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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]

Harvesting and culling are methods used to monitor and manage wildlife diseases. An important consequence of these practices is a change in the genetic dynamics of affected populations that may threaten their long‐term viability. The effective population size (Ne) is a fundamental parameter for describing such changes as it determines the amount of genetic drift in a population. Here, we estimate Ne of a harvested wild reindeer population in Norway. Then we use simulations to investigate the genetic consequences of management efforts for handling a recent spread of chronic wasting disease, including increased adult male harvest and population decimation. The Ne/N ratio in this population was found to be 0.124 at the end of the study period, compared to 0.239 in the preceding 14 years period. The difference was caused by increased harvest rates with a high proportion of adult males (older than 2.5 years) being shot (15.2% in 2005–2018 and 44.8% in 2021). Increased harvest rates decreased Ne in the simulations, but less sex biased harvest strategies had a lower negative impact. For harvest strategies that yield stable population dynamics, shifting the harvest from calves to adult males and females increased Ne. Population decimation always resulted in decreased genetic variation in the population, with higher loss of heterozygosity and rare alleles with more severe decimation or longer periods of low population size. A very high proportion of males in the harvest had the most severe consequences for the loss of genetic variation. This study clearly shows how the effects of harvest strategies and changes in population size interact to determine the genetic drift of a managed population. The long‐term genetic viability of wildlife populations subject to a disease will also depend on population impacts of the disease and how these interact with management actions. [ABSTRACT FROM AUTHOR]

Conservation reintroduction is an increasingly applied tool for population restoration. The choice of source population is important from a conservation genetic perspective, but there is ambiguity in IUCN policies surrounding reintroductions from (semi‐)domestic sources. After the depopulation of an entire wild reindeer population due to detection of chronic wasting disease in Norway, the plan is to re‐establish reindeer after years of fallowing. Establishing wild reindeer has become challenging due to arguments for disease control favoring a semidomestic origin of the reintroduced stock. Selection is strong during domestication, and feralization does not lead to a full reversal towards wild traits. From a conservation perspective, we advocate future guidelines to include a ranking when wild, captive, semidomestic, and domestic stocks are available for reintroductions, in order to avoid feralization whenever possible during reintroductions and rewilding efforts. [ABSTRACT FROM AUTHOR]

Reindeer (Rangifer tarandus) is an emblematic species with several recognized subspecies. Two reindeer subspecies are present in Norway: the wild and semi-domestic European tundra reindeer (R. tarandus tarandus) in continental Norway, and Svalbard reindeer (R. tarandus platyrhynchus) endemic to this archipelago. The main aim of this paper is to give a descriptive and quantified analysis of the modern wild reindeer morphological diversity. The morphometric variation was quantified, based on 262 adult specimens of both sexes, by both linear measurements, analysed through log shape ratio computed from post-cranial bones and teeth measurements, and landmarks and sliding semi-landmarks based geometric morphometrics (GMM) to quantify molars size and shape. All anatomical parts (teeth, metatarsals, metacarpals) highlighted differences between the continental and insular subspecies. Our main results pointed out morphometrics characteristics of nowadays reindeer subspecies, like differences in proportions between the size of metapodials or lower cheek teeth with the body size, that could be of great interest for archaeozoological research. [ABSTRACT FROM AUTHOR]

In a landscape with patchily distributed forage resources, an animal's distribution may reflect the distribution of the resources if the population is forage-limited in time or space. This may be particularly explicit in climatically extreme and seasonally variable environments, notably alpine and polar environments during winter. Sustainable management considers the amount of available alpine ground lichen in winter as a predictor of carrying capacity for the last remaining populations of wild European Mountain reindeer Rangifer tarandus tarandus in alpine environments in South Norway. Ground lichen growth is constrained to elevated, wind-blown, snow-free ridges. However, wild Mountain reindeer also persist in areas providing little lichen resources. Our alternative functional hypothesis is that the critical resource is the amount of snow-free feeding areas during winter, which provide direct access to forage, likely to be energy-profitable regardless of the type of vegetation. We sampled animal-borne videos from wild Mountain reindeer during maximum accumulation of snow in late winter/spring, in three contrasting areas providing variable amounts of ground lichen and alternative vegetation resources. Direct observations of reindeer foraging via videos document an active selection and strong preference for feeding on snow-free patches, regardless of type of vegetation. Active 'cratering' in snow was not observed. In contrast, walking behaviours occurred much more frequently across snow-covered areas. Remote sensing data and analyses corroborated these observations. In the sustainable management of wild Mountain reindeer amounts of vegetated snow-free areas is an important functional predictor of winter carrying capacity. [ABSTRACT FROM AUTHOR]

The management of infectious wildlife diseases often involves tackling pathogens that infect multiple host species. Chronic wasting disease (CWD) is a prion disease that can infect most cervid species. CWD was detected in reindeer (Rangifer tarandus) in Norway in 2016. Sympatric populations of red deer (Cervus elaphus) and moose (Alces alces) are at immediate risk. However, the estimation of spillover risk across species and implementation of multispecies management policies are rarely addressed for wildlife. Here, we estimated the broad risk of CWD spillover from reindeer to red deer and moose by quantifying the probability of co‐occurrence based on both (1) population density and (2) habitat niche overlap from GPS data of all three species in Nordfjella, Norway. We describe the practical challenges faced when aiming to reduce the risk of spillover through a marked reduction in the population densities of moose and red deer using recreational hunters. This involves setting the population and harvest aims with uncertain information and how to achieve them. The niche overlap between reindeer and both moose and red deer was low overall but occurred seasonally. Migratory red deer had a moderate niche overlap with the CWD‐infected reindeer population during the calving period, whereas moose had a moderate niche overlap during both calving and winter. Incorporating both habitat overlap and the population densities of the respective species into the quantification of co‐occurrence allowed for more spatially targeted risk maps. An initial aim of a 50% reduction in abundance for the Nordfjella region was set, but only a moderate population decrease of less than 20% from 2016 to 2021 was achieved. Proactive management in the form of marked population reduction is invasive and unpopular when involving species of high societal value, and targeting efforts to zones with a high risk of spillover to limit adverse impacts and achieve wider societal acceptance is important. [ABSTRACT FROM AUTHOR]

