We have estimated the average number of brown bears Ursus arctos L. in Finnmark, the northernmost county in Norway. We started by estimating the number of bears where reproduction has been documented in the Pasvik Valley (1,330 km2) and published densities of brown bears from 1) female concentration areas in Sweden and northern Russia (ca. 5 bears per 1 000 km2), and 2) an intensively studied area in northern Sweden (12.6 bears per km2). We then expanded this estimate to all of Finnmark using observations of bears far from the Pasvik Valley. We estimate that there are on average 7 - 17 bears in Sør-Varanger Municipality, and totally 8 - 21 in Finnmark County. The brown bears in Finnmark comprise 31 - 38% of the total estimated number of bears in Norway of 26 - 55, respectively. An area of only 1,330 km2 in the Pasvik Valley is the major Norwegian brown bear area, contains about 30% of the bears in Norway, and is the area where reproduction is observed most regularly.

Large omnivores at the top of food webs play a key role in ecosystems, as their ability to feed on multiple trophic levels stabilizes food-web dynamics and impacts ecosystem functioning. However, it is largely unexplored how large omnivores adapt their trophic interactions to altered resource availability under global change, particularly in terrestrial ecosystems. Here, we combine macroecological and paleoecological approaches and reveal that extant bears, the largest terrestrial omnivores, adapt their trophic position in food webs dynamically to net primary productivity and growing season length. Throughout their geographic ranges, extant bears occupy higher trophic positions in unproductive ecosystems with short growing seasons than in productive ecosystems with long growing seasons. Consistent with this geographic pattern, the trophic position of the brown bear sharply decreased at the transition from the Late Pleistocene to the Holocene, coinciding with an increase in net primary productivity and growing season length. These findings demonstrate that trophic interactions of omnivores are not static but change dynamically in response to environmental change. Our findings suggest that global change impacts on primary production and vegetation seasonality may trigger shifts in the functional role of omnivores, with consequences for food webs and ecosystem functions. Significance statement Large omnivores play a key role in ecosystems, as they stabilize food-web dynamics and impact ecosystem functioning. However, how omnivores adapt their trophic interactions to changes in resource availability under global change remains unexplored. Combining macroecological and paleoecological approaches, we show that extant bears, the largest terrestrial omnivores, occupy lower trophic positions in food webs as net primary productivity and growing season length increase. This trophic adaptation is evident across the geographic ranges of all extant terrestrial bear species and for brown bears at the transition from the Late Pleistocene to the Holocene. Therefore, impacts of global change on primary production and vegetation seasonality may trigger shifts in the functional role of omnivores, with consequences for food webs and ecosystems. One sentence summary Global changes in primary productivity and vegetation seasonality alter the functional role of large omnivores in terrestrial ecosystems. ### Competing Interest Statement The authors have declared no competing interest.

The Swedish brown bear Ursus arctos population is protected, but managed with legally defined hunting seasons. Management decisions (e.g., hunting quotas) are frequently changed and should be based on knowledge about demographic parameters, but collecting sufficient data in the field is time consuming and expensive. An efficient method to collect data on reproductive output could be counting placental scars in the uteri of female brown bears, because hunters in Sweden are required to collect samples (including reproductive organs) of harvested bears and submit them to the authorities. We assessed the reliability of placental scar counts to determine reproductive performance by counting the number of young with female radio-collared brown bears and comparing that with placental scar counts after those females had been harvested. We found that staining uteri improved the detection of placental scars. The differences between number of scars detected before and after staining the uteri, increased significantly with female age. The number of placental scars and number of observed cubs-of-the-year accompanying females corresponded well 2 and 3 years after birth; relatively small deviations between them might have occurred because of early cub mortality prior to the observations after leaving the den. Placental scar counts can provide accurate information on age of primiparity, evidence for reproductive aging (senescence), and reproductive productivity, and therefore inform decisions regarding adaptive management, sustainable hunting, and conservation.

