Bear Habitat Use Research Articles

Quantifying grizzly bear selection of natural and anthropogenic edges

Understanding the use of edges by threatened species is important for conservation and management. Whereas the effects of anthropogenic edges on threatened species have been studied, the effects of natural edges are unknown. We studied grizzly bear (Ursus arctos) habitat selection in relation to different landscape-level measures of edge, both natural and anthropogenic. We used a database of global positioning system telemetry data collected from 26 grizzly bears from 2005 to 2009 in the foothills of the Rocky Mountains in west-central Alberta, Canada. We quantified grizzly bear locations relative to natural edges extracted from satellite-derived land cover data and anthropogenic edges from existing vector datasets (roads, pipelines, and forest harvests). To compare edge distance from observed telemetry points statistically, we generated a distribution of expected points through a conditional randomization of an existing resource selection function describing grizzly bear habitat use without respect to edges. We also measured the density of edges within home ranges and compared this to the overall population to create an edge selection ratio. In general, females selected anthropogenic edges, whereas males selected natural edges. Both sexes selected the natural transition (edge) of shrub to conifer. Females had a greater selection ratio for road edges than males in all seasons, and males had a greater selection ratio for roads in the fall than in other seasons. Only females selected for pipeline edges. Our results indicated that edge habitat was selected by both males and females, mostly in the fall. Given human access to bear habitat is often facilitated by anthropogenic edges (e.g., roads), improved management of these features may minimize human conflicts. In particular, we highlight the importance of the natural transition of shrub to conifer to grizzly bears. © 2013 The Wildlife Society.

Managing sun bears in a changing tropical landscape

AbstractAimAcross the tropics, large‐bodied mammal species are threatened by rapid and widespread forest habitat conversion by either commercial logging or agricultural expansion. How such species use these habitats is an important area of research for guiding their future management. The tropical forest‐dwelling sun bear, Helarctos malayanus, is the least known of the eight bear species. Consequently, the IUCN/SSC Bear Specialist Group ranks research on this species as a top priority. This study aims to investigate landscape variables that influence sun bear habitat use in forests under varying levels of degradation and protection.LocationA 20,998 km2 Sumatra forest landscape covering Kerinci Seblat National Park (KSNP), Batang Hari Protection Forest (BHPF) and neighbouring logging and agricultural concessions.MethodsAn occupancy‐based sampling technique using detection/non‐detection data with 10 landscape covariates was applied in six study areas that operated a total of 125 camera traps. The potential differences between habitat use (ψ) of sun bears were first modelled with broad‐scale covariates of study area, land‐use types and forest type. Sun bear habitat use was then investigated with the finer‐scale landscape features associated within these areas.ResultsFrom 10,935 trap nights, sun bears were recorded at altitudes ranging from 365 to 1791 m. At a broad‐scale, habitat use increased with protection status, being highest in KSNP (0.688 ± 0.092, ± SE) and BHPF (0.621 ± 0.110) compared to production (0.418 ± 0.121) and convertible (0.286 ± 0.122) forests. Within these areas, sun bears showed a preference for forest that was further from public roads and villages and at a lower elevation.Main conclusionsThe habitat suitability model identified several high‐quality habitat patches outside of the priority conservation areas for immediate protection. Consequently, conservation management strategies should emphasize the importance of high conservation value forests and prohibit further conversion of threatened lowland forests.

Biological and Social Investigation of Human–Black Bear Conflicts in the Panhandle of Florida

As human–black bear conflicts increase, developing conflict mitigation strategies that account for both biological and social understanding has become a primary objective of managers. We examined black bear habitat use in the Florida Panhandle to understand its impact on the spatial distribution of conflicts. Focus groups were conducted with local residents and wildlife professionals to obtain participants' beliefs, attitudes, and preferences toward bears and conflict management approaches. Findings suggest bears prefer using areas located closer to humans and that while participants generally supported the regional presence of bears there was no consensus on how to manage human–bear conflicts. Several habitat and human management implications were identified along with suggestions for additional research. Improving biological and social understanding on the causes of human–black bear conflicts and the efficacy of various mitigation strategies can advance collaboration between the public and wildlife professionals and facilitate agreement on socially acceptable conflict management strategies.

