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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]

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]

Context: Anthropogenic habitat loss and fragmentation are major threats to ecosystems and a focus in conservation. However, conservation is often limited to considerations of site-level processes neglecting the effect of the surrounding landscape that might limit the effectiveness of restoration efforts. Objectives: Using seismic lines in Alberta’s oil sands as a case study, we demonstrate an approach that integrates spatial configuration of anthropogenic footprints to prioritize habitat defragmentation. Methods: We quantified the effects of seismic line density and configuration on functional footprints for caribou, butterfly diversity, and vascular plant diversity, to predict whether edge effects are more pronounced under different line densities and configurations. We then estimated the portion of the original functional footprint that would persist in the landscape due to the co-occurrence with other anthropogenic activities. Results: We found that functional footprint for caribou grows rapidly as habitat loss increases. In contrast, butterflies and plants exhibited a more gradual and linear growth in functional footprints at more local scales. This effect varies based on configuration of lines, either suppressing or facilitating the effect of habitat loss on functional habitats. Finally, restoration of all seismic lines without considering other footprints would reduce the original functional footprint by only 57% for caribou. Conclusions: Restoration efforts for habitat defragmentation rarely consider the spatial configuration of linear features, particularly as it relates to the co-occurrence of other footprints that are not being restored. Our functional approach to defragmentation of habitat encompasses different spatial concepts related to anthropogenic forest fragmentation and allows up to a 25-fold gain in cost-effectiveness for seismic lines restoration. [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]

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]

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]

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]

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]

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]

Marker-assisted selection for improving reindeer meat production is at the early stages of development, which requires analysis of variation within the candidate genes for meat production. The calpastatin and androgen receptor genes were chosen as such genes to study their variability in reindeer. In different domesticated animal species, polymorphisms and indels in the androgen receptor gene were associated with growth and weight characteristics. Based on the results from many studies, sequence variation in the calpastatin CAST gene region was associated with meat quality and meat production of livestock. Principal component analysis of CAST variability grouped wild and domestic deer from Yakutia, as well as wild and domestic deer from Amur oblast, which implies gene flow between local breeds of domesticated deer and wild populations. At the same time, in the case of three microsatellite loci found in the present study in the intron of the androgen receptor gene, principal component analysis separated wild and domestic deer. [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]

Better knowledge of genetic relationships between the Fortymile caribou herd and its neighbors is needed for conservation decision-making in Canada. Here, we contribute the first fine-scale analysis of genetic population structure in nine contiguous caribou herds at the geographic boundaries between Barren-ground and Northern Mountain caribou, and at the Alaska-Yukon border. Using pairwise differentiation metrics, STRUCTURE, and discriminant analysis of principal components (DAPC) to analyze 15 microsatellite loci in 379 caribou, we found complex patterns of genetic differentiation. The Fortymile was the only herd assigned to more than one genetic cluster, indicative of its history as a larger herd whose range expansions and gene flow to other herds were likely important to maintaining diversity across a functioning genetic metapopulation. Some small herds (Chisana, Klaza, and White Mountains) were genetically distinct, while others (Hart River, Clear Creek, Mentasta) exhibited little differentiation from herds they occasionally overlap, including herds assigned to different conservation units (DUs). This genetic connectivity does not result from demographic connectivity, as episodic contact during rut, rather than herd switching, is the likely mechanism. Unusually, one small herd (White Mountains) maintained genetic differentiation despite rut overlap with Fortymile. Our data reveal that some herds with different ecological and behavioral attributes are demographically independent but nonetheless genetically connected. Thus, we suggest that managing caribou for an appropriate level of genetic connectivity, while also supporting herd persistence, will be essential to conserve caribou genetic diversity in the region. [ABSTRACT FROM AUTHOR]

Abstract 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.

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]

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.

