Pattern of space use by female black bears in the White River National Wildlife Refuge,Arkansas, USA

The manner in which space is used by animals may influence several aspects of biology, including the pattern of resource use and intra-specific competition. We monitored 16 radio-collared female black bears (Ursus americanus) for 9,216 radio days during 1993–1995 in the White River National Wildlife Refuge (WRNWR), Arkansas, U.S.A. to investigate space use patterns. Annual home ranges (95% convex polygon) ranged from 2.10 to 11.34 km² with a mean (± SD) size of 4.90 (± 2.09) km² (n = 16). Largest home ranges were occupied by 2 females with yearlings during one year of study. Home ranges among neighbouring bears overlapped considerably. Although bears maintained larger home ranges during summer, the size of home range did not differ among seasons (P > 0.50). Our estimates of home range size for female black bears were smaller than those obtained in a study of the same population during 1979–1982. Because the size of the bear population at WRNWR was substantially smaller (about 130 bears) during 1979–1982 compared to the present population of ≥348 bears, these results suggested that population density and size of female black bear home ranges may be negatively correlated. Conservation implications of density-dependent space use pattern are also discussed.     

Resource Selection by Recolonizing American Black Bears

American black bears (Ursus americanus) were extirpated from Oklahoma, USA, in the early twentieth century but have since recolonized eastern portions of the state after immigrating from Arkansas, where they were successfully translocated. Within the last 2 decades, a population of black bears was detected in the Oklahoma Ozark region, prompting studies to determine population size, growth rate, and genetic makeup. To understand how black bears were recolonizing the human-dominated landscape, we investigated resource selection at 2 scales. Between 2011 and 2016, we collected global positioning system collar spatial data for 10 males and 13 females. We calculated average kernel density home ranges on a seasonal scale for all collared bears. We used generalized linear mixed models to calculate resource selection functions at the study area, defined by locations of all radio-collared black bears (second order) and the scale of individual black bear home ranges (third order). Resource selection did not differ significantly by sex. Black bears across seasons and scales selected riparian forest and moist oak (Quercus spp.) forest land cover types and mostly selected against indicators of human activity (e.g., pasture-prairie, anthropogenic land cover types, roads, and areas of high human population density). Black bears also selected areas with rugged terrain at high elevations, although not consistently across seasons and scales. Black bear recolonization appeared to be negatively affected by areas and features characterized as human-altered. Further expansion of the range of black bears may be limited by anthropogenic disturbance in the region. © 2021 The Wildlife Society.     

Estimating home-range size: when to include a third dimension?

Most studies dealing with home ranges consider the study areas as if they were totally flat, working only in two dimensions, when in reality they are irregular surfaces displayed in three dimensions. By disregarding the third dimension (i.e., topography), the size of home ranges underestimates the surface actually occupied by the animal, potentially leading to misinterpretations of the animals' ecological needs. We explored the influence of considering the third dimension in the estimation of home‐range size by modeling the variation between the planimetric and topographic estimates at several spatial scales. Our results revealed that planimetric approaches underestimate home‐range size estimations, which range from nearly zero up to 22%. The difference between planimetric and topographic estimates of home‐ranges sizes produced highly robust models using the average slope as the sole independent factor. Moreover, our models suggest that planimetric estimates in areas with an average slope of 16.3° (±0.4) or more will incur in errors ≥5%. Alternatively, the altitudinal range can be used as an indicator of the need to include topography in home‐range estimates. Our results confirmed that home‐range estimates could be significantly biased when topography is disregarded. We suggest that study areas where home‐range studies will be performed should firstly be scoped for its altitudinal range, which can serve as an indicator for the need for posterior use of average slope values to model the surface area used and/or available for the studied animals.     

Black bear spatial responses to the Wallow Wildfire in Arizona

The Wallow Fire, the largest wildfire in Arizona history, encompassed 2,170 km² and provided a rare opportunity to examine habitat selection and home ranges of American black bears (Ursus americanus) before and after a wildfire. We had fitted global positioning system (GPS) collars on 47 bears from 2005 to April 2011, and 10 of these were still collared when the fire started in May 2011. We captured and collared an additional 7 black bears within the fire perimeter post-fire (Jul–Sep 2011 and Jun 2012). To evaluate how black bears were affected by the fire, we fit a step selection function using a conditional mixed effects Poisson regression model to estimate the relative strength of black bear habitat selection in response to burn severity. Additionally, we estimated home range sizes using an autocorrelated kernel density estimator by means of a continuous-time movement model. We then used a generalized linear model with a negative binomial error distribution and mixed effects to estimate the effect of the burn severity on black bear home range size, while controlling for sex and drought. In spring and summer in years prior to the fire, bears selected areas that later burned in the fire. After the fire, bears used all burn severities, but their selection for high-severity burns decreased significantly in summer 2011 and fall 2012. Home range sizes were 3.06 times larger pre-fire than post-fire. Our study demonstrates that black bears continued to use all burn severities after a major wildfire, and that post-fire conditions did not result in expanded black bear home ranges.     

