species for novel investigations in the field of bioacoustics. We investigated whether some acoustic parameters of male rutting vocalisations were good indicators of age and body weight (used as an index for body size). We did this by performing acoustic analyses using recordings collected from a semi-domesticated reindeer population in northern Finland. We found the age of subadult males (aged 2.5–4.5 years) to be negatively correlated with formant F3 and formant spacing, suggesting that their vocalisations convey information on the caller's age. Individual formant frequencies were not affected by male body weight, but formant spacing was lower in heavier males. Despite the presence of the laryngeal air sac, formant spacing seems to be an acoustic parameter influencing mate and rival assessment in reindeer as it gives an honest indication of male body size. We discuss the importance of reliable acoustic cues to quality indices in sexual selection contexts. [ABSTRACT FROM AUTHOR]

Changing climatic conditions is a perpetual circumstance for mankind. In this study, we investigate local environmental and climatic changes near Kangerlussuaq, west Greenland. Our reconstruction is based on a lake sediment core and methods include chemical proxies and a palynological analysis. The investigated site is located 15 km from the Aasivissuit Inuit summer hunting ground, which has been in use for caribou hunting for more than 2000 years. The presented climatic reconstruction covers the time from c. 560 CE to present time. We identify three distinct periods of climate regimes: From c. 560–1100 CE conditions were stable, warm and humid, and summer temperatures were 1.5–2°C warmer than today. 1100–1600 was a period of cooler and very arid conditions with more sea ice, corresponding to the Neoglacial cooling. In this period, we detect two wildfire events and subsequent temporary caribou abandonment of the area. From 1600 to present we find increasingly warmer conditions with more precipitation and less extensive sea ice cover, gradually approaching today's climate regime in Kangerlussuaq. We review the existing literature regarding the Aasivissuit summer hunting ground, which was first used concurrently with the detected cooling. Despite climatic deterioration, the hunting ground was regularly in use throughout the Neoglacial and onwards, with peak hunting intensity in the early 1700s. The detected wildfires and reindeer abandonment are interpreted to be localized events at the coring site and did not affect the hunting ground. Our findings highlight the resilience of the Inuit hunters to climatic changes as well as the advantages and limitations of local environmental reconstructions. [ABSTRACT FROM AUTHOR]

Reindeer have long been served as vital subsistence resources for inhabitants of Arctic and subarctic regions owing to their domestication. However, the evolutionary relationships and divergence times among different reindeer populations, genetic traits that distinguish domesticated reindeer, and factors that contribute to their relative docility compared with that of other Cervidae specie, remain unclear. In this study, we sequenced the genomes of 32 individuals from wild and domestic reindeer populations that inhabit Arctic and subarctic regions. We found that reindeer experienced 2 or more independent domestication events characterized by weak artificial selection pressure and limited significant differences in genomic parameters between wild and domestic populations. Alterations in conserved noncoding elements in the reindeer genomes, particularly those associated with nervous system development, may have contributed to their domestication by rendering the nervous system less responsive. Together, our results suggest that inherent species-specific traits, rather than intense artificial selection, may have played a significant role in the relatively docile behavior of reindeer and offer valuable insights into the domestication process of these animals. [ABSTRACT FROM AUTHOR]

Encounters between animals occur when animals are close in space and time. Encounters are important in many ecological processes including sociality, predation and disease transmission. Despite this, there is little theory regarding the spatial distribution of encounters and no formal framework to relate environmental characteristics to encounters. The probability of encounter could be estimated with resource selection functions (RSFs) by comparing locations where encounters occurred to available locations where they may have occurred, but this estimate is complicated by the hierarchical nature of habitat selection.We developed a method to relate resources to the relative probability of encounter based on a scale‐integrated habitat selection framework. This framework integrates habitat selection at multiple scales to obtain an appropriate estimate of availability for encounters. Using this approach, we related encounter probabilities to landscape resources. The RSFs describe habitat associations at four scales, home ranges within the study area, areas of overlap within home ranges, locations within areas of overlap, and encounters compared to other locations, which can be combined into a single scale‐integrated RSF. We apply this method to intraspecific encounter data from two species: white‐tailed deer (Odocoileus virginianus) and elk (Cervus elaphus) and interspecific encounter data from a two‐species system of caribou (Rangifer tarandus) and coyote (Canis latrans).Our method produced scale‐integrated RSFs that represented the relative probability of encounter. The predicted spatial distribution of encounters obtained based on this scale‐integrated approach produced distributions that more accurately predicted novel encounters than a naïve approach or any individual scale alone.Our results highlight the importance of accounting for the conditional nature of habitat selection in estimating the habitat associations of animal encounters as opposed to 'naïve' comparisons of encounter locations with general availability. This method has direct relevance for testing hypotheses about the relationship between habitat and social or predator–prey behaviour and generating spatial predictions of encounters. Such spatial predictions may be vital for understanding the distribution of encounters driving disease transmission, predation rates and other population and community‐level processes. [ABSTRACT FROM AUTHOR]