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]

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]

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]

Individuals that isolate themselves to give birth can use more than one strategy in choosing birth sites to maximize reproductive success. Previous research has focused on the consistency in the use of the same birth‐site across years (i.e., spatial fidelity), but individuals alternatively may use similar habitat conditions across years (i.e., habitat fidelity). Using GPS telemetry, we determined whether woodland caribou expressed spatial or habitat fidelity during calving, and evaluated intrinsic and extrinsic factors associated with expressing either type of fidelity. We identified 56 individuals with ≥2 putative birth events, via a movement‐based model, across northern Ontario between 2010 and 2014. Individuals were classified as expressing (1) spatial fidelity by comparing sequential calving locations to a random spatial distribution of available calving locations, (2) habitat fidelity using a logistic use model compared to a null (intercept only) model, (3) no fidelity (neither criterion met), or (4) both spatial and habitat fidelity (both criteria met). Across all individuals, 37% expressed no fidelity (36 of 98), 15% expressed only spatial fidelity (15 of 99), 35% expressed only habitat fidelity (34 of 98), and 14% expressed both spatial and habitat fidelity (14 of 98). Older individuals were more likely to express spatial fidelity, whereas lower availability of upland and lowland conifer forests without linear features increased the probability an individual expressed habitat fidelity. Our results indicate that managing for caribou calving needs to consider protecting both specific, known birthing sites, but also broad‐scale areas of preferred habitat for calving. Understanding the mechanisms that influence caribou expressing calving fidelity, and associated fitness costs, is crucial for the conservation of the species. [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]

Density dependence is a fundamental ecological process. In particular, animal habitat selection and social behavior often affect fitness in a density-dependent manner. The Ideal Free Distribution (IFD) and niche variation hypothesis (NVH) present distinct predictions associated with Optimal Foraging Theory about how the effect of habitat selection on fitness varies with population density. Using caribou (Rangifer tarandus) in Canada as a model system, we test competing hypotheses about how habitat specialization, social behavior, and annual reproductive success (co)vary across a population density gradient. Within a behavioral reaction norm framework, we estimate repeatability, behavioral plasticity, and covariance among social behavior and habitat selection to investigate the adaptive value of sociality and habitat selection. In support of NVH, but not the IFD, we find that at high density habitat specialists had higher annual reproductive success than generalists, but were also less social than generalists, suggesting the possibility that specialists were less social to avoid competition. Our study supports niche variation as a mechanism for density-dependent habitat specialization. Social behavior and habitat specialization are often linked through density-dependence and their effects on fitness. Here, the authors show that in caribou, these traits are density-dependent, but only habitat specialization has an effect on fitness. [ABSTRACT FROM AUTHOR]

Interpretations of Late Pleistocene hominin adaptative capacities by archaeologists have focused heavily on their exploitation of certain prey and documented contemporary behaviours for these species. However, we cannot assume that animal prey-taxa ecology and ethology were the same in the past as in the present, or were constant over archaeological timescales. Sequential isotope analysis of herbivore teeth has emerged as a particularly powerful method of directly reconstructing diet, ecology and mobility patterns on sub-annual scales. Here, we apply 87Sr/86Sr isotope analysis, in combination with δ18O and δ13C isotope analysis, to sequentially sampled tooth enamel of prevalent herbivore species that populated Europe during the Last Glacial Period, including Rangifer tarandus, Equus sp. and Mammuthus primigenius. Our samples come from two open-air archaeological sites in Central Germany, Königsaue and Breitenbach, associated with Middle Palaeolithic and early Upper Palaeolithic cultures, respectively. We identify potential inter- and intra-species differences in range size and movement through time, contextualised through insights into diet and the wider environment. However, homogeneous bioavailable 87Sr/86Sr across large parts of the study region prevented the identification of specific migration routes. Finally, we discuss the possible influence of large-herbivore behaviour on hominin hunting decisions at the two sites. Using multi-isotope analysis of tooth enamel of reindeer, equids and mammoth from the archaeological sites of Königsaue and Breitenbach, the authors identify shifts in ranging behaviour of these hominin prey species during the Last Glacial Period in Central Germany. [ABSTRACT FROM AUTHOR]

A challenge for management of wildlife species is the assessment of the effect of roads on migration. We developed models to estimate the spatial (zone of influence (ZOI)) and temporal (delays in migration) effects of roads, and test whether road closures reduced delays in migration. We analyzed collar (2011–2019) and road survey data from two barren-ground caribou (Rangifer tarandus groenlandicus (Borowski, 1780)) herds to assess the impact of a 171 km mine road that bisects their migration corridor. We estimated ZOIs of 16–17 km prior to crossing the road during 2018 and 2019, and 3.0 km after crossing. Estimates of mean delay were 4.3 and 2.5 days for 2018 and 2019, which were reduced by 28%–68% (1.2–1.7 days) if roads were closed when caribou were within the ZOI. In 2017–2018, when the road was extended 64 km north, caribou were 12% less likely to deflect north around the road, therefore increasing delays. Road surveys indicated aggregation of caribou prior to crossing the road, with few caribou observed after crossing, a finding supported by collar data. Our methods can estimate the spatial and temporal effects of roads for any wildlife species and assess mitigation strategies in reducing delays in migration. [ABSTRACT FROM AUTHOR]