Space Use and Habitat Selection by Female Louisiana Black Bears in the Tensas River Basin of Louisiana

Abstract: Studies of space use and habitat selection of endangered species are useful for identifying factors that influence fitness of individuals and viability of populations. However, there is a lack of published information regarding these behaviors for the federally threatened Louisiana black bear (Ursus americanus luteolus). We documented space use and habitat selection for 28 female black bears in 2 subpopulations of the Tensas River Basin population in northeast Louisiana, USA. The Tensas subpopulation inhabits a relatively large (>300-km²) contiguous area of bottomland hardwood forest, whereas the Deltic subpopulation exists mainly in 2 small (<7-km²) forested patches surrounded by an agricultural matrix. Females on Deltic maintained smaller seasonal and annual home ranges than females on Tensas (all P < 0.04), except for females with cubs during spring. On Tensas, females with cubs maintained smaller home ranges than females without cubs during spring (P = 0.01), but we did not detect this difference on Deltic or in other seasons. Females on Tensas and Deltic exhibited differences in habitat selection when establishing home ranges and within home ranges (P < 0.001). Deltic females selected mature bottomland hardwood forests and avoided agricultural habitats at both spatial scales. Tensas females selected a mixture of swamps, mature and regenerating forests, and exhibited variation in selection across scale, season, and reproductive status. We suggest that differences in space use and habitat selection between Tensas and Deltic are at least partially due to habitat differences at the landscape (i.e., amount of forested habitat) and patch (i.e., food availability) scales. Our results contribute to the understanding of factors that influence space use and habitat selection by black bears and provide specific information on habitat types selected by Louisiana black bears to agencies involved in habitat protection and restoration for this threatened subspecies.     

Standardising Home Range Studies for Improved Management of the Critically Endangered Black Rhinoceros

Comparisons of recent estimations of home range sizes for the critically endangered black rhinoceros in Hluhluwe-iMfolozi Park (HiP), South Africa, with historical estimates led reports of a substantial (54%) increase, attributed to over-stocking and habitat deterioration that has far-reaching implications for rhino conservation. Other reports, however, suggest the increase is more likely an artefact caused by applying various home range estimators to non-standardised datasets. We collected 1939 locations of 25 black rhino over six years (2004–2009) to estimate annual home ranges and evaluate the hypothesis that they have increased in size. A minimum of 30 and 25 locations were required for accurate 95% MCP estimation of home range of adult rhinos, during the dry and wet seasons respectively. Forty and 55 locations were required for adult female and male annual MCP home ranges, respectively, and 30 locations were necessary for estimating 90% bivariate kernel home ranges accurately. Average annual 95% bivariate kernel home ranges were 20.4 ± 1.2 km², 53 ±1.9% larger than 95% MCP ranges (9.8 km² ± 0.9). When home range techniques used during the late-1960s in HiP were applied to our dataset, estimates were similar, indicating that ranges have not changed substantially in 50 years. Inaccurate, non-standardised, home range estimates and their comparison have the potential to mislead black rhino population management. We recommend that more care be taken to collect adequate numbers of rhino locations within standardized time periods (i.e., season or year) and that the comparison of home ranges estimated using dissimilar procedures be avoided. Home range studies of black rhino have been data deficient and procedurally inconsistent. Standardisation of methods is required.     