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Niche modeling is typically used to assess the effects of anthropogenic land use and climate change on species distributions and to inform spatial conservation planning. These models focus on the suitability of local biotic and abiotic conditions for a species in environmental space (E‐space). Although movements also affect species occurrence, efforts to formally integrate geographic space (G‐space) into niche modeling have been hindered by the lack of comprehensive theoretical frameworks. We propose the "functional habitat" framework to define areas that are simultaneously of high quality in E‐space, and functionally connected to other suitable habitats in G‐space. Originating in metapopulation ecology, approaches have been developed to assess the amount of suitable connected habitats, based on the proximity between pairs of locations. Using network theory, which operates in topological space (T‐space, defined by a network), we extended these metapopulation approaches to integrate movement constraints in G‐space with niche modeling in E‐space. We demonstrate the functional habitat framework using empirical data (GPS tracking and population monitoring) throughout the European wild mountain reindeer (Rangifer t. tarandus) distribution range. We show that functional habitat outperforms traditional suitability in explaining the species' distribution. This approach integrates effects from habitat loss and fragmentation for spatial conservation planning, and avoids overemphasizing small, inaccessible areas with locally suitable habitats. The functional habitat framework formally integrates biotic, abiotic, and movement constraints in niche modeling using network theory, thus opening a wide range of applications in spatial conservation planning. [ABSTRACT FROM AUTHOR]

Although biodiversity is crucial for Sustainable Development Goals (SDGs), following the current trajectory, we risk failing SDG 15. Using a new indicator quantifying the loss of functional habitat (habitat that is simultaneously suitable and well-connected), we show that the real impact of renewable energy is far larger than previously assumed. Specifically, we estimate that the construction of hydropower reservoirs in south Norway caused a loss of ca. 222 km2 of functional habitat for wild reindeer (Rangifer tarandus)—which is far larger than assumed based on land inundation indices (110 km2). Fully mitigating these impacts is challenging: scenario analyses reveal that the measures proposed by societal actors would yield only a fraction of the habitat lost (2–12 km2) and could cause trade-off risks with other SDGs. Using indices of functional connectivity is crucial for environmental impact assessments, as entire ecological networks for several species can be affected far beyond the reservoirs. [ABSTRACT FROM AUTHOR]

Climate changes may lead to tipping points where the epidemiological characteristics of infectious wildlife diseases suddenly change, leading to outbreaks. However, empirically documented cases of the extent to which emerging infectious diseases (EIDs) affect populations of large vertebrates are few, partly because of the limited surveillance of remote wildlife populations. EIDs may potentially lead to higher mortality than mean mortality levels. Here, we quantified the likely impact of digital necrobacillosis on the survival and population dynamics of wild alpine reindeer (Rangifer tarandus) in Hardangervidda National Park (NP), Norway. The outbreak of digital necrobacillosis in 2019 contributed to a decrease in the summer survival rate of juveniles to 51% compared to an average of 88% in 2005–2018 and 77% in 2020. However, since the outbreak mainly reduced juvenile survival, the impact on short‐term population dynamics was moderate, lowering the population growth rate (λ) before harvest from an average value of 1.18 (2005–2018) to 1.08 (2019) before harvest. In 2019, anomalous climate conditions with a high daily mean temperature combined with the highest recorded daily precipitation in late summer were observed. Further studies are required to document the pathological development of digital necrobacillosis across demographic groups and proximate and ultimate causes of mortality. [ABSTRACT FROM AUTHOR]

Attraction sites are important for environmental pathogen transmission and spillover. Yet, their role in wildlife disease dynamics is often poorly substantiated. Herein, we study the role of salt licks as potential attraction sites for the spillover of gastrointestinal parasites from domestic sheep to wild reindeer. Eggs from the introduced sheep nematode Nematodirus battus were found in faecal samples of both species, suggestive of spillover. DNA metabarcoding of soil, collected at salt licks, revealed that N. battus, in addition to Teladorsagia circumcincta, were the most frequently occurring parasitic nematodes, with a significantly higher prevalence of nematodal DNA in salt lick soil compared to soil from control sites nearby. The finding of similar DNA haplotypes of N. battus in sheep, reindeer, and salt lick soil supports the hypothesis of spillover to reindeer via salt licks. More detailed investigation of the genetic diversity of N. battus across these hosts is needed to draw firm conclusions. Infection with these sheep nematodes could potentially explain a recently observed decline in the calf recruitment rate of the Knutshø reindeer herd. This study also supports the hypothesized role of artificial salt licks as hot spots for the transmission of environmentally persistent pathogens and illustrates the importance of knowledge about such attraction points in the study of disease in free-roaming animals. [ABSTRACT FROM AUTHOR]