There are about 2,700 bears in the central and northern parts of Sweden, about 150 bears in Norway (most of them along the Swedish, Finnish, and Russian borders), and about 2,400 in Finland, mostly in the eastern parts of the country. The conservation status of the brown bear is considered "Near Threatened" in Sweden and Finland and "Endangered" in Norway. All three countries have well-developed population monitoring programs, but the methods used differ widely. However, because these countries share the same population of bears, cross-border collaboration in research, management, and the sharing of information is well established. All three countries have damage compensation systems in place, however, the type of damages vary; in Sweden and Finland they are mainly due to depredation of semi-domestic reindeer in the northern parts of the countries, while damages in Norway are mainly related to the depredation of free-grazing sheep and they are concentrated in the eastern part of the country, along the border with Sweden. Bears in Sweden and Norway are managed at the regional level, while bears in Finland are managed on the national level. Hunting of bears is allowed in all three countries nowadays.

The Scandinavian Brown Bear Research Project began in northern Sweden in 1984 and central Sweden in 1985. It quickly became a cooperative Swedish study between the conservation management authority and the Hunters’ Association in Sweden. This cooperative philosophy was continued by expanding to a Swedish-Norwegian cooperation in 1987 and a continually increasing internationalisation throughout the project’s history. During the 35 years from 1984-2018, the period considered here, the project focused on following individual bears from birth to death. We combined research on management-relevant and general ecological topics. The project became one of the world’s most successful research projects on large carnivores (actually, on birds or mammals), with 263 scientific papers in international peer-reviewed journals, 35 completed PhD degrees, and 101 completed master’s degrees. We believe that one reason for this success was creating a dynamic “research family” of international experts and international students.

Background Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The amplitude of metabolic rate reduction in hibernators is dependent on body mass of the species. Small hibernators have high metabolic rates when euthermic but experience a drastic decrease in body temperature during torpor, which is necessary to reach a very low metabolic rate. Conversely, large hibernators, such as the brown bear ( Ursus arctos ), show a moderate decrease in temperature during hibernation, thought to be related to the bear’s large size. We studied body mass, abdominal body temperature, heart rate, and accelerometer-derived activity from 63 free-ranging brown bears (1–15 years old, 15–233 kg). We tested for relationships between body mass and body temperature, heart rate, and hibernation duration. Results The smallest individuals maintained lower body temperatures during hibernation, hibernated longer, and ended hibernation later than large bears. Unlike body temperature, winter heart rates were not associated with body mass. In summer, the opposite pattern was found, with smaller individuals having higher body temperature and daytime heart rates. Body mass was associated with body temperature in the winter hypometabolic state, even in a large hibernating mammal. Smaller bears, which are known to have higher thermal conductance, reached lower body temperatures during hibernation. During summer, smaller bears had higher body temperatures and daytime heart rates, a phenomenon not previously documented within a single mammalian species. Conclusion We conclude that the smallest bears hibernated more deeply and longer than large bears, likely from a combined effect of basic thermodynamics, the higher need for energy savings, and a lower cost of warming up a smaller body.

Global climate change has a significant effect on species, as environment conditions change, causing many species' distributions to shift. During the last three million years, the earth has experienced glacial oscillations, forcing some species to survive in ice-free refugia during glacial periods and then disperse postglacially. In this study, by assessing the potential distribution of Siberian Grouse (Falcipennis falcipennis), we used Global Circular Models and Representative Concentration Pathways to model their pattern of range changes during glacial oscillations and the potential impact of present global warming. We used 158 location records of Siberian Grouse to generate a full climate model using 19 bioclimate variables in MaxEnt. We discarded variables with a correlation coefficient larger than 0.8 and relatively lower modeling contributions between each pair of correlated variables. Using the remaining variables, we created a normally uncorrelated simple climate model to predict the possible distribution of Siberian Grouse from the most recent Ice Age to present and to 2070. Then we added geographical data and the human interference index to construct a multiple factor full model to evaluate which were important in explaining the distribution of Siberian Grouse. The Total Suitability Zone (P ​≥ ​0.33) of Siberian Grouse is about 243,000 ​km2 and the Maximum Suitability Zone (P ​≥ ​0.66) is 36,000 ​km2 and is confined to the Russian Far East. Potential habitat modeling suggested that annual precipitation, annual mean temperature, and the distance from lakes are the most explanatory variables for the current distribution of Siberian Grouse. The distribution center moved to the southeast during the Last Glacial Maximum and spread back to the northwest after the ice melted and temperatures rose. The total area range of Siberian Grouse experienced a dramatic loss during the Last Glacial Maximum. Global warming is presently forcing the Siberian Grouse to migrate northward with a contraction of its range. There is an urgent need to protect its habitat, because little of its Maximum Sustainable Zone is protected, although there are some large reserves in that area.

