Reindeer Research Articles

Erasing anthropogenic disturbance: Natural revegetation of linear features following wildfire, and the implications for woodland caribou (Rangifer tarandus caribou) habitat management.

The federal recovery strategy for woodland caribou identifies wildfires within the last 40 years and anthropogenic disturbance visible at a scale of 1:50,000, including a 500-m buffer, as disturbed. Long-term vegetation recovery on linear features post-fire has not yet been documented. We examined vegetation recovery including stem density and height, hiding cover, and reindeer lichen cover along 40+ year-old legacy linear features in Northern Saskatchewan, in both uplands and lowlands 1–41 years post-fire. We compared these results with burned areas off-lines and unburned lines. On unburned lines in uplands there was minimal recovery, while there was significant recovery of stem count, height and hiding cover on burned lines and burned off-lines. Reindeer lichen cover and thickness remained significantly lower on burned lines and burned off-lines than on unburned lines until the 41-year age group, where there was no longer a significant difference. In lowlands, the stem density and stem height were initially significantly higher on unburned lines than on either burned lines or burned off-lines. After 27–32 years post-fire there was no longer a significant difference in stem densities. Our findings show that fires substantially accelerate natural revegetation and instigate a recovery that is similar on and off disturbance features in both uplands and lowlands. These findings can inform management decisions on restoration planning and calculation of range disturbance metrics. We suggest that the anthropogenic 500-m buffer should be removed post fire, as anthropogenic disturbance is reset, and anthropogenic disturbance should be classified as naturally recovering.

Anaesthetic management in adult reindeer (Rangifer tarandus tarandus) undergoing exploratory laparotomy for jejuno‐jejunal intussusception surgery resection

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

Estimating Mineral Requirements of Wild Herbivores: Modelling Arctic Caribou (Rangifer tarandus granti) in Summer.

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.

The effect of size and density on the mean retention time of particles in reindeer (Rangifer tarandus)

Particle passage from the reticulorumen (RR) depends on particle density and size. A classic way of assessing these effects is the use of plastic markers of varying density and size that are recovered in the faeces. Here, we report results of an experiment where four fistulated reindeer (Rangifer tarandus, 96 ± 12 kg) were fed two different diets (browse, voluntary dry matter intake [DMI] 70 ± 10 g/kg0.75/d; or a pelleted diet, DMI 124 ± 52 g/kg0.75/d) and dosed via fistula with 8 different particle types combining densities of 1.03, 1.22 and 1.44 g/ml and sizes of 1, 10 and 20 mm. Generally, particles that passed the digestive tract intact (not ruminated) did so relatively early after marker dosing, and therefore had shorter mean retention times (MRT) than ruminated particles. On the higher intake, the overall mean retention time (MRT) of particles was shorter, but this was not an effect of shorter MRT for either intact or ruminated particles, but due to a higher proportion of intact particles at the higher intake. This supports the concept that ruminants do not adjust chewing behaviour depending on intake, but that a lower proportion of digesta is submitted to rumination due to pressure-driven escape from the forestomach at higher gut fills. Compared to cattle (Bos primigenius taurus), muskoxen (Ovibos moschatus) and moose (Alces alces) that had received the same markers, reindeer had a lower proportion of 1 mm particles that passed intact. Our results support the concept that the critical size threshold for particles leaving the ruminant forestomach is dependent on body size. While the results likely do not represent findings peculiar for reindeer, they indicate fundamental mechanisms operating in the forestomach of ruminants.

Identification of Cervi Cornu (Cervus elaphus) and its formula granules based on PCR-RFLP