In northern British Columbia and southern Yukon woodland, caribou forage extensively on terrestrial lichens, predominately mat-forming Cladina species in late-successional pine-lichen woodlands. Many of these stands are now reaching a point in their development where lichen abundance declines as feather-moss mats increase. We evaluated the response of forest floor plant communities in pine-lichen woodlands from the southern Yukon Lewes Marsh partial-cutting trial 8 years after harvesting. Photoplot results documented a major decline (>60% ± 5.6% SE) in the mean surface area of existing large clumps of C. mitis in control (unharvested) treatments, whereas the mean surface area of large C. mitis clumps declined by 28% (±15% SE) in the one-third basal-area removal and showed an increase of 13.5% (±25% SE) in the two-thirds basal-area removal. Line intercept transects documented no changes in overall stand-level lichen abundance between pre-harvest (2012) and post-harvest (2021) measurements, while feather-moss mats and dwarf shrubs showed declines and increases, respectively, in partial-cutting harvest plots. Stand thinning may provide a bridging strategy to extend the period of forage lichen availability in late-seral pine-lichen woodlands, an important consideration in landscapes where increasing severity and frequency of fires are changing the seral-state distribution of caribou habitat. [ABSTRACT FROM AUTHOR]

The conservation of genetic diversity and connectivity is essential for the long-term persistence and adaptive ability of a species. Recent calls have been made for the inclusion of genetic diversity and differentiation measures in the assessment, management, and conservation of species. However, the literature often lacks direction on how to do so for species with continuous distributions or no distinct breaks in genetic connectivity. There are many considerations to overcome when investigating genetic diversity and connectivity of such species. We combine multiple genetic network methodologies with more traditional population genetic analyses within a single framework to address the challenges of investigating population structure and quantifying variation in genetic diversity and connectivity of wide-ranging species with continuous distributions. We demonstrate the efficacy and applicability of our framework through a study on woodland caribou (Rangifer tarandus) occupying the boreal forest of Canada; a species of significant conservation concern. The dataset consisted of 4911 unique individuals genotyped at 9 microsatellite loci, which were subsequently partitioned into 103 spatial nodes to create a population-based genetic network. The Walktrap community detection algorithm was used to detect hierarchical population genetic structure within the study area and node-based network metrics such as mean inverse edge weight and clustering coefficient were used to quantify the variation in genetic connectivity across the range. Lastly, genetic diversity was assessed by calculating allelic richness and heterozygosity of the nodes making up the network. The community detection analysis identified two communities at the coarsest scale to nine communities at the optimal partition. A strong pattern of Isolation by Distance (IBD) was found across the range at multiple scales. Furthermore, signs of genetic erosion along the study area’s southern boundaries were depicted by nodes presenting low genetic diversity and low centrality values. These results are important to the species status assessments in providing previously unavailable information on connectivity and diversity within and beyond the current local population units used in management. Our approach to quantify the patterns and extent of connectivity across the boreal range is comprehensive and could easily be adapted to other species. The results are robust and provide a solid foundation for the continued monitoring and recovery of the species.

Abstract 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.

Over a few past decades, theoretical, analytical, and methodological advances in genetics have revolutionized population genetic research, providing a better understanding of evolutionary processes and the history of populations and species. Methodologically, this progress is largely due to the invention of polymerase chain reaction technology and the introduction of microsatellite DNA markers. This review discusses trends in the use of microsatellite markers as effective tools for solving a wide range of issues in population genetics, conservation and evolutionary biology of the only species of the genus Rangifer – reindeer. Based on the analysis of both experimental and review publications (78 sources) of the scientific teams of the Russian Federation, Canada, the United States of America, Ireland, Japan, China, Norway the first works on the successful amplification of reindeer microsatellites have been summarized. There has been demonstrated the significance of the data of markers for studying intra- and inter-population diversity, differentiation, genetic relationships, the impact of anthropogenic factors on genetic diversity and genetic isolation of populations, as well as for reconstructing the evolutionary history of the various reindeer forms.