Hunting of cervids is commonly regulated by quotas that are specific to sex and age groups. There is substantial cultural variation in how quotas are regulated. In Scandinavia, the entire quotas are often not shot making deer management potentially less predictable. However, the effect of quota size and demographic composition on harvest offtake by recreational hunters has, to a limited extent, been empirically investigated in Scandinavia. Hunters are limited by time and opportunity and may not respond to changes in quota, as anticipated by managers. We analysed the variation in the proportion of quotas filled depending on quota size relative to population size and demographic composition of quotas during the period of 1986–2019 involving a population size varying from approximately 5000 to 15,000 reindeer on Hardangervidda, Norway. We found that the proportion of quota being filled by hunters varied substantially (12–48%) on an annual basis. The quota occasionally exceeded the estimated population size, but the proportion of the quota filled increased the higher the population size was relative to the quota size. The proportion of quota being filled by hunters was markedly lower for calf licences. High annual variation in the proportion of quota being filled by hunters causes considerable implementation uncertainty when managers aim to regulate cervid populations. Nevertheless, there was a strong correlation between quota size and harvest size. Facing new management requirements, a harvest rate of ~ 47% of the adult male population size was achieved in 2019, compared to an average of 16%. Hence, managers compensated for the low proportion of quota being filled by increasing quotas to reach target harvesting aims, but there remains a limit as to how precisely such a wide-ranging reindeer population can be regulated using recreational hunters. [ABSTRACT FROM AUTHOR]

Many publications make use of opportunistic data, such as citizen science observation data, to infer large‐scale properties of species' distributions. However, the few publications that use opportunistic citizen science data to study animal ecology at a habitat level do so without accounting for spatial biases in opportunistic records or using methods that are difficult to generalize. In this study, we explore the biases that exist in opportunistic observations and suggest an approach to correct for them. We first examined the extent of the biases in opportunistic citizen science observations of three wild ungulate species in Norway by comparing them to data from GPS telemetry. We then quantified the extent of the biases by specifying a model of the biases. From the bias model, we sampled available locations within the species' home range. Along with opportunistic observations, we used the corrected availability locations to estimate a resource selection function (RSF). We tested this method with simulations and empirical datasets for the three species. We compared the results of our correction method to RSFs obtained using opportunistic observations without correction and to RSFs using GPS‐telemetry data. Finally, we compared habitat suitability maps obtained using each of these models. Opportunistic observations are more affected by human access and visibility than locations derived from GPS telemetry. This has consequences for drawing inferences about species' ecology. Models naïvely using opportunistic observations in habitat‐use studies can result in spurious inferences. However, sampling availability locations based on the spatial biases in opportunistic data improves the estimation of the species' RSFs and predicted habitat suitability maps in some cases. This study highlights the challenges and opportunities of using opportunistic observations in habitat‐use studies. While our method is not foolproof it is a first step toward unlocking the potential of opportunistic citizen science data for habitat‐use studies. [ABSTRACT FROM AUTHOR]

Optimal foraging models predict that individual animals will optimize net energy gain by intensifying forage activity and/or reducing forage energy cost. Then, the free distribution model predicts an animal's distribution in a patchy landscape will match the distribution of the resources. If not modified by other factors, such patterns may be expected to be particularly explicit in variable and extreme, forage‐limited, and patchy environments, notably alpine and Arctic environments during winter. The large ungulate wild mountain reindeer (Rangifer tarandus tarandus) surviving in such environments is used as a model during the forage‐limited winter season. The largest wild reindeer area in Western Europe (Hardangervidda, 8130 km2) is actively managed to sustain 10,000–12,000 wild reindeer. Since 2001, 104 different individuals have been GPS‐tracked at 3‐hr intervals. In winter, mountain reindeer may either choose to seek out and forage in patchy snow‐free habitats, typically on top of wind‐blown ridges, or use energy‐demanding digging through the snow to reach ground forage (cratering). We use late April satellite data from Landsat 5 and 8 (30 × 30 m), airborne laser scanning subsampling (processed to 1 × 1 m grid), and topographic information (1 m resolution) derived from digital aerial photographs (0.25 × 0.25 m resolution) to delineate snow‐free patches, constituting less than 694 km2. By overlaying recorded wild reindeer GPS positions winters 2001–2017 (188,942 positions), we document a strong positive selection for snow‐free patches, which were used about four times more frequently than expected from a "random walk" model. On a daily basis, the preference for snow‐free areas was slightly stronger in the evenings. In the sustainable management of wild mountain reindeer, the area of snow‐free patches is an important predictor of winter forage availability and important winter source areas. It may be derived from remote sensing data. [ABSTRACT FROM AUTHOR]

Tourism and recreation in protected areas may compromise conservation values if their forms and volumes exceed the area's tolerance. Disturbance-sensitive species such as wild and semi-domestic reindeer (Rangifer tarandus tarandus) in most mountain areas in Fennoscandia are particularly vulnerable to humans, but disturbance research seldom includes data on the human component of this co-existence. By estimating the visitor volume in space and time and visitor characteristics in the largest national park and wild reindeer range in Norway we analyzed reindeer trail crossing propensity and examined the spatial overlap between humans and GPS-collared female reindeer (n = 98) during summer. The data showed that female reindeer herds used areas with overall less human traffic and recreational infrastructure. Reindeer herds started avoiding crossing hiking trails used by more than 10–15 persons per day and avoided crossing trails when visitor volumes exceeded 30–50 persons per day. During the hunting season, the herds were largely dispersed and crossed over trails independent of visitor volume, indicating a collective flight response to hunters. We discuss how including data on human use can further our understanding of ecological effects in disturbance research and how it can improve management interventions for better co-existence between humans and reindeer. [ABSTRACT FROM AUTHOR]