Although communication is considered crucial for collaboration in natural resource management (NRM), its role has so far been superficially studied. In this paper, we present a way to investigate this communication by focusing on its implicit aspects. We observed and examined communication in three processes that aimed to find solutions to predator-reindeer problems through collaboration between reindeer herders and wildlife authorities in northern Sweden. Despite the three processes sharing the same external and internal conditions, they developed in completely different directions. We explain this by considering each process as a social practice and identifying the character of the normative structures guiding its members' sense-making and action. We show how the structures emerged, were reproduced and affected the course of events and outcomes of each process. We conclude that recognising the significance of the implicit aspects of communication offers novel opportunities to better understand collaboration in NRM. [ABSTRACT FROM AUTHOR]

Social competition for resources is widespread among animals. Females of many species compete for foraging resources through interference competition, which is a behavioural interaction between animals that reduces an individual's access to shared resources. In addition to competition from other females, females also often face harassment from males during and after the breeding season. The female competition hypothesis predicts that female-initiated aggression associated with foraging competition increases as a function of group size, but we expected this effect to be more pronounced in higher quality foraging habitat. The male harassment hypothesis predicts that male harassment of females should also increase as a function of group size as well as a function of the ratio of males to other group members. Here, we tested the female competition and male harassment hypotheses for caribou (Rangifer tarandus) within the context of variation in the social environment (i.e., group size and sex ratio) and the physical environment (i.e., variation in habitat quality). We conducted focal observations of caribou on Fogo Island, Newfoundland, over three years and quantified aggressive social interactions in different habitat types to test our hypotheses. Specifically, we took advantage of natural variation in caribou behaviour in our system and observed caribou foraging in an enhanced habitat (i.e., recreational sports complex field) and natural habitat (i.e., lichen barrens). We found limited support for the female competition hypothesis, possibly because of females' propensity to increase foraging rates in enhanced habitats. By contrast, we found strong support for the male harassment hypothesis, where males increase the frequency of harassment as group size increased. Our results suggest costs of grouping for female caribou in the post-rut time period may be related to the presence of males potentially seeking mating opportunities. [ABSTRACT FROM AUTHOR]

The structure of cellular prion proteins encoded by the prion protein gene (PRNP) impacts susceptibility to transmissible spongiform encephalopathies, including chronic wasting disease (CWD) in deer. The recent emergence of CWD in Northern European reindeer (Rangifer tarandus), moose (Alces alces alces) and red deer (Cervus elaphus), in parallel with the outbreak in North America, gives reason to investigate PRNP variation in European deer, to implement risk assessments and adjust CWD management for deer populations under threat. We here report PRNP-sequence data from 911 samples of German red, roe (Capreolus capreolus), sika (Cervus nippon) and fallow deer (Dama dama) as well as additional data from 26 Danish red deer close to the German border and four zoo species not native to Germany. No PRNP sequence variation was observed in roe and fallow deer, as previously described for populations across Europe. In contrast, a broad PRNP variation was detected in red deer, with non-synonymous polymorphisms at codons 98, 226 and 247 as well as synonymous mutations at codons 21, 78, 136 and 185. Moreover, a novel 24 bp deletion within the octapeptide repeat was detected. In summary, 14 genotypes were seen in red deer with significant differences in their geographical distribution and frequencies, including geographical clustering of certain genotypes, suggesting "PRNP-linages" in this species. Based on data from North American CWD and the genotyping results of the European CWD cases, we would predict that large proportions of wild cervids in Europe might be susceptible to CWD once introduced to naive populations. [ABSTRACT FROM AUTHOR]