Growing white‐tailed deer populations in Canada's boreal forest are linked to declines of threatened boreal caribou populations. Recent work by Dickie et al. (2024) shows that climate plays a stronger role than anthropogenic habitat alteration in impacting deer white‐tailed deer density, however we contend that these findings are not robust due to insufficient data and the analysis used is sensitive to data scaling approach. We demonstrate approximately equal but opposite effects of climate and alteration on white‐tailed deer population density, and emphasize the importance of robust analyses involving contentious conservation issues. [ABSTRACT FROM AUTHOR]

In a study published in Global Change Biology, Dickie et al. examined the effects of climate and habitat alteration on white-tailed deer density. They found that both factors contribute to deer densities, but climate plays a particularly strong role. A critique by Barnas et al. raised concerns about data transformations and model overfitting, but Dickie et al. argue that these criticisms are unfounded or align with their original conclusions. They emphasize that management decisions must consider the impact of climate change, which is predicted to increase in the future, in order to address the decline of woodland caribou populations. [Extracted from the article]

The article discusses a study conducted in British Columbia, Canada, during the COVID-19 pandemic to observe the effects of reduced human activity on woodland caribou. The study analyzed caribou home ranges before, during, and after the pandemic and found that home ranges were largest during the pandemic. However, the study did not find evidence that heli-skiing, which was reduced during the pandemic, was the cause of the increase in home range size. The study suggests that other factors, such as weather and snow conditions, may have influenced the caribou's behavior. Therefore, the conclusion that caribou were released from a "landscape of fear" during the pandemic is not currently supported. [Extracted from the article]

Many large carnivores, despite widespread habitat alteration, are rebounding in parts of their former ranges after decades of persecution and exploitation. Cougars (Puma concolor) are apex predator with their remaining northern core range constricted to mountain landscapes and areas of western North America; however, cougar populations have recently started rebounding in several locations across North America, including northward in boreal forest landscapes. A camera‐trap survey of multiple landscapes across Alberta, Canada, delineated a range edge; within this region, we deployed an array of 47 camera traps in a random stratified design across a landscape spanning a gradient of anthropogenic development relative to the predicted expansion front. We completed multiple hypotheses in an information‐theoretic framework to determine if cougar occurrence is best explained by natural land cover features, anthropogenic development features, or competitor and prey activity. We predicted that anthropogenic development features from resource extraction and invading white‐tailed deer (Odocoileus virgianius) explain cougar distribution at this boreal range edge. Counter to our predictions, the relative activity of native prey, predominantly snowshoe hare (Lepus americanus), was the best predictor of cougar occurrence at this range edge. Small‐bodied prey items are particularly important for female and sub‐adult cougars and may support breeding individuals in the northeast boreal forest. Also, counter to our predictions, there was not a strong relationship detected between cougar occurrence and gray wolf (Canis lupus) activity at this range edge. However, further investigation is recommended as the possibility of cougar expansion into areas of the multi‐prey boreal system, where wolves have recently been controlled, could have negative consequences for conservation goals in this region (e.g. the recovery of woodland caribou [Rangifer tarandus caribou]). Our study highlights the need to monitor contemporary distributions to inform conservation management objectives as large carnivores recover across North America. [ABSTRACT FROM AUTHOR]