Prion diseases constitute a class of invariably fatal and degenerative encephalopathies. Chronic Wasting Disease (CWD) is a contagious prion disease among cervids, which is spreading and causing marked population declines in USA and Canada. The first outbreak of CWD in Europe was discovered in a reindeer population in Norway in 2016. In the worst-case scenario with continental-wide spreading of CWD in Eurasia, an annual harvest of around 4 million cervids is at stake only in Europe, with huge economic and cultural significance. An in situ origin of CWD was suspected, and it appear urgent to identify the likely cause to prevent future emergences. Here, we document the novel phenomenon of extensive antler cannibalism prior to shedding among reindeer in the CWD-infected population. The extent of antler cannibalism increased over the last decades when CWD emerged, and included ingestion of vascularized antlers. Ingestion of tissues from conspecifics is a risk factor for the emergence of prion diseases, where the presence of extensive antler cannibalism opens the intriguing possibility of a 'Kuru-analogue' origin of CWD among the reindeer in Europe. Based on general insight on pathology of prion diseases and strain selection processes, we propose an hypothesis for how contagious CWD may emerge from sporadic CWD under the unique epidemiological conditions we document here. More research is required to document the presence of prions in reindeer antlers, and whether antler cannibalism actually led to a strain selection process and the emergence of a contagious form of CWD from a sporadic form of CWD. [ABSTRACT FROM AUTHOR]

Hunting and culling are frequently used to combat infectious wildlife diseases. The aim is to markedly lower population density in order to limit disease transmission or to eradicate the host. Massive host culling can yield a trade‐off when combating wildlife disease; it follows that intrusive actions may have unintended behavioural side effects, leading to the geographic spread of disease. The manner in which such excessive hunting and culling of hosts can affect the movement and dispersion of cervids has not been studied.In this study, we quantified the behaviour (daily movements and habitat use) and dispersion of GPS‐marked reindeer (n = 24) before and during the eradication of an entire population (>2,000 reindeer) infected with chronic wasting disease (CWD) in Norway. We compared behaviour and dispersion during 10 ordinary hunting seasons (2007–2016), an extended hunting season (2017) and marksmen culling (2017/2018).Seasonality had a major impact on movements. Reindeer movements during the early hunting season (20 August–20 September) did not increase the overall movements compared to that in the pre‐hunt season (20 July–19 August), while extended hunting into October (as in 2017) and marksmen culling from November to February markedly increased daytime movements relative to that normally observed in this time of the year. Towards the end of the eradication, the remaining reindeer sought refuge at restricted high‐elevation areas with limited forage production. Reindeer used novel areas towards the perimeter of the range, but active herding during culling stopped one herd from leaving the CWD zone.Synthesis and applications. With emerging wildlife diseases, host culling is becoming a more frequently used tool for managers in Europe. Our study highlights the potential trade‐off between combating disease transmission within a population and the risk of geographic spread. Such insight is important to design mitigation measures, such as perimeter fencing or herding, to avoid the risk of the geographic spread of disease in cases of severe and economically important wildlife diseases. [ABSTRACT FROM AUTHOR]

Space demanding mammalian species, such as reindeer, are in decline worldwide due to habitat loss and fragmentation. Policy to restore connectivity of reindeer habitat is now put to an abrupt halt in several areas because of an outbreak of Chronic Wasting Disease in Norway, and replaced with deliberate fragmentation of the landscape by enhancing barrier effects of linear structures. [ABSTRACT FROM AUTHOR]

Most populations of large mammals in developed countries are managed by human hunting, but there are surprisingly few empirical studies about the benefits and limitations of using recreational hunters to achieve specific management objectives. In particular, the extensive host culling required to markedly reduce population densities to combat some wildlife diseases may conflict with the management aims of landowners and hunters. This is particularly acute in the case of chronic wasting disease (CWD) in cervids, which has now emerged in reindeer (Rangifer tarandus) in Norway. We analyzed the relative efficacy of approximately 1,000 recreational hunters and 30 professional marksmen during the eradication of the entire CWD‐infected population of >2,000 reindeer in Norway. The government changed a series of legislation that would normally limit the efficacy of recreational hunters; these changes were linked to the duration of the hunting season, the specificity and size of the quotas, and spatial access rights. Efforts were taken to reduce both the searching time (hunters were given information on herd whereabouts) and handling time (helicopter aid for transport) of the recreational hunters. We compared 1) recreational hunting under ordinary legislation (up to 2016), 2) recreational hunting with less legislation (2017), and 3) culling by marksmen that were allowed to use both snowmobile and helicopter. Despite all of the changes in legislation, harvest by recreational hunters only increased from 241–316 during 2014–2016 to 582 reindeer in 2017 and was below management targets, while marksmen culled 1,399 reindeer, with a daily average and maximum offtake well above that of the hunters. The hunters shot more animals in the early season and during weekends. Offtake by both the hunters and marksmen were equally negatively affected by fog, which reduced visibility. We discuss the relative merits of using hunters and marksmen for wildlife control in general and limits to how legislation can increase offtake. We highlight the need for more research into how the use of marksmen comes with a cost in terms of social conflict. © 2019 The Authors. Wildlife Society Bulletin published by Wiley Periodicals, Inc. on behalf of The Wildlife Society. Cervids are keystone species with enormous cultural and economic values, and the emergence of chronic wasting disease among reindeer in Europe was a major concern. We assessed the ability of recreational hunting and marksmen culling to aid in host eradication required for combating wildlife disease. [ABSTRACT FROM AUTHOR]

This article discusses how studying rhythms can help us better understand and manage spatiotemporal tensions in social-ecological landscapes, highlighting the potential of rhythmanalysis as a tool for crossing scientific and methodological borders. The empirical material is from a study of human and non-human users and uses of the highly valued Dovrefjell mountain area in Norway, with particular attention to the much-debated Snøheim Road. We take an in-depth view of three different, but interrelated, rhythms at Dovrefjell and discuss how intervening through rhythms can be a fruitful way to approach landscape management. By simultaneously 'listening' to different rhythms, this approach helps us to understand and reduce spatiotemporal tensions between social, cultural and ecological uses of a landscape. [ABSTRACT FROM AUTHOR]