Cervi Cornu is the ossified antler, or the base antler that falls off in the spring of the following year after the pilose antler is sawn off from Cervus elaphus or C. nippon, as a precious traditional Chinese medicine, has been recognized for its medicinal value and widely used in clinical practice. However, the origins of Cervi Cornu are miscellaneous, and Cervi Cornu is even mixed with adulterants in the market. Currently, there is a shortage of ways to identify Cervi Cornu and no standard to control the quality of Cervi Cornu. So it is valuable to develop a way to effectively identify Cervi Cornu from the adulterants. In this study, the differences in the mitochondrial barcode cytochrome b(Cytb) gene sequences of C. elaphus, C. nippon and their related species were compared and the specific single nucleotide polymorphism(SNP) sites on the Cytb sequences of Cervi Cornu were screened out. According to the screened SNPs, Cervi Cornu-specific primers dishmy-F and dishmy-R were designed. The PCR system was established and optimized, and the tolerance and feasibility of Taq polymerases and PCR systems affecting the repeatability of the PCR method were investigated. The amplification products of C. elaphus and C. nippon were digested using the restriction enzyme MseⅠ. The results showed that after electrophoresis of the product from PCR with the annealing temperature of 56 ℃ and 35 cycles, a single specific band at about 100 bp was observed for C. elaphus samples, and the product of C. elaphus samples was 60 bp shorter than that of C. nippon samples. There was no band for adulterants from other similar species such as Alces alces, Rangifer tarandus, Odocoileus virginianus, O. hemionus, Cap-reolus pygargus, Przewalskium albirostis and negative controls. The polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method established in this study can quickly and accurately identify Cervi Cornu originated from C. elaphus in crude drugs, standard decoctions, and formula granules, and distinguish the origins of Cervi Cornu products, i.e., C. nippon and similar species. This study can be a reference for other studies on the quality standard of other formula granules of traditional Chinese medicines.

Variation in stable carbon (δ13C) and nitrogen (δ15N) isotope compositions along antlers of Qamanirjuaq caribou (Rangifer tarandus groenlandicus).

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.

Securing the boundaries of wilderness in northern Alaska, 1892–1950

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.

Ancient reindeer mitogenomes reveal island-hopping colonisation of the Arctic archipelagos

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.

Camera trap sampling protocols for open landscapes: The value of time‐lapse imagery

AbstractCamera 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.

A submerged Stone Age hunting architecture from the Western Baltic Sea

The Baltic Sea basins, some of which only submerged in the mid-Holocene, preserve Stone Age structures that did not survive on land. Yet, the discovery of these features is challenging and requires cross-disciplinary approaches between archeology and marine geosciences. Here, we combine shipborne and autonomousunderwater vehicle hydroacoustic data with up to a centimeter range resolution, sedimentological samples, and optical images to explore a Stone Age megastructure located in 21 m water depth in the Bay of Mecklenburg, Germany. The structure is made of 1,673 individual stones which are usually less than 1 m in height, placed side by side over a distance of 971 m in a way that argues against a natural origin by glacial transport or ice push ridges. Running adjacent to the sunken shoreline of a paleolake (or bog), whose youngest phase was dated to 9,143 ±36 ka B.P., the stonewall was likely used for hunting the Eurasian reindeer (Rangifer tarandus) during the Younger Dryas or early Pre-Boreal. It was built by hunter-gatherer groups that roamed the region after the retreat of the Weichselian Ice Sheet. Comparable Stone Age megastructures have become known worldwide in recent times but are almost unknown in Europe. The site represents one of the oldest documented man-made hunting structures on Earth, and ranges among the largest known Stone Age structure in Europe. It will become important for understanding subsistence strategies, mobility patterns, and inspire discussions concerning the territorial development in the Western Baltic Sea region.

Individual and temporal variation in movement patterns of wild alpine reindeer and implications for disease management

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.

A palaeogenomic investigation of overharvest implications in an endemic wild reindeer subspecies.

Overharvest can severely reduce the abundance and distribution of a species and thereby impact its genetic diversity and threaten its future viability. Overharvest remains an ongoing issue for Arctic mammals, which due to climate change now also confront one of the fastest changing environments on Earth. The high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus), endemic to Svalbard, experienced a harvest-induced demographic bottleneck that occurred during the 17-20th centuries. Here, we investigate changes in genetic diversity, population structure, and gene-specific differentiation during and after this overharvesting event. Using whole-genome shotgun sequencing, we generated the first ancient and historical nuclear (n = 11) and mitochondrial (n = 18) genomes from Svalbard reindeer (up to 4000 BP) and integrated these data with a large collection of modern genome sequences (n = 90) to infer temporal changes. We show that hunting resulted in major genetic changes and restructuring in reindeer populations. Near-extirpation followed by pronounced genetic drift has altered the allele frequencies of important genes contributing to diverse biological functions. Median heterozygosity was reduced by 26%, while the mitochondrial genetic diversity was reduced only to a limited extent, likely due to already low pre-harvest diversity and a complex post-harvest recolonization process. Such genomic erosion and genetic isolation of populations due to past anthropogenic disturbance will likely play a major role in metapopulation dynamics (i.e., extirpation, recolonization) under further climate change. Our results from a high-arctic case study therefore emphasize the need to understand the long-term interplay of past, current, and future stressors in wildlife conservation.