Effect of mast production on home range use of Japanese black bears

AbstractAlthough bears may expand their home ranges in times of low food availability, it is unclear what mechanisms directly affect home range extension in times of low mast production in Japanese forests. To clarify the relationship between home range utilization by Japanese black bears (Ursus thibetanus) and abundance and distribution of mast production, we collected data on habitat use from 13 bears (6 M and 7 F) fitted with Global Positioning System (GPS) collars equipped with activity sensors in the Ashio‐Nikko Mountains on the eastern part of Honshu Island, Japan, during 2006–2008. We also collected data on mast production by 5 Fagaceae species. We categorized each fall as either poor (2006) or relatively‐good (2007 and 2008) based on mast production. Bears used small patches in their large home ranges and the distances between core areas increased in the fall of 2006, when the mast of Japanese oak (Quercus crispula) were poorly distributed. Our findings suggest that localized patches of Japanese oak are the staple food for bears in our study area, even in poor mast years. However, in the fall of 2006, we also found that bears moved to lower elevations, relative to 2007 and 2008, in search of alternative foods (e.g., Konara oak [Q. serrata] and Japanese chestnut [Castanea crenata]), which were mostly at lower elevations and produced mast consistently over the study period. Our results suggest that dispersion and elevational distribution of mast‐producing trees affect bear habitat use in fall, as well as amount of mast. © 2011 The Wildlife Society.

Remote sensing and forest inventory for wildlife habitat assessment

Researchers and managers undertaking wildlife habitat assessments commonly require spatially explicit environmental map layers such as those derived from forest inventory and remote sensing. However, end users of geospatial products must often make choices regarding the source and level of detail required for characterizing habitat elements, with few published resources available for guidance. We appraised three environmental data sources that represent options often available to researchers and managers in wildlife ecological studies: (i) a pre-existing forest inventory; (ii) a general-purpose, single-attribute remote sensing land cover map; and (iii) a specific-purpose, multi-attribute remote sensing database. The three information sources were evaluated with two complementary analyses: the first designed to appraise levels of map quality (assessed on the basis of accuracy, vagueness, completion, consistency, level of measurement, and detail) and the second designed to assess their relative capacity to explain patterns of grizzly bear ( Ursus arctos) telemetry locations across a 100,000-km 2 study area in west-central Alberta, Canada. We found the forest inventory database to be reasonably functional in its ability to support resource selection analysis in regions where coverage was available, but overall, the data suffered from quality issues related to completeness accuracy, and consistency. The general-purpose remote sensing land cover product ranked higher in terms of overall map quality, but demonstrated a lower capacity for explaining observed patterns of grizzly bear habitat use. We found the best results using the specific-purpose, multi-attribute remote sensing database, and recommend that similar information sources be used as the foundation for wildlife habitat studies whenever possible, particularly those involving large areas that span jurisdictional boundaries.

The impact of landscape disturbance on grizzly bear habitat use in the Foothills Model Forest, Alberta, Canada

The Rocky Mountains in Alberta, Canada are subject to a growing number of human activities that cause landscape disturbances. This region is important for large carnivore species such as grizzly bears, whose population decline is a serious management concern. Understanding the impact of landscape disturbance on grizzly bear habitat use is necessary to effectively manage this region and beyond. The goal of this research is to explore the spatial–temporal pattern of habitat use and to characterize the impact of disturbance on use through time. Research was conducted using radio-telemetry location data of female grizzly bears from 1999 to 2003. Kernel home ranges were created annually for three foraging seasons: hypophagia, early hyperphagia, and late hyperphagia. For each season, locations (30 m × 30 m grid cells) were characterized by the temporal persistence or variability in annual use by grizzly bears. Spatial–temporal trends were then compared for disturbed and undisturbed landscapes. Results indicate that in some foraging seasons, particularly hypophagia, the grizzly bear population's use of disturbed areas was proportionally higher than use in undisturbed areas. In other foraging seasons the trends are less clear, but all show instances of preferential selection of disturbed areas. Given that grizzly bear mortality tends to rise when bears use disturbed areas, this preferential selection of disturbed areas is a management concern. To enhance conservation efforts it may be beneficial to control human use in high-quality habitats. This protection may be most important for high-quality habitats used in the spring, as bears appeared to use smaller areas during this period.

Testing a Mahalanobis Distance Model of Black Bear Habitat Use in the Ouachita Mountains of Oklahoma

Abstract: Regional wildlife‐habitat models are commonly developed but rarely tested with truly independent data. We tested a published habitat model for black bears (Ursus americanus) with new data collected in a different site in the same ecological region (i.e., Ouachita Mountains of Arkansas and Oklahoma, USA). We used a Mahalanobis distance model developed from relocations of black bears in Arkansas to produce a map layer of Mahalanobis distances on a study area in neighboring Oklahoma. We tested this modeled map layer with relocations of black bears on the Oklahoma area. The distributions of relocations of female black bears were consistent with model predictions. We conclude that this modeling approach can be used to predict regional suitability for a species of interest.