Infection patterns linked to age and sex are crucial to predict the population dynamic effects of diseases in long-lived species. How such demographic patterns of infection arise is often multifactorial, although the cause is commonly seen as a combination of immune status as well as variation in pathogen exposure. Prion diseases are particularly interesting, as they do not trigger an adaptive immune response; hence, differences in pathogen exposure linked to behavior could be the prime determinant of the pattern of infection. In cervids, the fatal prion disease, chronic wasting disease (CWD), is spreading geographically, with economic and cultural consequences in affected areas in North America, and all infected individuals eventually die from disease-associated sequelae if they live long enough. Understanding the causes of the demographic pattern of infection with CWD is therefore urgent but is limited by the fact that reported data primarily come from related deer species in North America. The recent (detected 2016) emergence of CWD among wild alpine reindeer (Rangifer tarandus) in Norway with a different social organization, that is, no home range behavior and no matrilineal female groups, offers an opportunity to advance our understanding of how behavior influences the infection patterns. Testing of 1081 males and 1278 females detected 19 animals positive for abnormal prion protein in brain and/or lymphatic tissues. No calves and only one male yearling were infected, with the remaining positives being adults (representing 1.5% of adult males and 0.5% of adult females). We found a strong sex-biased infection pattern in reindeer (with infection 2.7 times more likely in adult males), which is similar to the results reported in mule deer and white-tailed deer. The hazard of being detected as positive increased with age in males. There was no close genetic relatedness among positive animals. The results were consistent with the within-group contact of males being a possible major route of transmission. We discuss the demographic pattern of infection with CWD in view of the lack of stable home range behavior and other key behavioral traits of reindeer relevant to understanding pathogen exposure in general. [ABSTRACT FROM AUTHOR]

Surveillance of wildlife diseases is logistically difficult, and imperfect detection is a recurrent challenge for disease estimation. Using citizen science can increase sample sizes, but it is associated with a cost in terms of the anatomical type and quality of the sample. Additionally, biological tissue samples from remote areas lose quality due to autolysis. These challenges are faced in the case of emerging chronic wasting disease (CWD) in cervids.Here, we develop a stochastic scenario tree model of diagnostic sensitivity, allowing for a mixture of tissue sample types (lymph nodes and brain) and qualities while accounting for different detection probabilities during the CWD infection, lasting 2–3 years. We apply the diagnostic sensitivity in a Bayesian framework, enabling estimation of age‐class‐specific true prevalence, including the prevalence in latent, recently infected stages. We provide a simulation framework to estimate the sensitivity of the surveillance system (i.e., the probability of detecting the infection in a given population), when detectability varies among individuals due to different disease progression.We demonstrate the utility of our framework by applying it to the recent emergence of CWD in a European population of reindeer. We estimated apparent CWD prevalence at 1.2% of adults in the infected population of wild reindeer, while the true prevalence was 1.6%. The sensitivity estimation of the CWD surveillance was performed in an adjacent small (c. 500) and a large (c. 10,000) reindeer population, demonstrating low certainty of CWD absence.Our method has immediate application to the mandatory testing for CWD in EU countries commencing in 2018. Similar approaches that account for latent stages and a serial disease progression in various tissues with a temporal pattern of diagnostic sensitivity may enhance the estimation of the prevalence of wildlife diseases more generally. [ABSTRACT FROM AUTHOR]

We developed a model for estimating demographic rates and population abundance based on multiple data sets revealing information about population age- and sex structure. Such models have previously been described in the literature as change-in-ratio models, but we extend the applicability of the models by i) using time series data allowing the full temporal dynamics to be modelled, by ii) casting the model in an explicit hierarchical modelling framework, and by iii) estimating parameters based on Bayesian inference. Based on sensitivity analyses we conclude that the approach developed here is able to obtain estimates of demographic rate with high precision whenever unbiased data of population structure are available. Our simulations revealed that this was true also when data on population abundance are not available or not included in the modelling framework. Nevertheless, when data on population structure are biased due to different observability of different age- and sex categories this will affect estimates of all demographic rates. Estimates of population size is particularly sensitive to such biases, whereas demographic rates can be relatively precisely estimated even with biased observation data as long as the bias is not severe. We then use the models to estimate demographic rates and population abundance for two Norwegian reindeer (Rangifer tarandus) populations where age-sex data were available for all harvested animals, and where population structure surveys were carried out in early summer (after calving) and late fall (after hunting season), and population size is counted in winter. We found that demographic rates were similar regardless whether we include population count data in the modelling, but that the estimated population size is affected by this decision. This suggest that monitoring programs that focus on population age- and sex structure will benefit from collecting additional data that allow estimation of observability for different age- and sex classes. In addition, our sensitivity analysis suggests that focusing monitoring towards changes in demographic rates might be more feasible than monitoring abundance in many situations where data on population age- and sex structure can be collected. [ABSTRACT FROM AUTHOR]

Using dental microwear textural analysis, we aim to explore variations in feeding habits within and between wild reindeer populations ( Rangifer tarandus) in Norway. Specimens from the two wild reindeer areas of Knutshø and Hardangervidda were hunted between late August and the end of September 2014, and found to share very similar topological and ecological characteristics (continental alpine tundra). Despite the homogenisation of plant resources at the end of the snow-free period, dental microwear textural analysis on cheek teeth indicates differences in feeding behaviors between the two populations, in that reindeer from Knutshø might display a more 'grazing' signal than the ones from Hardangervidda. Such differences in dental microwear textures reflect the differences in feeding habits that could be linked with differences in population density of reindeer. The Knutshø reindeer density is lower than at Hardangervidda, where primary food resources like grasses, sedges, and lichens are less abundant. Analyses also show the differences in gender for the population of Knutshø, but more studies are necessary for the clearest interpretation of data. Our results emphasize the need to explore local variations at a monthly time frame in order to better assess the versatility of dental microwear textures before applying this kind of analysis to either extant or extinct multi-population scales. [ABSTRACT FROM AUTHOR]