Age estimation is crucial for investigating animal populations in the past and present. Visual examination of tooth wear and eruption is one of the most common ageing methods in zooarchaeology, wildlife management, palaeontology, and veterinary research. Such approaches are particularly advantageous because they are non-destructive, can be completed using photographs, and do not require specialized training. Several tooth wear and eruption methods have been developed for Rangifer tarandus, a widely distributed and long-utilized species in the North. This paper evaluates the practicality and effectiveness of three existing visual tooth wear and eruption methods for this species using a large known-age sample from several caribou populations in northern Canada (Bluenose East, Bluenose West, Dolphin-Union, Qamanirjuaq, and Beverly herds). These methods are evaluated based on: (1) the amount of error and bias between estimated and actual ages, (2) suitable and interpretable results, (3) user-friendly and unambiguous procedures, and (4) which teeth and visual features of those teeth are used to record wear and eruption status. This study finds that the three evaluated methods all have variable errors and biases, and two show extensive biases when applied to older individuals. Demographic data is simpler to generate and more flexible to report when methods allow age to be estimated as a continuous or discrete variable, rather than as age ranges. The dentition samples used by two of the previously developed methods impact their applicability to other populations of Rangifer. In one existing method, individuals were unavailable from some age ranges leaving gaps when assigning ages. For another Rangifer-ageing method, the population utilized was too distinct in morphology or diet to be used with the Canadian caribou analyzed here. Additional refinement of tooth wear and eruption ageing methods will benefit zooarchaeological research on reindeer and caribou remains. [ABSTRACT FROM AUTHOR]

Surveillance of endoparasites at the host community level is rarely reported for ungulates. Yet, changes in the composition and abundance of species in ungulate assemblages, coupled with environmental and climate change, bring into focus the need for baseline data on endoparasite occurrence in host species at the community level. We investigated the prevalence and intensity of eggs of endoparasites in feces of a dynamic boreal ungulate community in Yukon, Canada, that included reintroduced bison (Bison bison), as well as introduced elk (Cervus canadensis), naturally colonizing mule deer (Odocoileus hemionus), and resident populations of caribou (Rangifer tarandus), moose (Alces americanus), and thinhorn sheep (Ovis dalli). We also examined the change in endoparasite prevalence and intensity in bison fecal samples collected eight years apart. The prevalence of eggs detected in feces differed across species for most endoparasite groups. We also provide new records of several endoparasites in novel hosts or new geographic records. We detected a substantially greater prevalence and intensity of trichostrongyle-type eggs in bison feces between samples collected eight years apart. Our data emphasize the need for targeted pathogen surveillance programs to monitor the movement of various ungulate and associated endoparasites. This is particularly pertinent since our data potentially supports evidence for the continued northward expansion and host switching of protostrongylid species, which may have health implications for animals at a new interface. [ABSTRACT FROM AUTHOR]

Anthropogenic habitat alteration and climate change are two well‐known contributors to biodiversity loss through changes to species distribution and abundance; yet, disentangling the effects of these two factors is often hindered by their inherent confound across both space and time. We leveraged a contrast in habitat alteration associated with the jurisdictional boundary between two Canadian provinces to evaluate the relative effects of spatial variation in habitat alteration and climate on white‐tailed deer (Odocoileus virginianus) densities. White‐tailed deer are an invading ungulate across much of North America, whose expansion into Canada's boreal forest is implicated in the decline of boreal caribou (Rangifer tarandus caribou), a species listed as Threatened in Canada. We estimated white‐tailed deer densities using 300 remote cameras across 12 replicated 50 km2 landscapes over 5 years. White‐tailed deer densities were significantly lower in areas where winter severity was higher. For example, predicted deer densities declined from 1.83 to 0.35 deer/km2 when winter severity increased from the lowest value to the median value. There was a tendency for densities to increase with increasing habitat alteration; however, the magnitude of this effect was approximately half that of climate. Our findings suggest that climate is the primary driver of white‐tailed deer populations; however, understanding the mechanisms underpinning this relationship requires further study of over‐winter survival and fecundity. Long‐term monitoring at the invasion front is needed to evaluate the drivers of abundance over time, particularly given the unpredictability of climate change and increasing prevalence of extreme weather events. [ABSTRACT FROM AUTHOR]