Sporadic cases of chronic wasting disease in old moose - an epidemiological study.

Transmissible spongiform encephalopathies or prion diseases comprise diseases with different levels of contagiousness under natural conditions. The hypothesis has been raised that the chronic wasting disease (CWD) cases detected in Nordic moose (Alces alces) may be less contagious, or not contagious between live animals under field conditions. This study aims to investigate the epidemiology of CWD cases detected in moose in Norway, Sweden and Finland using surveillance data from 2016 to 2022.In total, 18 CWD cases were detected in Nordic moose. All moose were positive for prion (PrPres) detection in the brain, but negative in lymph nodes, all were old (mean 16 years; range 12-20) and all except one, were female. Age appeared to be a strong risk factor, and the sex difference may be explained by few males reaching high age due to hunting targeting calves, yearlings and males.The cases were geographically scattered, distributed over 15 municipalities. However, three cases were detected in each of two areas, Selbu in Norway and Arjeplog-Arvidsjaur in Sweden. A Monte Carlo simulation approach was applied to investigate the likelihood of such clustering occurring by chance, given the assumption of a non-contagious disease. The empirical P-value for obtaining three cases in one Norwegian municipality was less than 0.05, indicating clustering. However, the moose in Selbu were affected by different CWD strains, and over a 6 year period with intensive surveillance, the apparent prevalence decreased, which would not be expected for an ongoing outbreak of CWD. Likewise, the three cases in Arjeplog-Arvidsjaur could also indicate clustering, but management practices promotes a larger proportion of old females and the detection of the first CWD case contributed to increased awareness and sampling.The results of our study show that the CWD cases detected so far in Nordic moose have a different epidemiology compared to CWD cases reported from North America and in Norwegian reindeer (Rangifer tarandus tarandus). The results support the hypothesis that these cases are less contagious or not contagious between live animals under field conditions. To enable differentiation from other types of CWD, we support the use of sporadic CWD (sCWD) among the names already in use.

Lessons learned and lingering uncertainties after seven years of chronic wasting disease management in Norway

Chronic wasting disease (CWD) is well known among cervids in North America. Nevertheless, management faced different types and degrees of uncertainty when CWD was first detected in reindeer Rangifer tarandus in Nordfjella, Norway in 2016. We present a timeline of the efforts to control CWD, and identify how the process, measurement, environmental, and implementation uncertainties developed from the onset (2016) to the current situation (2023) after seven years of CWD management. In the ‘acute' phase (2016–2019), political ambitions were high and depopulation of the Nordfjella reindeer area involving marksmen aimed at eradicating CWD. Subsequently, increased surveillance and increased male harvest was used to enable early detection or to achieve ‘freedom‐from‐CWD' status of the adjacent populations. The second phase (2020‐now) came when cases were detected in the large reindeer population in Hardangervidda. Management authorities postponed culling using marksmen, signifying an important change, with more emphasis on socio‐political acceptance and consideration of the negative long‐term consequences of conflicts with local stakeholders. The subsequent dialogue processes between scientists and local management ended in joint advice. However, the Ministry set aside all advice in 2022, halting further actions, after pressure and negative media attention. During this period, there was no clear research plan to increase knowledge of CWD to reduce process uncertainty; however, large surveillance investments were made to reduce measurement uncertainty. Despite this, detecting and estimating CWD among reindeer at low prevalence remains a key challenge. Governance challenges have emerged as significant implementation uncertainties, partly due to the uncertain occurrence of CWD.

DNA barcoding for the identification and authentication of medicinal deer (Cervus sp.) products in China.