In Sweden, Indigenous Sámi reindeer pastoralists must find effective ways to improve ecological conditions conducive to natural pasture-based reindeer pastoralism in a rapidly changing environment. In particular, they must challenge the conventional climate policy agenda of the dominant economic and political actors. This paper seeks to contribute to the emergence of a social movement that can push for reforms towards such improvements. Theoretically, we combine a theory of hegemony and counter-hegemonic politics, and the contentious politics approach to social movement theory, to discuss how meaningful reforms could be achieved by assembling a broad social coalition. Empirically, we examine 10 years of data from a public media outlet that reports on Sámi issues to show what demands are being made, who is making them, and the reforms and changes in social relations that they imply. The analysis identifies current coalitions and demand clusters. We discuss potential opportunities for a new reform agenda and actor constellations, with a focus on rural and Indigenous cultures and livelihoods, in relation to a broader environmental movement. [ABSTRACT FROM AUTHOR]

Chronic wasting disease (CWD), a prion disease affecting cervids, has been known in North America (NA) since the 1960s and emerged in Norway in 2016. Surveillance and studies have revealed that there are different forms of CWD in Fennoscandia: contagious CWD in Norwegian reindeer and sporadic CWD in moose and red deer. Experimental studies have demonstrated that NA CWD prions can infect various species, but thus far, there have been no reports of natural transmission to non-cervid species. In vitro and laboratory animal studies of the Norwegian CWD strains suggest that these strains are different from the NA strains. In this work, we describe the intracerebral transmission of reindeer CWD to six scrapie-susceptible sheep. Detection methods included immunohistochemistry (IHC), western blot (WB), enzyme-linked immunosorbent assay (ELISA), real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA). In the brain, grey matter vacuolation was limited, while all sheep exhibited vacuolation of the white matter. IHC and WB conventional detection techniques failed to detect prions; however, positive seeding activity with the RT-QuIC and PMCA amplification techniques was observed in the central nervous system of all but one sheep. Prions were robustly amplified in the lymph nodes of all animals, mainly by RT-QuIC. Additionally, two lymph nodes were positive by WB, and one was positive by ELISA. These findings suggest that sheep can propagate reindeer CWD prions after intracerebral inoculation, resulting in an unusual disease phenotype and prion distribution with a low amount of detectable prions. [ABSTRACT FROM AUTHOR]

Caribou (Rangifer tarandus) undergo exceptionally large, annual synchronized migrations of thousands of kilometers, triggered by their shared environmental stimuli. The proximate triggers of those migrations remain mysterious, though snow characteristics play an important role due to their influence on the mechanics of locomotion. We investigate whether the snow melt–refreeze status relates to caribou movement, using previously collected Global Positioning System (GPS) caribou collar data. We analyzed 117 individual female caribou with >30,000 observations between 2007 and 2016 from the Bathurst herd in Northern Canada. We used a hierarchical model to estimate the beginning, duration, and end of spring migration and compared these statistics against snow pack melt characteristics derived from 37 GHz vertically polarized (37V GHz) Calibrated Enhanced-Resolution Brightness Temperatures (CETB) at 3.125 km resolution. The timing of migration for Bathurst caribou generally tracked the snowmelt onset. The start of migration was closely linked to the main melt onset in the wintering areas, occurring on average 2.6 days later (range −1.9 to 8.4, se 0.28, n = 10). The weighted linear regression was also highly significant (p-value = 0.002, R 2 = 0.717 ). The relationship between migration arrival times and the main melt onset on the calving grounds ( R 2 = 0.688, p-value = 0.003), however, had a considerably more variable lag (mean 13.3 d, se 0.67, range 3.1–20.4). No migrations ended before the main melt onset at the calving grounds. Thawing conditions may provide a trigger for migration or favorable conditions that increase animal mobility, and suggest that the snow properties are more important than snow presence. Further work is needed to understand how widespread this is and why there is such a relationship. [ABSTRACT FROM AUTHOR]