The Chinese Grouse（Tetrastes sewerzowi） and Hazel Grouse（T. bonasia） are sibling species that are well-adapted to harsh high-altitude and latitude habitats. In the current study, we sampled and sequenced 29 Chinese Grouse（n=16） and Hazel Grouse（n=13） from eight locations in China, Sweden,Germany, and northeast Poland to analyze population genetic diversity and structure, introgression, and local adaptation.

We report the first survey of ecto- and endoparasites of brown bears (Ursus arctos gobiensis) in the Gobi Desert, Mongolia. We collected 40 ticks from 1 female (21 yr old, 48 kg) and 2 males (10 yr, 155 kg; 5 yr, 108 kg) captured for research purposes in May 2018. We found Dermacentor nutalli (n = 35 ticks, 87.5%) on both male bears and Hyalomma asiaticum (n = 5 ticks, 12.5%) on one male. The female had no ticks. We also collected a fecal sample from each captured bear, and an additional 15 fecal samples in the field. Two (11%) of the 18 fecal samples collected contained eggs of Strongyloides spp.; 1 fecal (10-yr-old male) sample had 2 eggs, and 1 fecal sample collected in the field contained 1 egg. This is the first documentation of parasites of wild bears in Mongolia.

Threat to human safety is the most dramatic conflict between humans and large carnivores. Although carnivore attacks are generally rare, bears are relatively often involved. Here, we reveal an association between human encroachment into the landscape, that is, increasing road density, and brown bear‐caused human casualties (injuries and fatalities) in Russia. In European Russia, the frequency of casualties correlated positively with bear population size and negatively with the presence of Siberian pine, a crucial bear food in the predenning period and a commonly gathered human resource. In Siberia, however, the number of casualties was not related to the number of bears, but it was positively associated with both road density and the presence of Siberian pine. Increasing casualties there were seemingly linked to increasing access to areas where both humans and bears concentrated simultaneously to harvest the same resource, edible pine seeds. The latter are more often collected commercially in Siberia than in European Russia. Our study shows the link between habitat degradation and human–wildlife conflict. Indeed, interacting effects of habitat change and coexistence with large carnivores deserve further attention, as we illustrate here for Russian forests; a wide boreal ecosystem where human encroachment can have severe repercussions for wildlife and ecosystem functioning at multiple spatial levels.

Previous studies have reported a relationship between brain size and cognitive ability in several species. In this study, we found that adult chestnut thrushes were less exploratory than juveniles. Chestnut thrushes with a larger head volume were more likely to learn a novel skill than individuals with a smaller head volume. Furthermore, individuals with a larger head volume relative to their tarsus length learned the novel skill more quickly. Recent comparative studies on fish and mammals have suggested that brain size is associated with cognitive ability, such as problem solving and self-control; larger-brained individuals are assumed to have better cognitive ability. However, it remains largely unexplored whether larger-brained birds perform better in learning and spatial memory tests. Here, we used two experiments (novel skill learning task and spatial memory task) to examine whether head volume (proxy for brain size) could predict the learning performance and spatial performance in wild chestnut thrushes (Turdus rubrocanus). First, we found that chestnut thrushes with larger head volume were more likely to learn the novel skill than individuals with smaller head volume. Second, individuals with larger head volume relative to their tarsus (relative head volume) learned the novel skill faster. Age, sex, and exploratory tendency of individuals were not related to learning performance or learning speed. Finally, head volume, relative head volume and age was not associated with spatial performance in the spatial memory tasks. Together, these findings provided empirical evidences for the relationship between head volume and the ability of novel skill learning, and also provide a non-invasive method for studying the relationship between cognitive ability and head volume in other bird species.