1. The loss, fragmentation and degradation of habitat everywhere on Earth prompts increasing attention to identifying landscape features that support animal movement (corridors) or impedes it (barriers). Most algorithms used to predict corridors assume that animals move through preferred habitat either optimally (e.g. least cost path) or as random walkers (e.g. current models), but neither extreme is realistic. 2. We propose that corridors and barriers are two sides of the same coin and that animals experience landscapes as spatiotemporally dynamic corridor-barrier continua connecting (separating) functional areas where individuals fulfil specific ecological processes. Based on this conceptual framework, we propose a novel methodological approach that uses high-resolution individual-based movement data to predict corridor-barrier continua with increased realism. 3. Our approach consists of two innovations. First, we use step selection functions (SSF) to predict friction maps quantifying corridor-barrier continua for tactical steps between consecutive locations. Secondly, we introduce to movement ecology the randomized shortest path algorithm (RSP) which operates on friction maps to predict the corridor-barrier continuum for strategic movements between functional areas. By modulating the parameter, which controls the trade-off between exploration and optimal exploitation of the environment, RSP bridges the gap between algorithms assuming optimal movements (when Θ approaches infinity, RSP is equivalent to LCP) or random walk (when Θ → 0, RSP → current models). 4. Using this approach, we identify migration corridors for GPS-monitored wild reindeer (Rangifer t. tarandus) in Norway. We demonstrate that reindeer movement is best predicted by an intermediate value of Θ, indicative of a movement trade-off between optimization and exploration. Model calibration allows identification of a corridor-barrier continuum that closely fits empirical data and demonstrates that RSP outperforms models that assume either optimality or random walk. 5. The proposed approach models the multiscale cognitive maps by which animals likely navigate real landscapes and generalizes the most common algorithms for identifying corridors. Because suboptimal, but non-random, movement strategies are likely widespread, our approach has the potential to predict more realistic corridor-barrier continua for a wide range of species. [ABSTRACT FROM AUTHOR]

Strictly speaking, fundamental niches are inestimable. Nevertheless, ecologists attempt approximating them to understand species' distribution and plasticity to environmental changes, with invaluable repercussions on both theoretical and applied ecology. So far, individual-based habitat selection models only characterized realized niches of populations delimited by physical (e.g. fences), historical (colonization) and biotic (competition) barriers constraining access to a subset of resources available to the species. As populations with different realized niches share the same fundamental niche, we developed a novel framework to scale-up response curves from population-scale habitat selection models to approximate the species' optimal habitat choices, unbiased by barriers constraining accessibility. We used GPS-locations from 147 wild mountain reindeer Rangifer t. tarandus, belonging to 7 of the remaining populations scattered throughout the subspecies' range. We linked individual choices to accessible habitat features using conditional-logistic regression with log-link function in a use-available design. Focal variables were modeled using 2nd degree polynomials on log-scale, which correspond to a Gaussian curve used to approximate the fundamental niche optimum (curve mean) and breadth (variance). Using both real and simulated data we demonstrate that robust approximations of a fundamental niche optimum and breadth can be estimated using a relatively small number of representative populations with relatively few individuals. While each classical realized niche model had strong predictive power for the focal population but poorly predicted across populations, the approximation of the fundamental niche allowed for robust inter-population comparisons in habitat quality. The proposed approach brings individual-based habitat selection models forward along the continuum from investigating the realized niche of a population towards investigating a species' fundamental niche, and allows us to quantify empirically the relationship between realized and fundamental niches. This allows improving the understanding of differences in fitness among populations, the prediction of species' distributions and plasticity to environmental changes, and suggestions for mitigation priorities. [ABSTRACT FROM AUTHOR]

Norwegian wild reindeer Rangifer tarandus tarandus are divided into 23 virtually isolated populations, primarily due to the abandonment of traditional migration and movement corridors caused by the development of infrastructures. By conducting a nation-wide, interdisciplinary pre-post study on a temporal scale spanning centuries, we modelled current reindeer movements with respect to archaeological findings to quantify long-term changes in area use related to anthropogenic disturbance. The location of 3,113 pitfall traps and hunting blinds, built 600-2000 years ago and used until 350-400 years ago, testified the location of traditional movement corridors. Current movement routes were delineated using Brownian Bridge Movement Models based on 147 reindeer GPS-monitored during 10 years. Using Path Analysis we quantified direct, indirect and total effects of different infrastructures within multiple scales (1, 5, and 10 km-radius buffers) on the current probability of use of ancient movement corridors. Tourist cabins and roads had the strongest long-term direct effects at most scales: 1 tourist cabin and 1 km road within a 1 km-radius buffer would lead, respectively, to complete area abandonment, and to a 46 % decrease in the probability of use. Power lines and private cabins had significant indirect effects on area use through their effect on roads, while hiking trails and, in particular, hydroelectric dams had highly variable effects, not significant at a nation-wide scale. Finally, we provide a flexible tool to estimate the potential long-term direct and cumulative effects of different types of infrastructures at the desired spatial scale to be used for the development of future sustainable land management plans. [ABSTRACT FROM AUTHOR]