Deer products from sika deer (Cervus nippon) and red deer (C. elaphus) are considered genuine and used for Traditional Chinese Medicine (TCM) materials in China. Deer has a very high economic and ornamental value, resulting in the formation of a characteristic deer industry in the prescription preparation of traditional Chinese medicine, health food, cosmetics, and other areas of development and utilization. Due to the high demand for deer products, the products are expensive and have limited production, but the legal use of deer is limited to only two species of sika deer and red deer; other wild deer are prohibited from hunting, so there are numerous cases of mixing and adulteration of counterfeit products and so on. There have been many reports that other animal (pig, cow, sheep, etc.) tissues or organs are often used for adulteration and confusion, resulting in poor efficacy of deer traditional medicine and trade fraud in deer products. To authenticate the deer products in a rapid and effective manner, the analysis used 22 deer products (antler, meat, bone, fetus, penis, tail, skin, and wool) that were in the form of blind samples. Total DNA extraction using a modified protocol successfully yielded DNA from the blind samples that was useful for PCR. Three candidate DNA barcoding loci, cox1, Cyt b, and rrn12, were evaluated for their discrimination strength through BLAST and phylogenetic clustering analyses. For the BLAST analysis, the 22 blind samples obtained 100% match identity across the three gene loci tested. It was revealed that 12 blind samples were correctly labeled for their species of origin, while three blind samples that were thought to originate from red deer were identified as C. nippon, and seven blind samples that were thought to originate from sika deer were identified as C. elaphus, Dama dama, and Rangifer tarandus. DNA barcoding analysis showed that all three gene loci were able to distinguish the two Cervus species and to identify the presence of adulterant species. The DNA barcoding technique was able to provide a useful and sensitive approach in identifying the species of origin in deer products.

To the History of Reindeer and Reindeer Husbandry in Eastern Fennoscandia

The hypotheses of the reindeer appearance in Eastern Fennoscandia are discussed. Probably, reindeer appeared in the south of the Scandinavian Peninsula and then moved along the coast of the Norwegian Sea. Further, it dispersed along the Barents Sea to the north of Finland and to the northwest of the Kola Peninsula. The occupancy of the central and northeastern parts of the Kola Peninsula, apparently, took place along the mainland of the peninsula, fi rst in the southern and then in the eastern direction. Forest reindeer entered Eastern Fennoscandia 8–9 thousand years ago: fi rst in central Karelia, much later in Finland, and, possibly, to the south of the Kola Peninsula (Siivonen, 1979; Rankama, Ukkonen, 2001). Currently, Eastern Fennoscandia is inhabited by three subspecies of reindeer: European tundra deer (Rangifer tarandus tarandus (L.)), forest reindeer (Rangifer tarandus fennicus Lönnb.), and Siberian tundra reindeer (Rangifer tarandus sibiricus (L.)) appeared here in 1887 with the arrival of reindeer herders from the Bolshezemelskaya tundra. The existence of wild reindeer in Fennoscandia is closely related to domestic reindeer husbandry. Reindeer husbandry severely limited the distribution of the wild form, and as a result, the European tundra reindeer survived in Fennoscandia in the form of geographically isolated pockets of various sizes only in Norway and on the Kola Peninsula. Genetic studies have shown that, despite the longterm coexistence of the domesticated tundra reindeer and the native wild form in the eastern part of the Kola Peninsula, the wild reindeer preserved his genetic uniqueness. To the south, in Karelia, the main tasks now should be the protection and restoration of wild forest reindeer

Silviculture treatments hasten seedling growth on seismic disturbances in boreal treed fens

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.

Deer in the extreme north-east of Russia: Koryak ecotype (Rangifer Tarandus L.)

Purpose: the study of economic and significant indicators of the Koryak ecotype of the northern deer.Materials and methods. The model for the study of the Koryak ecotype was the livestock of animals in agricultural enterprises for breeding the northern deer in the Kamchatka Peninsula during the stable development of the industry, with a total number of more than 125 thousand individuals. The entire number of deer was contained in 86 herds, on average in one herd, up to 1,400-1500 animals fell. Zootechnical information was taken from annual reports of deer farms. In the study of farms, indicators used in the reindeer husbandry industry were taken: the number of deer at the beginning of the year; the uterus in the structure of the herd (the number of important and heels in % to the total number of deer); offspring - received living calves at the end of the hotel per 100 uterus, %; DWT - a business exit of calves at the end of the year per 100 uterus, %; SVP - the safety of the adult number of deer at the end of the year, %; Production of meat in live weight, taking into account growth per 100 January deer, in C; Live weight of sexual age groups, kg.Results. The reindeer husbandry of the territory was distinguished by high quality indicators. The specific gravity of the uterus in the structure of the herd was maintained at 60 % and higher. The deer of this ecotype has good reproductive properties, on average at the end of the hotel there were more than 86 calves per 100 queens. The business yield of young animals at the end of the year on average ecotip was 80.6 % with fluctuations from 73 to 86.5 %, which confirms the high reproductive properties and viability of the young deer group of the northern deer. The safety indicator of the adult livestock at the end of the year was at the level of 93.9 % with fluctuations in individual populations from 90.4 % to 96.5 %. The production of meat in live weight, taking into account the growth of 100 deer according to individual scope, was flukes from 28 to 31.5 c, with an average ecotype value over 29.2 c. In terms of live weight of the Koryak ecotype deer, they exceeded the analogues of the sexual age groups of deer in the Chukotsk AO by 1.0-7.7 %, which confirms their high household chores. When crossing the deer of the Koryak ecotype and the Chukotka breed, a manifestation of heterosis was noted, since the estates significantly exceeded both initial parental forms in live weight, the preservation of the livestock, the business exit of young animals increased, and the production of meat increased. The identification of highly productive ecotypes and the creation on their basis of in -breed structures will increase the productivity of the northern deer.