Background: Climate is an important driver of ungulate life-histories, population dynamics, and migratory behaviors. Climate conditions can directly impact ungulates via changes in the costs of thermoregulation and locomotion, or indirectly, via changes in habitat and forage availability, predation, and species interactions. Many studies have documented the effects of climate variability and climate change on North America's ungulates, recording impacts to population demographics, physiology, foraging behavior, migratory patterns, and more. However, ungulate responses are not uniform and vary by species and geography. Here, we present a systematic map describing the abundance and distribution of evidence on the effects of climate variability and climate change on native ungulates in North America. Methods: We searched for all evidence documenting or projecting how climate variability and climate change affect the 15 ungulate species native to the U.S., Canada, Mexico, and Greenland. We searched Web of Science, Scopus, and the websites of 62 wildlife management agencies to identify relevant academic and grey literature. We screened English-language documents for inclusion at both the title and abstract and full-text levels. Data from all articles that passed full-text review were extracted and coded in a database. We identified knowledge clusters and gaps related to the species, locations, climate variables, and outcome variables measured in the literature. Review findings: We identified a total of 674 relevant articles published from 1947 until September 2020. Caribou (Rangifer tarandus), elk (Cervus canadensis), and white-tailed deer (Odocoileus virginianus) were the most frequently studied species. Geographically, more research has been conducted in the western U.S. and western Canada, though a notable concentration of research is also located in the Great Lakes region. Nearly 75% more articles examined the effects of precipitation on ungulates compared to temperature, with variables related to snow being the most commonly measured climate variables. Most studies examined the effects of climate on ungulate population demographics, habitat and forage, and physiology and condition, with far fewer examining the effects on disturbances, migratory behavior, and seasonal range and corridor habitat. Conclusions: The effects of climate change, and its interactions with stressors such as land-use change, predation, and disease, is of increasing concern to wildlife managers. With its broad scope, this systematic map can help ungulate managers identify relevant climate impacts and prepare for future changes to the populations they manage. Decisions regarding population control measures, supplemental feeding, translocation, and the application of habitat treatments are just some of the management decisions that can be informed by an improved understanding of climate impacts. This systematic map also identified several gaps in the literature that would benefit from additional research, including climate effects on ungulate migratory patterns, on species that are relatively understudied yet known to be sensitive to changes in climate, such as pronghorn (Antilocapra americana) and mountain goats (Oreamnos americanus), and on ungulates in the eastern U.S. and Mexico. [ABSTRACT FROM AUTHOR]

Context: Large-scale natural disturbances are crucial drivers of ecosystem function and composition for many forested ecosystems. In the last century, the prevalence of anthropogenic disturbances has increased across Canada’s boreal forest. Habitat disturbance from timber harvest and wildfire is linked to declines of boreal species, including woodland caribou (Rangifer tarandus caribou). Objectives: We tested how disturbances influenced the recovery trajectory of ecological indicators of timber, biodiversity, and wildlife habitat through time following timber harvest and wildfire across the boreal forest of Alberta, Canada. Methods: During 2021 and 2022, we collected field data from 251 timber harvested and 264 burned stands (0–40 years since disturbance), as well as 256 older forest stands used by caribou (> 40 years since disturbance). Field data included metrics of stand attributes (e.g., basal area, stems per hectare), coarse woody debris (CWD), and abundance of forage for caribou, moose (Alces americanus), and bears (black bear: Ursus americanus, grizzly bear: Ursus arctos). Results: Basal area of trees and stems per hectare recovered more quickly in timber harvest sites when compared to wildfire sites, but as time since disturbance increased there were no differences in these attributes among timber harvest, wildfire, and caribou use sites. CWD was greatest in recently burned sites, but declined over time to be similar in quantity as in harvested stands and older forest stands. Terrestrial lichens, important forage for caribou, were most abundant in the older caribou use sites, whereas forage for moose and bears, including shrubs, was most abundant in younger timber harvest and wildfire sites. Conclusions: Our results demonstrate that timber harvesting may result in a quicker development of timber volume when compared to wildfire. However, this anthropogenic disturbance is less advantageous for the development of caribou habitat. [ABSTRACT FROM AUTHOR]