The development of roads and associated infrastructure has interrupted several traditional migrations of wild reindeer (Rangifer tarandus tarandus) in Norway. The population in the Setesdal Austhei wild reindeer area still migrates from winter to calving grounds by semi-annually crossing a cabin-lined road through a narrow corridor, in which further anthropogenic development is planned. To understand if and how infrastructure affected reindeer migration patterns we studied the movements of 10 female reindeer equipped with GPS collars between 2002 and 2010. First, we identified the start and end of the migration period, and then we compared trajectory parameters (net displacement, step length and turning angles) recorded during migration with those recorded in proximity of the road. The analysis of the net displacement indicated that during spring migration reindeer moved at a constant pace towards the calving ground covering a net linear distance of 25 km in 40 days. In the middle of migration, reindeer changed travel direction and roamed parallel to the road for ca. 5 days without approaching further, possibly searching for an undisturbed place and time to cross. Reindeer finally crossed the road before daylight with highly directed movements, increasing their travel speed up to the highest values recorded during migration (4 km/3 hrs vs. 0.5 km/3 hrs). After crossing, reindeer moved quickly toward their calving ground covering the remaining 25 km net distance in less than a week. Migration patterns were markedly affected by disturbance during spring, as the road crossings occurred in the period characterized by the high traffic volume and intense human activities related to Easter holidays; during autumn, on the contrary, the hampering effect of the road was minimal. The results suggest that the current disturbance associated to the road hampers spring migration and might delay the arrival to the calving ground. The planned construction of a large number of recreational cabins in the migration corridor has the potential to threaten the migration and obstruct the access to the calving ground. [ABSTRACT FROM AUTHOR]

Anthropogenic fragmentation of habitat and populations is recognized as one of the most important factors influencing loss of biodiversity. Since it is difficult to quantify demographic parameters in small populations, we need alternative methods to elucidate important factors affecting the viability of local populations. The Fennoscandian arctic fox inhabits a naturally fragmented alpine tundra environment, but historic anthropogenic impacts have further fragmented its distribution. After almost 80 yr of protection, the population remains critically endangered. Both intrinsic factors (related to the isolation and size of sub-populations) and extrinsic factors (related to environmental conditions influencing patch quality and interspecific competition) have been proposed as explanations for the lack of population growth. To distinguish between these hypotheses, we conducted a spatially explicit analysis that compares areas where the species has persisted with areas where it has become locally extinct. We used characteristics of the fragments of alpine tundra habitat and individual arctic fox breeding dens (including both currently active dens and historically active dens) within the fragments to evaluate the importance of habitat characteristics and connectivity in explaining variation in persistence within a fragment. The number of reproductive events in a fragment was related to the size of the fragment, but not more than expected following a 1:1 relationship, suggesting little effect of fragment size on the relative number of reproductions. The likelihood of a den being used for breeding was positively associated with factors minimising interspecific competition as well as increasing within-fragment connectivity. These results support the idea that the failure of Fennoscandian arctic fox to recover is caused by demographic factors that can be related to fine-scale Allee or Allee-like effects, as well as environmental influences related to increased competition and exclusion by red foxes. [ABSTRACT FROM AUTHOR]

We studied reindeer (Rangifer tarandus tarandus) distribution in relation to possible travel barriers (roads and power lines) in south-central Norway, 1997-2000, using lichen biomass as an indicator of reindeer use. We recorded lichen cover on both sides of potential barriers within comparable habitat in 42 sites for 3 different reindeer herds. We used cover-biomass regressions to assess the relationship between lichen cover and biomass. In 2 of the regions, lichen biomass was 5.3 times and 2.8 times higher in areas isolated by.2 parallel power lines and an adjacent winter-closed road compared to biomass on the other side of the potential barrier. In a third region, lichen biomass did not vary significantly between areas on either side of a single winter-closed road. Lichen biomass data suggested that wild reindeer used both sides of a closed road in winter, whereas 2 parallel power lines and a winter-closed road in combination reduced reindeer migration and resulted in very different grazing pressures on either side of the power lines, even 30 years after the power lines were constructed. Construction of power lines, and particularly parallel power lines, should thus be avoided in wild reindeer habitat. Fragmentation of wild reindeer ranges in Norway results in a substantial reduction in available ranges and traditional migration routes between important seasonal ranges, with a likely overall reduction in carrying capacity. [ABSTRACT FROM AUTHOR]

Studies synchrony in Svalbard reindeer population dynamics. Growth rates of Svalbard reindeer; Correlated environmental variation; Local climate synchronicity.

We investigated the distribution of wild reindeer (Rangifer tarandus tarandus) from aerial surveys in 1986–1998 in 622 contiguous 4-km2 grid squares in relation to density of power lines, roads and ski trails in the Nordfjella region, south-central Norway. Density of reindeer was significantly lower in developed quadrats compared to undeveloped quadrats and decreased with increasing density of development. No reindeer were observed in areas exceeding 1.3 km/km2 of linear structures and only 1.1% of the reindeer were observed in areas exceeding 0.8 km/km2 of linear structures, an area constituting 17% of the study area. The results imply that development, and also the degree of development, affect the availability of range for wild reindeer. Furthermore, the results suggest that reindeer may abandon areas once disturbance exceeds a critical level. We conclude that there is a need for cumulative impact assessments of the overall development in Norwegian mountain regions, to preserve the last remaining wild reindeer populations in Europe. [ABSTRACT FROM AUTHOR]

The shift in emphasis from single species to ecosystem conservation is revealing how community interactions can potentially influence single species viability and conservation. Although there is much theory and empirical data concerning the dynamic consequences of exploitative interactions, there is still a very poor understanding of the effects of interference interactions. Recent studies, as shown in this review, have documented widespread effects of such interactions among mammalian carnivores. Harassment, loss of kills and intraguild predation have been documented in a wide range of species. The demonstrated effects also include avoidance of larger carnivores in both time and space and reductions in one species density or even total exclusion from certain habitats or regions. Our review of the literature thus provides a range of empirical examples that together demonstrate that these interactions have very important implications on carnivore demography. We believe that the effects of interference might differ strongly from the effects of exploitative competition. This is because interference might have the potential to affect population growth in an inverse density-dependent manner and thereby also reduce population growth at low densities, therefore increasing extinction probabilities. These factors need to be considered when planning future multi-species conservation. Further research into the temporal and spatial aspects of co-existence are required if diverse guilds and communities are to be conserved. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the social organization and behavior of arctic foxes (Alopex lagopus) in central Norway where the major rodent prey were cyclic. Methodology of the study; Results and discussion on the study.