Black Bear Movement and Food Conditioning in an Exurban Landscape

Conflicts between humans and wildlife have become increasingly important challenges for resource managers along the urban-wildland interface. Food conditioning (i.e., reliance by an animal on anthropogenic foods) of American black bears (Ursus americanus) is related to conflict behavior (i.e., being bold or aggressive toward humans, consuming human food or garbage, causing property damage) and often occurs in communities adjacent to Great Smoky Mountains National Park (GRSM or Park), USA. The goal of our study was to evaluate black bear space use in GRSM and in exurban areas on surrounding private lands and to identify factors associated with food conditioning and conflict behavior. We radio-collared 53 bears (29 males, 24 females) from 2015 to 2017 to compare space use characteristics and used carbon isotopic signatures (δ¹³C) from bear hair to assess food conditioning. We then performed an integrated step selection function (iSSF) analysis to characterize and compare movement and resource use as related to food conditioning. Based on the stable isotope analyses, 24 bears were classified as food conditioned (FC; 16 males and 8 females) and 37 were not food conditioned (NFC; 14 males and 23 females). Annual 95% kernel density estimate (KDE) home ranges and 50% KDE core area estimates of female and male bears did not differ by level of food conditioning (i.e., mean δ¹³C), but 95% and 50% home ranges of FC females were smaller than NFC females when data from 2015, a year of food scarcity and abnormally large home ranges, were excluded. The mean proportion of exurban development (e.g., roads, buildings, openings) within 95% KDE and 50% KDE home ranges of females increased with mean δ¹³C (i.e., greater food conditioning). The iSSF models indicated that FC bears were more likely to use forest openings associated with higher levels of development than NFC bears. We used those models to demonstrate how landscape modifications can reduce bear use of exurban areas, particularly for NFC bears. Our stable isotope, movement, and resource use data indicate that conflict behaviors displayed by many bears within GRSM were learned in areas outside Park boundaries. © 2020 The Wildlife Society.     

Using spatially‐explicit capture–recapture models to explain variation in seasonal density patterns of sympatric ursids

Understanding how environmental factors interact to determine the abundance and distribution of animals is a primary goal of ecology, and fundamental to the conservation of wildlife populations. Studies of these relationships, however, often assume static environmental conditions, and rarely consider effects of competition with ecologically similar species. In many parts of their shared ranges, grizzly bears Ursus arctos and American black bears U. americanus have nearly complete dietary overlap and share similar life history traits. We therefore tested the hypothesis that density patterns of both bear species would reflect seasonal variation in available resources, with areas of higher primary productivity supporting higher densities of both species. We also hypothesized that interspecific competition would influence seasonal density patterns. Specifically, we predicted that grizzly bear density would be locally reduced due to the ability of black bears to more efficiently exploit patchy food resources such as seasonally abundant fruits. To test our hypotheses, we used detections of 309 grizzly and 597 black bears from two independent genetic sampling methods in spatially‐explicit capture–recapture (SECR) models. Our results suggest grizzly bear density was lower in areas of high black bear density during spring and summer, although intraspecific densities were also important, particularly during the breeding season. Black bears had lower densities in areas of high grizzly bear density in spring; however, density of black bears in early and late summer was best explained by primary productivity. Our results are consistent with the hypothesis that smaller‐bodied, more abundant black bears may influence the density patterns of behaviorally‐dominant grizzly bears through exploitative competition. We also suggest that seasonal variation in resource availability be considered in efforts to relate environmental conditions to animal density.     

黑龙江省10年来熊类资源的分布及变动趋势

熊类是大型动物,其毛皮、油脂以及胆、掌、肉等都有很高的利用价值,因此,在黑龙江省林区,熊类历来是重要的狩猎对象。然而,熊是大型猛兽,每被击伤或受惊扰,常凶猛袭人,故猎熊并非易事。历史文献中曾记载:“熊矫捷而罴憨猛,皆兽之绝有力者”,又说,“刺虎者,不过五人一排…刺熊罴,非十人不能胜。盖其力倍于虎也”(《满洲源流考》)。现在,黑龙江省的猎人,通常是在冬季待熊在树洞或地穴中冬眠时进行猎杀,即猎取洞中冬眠的熊,俗称“掏仓子”,或在春季捕捉刚出洞的幼熊,故每年都有一定的猎取量。     

试论山地的生态特征及山地生态学的研究内容

山地是一个生态复杂系统,它具有特定的结构和功能,拥有丰富的生物多样性资源、水资源、矿产资源和旅游资源。开展山地生态学研究对阐明山地系统的结构与功能、山地的生态现象与过程,以及合理开发利用和保护山地资源都有极为重要的意义。本文在简要分析山地地形的主要要素对生态因子影响的基础上,对山地的生态效应进行了归纳,探讨了山地生态学应包含的主要研究内容。作者认为,在山区,地形地貌是形成山地结构和功能以及各种生态现象和过程的最根本因素,它通过改变地表的光、热、水、土、肥等生态因子而发生作用。因此,山地生态学应把地形地貌与各种生态现象和过程的相互作用作为其核心的研究内容。作者提出,山地生态学研究主要包括：山地生态复杂性与生物多样性、山地气候变化、山地生态工程、山区可持续发展综合研究以及山地生态学研究技术与方法论等内容。     