Simple Summary: Wild herbivores require minerals to grow and maintain their skeleton and to catalyze their metabolic reactions. Herbivores acquire minerals from forage plants and, ultimately, the soils and waters that support seasonal plant growth. We know that seasonal changes in the quality and abundance of forage plants drive the movements of wild ungulates. However, the role of minerals in the movement and production of ungulates is poorly understood because the mineral requirements of wild species are poorly described. We describe a framework to estimate the minimum concentration of forage minerals required by female caribou, a wild ungulate with both migratory and sedentary ecotypes. We used measures of body mass and milk yield to determine the demand for minerals as the food intake changed with the season. We found that the minimum dietary concentrations (mg·kg−1) of macro-minerals (Ca, P, Mg, Na, K) declined as the food intake increased over the summer. The minimum dietary concentrations of micro-minerals (Fe, Mn, Cu, Zn) were heavily influenced by body mass gain, which increased through late lactation as food intakes rose. Our framework may be applied to other wild ungulates to assess the impacts of changing forage supplies on individuals and populations. Mineral requirements are poorly described for most wildlife. Consequently, the role of forage minerals in movement and productivity are poorly understood for sedentary and migratory ungulates, such as reindeer and caribou (Rangifer tarandus). We applied estimates of maintenance, lactation, body mass change, and antler growth to production curves (body mass, daily intake, and milk yield) for female caribou to calculate their mineral requirements over summer. The total requirements (mg or g·d−1) were divided by the daily intake (kg·d−1) to estimate the minimum concentration of minerals required in the diet (mg or g·kg−1) to balance demand. The daily requirements (mg·d−1) of all minerals increased from parturition to the end of summer. The minimum dietary concentrations (mg·kg−1) of macro-minerals (Ca, P, Mg, Na, K) declined as food intake (kg·d−1) increased over summer. The minimum dietary concentrations (Fe, Mn, Cu, Zn) were heavily influenced by body mass gain, which increased through late lactation even though food intakes rose. Our modeling framework can be applied to other wild ungulates to assess the impacts of changing forage phenology, plant community compositions, or environmental disturbances on movement and productivity. [ABSTRACT FROM AUTHOR]

Annual antler growth begins in the spring and is completed by late summer for male caribou (Rangifer tarandus groenlandicus) from the Qamanirjuaq herd (Nunavut, Canada), aligned with both the spring migration and a seasonal dietary shift. Antlers may provide a non‐lethal means of studying short‐ and long‐term changes in caribou ecology through incorporated isotopes of carbon (δ13C) and nitrogen (δ15N). We sampled the antlers of 12 male caribou from the Qamanirjuaq herd culled in September 1967. We predicted that serial sampling of antlers would reflect the known seasonal dietary change from lichen to grass‐like and shrub diet based on rumen contents from individuals culled during the same period. The δ13C and δ15N were analyzed in food sources and every 3 cm along each antler's length. The carbon isotope compositions of collagen (δ13Ccol) varied by ~0.5‰ among individuals and within antlers, while the carbon isotope compositions of antler bioapatite (δ13CCO3) increased by 1–1.5‰ from pedicle to tip. Values of δ15Ncol increased within antlers by 1–3‰ from pedicle to tip and varied by 3‰ among the individuals sampled. Antler collagen was lower in δ15Ncol by ~1‰ relative to bone collagen. Bayesian mixing models were conducted to test for changes in dietary proportions from antler isotope compositions. Mixing models did not indicate significant dietary shifts for any individual during antler formation, showing consistently mixed diets of fungi, horsetail, lichen, and woody plants. Increases in δ15Ncol in antler tissue could, therefore, correspond to subtle seasonal dietary changes and/or the physiological stress of antler tissue development. [ABSTRACT FROM AUTHOR]

Camera traps (CT) have been used to study a wide diversity of wildlife around the world. However, despite their widespread use, standardized protocols are lacking, potentially leading to reduced efficiency and inhibiting study comparisons, generalizability, and repeatability. While there are general guidelines and considerations researchers should be aware of when designing a CT survey, studies have shown the vital importance of selecting sampling schemes and camera settings tailored to specific characteristics of the wildlife system of interest. For many species and regions, optimal sampling protocols have not been thoroughly evaluated, especially in vast open landscapes. We used CT data on barren‐ground caribou (Rangifer tarandus) in the open landscape of arctic Alaska as a case study to evaluate and quantify the influence of camera trigger type (i.e., motion detection vs. time‐lapse) and time‐lapse interval on data generation to inform sampling protocols for future CT research in this system or others like it. Comparing camera trigger types, we found 5 min interval time‐lapse generated seven‐times more images containing caribou compared to motion detection. However, the detection rate of motion detection was over 11‐times greater than time‐lapse resulting in more efficient data collection with respect to camera battery life, data storage, and data processing time. Exploring the effect of time‐lapse interval length, we found detections were highly sensitive to interval length with a 30 min interval producing 33.7% fewer images containing caribou and identifying 22.2% fewer trap days containing caribou compared to a 5 min interval. Our results provide insight into effective CT sampling protocols for open landscapes and highlight the importance of critically evaluating and selecting camera settings that account for characteristics of the study system to ensure adequate data is generated efficiently to address study objectives. [ABSTRACT FROM AUTHOR]