In the European north, there is a growing trend for Sámi reindeer herding communities to enter negotiated agreements with developers on projects that aim to exploit land and natural resources. This paper offers, for the first time, an evaluation of the content of a selection of these agreements, drawing on a sample of 15 agreements from five communities in Sweden. The evaluation was conducted from a Sámi perspective on how the agreements affect the ability of herding communities to safeguard reindeer wellbeing. The overall conclusion is that the agreements provide some positive contributions to mitigate harm to the reindeer, but also contribute considerable risks. We argue that agreements might have a meaningful role to play in the integration of Sámi rights in land and resource decisions, but herding communities have considerable space to increase the range of clauses – guided by larger goals of Sámi self-determination. [ABSTRACT FROM AUTHOR]

Competition for resources and space can drive forage selection of large herbivores from the bite through the landscape scale. Animal behaviour and foraging patterns are also influenced by abiotic and biotic factors.Fine‐scale mechanisms of density‐dependent foraging at the bite scale are likely consistent with density‐dependent behavioural patterns observed at broader scales, but few studies have directly tested this assertion.Here, we tested if space use intensity, a proxy of spatiotemporal density, affects foraging mechanisms at fine spatial scales similarly to density‐dependent effects observed at broader scales in caribou. We specifically assessed how behavioural choices are affected by space use intensity and environmental processes using behavioural state and forage selection data from caribou (Rangifer tarandus granti) observed from GPS video‐camera collars using a multivariate discrete‐choice modelling framework.We found that the probability of eating shrubs increased with increasing caribou space use intensity and cover of Salix spp. shrubs, whereas the probability of eating lichen decreased. Insects also affected fine‐scale foraging behaviour by reducing the overall probability of eating. Strong eastward winds mitigated negative effects of insects and resulted in higher probabilities of eating lichen. At last, caribou exhibited foraging functional responses wherein their probability of selecting each food type increased as the availability (% cover) of that food increased.Space use intensity signals of fine‐scale foraging were consistent with density‐dependent responses observed at larger scales and with recent evidence suggesting declining reproductive rates in the same caribou population. Our results highlight potential risks of overgrazing on sensitive forage species such as lichen. Remote investigation of the functional responses of foraging behaviours provides exciting future applications where spatial models can identify high‐quality habitats for conservation. [ABSTRACT FROM AUTHOR]

Basic methods of population genetics and animal breeding and mathematical methods of machine learning used in animal breeding are analyzed. CatBoost library models were trained on the example of two domesticated species—horse (Equus caballus) and reindeer (Rangifer tarandus). Data from microsatellite panels of loci 16 and 17, respectively, were used to train the model using data on domesticated and wild reindeer, European and Russian horse breeds. The standard indicators (Accuracy, Precision, Recall, and F1) were calculated, and confusion matrices were constructed to assess the success of the model. New possibilities for identifying animal breed affiliation are shown. [ABSTRACT FROM AUTHOR]

As seasonal migratory animals, reindeer inhabit the natural habitats in Arctic regions and have evolved their hindlimb joints to adapt to the complex ground conditions there. Inverse dynamics of the joints is an important tool to study foot functions. Herein, with a motion tracking system and plantar pressure data based on kinematics and inverse dynamics of hindlimbs, we investigated the changes in joint angles, net joint moments, net joint powers, and work of reindeer at different speeds. Reindeer may adopt different movement patterns to efficiently utilize energy and adapt to the demands of different gaits and speeds. The joint ranges of motion (ROM) of the ankle joint (αb), metatarsophalangeal (MTP) joint (αc), and interphalangeal joint (αd) of the hindlimbs were about 20.73°–28.87°, 40.37°–47.69°, and 24.47°–26.18°, respectively. The ankle joint produced positive work to provide propulsion. The positive work done at the ankle joint during walking, slow trotting, and fast trotting was 8.61 × 10–2, 9.25 × 10–2, and 15.44 × 10–2 J·kg−1, respectively. The MTP and interphalangeal joints both absorbed energy during walking, slow trotting, and fast trotting. The energy absorption at the respective speeds was 12.53 × 10–2, 13.57 × 10–2, and 19.90 × 10–2 J·kg−1, respectively, by the MTP joint and was 9.49 × 10–2, 7.71 × 10–2, and 10.26 × 10–2 J·kg−1, respectively, by the interphalangeal joint. The MTP joint and interphalangeal joint of the hindlimbs serve as the primary sites for energy storage and release, functioning as an elastic system. This study contributes to a deeper understanding about the biomechanical properties of hindlimb joints and provides a theoretical basis for designing extremity robots in extreme environments through analyzing the functional characteristics of reindeer foot joints. [ABSTRACT FROM AUTHOR]