Population-level resource selection by sympatric brown and American black bears in Alaska

Distribution theory predicts that for two species living in sympatry, the subordinate species would be constrained from using the most suitable resources (e.g., habitat), resulting in its use of less suitable habitat and spatial segregation between species. We used negative binomial generalized linear mixed models with fixed effects to estimate seasonal population-level resource selection at two spatial resolutions for female brown bears (Ursus arctos) and female American black bears (U. americanus) in southcentral Alaska during May–September 2000. Black bears selected areas occupied by brown bears during spring which may be related to spatially restricted (i.e., restricted to low elevations) but dispersed or patchy availability of food. In contrast, black bears avoided areas occupied by brown bears during summer. Brown bears selected areas near salmon streams during summer, presumably to access spawning salmon. Use of areas with high berry production by black bears during summer appeared in response to avoidance of areas containing brown bears. Berries likely provided black bears a less nutritious, but adequate food source. We suggest that during summer, black bears were displaced by brown bears, which supports distribution theory in that black bears appeared to be partially constrained from areas containing salmon, resulting in their use of areas containing less nutritious forage. Spatial segregation of brown and American black bears apparently occurs when high-quality resources are spatially restricted and alternate resources are available to the subordinate species. This and previous work suggest that individual interactions between species can result in seasonal population-level responses.     

Extensive Predator Space Use Can Limit the Efficacy of a Control Program

ABSTRACT Reduced to small isolated groups by anthropogenic habitat losses or habitat modifications, populations of many endangered species are sensitive to additive sources of mortality, such as predation. Predator control is often one of the first measures considered when predators threaten survival of a population. Unfortunately, predator ecology is often overlooked because relevant data are difficult to obtain. For example, the endangered Gaspésie caribou (Rangifer tarandus caribou) has benefited from 2 periods of predator control that targeted black bears (Ursus americanus) and coyotes (Canis latrans) in an attempt to reduce predation on caribou calves. Despite a high trapping effort, the number of predators removed has remained stable over time. To assess impact of predator movements on efficacy of a control program, we studied space use of 24 black bears and 16 coyotes over 3 years in and around the Gaspésie Conservation Park, Quebec, Canada, using Global Positioning System radiocollars. Annual home ranges of black bears averaged 260 km² and 10 individuals frequented area used by caribou. Annual home ranges of resident coyotes averaged 121 km², whereas dispersing coyotes covered >2,600 km². Coyotes were generally located at lower altitudes than caribou. However, because coyotes undertook long-distance excursions, they overlapped areas used by caribou. Simulations based on observed patterns showed that 314 bears and 102 coyotes potentially shared part of their home range with areas used by female caribou during the calving period. Despite low densities of both predator species, extensive movement and use of nonexclusive territories seem to allow predators to rapidly occupy removal areas, demonstrating the need for recurrent predator removals. Our results underscore the necessity of considering complementary and alternative solutions to predator control to assure long-term protection of endangered species.     

Determinants of Home Range Size for Polar Bears (Ursus maritimus)

The mean home range size of female polar bears ( Ursus maritimus ; 125 100 km² ± 11 800; n  = 93) is substantially larger than the predicted value (514 km²) for a terrestrial carnivore of similar weight. To understand this difference, we correlated home range size and sea ice characteristics. Home range size was related to (i) the ratio of land vs. sea within a given home range (42% of explained variance), and (ii) seasonal variation in ice cover (24%). Thus, bears using land during the ice-free season had larger home ranges and bears living in areas of great seasonal variation in ice cover also had larger home ranges. In another analysis we investigated how variation in a bear's environment in space and time affects its choice of home range. We found that polar bears adjusted the size of their home range according to the amount of annual and seasonal variation within the centre of their home range. For example, polar bears experiencing unpredictable seasonal and annual ice tended to increase their home range size if increasing home range size resulted in reducing variation in seasonal and annual ice. Polar bears make trade-offs between alternate space-use strategies. Large home ranges occur when variable ice cover is associated with more seals but also a more unpredictable distribution of those seals.     