This paper examines the socio-ecological implications of reindeer-caribou hybridization during the rise and collapse of the reindeer industry in Alaska. Following their introduction in the late nineteenth century, reindeer populations increased dramatically as herds spread throughout the territory. As populations increased, domesticated reindeer often escaped from their herds and ran off with migratory caribou. By the 1920s, Alaskan wildlife managers and scientists came to view feral reindeer as a form of biological pollution and a threat to the health and purity of the region's wild caribou. Despite divergent evolutionary histories, reindeer and caribou are related at the subspecies level and can interbreed to produce hybridized offspring. I argue that managerial anxieties about reindeer-caribou hybridization were bound up with broader concerns regarding race and related efforts to protect ostensibly pure spaces of wilderness and nature. Throughout the paper, I consider managerial attempts to mitigate reindeer-caribou hybridization in northern Alaska, which included the demarcation and reinforcement of conceptual and spatial boundaries between wild and domesticated forms of life. However, between the late nineteenth and mid-twentieth centuries, feral reindeer and hybridized caribou repeatedly demonstrated the violability of the biological categories and conceptual boundaries that wildlife managers employed as they sought to order life on the northern tundra. • Considers the historical geography of reindeer-caribou hybridization in northern Alaska. • Demonstrates that managerial anxiety about hybridization was connected to concerns about race. • Shows how managerial responses to hybridization shaped the geographies of wilderness in Alaska. • Develops a spatial historical approach to science, environment, and conservation in Alaska. [ABSTRACT FROM AUTHOR]

Seismic lines in western Canada's boreal region are linear disturbances that affect the habitat of threatened woodland caribou (Rangifer tarandus caribou). To hasten the return of forest cover and ultimately to restore caribou habitat, restoration managers use silviculture treatments in wet areas that involve the mechanical mounding of seismic lines to create artificial hummocks. Tree planting then takes place on top of these hummocks. However, the effectiveness of this silviculture technique for restoring seismic lines in peatlands is largely untested. Here we sampled incremental height growth of coniferous seedlings at 41 seismic line plots in poor and rich treed fens in northeast Alberta, Canada. We compared lines that had been treated with inverted mounding (a type of mechanical mounding) and subsequent tree planting, to nearby lines that were left untreated for natural recovery. We used generalized linear mixed models to test the effect of silviculture treatments on 5‐year growth increments of black spruce (Picea mariana) and tamarack (Larix laricina). Overall, we found that mounding and tree planting improved seedling growth compared to seismic lines regenerating naturally. However, growth responses were found to vary by species, ecosite, initial seedling size, and light availability. This suggests that site‐specific prioritization of mounding within peatlands may be more efficient considering the widespread nature of seismic lines. Future experiments testing growth responses to other mounding techniques that are designed to preserve the soil profile. It is also important for managers to weigh restoration goals beyond tree establishment and an accelerated return to forest cover. [ABSTRACT FROM AUTHOR]

Climate warming at the end of the last glacial period had profound effects on the distribution of cold-adapted species. As their range shifted towards northern latitudes, they were able to colonise previously glaciated areas, including remote Arctic islands. However, there is still uncertainty about the routes and timing of colonisation. At the end of the last ice age, reindeer/caribou (Rangifer tarandus) expanded to the Holarctic region and colonised the archipelagos of Svalbard and Franz Josef Land. Earlier studies have proposed two possible colonisation routes, either from the Eurasian mainland or from Canada via Greenland. Here, we used 174 ancient, historical and modern mitogenomes to reconstruct the phylogeny of reindeer across its whole range and to infer the colonisation route of the Arctic islands. Our data shows a close affinity among Svalbard, Franz Josef Land and Novaya Zemlya reindeer. We also found tentative evidence for positive selection in the mitochondrial gene ND4, which is possibly associated with increased heat production. Our results thus support a colonisation of the Eurasian Arctic archipelagos from the Eurasian mainland and provide some insights into the evolutionary history and adaptation of the species to its High Arctic habitat. [ABSTRACT FROM AUTHOR]

The Aullaviat/Anguniarvik Traditional Conservation Area is the final piece of a vast network protecting the northern stretch of the [...]