1. Population size, calves per female, female mean age and adult sex ratio of a moose (Alces alces) population in Vefsn, northern Norway were reconstructed from 1967 to 1993 using cohort analysis and catch-at-age data from 96% (6752) of all individuals harvested. 2. The dynamics of the population were influenced mainly by density-dependent harvesting, stochastic variation in climate and intrinsic variation in the age-structure of the female segment of the population. 3. A time delay in the assignment of hunting permits in relation to population size increased fluctuations in population size. 4. Selective harvesting of calves and yearlings increased the mean age of adult females in the population, and, because fecundity in moose is strongly age-specific, the number of calves per female concordantly increased. However, after years with high recruitment, the adult mean age decreased as large cohorts entered the adult age-groups. This age-structure effect generated cycles in the rate of recruitment to the population and fluctuations introduced time-lags in the population dynamics. 5. An inverse relationship between recruitment rate and population density, mediated by a density-dependent decrease in female body condition, could potentially have constituted a regulatory mechanism in the dynamics of the population, but this effect was counteracted by a density-dependent increase in the mean age of adult females. 6. Stochastic variation in winter snow depth and summer temperature had delayed effects on recruitment rate and in turn population growth rate, apparently through effects on female body condition before conception. [ABSTRACT FROM AUTHOR]

Tests the relationship between placental scars and litter size in Arctic fox. Testing the effects of abortion by examination of uteri from females; Estimating individual litter size from a linear relationship between scars.

The successful mitigation of emerging wildlife diseases may involve controversial host culling. For livestock, 'preemptive host culling' is an accepted practice involving the removal of herds with known contact to infected populations. When applied to wildlife, this proactive approach comes in conflict with biodiversity conservation goals. Here, we present an alternative approach of 'proactive hunting surveillance' with the aim of early disease detection that simultaneously avoids undesirable population decline by targeting demographic groups with (1) a higher likelihood of being infected and (2) a lower reproductive value. We applied this harvesting principle to populations of reindeer to substantiate freedom of chronic wasting disease (CWD) infection. Proactive hunting surveillance reached 99% probability of freedom from infection (<4 reindeer infected) within 3–5 years, in comparison to ~10 years using ordinary harvest surveillance. However, implementation uncertainties linked to social issues appear challenging also with this kind of host culling. Rarely are the outcomes of mathematical (probability) models of wildlife disease detection used to inform policy or management changes. Here the authors develop a proactive hunting surveillance program that shortened the time required to establish freedom from chronic wasting disease at the population level in reindeer. [ABSTRACT FROM AUTHOR]

The Arctic fox (Vulpes lagopus L.) is listed as extinct in Finland, endangered in Sweden and critically endangered in Norway. Around 2000 there were only 40-60 adult individuals left, prompting the implementation of conservation actions, including a captive breeding programme founded from wild-caught pups. The initial breeding trials failed, probably because of stress among captive animals, and the programme was radically changed in 2005. Eight large enclosures within the species’ historical natural habitat were established, which had the positive effect of all pairs breeding in 2007. As of 2015, 385 pups (yearly average 37) were produced. In this ongoing programme, pups are released the winter (January-February) following their birth and have had an average first-year survival of 0.44. The release sites are prepared with artificial dens and a network of supplementary food dispensers, designed to work exclusively for the Arctic fox. After just four to seven years of releases, populations have been effectively re-established in three mountain areas where the species had been locally extinct. One of the newly re-established populations has become the largest population in Norway. Several other populations, including Swedish ones, have benefited considerably from successful immigration of released foxes. The number of wild-born pups that are descendants of released foxes has likely exceeded 600, and in 2014 50% of all free-living breeding pairs in mainland Norway included released foxes or their descendants. The Norwegian Arctic fox captive breeding programme has proven to be an important conservation action for the recovery of the Scandinavian Arctic fox population. [ABSTRACT FROM AUTHOR]

The Arctic fox (Vulpes lagopusL.) is listed as extinct in Finland, endangered in Sweden and critically endangered in Norway. Around 2000 there were only 40–60 adult individuals left, prompting the implementation of conservation actions, including a captive breeding programme founded from wild-caught pups. The initial breeding trials failed, probably because of stress among captive animals, and the programme was radically changed in 2005. Eight large enclosures within the species’ historical natural habitat were established, which had the positive effect of all pairs breeding in 2007. As of 2015, 385 pups (yearly average 37) were produced. In this ongoing programme, pups are released the winter (January–February) following their birth and have had an average first-year survival of 0.44. The release sites are prepared with artificial dens and a network of supplementary food dispensers, designed to work exclusively for the Arctic fox. After just four to seven years of releases, populations have been effectively re-established in three mountain areas where the species had been locally extinct. One of the newly re-established populations has become the largest population in Norway. Several other populations, including Swedish ones, have benefited considerably from successful immigration of released foxes. The number of wild-born pups that are descendants of released foxes has likely exceeded 600, and in 2014 50% of all free-living breeding pairs in mainland Norway included released foxes or their descendants. The Norwegian Arctic fox captive breeding programme has proven to be an important conservation action for the recovery of the Scandinavian Arctic fox population. [ABSTRACT FROM PUBLISHER]