Home ranges in moving habitats: polar bears and sea ice

Home range size estimates are often used to assess the amount of space required for animals to perform the activities essential for their survival and reproduction. However, in moving environments, traditional home range estimates may be ill suited to this task. In particular, traditional home range estimates are inaccurate representations of the space required by polar bears Ursus maritimus. The sea ice is the prime foraging platform of polar bears, and estimating the amount of ice encountered by bears may provide a better approximation of space use. We develop a technique to make these estimates. Our results confirm that polar bears use more space than terrestrial carnivores to find the resources and conditions they require. We also show that the traditional geographic home range can underestimate both the movement of bears and the amount of space encountered. Moreover, area of ice encountered increased with ice drift, indicating that bears living on highly mobile ice might be exposed to higher energetic costs, and potentially larger energetic gains, than bears inhabiting more stable ice. The methods and concepts presented here can serve as a foundation for new approaches to study the space use of the many species living in moving environments.     

Space Use,Survival, Movements,and Reproduction of Reintroduced Louisiana Black Bears

ABSTRACT Studies of reintroduced animals are beneficial to evaluate the success of reintroduction programs and to understand factors influencing fitness of reintroduced individuals. The geographic distribution of the federally threatened Louisiana black bear (Ursus americanus luteolus) has been reduced to 3 isolated populations due to habitat loss and excessive harvest. We reintroduced 23 adult female Louisiana black bears and their cubs to east-central Louisiana, USA, and documented postrelease space use, survival, movements, and reproduction. Individual females used larger home ranges after reintroduction than they had in the source population (P = 0.037). Spring ranges of reintroduced females were smaller than summer, autumn, and annual ranges (all P < 0.09), which did not differ from each other (all P > 0.60). Survival of reintroduced females did not differ between their first (S = 0.933) and second (S = 1.00) year after release or from annual survival of females in the source population (S = 0.964–1.00). Mean straight-line distance traveled by females from their release sites to the center of established home ranges or last recorded locations was 22.7 km. Six females reproduced after reintroduction and produced 15 cubs. Mean postrelease litter size of parturient reintroduced females (2.5) was similar to reported mean litter size of females in the source population (2.4). Our results suggest that the Louisiana reintroduction program is proceeding favorably; however, future studies should continue to monitor survival and reproduction of reintroduced females in Louisiana. Additional demographic parameters (i.e., cub survival) should be estimated to allow for population viability analysis to determine if the new population is self-sustaining.     

Geographic distribution patterns of melanistic Arabian Wolves,Canis lupus arabs (Pocock), in Saudi Arabia (Mammalia: Carnivora)

Melanism is a common colour polymorphism in carnivores, and may have adaptive relevance in certain ecological scenarios. This coat colour variation is present in Arabian Wolves Canis lupus arabs, a widely distributed species in the Arabian Peninsula, especially in western Highlands of Saudi Arabia. Data collection involved field surveys conducted between 2010 and 2017 including active searches for black wolf carcasses, records of live animals encountered during field surveys, and by using >100 camera traps. Niche models were generated for non-melanistic and melanistic wolves based on environmental predictors aiming to discover geographic patterns of distinct phenotypes distribution in this area. In this study, melanistic wolves were recorded at 12 locations from western highlands ranges. Niche model predicts suitability for melanistic and non-melanistic wolves mainly in western highlands and found that melanistic wolves were encountered in regions where moisture is high, predicting a close relationship between humidity and the presence of black animals.     

Identifying plant traits associated with topographic contrasts in a rugged and diverse region (Klamath‐Siskiyou Mts,OR, USA)

Rugged topography affects species distributions and community composition by creating contrasting mesic (cool, moist) and xeric (warm, dry) microclimates on adjacent slopes. This microclimatic heterogeneity is thought to have contributed to species survival during past climate fluctuations. Within a rugged and botanically rich region, we asked what functional, distributional, and/or biogeographic traits distinguished the species significantly associated with xeric or mesic microclimates. For each of 236 species in 4773 plots in the Klamath‐Siskiyou Mountains, we tested for significant associations with mesic or xeric topographic microclimates inferred from high‐resolution topographic variables. For the subset of species showing significant associations, we then compared their functional traits, biogeographic origins, and macroclimatic attributes to those of other species. We also tested the dependence of topographic associations on elevation, canopy cover, and soil type. Many species in the region (40%) showed significant tendencies to be found only in either mesic or xeric topography. ‘Mesic’ species tended to be of northern biogeographic origin and to have geographic ranges with higher mean precipitation; ‘xeric’ species had the opposite attributes. Species occurred more often in mesic microclimates when they occurred on low‐nutrient serpentine soils, and were more often found in xeric microclimates at high elevations. Functional traits such as specific leaf area were not significant predictors of species association with topographic microclimate. Biogeographic origins and the mean precipitation (rather than temperature) of species geographic ranges are the best indicators of species that are found in cool/moist northerly or hot/dry southerly microclimates.     