The environmental conditions experienced by hunter‐gatherers during the second part of the Upper Palaeolithic (ca. 28 000–15 000 cal bp) are poorly known in the mid‐elevation volcanic mountains of the Massif Central in southern France. The stable isotope ratios of carbon and nitrogen (13C/12C and 15N/14N expressed as δ13C and δ15N values) in bone collagen of large herbivores can track their diet and habitat, reflecting local abiotic conditions (temperature, aridity, altitude). Due to poor preservation of skeletal organic matter in the region, new radiocarbon dating was conducted on a limited number of quality‐controlled collagen samples, based on a minimum carbon content of 30%. They document three main phases of occupation corresponding to the Final Gravettian, the Badegoulian and the Magdalenian, each of which is represented in different regions of the Allier and Loire valleys. Over time, a decrease in horse δ15N values, the best documented species of large herbivores, is found between the Final Gravettian (ca. 26 700–25 600 cal bp), around the Last Glacial Maximum and the Badegoulian (ca. 21 900–19 200 cal bp), followed by an increase in δ15N and δ13C values during the Magdalenian (ca. 19 100–16 600 cal bp). During the Badegoulian, the δ15N values of the horses were lower than those of their counterparts in southwestern France, testifying to harsh climatic conditions favourable to a tundra‐like landscape, also reflected in the higher horse and reindeer δ13C values in the Allier valley compared to those in southwestern France. The relatively high δ13C and low δ15N values of a Final Gravettian wolf from the Allier valley suggests reindeer as a preferred prey, in line with their high abundance in the archaeological sites. Game access, rather than climatic conditions or lithic resources, seems to have motivated human groups to occupy the Massif Central during the Upper Palaeolithic. [ABSTRACT FROM AUTHOR]

Reindeer, called caribou in North America, has a circumpolar distribution and all extant populations belong to the same species (Rangifer tarandus). It has survived the Holocene thanks to its immense adaptability and successful coexistence with humans in different forms of hunting and herding cultures. Here, we examine the paternal and maternal history of Rangifer based on robust Y‐chromosomal and mitochondrial DNA (mtDNA) trees representing Eurasian tundra reindeer, Finnish forest reindeer, Svalbard reindeer, Alaska tundra caribou, and woodland caribou. We first assembled Y‐chromosomal contigs, representing 1.3 Mb of single‐copy Y regions. Based on 545 Y‐chromosomal and 458 mtDNA SNPs defined in 55 males, maximum parsimony trees were created. We observed two well separated clades in both phylogenies: the "EuroBeringian clade" formed by animals from Arctic Islands, Eurasia, and a few from North America and the "North American clade" formed only by caribou from North America. The time calibrated Y tree revealed an expansion and dispersal of lineages across continents after the Last Glacial Maximum. We show for the first time unique paternal lineages in Svalbard reindeer and Finnish forest reindeer and reveal a circumscribed Y haplogroup in Fennoscandian tundra reindeer. The Y chromosome in domesticated reindeer is markedly diverse indicating that several male lineages have undergone domestication and less intensive selection on males. This study places R. tarandus onto the list of species with resolved Y and mtDNA phylogenies and builds the basis for studies of the distribution and origin of paternal and maternal lineages in the future. [ABSTRACT FROM AUTHOR]