Competition between apex predators can alter the strength of top-down forcing, yet we know little about the behavioral mechanisms that drive competition in multipredator ecosystems. Interactions between predators can be synergistic (facilitative) or antagonistic (inhibitive), both of which are widespread in nature, vary in strength between species and across space and time, and affect predation patterns and predator-prey dynamics. Recent research has suggested that gray wolf (Canis lupus) kill rates decrease where they are sympatric with brown bears (Ursus arctos), however, the mechanisms behind this pattern remain unknown. We used data from two long-term research projects in Scandinavia (Europe) and Yellowstone National Park (North America) to test the role of interference and exploitation competition from bears on wolf predatory behavior, where altered wolf handling and search time of prey in the presence of bears are indicative of interference and exploitation competition, respectively. Our results suggest the mechanisms driving competition between bears and wolves were dependent on the season and study system. During spring in Scandinavia, interference competition was the primary mechanism driving decreased kill rates for wolves sympatric with bears; handling time increased, but search time did not. In summer, however, when both bear and wolf predation focused on neonate moose, the behavioral mechanism switched to exploitation competition; search time increased, but handling time did not. Alternartively, interference competition did affect wolf predation dynamics in Yellowstone during summer, where wolves prey more evenly on neonate and adult ungulates. Here, bear presence at a carcass increased the amount of time wolves spent at carcasses of all sizes and wolf handling time for small prey, but decreased handling time for the largest prey. Wolves facilitate scavenging opportunities for bears, however, bears alter wolf predatory behavior via multiple pathways and are primarily antagonistic to wolves. Our study helps to clarify the behavioral mechanisms driving competition between apex predators, illustrating how interspecific interactions can manifest into population-level predation patterns.

Comparing life history traits among populations that have been separated genetically for several hundred thousand years, but live in similar habitats on different continents, may help us understand how ecological and anthropomorphic factors shape life histories. We compared patterns of growth in body length and mass, and the influence of population density, habitat quality (NDVI), and reproduction on age-specific length and mass of male and female brown bears between Alberta, Canada, and Sweden. We found that Swedish females were significantly smaller in both length and mass than Alberta females. Swedish females also reached primiparity earlier and at a smaller mass and length. However, there were no continental differences in the patterns of growth in males. We found strong positive effects of NDVI, but only weak negative effects of population density on female mass and length in both areas. Generally, especially mass of Alberta females was more strongly affected by NDVI and density than for Swedish females. Reproduction had stronger negative effects on female mass in Alberta than in Sweden. We found no effects of NDVI and population density on male mass and body length in both areas. The larger variation in female growth and size between the areas, in contrast to males, may be related to differences in female reproductive investment due to differences in population trends, i.e., earlier reproduction in increasing populations or populations below carrying capacity, or to different selection pressures in the past, potentially due to human persecution. Swedish females exhibited characteristics typical of increasing populations, whereas Alberta females exhibited characteristics typical of stable or decreasing populations. The difference in reproduction investment means that Swedish bears can be harvested at higher rates, whereas Alberta bears must be managed more conservatively.

Recreation is a crucial contribution of nature to people, relevant for forest ecosystems. Large carnivores (LCs) are important components of forests, however, their contribution to forest recreational value has not yet been evaluated. Given the current expansion of LC populations, the ongoing forest conservation debate, and the increasing use of nature for recreational purposes, this is a timely study. We used discrete choice experiments and willingness-to-travel to determine people’ preferences for both forest structural characteristics and presence of four LC species in Poland (N = 1097 respondents) and Norway (N = 1005). In both countries, two-thirds of the respondents (termed ‘wildness-positive’) perceived LCs as contributing positively to forest recreational value and preferred to visit old forests with trees of different species and ages and presence of dead wood (i.e. natural forests). Respondents with negative preferences towards LCs preferred more intensively managed forest (‘wildness-negative’); their preferences were stronger than in wildness-positive respondents and in Norway. Preferences towards wild nature were highly polarized and there were hardly neutral people. Our results showed a strong link between preferences for LC presence and forest structure, and reflected the dualism of human-nature relationships. This study highlights the need to consider the contribution of forests and LCs to human recreation services in ecosystem management policies.