Simultaneous estimation of the temporal and spatial extent of animal migration using step lengths and turning angles

BackgroundAnimals of many different species, trophic levels, and life history strategies migrate, and the improvement of animal tracking technology allows ecologists to collect increasing amounts of detailed data on these movements. Understanding when animals migrate is important for managing their populations, but is still difficult despite modelling advancements.MethodsWe designed a model that parametrically estimates the timing of migration from animal tracking data. Our model identifies the beginning and end of migratory movements as signaled by change-points in step length and turning angle distributions. To this end, we can also use the model to estimate how an animal’s movement changes when it begins migrating. In addition to a thorough simulation analysis, we tested our model on three datasets: migratory ferruginous hawks (Buteo regalis) in the Great Plains, barren-ground caribou (Rangifer tarandus groenlandicus) in northern Canada, and non-migratory brown bears (Ursus arctos) from the Canadian Arctic.ResultsOur simulation analysis suggests that our model is most useful for datasets where an increase in movement speed or directional autocorrelation is clearly detectable. We estimated the beginning and end of migration in caribou and hawks to the nearest day, while confirming a lack of migratory behaviour in the brown bears. In addition to estimating when caribou and ferruginous hawks migrated, our model also identified differences in how they migrated; ferruginous hawks achieved efficient migrations by drastically increasing their movement rates while caribou migration was achieved through significant increases in directional persistence.ConclusionsOur approach is applicable to many animal movement studies and includes parameters that can facilitate comparison between different species or datasets. We hope that rigorous assessment of migration metrics will aid understanding of both how and why animals move.

Necropsy findings, meat control pathology and causes of loss in semi-domesticated reindeer (Rangifer tarandus tarandus) in northern Norway

BackgroundReindeer herding in Norway is based on traditional Sámi pastoralism with the animals free ranging throughout the year. The animals move over large areas in varying terrain and often in challenging weather conditions. Winter crises, such as difficult grazing conditions caused by icing or large amounts of snow, are survival bottlenecks for reindeer. Calves are especially vulnerable, and many may die from starvation during winter crises. Predation and starvation are the predominant narratives to explain losses, however, carcasses are difficult to find and often little remains after scavenging and decay. Documentation of the causes of death is therefore scarce.ResultsIn this study, we investigated the cause of reindeer mortality in Troms and Finnmark, Nordland and Trøndelag during 2017–2019. Necropsies (n = 125) and organ investigation (n = 13) were performed to document cause of death. Body condition was evaluated using visual fat score and bone marrow fat index. A wide range of causes of death was detected. The diagnoses were categorized into the following main categories: predation (n = 40), emaciation (n = 35), infectious disease (n = 20), trauma (n = 11), feeding related disease (n = 5), neoplasia (n = 4), others (n = 6) and unknown (n = 17). Co-morbidities were seen in a number of diagnoses (n = 16). Reindeer herders are entitled to economic compensation for reindeer killed by endangered predators, but a lack of documentation leads to a gap between the amount of compensation requested and what is awarded. An important finding of our study was that predators, during winter, killed animals in good as well as poor body condition. Emaciation was also shown to be associated with infectious diseases, and not only attributable to winter grazing conditions.ConclusionsThis study highlights the importance of examining dead reindeer to gain knowledge about why they die on winter pasture. The work presented herein also shows the feasibility and value of increased documentation of reindeer losses during winter.