For decades, researchers have employed sound to study the biology of wildlife, with the aim to better understand their ecology and behaviour. By utilizing on‐animal recorders to capture audio from freely moving animals, scientists can decipher the vocalizations and glean insights into their behaviour and ecosystem dynamics through advanced signal processing. However, the laborious task of sorting through extensive audio recordings has been a major bottleneck. To expedite this process, researchers have turned to machine learning techniques, specifically neural networks, to streamline the analysis of data. Nevertheless, much of the existing research has focused predominantly on stationary recording devices, overlooking the potential benefits of employing on‐animal recorders in conjunction with machine learning. To showcase the synergy of on‐animal recorders and machine learning, we conducted a study at the Kutuharju research station in Kaamanen, Finland, where the vocalizations of rutting reindeer were recorded during their mating season. By attaching recorders to seven male reindeer during the rutting periods of 2019 and 2020, we trained convolutional neural networks to distinguish reindeer grunts with a 95% accuracy rate. This high level of accuracy allowed us to examine the reindeers' grunting behaviour, revealing patterns indicating that older, heavier males vocalized more compared to their younger, lighter counterparts. The success of this study underscores the potential of on‐animal acoustic recorders coupled with machine learning techniques as powerful tools for wildlife research, hinting at their broader applications with further advancement and optimization. [ABSTRACT FROM AUTHOR]

The long‐term conservation of species at risk relies on numerous, and often concurrent, management actions to support their recovery. Generally, these actions are habitat‐based while others are focused on a species' position within its ecological community. Less studied are the impacts from human presence, despite evidence that human activity may reduce the area functionally available for occupancy or resource acquisition. In the winter of 2020/2021, COVID‐19‐related travel restrictions led to a reduction in helicopter‐assisted back‐country skiing (heli‐skiing). We examined how these reductions in heli‐skiing (termed the anthropause) affected the movement ecology and resource selection of southern mountain caribou (Rangifer tarandus caribou) as compared to two prior years (2018/2019 and 2019/2020) and the following year when heli‐skiing resumed (2021/2022). We found that home‐range size was on average 80–120% larger during the anthropause than in years of normal heli‐ski operations. Movement rates also varied among periods, with movement during the anthropause (11.9 km2/day) being higher than in 2019/2020 (7.8 km2/day) and 2021/2022 (8.7 km2/day), though similar to 2018/2019 (12.2 km2/day). Resource selection among periods did not differ, with caribou consistently selecting old forests, high elevations and gentle terrain. These results suggest that back‐country recreation, specifically heli‐skiing, may be limiting access to resources for southern mountain caribou. This limitation arises through reduced home‐range size within suitable late‐winter habitat, relative to when heli‐skiing is reduced or not occurring – consistent with Encounter Theory. While the demographic effects of reduced home‐range size and movement were not examined here, reduced access to resources likely compounds other stressors known to affect population viability of caribou. The results of this study demonstrate the impact that recreation can have on wildlife and highlight the need to consider heli‐skiing and other forms of recreation when developing recovery plans. [ABSTRACT FROM AUTHOR]

Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973–2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population‐based recovery actions at increasing population growth. Reducing potential limiting factors on threatened caribou populations offered a rare opportunity to identify the causes of decline and assess methods of recovery. Southern mountain caribou abundance declined by 51% between 1991 and 2023, and 37% of subpopulations were functionally extirpated. Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation, and combinations of wolf reductions with maternal penning or supplemental feeding provided rapid growth but were applied to only four subpopulations. As of 2023, recovery actions have increased the abundance of southern mountain caribou by 52%, compared to a simulation with no interventions. When predation pressure was reduced, rapid population growth was observed, even under contemporary climate change and high levels of habitat loss. Unless predation is reduced, caribou subpopulations will continue to be extirpated well before habitat conservation and restoration can become effective. [ABSTRACT FROM AUTHOR]

Land use conflicts are intensifying in Northern Sweden due to the increasing global demand for resources coupled with the green transition. In line with this, a thorough understanding of land use conflicts in the area is becoming necessary as economic activities expand and newer ones are developed. Hence, this paper aims to provide a systematic literature review of research on land use conflicts specific to Northern Sweden, focusing on various economic activities such as forestry, mining, tourism, energy sector and reindeer husbandry. Additionally, we aim to determine lessons learned and suggested ways forward based on a systematic review. We used Scopus and Web of Science on June 2023 and through descriptive statistical analysis of 33 articles, we summarized research trends and gaps. We found three main typologies of conflicts and five main themes of suggested ways forward. Recommendations agree that there should be a broader understanding of the underlying interests of the stakeholders; and there should be an inclusive, more participatory approach to discussing potential solutions, not to create an agreement but to come to an understanding. Beyond academic insights, the findings hold practical relevance for shaping effective land use policies. This paper offers valuable lessons that extend beyond the local context, informing broader discussions and policy considerations for sustainable land management in the larger Arctic setting, where similar challenges and resource demands are unfolding. [ABSTRACT FROM AUTHOR]