植被指数的地形效应研究进展

植被指数是定性、定量评估绿色植被的关键指标,已经广泛应用于地表植被的监测.森林多分布在地形复杂山区,利用植被指数进行森林植被信息反演时地形对其影响较大.本文从几何光学模型原理分析了冠层反射率的地形效应,分析比较完全比值型植被指数(简单比值植被指数SR、归一化植被指数NDVI和湿度调整植被指数MAVI)、非完全比值型植被指数(增强型植被指数EVI和土壤调整植被指数SAVI)、非比值型植被指数(减化比值植被指数RSR、修正归一化植被指数MNDVI和绿度植被指数GVI),以及地形调节植被指数TAVI对地形的响应,试图为复杂地形山区选取植被指数提供参考.最后分析了植被指数地形效应研究的不足并对未来发展进行展望.     

Grizzly bear responses to restrictions of recreation in Yellowstone National Park

Avoiding humans will be more difficult and energetically costly for animals as outdoor recreation increases and people venture farther into wildland areas that provide high-quality habitat for wildlife. Restricting human access can be an attractive management tool to mitigate effects of human recreation activities on wildlife; however, the efficacy of such measures is rarely assessed. In 1982, Yellowstone National Park identified areas important to grizzly bears (Ursus arctos) to help protect critical grizzly bear habitat and reduce the likelihood of human injuries by bears. Referred to as bear management areas (BMAs), human access is restricted in these areas for 2–8 months each year, with timing and type of restrictions varying by area. We examined 2 datasets to evaluate grizzly bear selection of BMAs and differences of bear density in BMAs and non-BMAs. First, we used 17 years of recent global positioning system telemetry data for grizzly bears to assess their selection of BMAs during periods when human access was allowed, and when access was restricted. We used step-selection functions to test the hypothesis that bears spend time in places that allow them to avoid people and select quality food sources. There was support that grizzly bears differentially select for BMAs regardless of whether human access was restricted at the time, compared with areas outside BMAs, and that selection changed with sex and season. Only males during the summer and hyperphagic seasons changed their selection of BMAs based on whether access restrictions were in place, and overall, male bears preferred unrestricted BMAs (BMAs without restrictions in place). Females preferentially selected BMAs regardless of whether the area had access restrictions in place only during the mating season. Individuals varied widely in their preference for BMAs and access restrictions. Bears likely choose to spend time in BMAs based on available food resources rather than restrictions to human access. Supporting this interpretation, our analyses indicated that a greater proportion of BMA in an area was associated with higher densities of grizzly bear. Thus, restrictions to human access likely help reduce the potential for human–bear interactions, accomplishing one of the original objectives for establishing the BMAs.     

When species’ ranges meet: assessing differences in habitat selection between sympatric large carnivores

Differentiation in habitat selection among sympatric species may depend on niche partitioning, species interactions, selection mechanisms and scales considered. In a mountainous area in Sweden, we explored hierarchical habitat selection in Global Positioning System-collared individuals of two sympatric large carnivore species; an obligate predator, the Eurasian lynx (Lynx lynx), and a generalist predator and scavenger, the wolverine (Gulo gulo). Although the species’ fundamental niches differ widely, their ranges overlap in this area where they share a prey base and main cause of mortality. Both lynx and wolverines selected for steep and rugged terrain in mountainous birch forest and in heaths independent of scale and available habitats. However, the selection of lynx for their preferred habitats was stronger when they were forming home ranges and they selected the same habitats within their home ranges independent of home range composition. Wolverines displayed a greater variability when selecting home ranges and habitat selection also varied with home range composition. Both species selected for habitats that promote survival through limited encounters with humans, but which also are rich in prey, and selection for these habitats was accordingly stronger in winter when human activity was high and prey density was low. We suggest that the observed differences between the species result primarily from different foraging strategies, but may also depend on differences in ranging and resting behaviour, home range size, and relative density of each species. Our results support the prediction that sympatric carnivores with otherwise diverging niches can select for the same resources when sharing main sources of food and mortality.