A 2‐year‐old, male reindeer (Rangifer tarandus tarandus) presented for further investigations and treatment of acute colic signs. On clinical investigations, an ultrasonographic abdominal exam revealed multiple hypomotile, dilated and fluid‐filled small intestinal loops. Based on clinical findings and increased signs of abdominal pain, small intestine obstruction was suspected, and an exploratory laparotomy was performed. The animal was premedicated with medetomidine (0.003 mg/kg) and butorphanol (0.05 mg/kg) intravenously. General anaesthesia was induced with ketamine (2 mg/kg intravenously) and propofol (3 mg/kg intravenously), and maintained with isoflurane in oxygen. Additional analgesia was provided with methadone (0.1 mg/kg intravenously) and ketamine (0.5 mg/kg intravenously). A jejuno‐jejunal intussusception requiring resection of approximately 6 inches (15 cm) was identified and jejuno‐jejuno anastomosis was performed. Fluid resuscitation was administered for treatment of hypotension during general anaesthesia. Recovery from anaesthesia was uneventful. Nevertheless, the deer was euthanased 5 days later due to clinical deterioration. [ABSTRACT FROM AUTHOR]

Since the 1950s, more than 200 000 km of roads have been built in Sweden’s forests, making them easily accessible and open to multiple uses. The aim of this study was to review the impacts of forest roads in Sweden from a broad perspective encompassing social, ecological, and environmental factors. The Swedish case is interesting because it has an extensive network of permanent forest roads which were built primarily for forestry-related transportation but are currently used by many other stakeholders for many different purposes. Forest roads not only facilitate transportation of wood, machinery, personnel, and equipment into and out of the forest but also enable emergency response to wildfires and support berry and mushroom picking, hunting, recreation, tourism, and access to second homes. The roads increase the opportunities for members of the public to experience forests in various ways. Conflicts arise when different interests collide, for example when the interests of the forest owner clash with those of commercial berry-picking companies, tourism entrepreneurs, or reindeer (Rangifer tarandus L.) herding. Forest roads may have ecological impacts such as barrier and disturbance effects, fragmentation or loss of habitats, altering fauna movement patterns, and changing the composition of plant and insect species. The environmental impacts of forest roads relate to, among other things, hydrology, water quality, and erosion. Predicted changes in the climate are likely to place new demands on Swedish forest roads but, despite their extent, this review shows that there is only a small amount of rather fragmented research on their social, ecological, and environmental consequences. Overall, few studies appear to cover both social and ecological/environmental factors and their interactions, either in Sweden or elsewhere. This review provides examples of such interactions in the case of Sweden, and suggests that more research into these and the specific social, ecological, and environmental factors involved is warranted.

Snow conditions in the High North are an important control on wintertime forage availability for reindeer, and under climate change, they are changing rapidly. In the European Arctic, this has the potential to disrupt traditional reindeer herding practices, reindeer health, and local culture (including that of Indigenous communities like the Sámi). At the same time, Norwegian coastal cities are competing to act as multi-model transportation hubs as sea-ice retreat creates expectations for increased marine accessibility. An “Arctic Railway” connecting Rovaniemi to Kirkenes has been proposed to support these port developments, but this route passes through rangelands managed by Sámi and local herding communities. This study develops an assessment of past and future snow characteristics relevant to reindeer health to provide a context for understanding the impacts of this infrastructure development. Climate model and detailed snowpack simulations were performed for 1950 to 2100 along the proposed route. Results show that deep snow becomes less frequent and spring thaw advances, favorable to reindeer. However, icy snow conditions become more frequent, potentially forcing herds from tundra and farmland to forested areas. This suggests policy alternatives that focus on the development and maintenance of migration corridors to allow appropriate movement of reindeer herds.