Spatial response of American black bears to prescribed fire in northwest Florida

Little is known about the effects of prescribed burning on American black bears (Ursus americanus) in the Southeastern Coastal Plain. In Florida, Eglin Air Force Base is home to 1 of 8 relatively disjunct populations of black bears (U. a. floridanus) in the state. Prescribed burning has been used on Eglin since the late 1980s to reduce the dense oak (Quercus spp.) midstory that occupies the longleaf pine (Pinus palustris)–wiregrass (Aristida beyrichiana) community. We studied black bear habitat use during 1994–96 to determine if temporal and spatial relationships existed between prescribed fire and black bear habitat use from 9 years of burning data. Within all habitat types, our results showed that black bears used unburned areas more than burned areas, both annually and seasonally. Among burned areas, black bear use was greatest in 3- and ≥5-year-old burns, both annually and seasonally, for most habitat types. Our results are consistent with published reports on timing of peak soft mast production following prescribed fire, and we conclude that higher use of particular burn ages was related to production of several soft-mast species. We suggest that longer burning cycles be applied within and adjacent to important habitats, like riparian zones, in the Southeastern Coastal Plain. Planning for juxtaposition of various successional post-fire stages is the best approach for managing habitats to maintain cover and availability of primary bear foods and effectively minimize the area needed to satisfy the needs of black bears.

Identifying Habitat Linkages for American Black Bears in North Carolina, USA

ABSTRACT Understanding landscape structure and the role of habitat linkages is important to managing wildlife populations in fragmented landscapes. We present a data‐based method for identifying local‐ and regional‐scale habitat linkages for American black bears (Ursus americanus) on the Albemarle‐Pamlico Peninsula of North Carolina, USA. We used weights‐of‐evidence, a discrete multivariate technique for combining spatial data, to make predictions about bear habitat use from 1,771 telemetry locations on 2 study areas (n = 35 bears). The model included 3 variables measured at a 0.2‐km2 scale: forest cohesion, forest diversity, and forest‐agriculture edge density, adequately describing important habitat characteristics for bears on our study area. We used 2 categories of unique habitat conditions to delineate favorable bear habitat, which correctly classified 79.5% of the bear locations in a 10‐fold model validation. Forest cohesion and forest‐agriculture edge density were the most powerful predictors of black bear habitat use. We used predicted probabilities of bear occurrence from the model to delineate habitat linkages among local and regional areas where bear densities were relatively high. Our models clearly identified 2 of the 3 sites previously recommended for wildlife underpasses on a new, 4‐lane highway in the study area. Our approach yielded insights into how landscape metrics can be integrated to identify linkages suitable as habitat and dispersal routes.

Assessment of Recreational Impace of Black Bear Habitat Use and Implication of Grizzly Bear Range Expansion in the Southern Tetons

Grizzly bears have been moving slowly southward in the Tetons and increasing their abundance over the last 20 years. Their distribution is now expanding into areas previously occupied by black bears only that are heavily developed and receive proportionately more recreational use. At the same time, white pine blister rust and other human­caused factors may reduce bear food abundance in the near future. Grand Teton National Park is now positioned for an unprecedented interplay of bears, declining bear food sources, and humans in a relatively small temporal and spatial scale. In a new study designed to provide information critical to future black and grizzly bear conservation in this area, 6 spread spectrum technology (SST) GPS radio collars were deployed on black bears in the southern end of Grand Teton National Park in 2005. SST collars allow interrogation of the data in the GPS unit on a regular basis. GPS units were programmed to record positions every 90 to 190 minutes, and data were downloaded aerially on a weekly basis. Four female bears, two with cubs of the year, an adult male, and a subadult male provided the bulk of approximately 2700 positions obtained in 2005, about 1560 of which were visted for detailed site analysis. Sites visited were based on a randomly selected 24 hour period for each bear each week, and all sites were visited within a week of the location's recording. Efforts in 2006 will focus more intensively on site visits and associated data collection and analyses.

Sloth bear habitat use in disturbed and unprotected areas of Madhya Pradesh, India

In the North Bilaspur Forest Division in Madhya Pradesh, India, the sloth bear (Melursus ursinus) population is ecologically isolated, and some bears have developed aggressive behavior. Available bear habitat is highly fragmented and degraded and is interspersed with human habitation. In this study we assessed habitat use patterns of sloth bears with the goal of establishing management guidelines to reduce human–bear conflicts. Goodness-of-fit comparisons showed that expected use of each habitat category differed from habitat availability. Bear sign was most frequent in sal forest followed by land near water, sal mixed forest, and mixed forest. However, bear use of terrain categories was not different from expected use. A large number of bear dens were near water and human settlements. Bears regularly used more than 50% of observed den sites. Because of nearness to human settlement and degraded habitat, bears largely depended on villages for food, resulting in frequent human–bear encounters, some of which led to maulings and fatalities. One management priority is to protect highly preferred habitats of sloth bears. Bear population control and translocation of bears from isolated habitat patches to more suitable areas may be carried out simultaneously with education and awareness programs to conserve this species and to mitigate human–bear conflicts on a long-term basis.

Landscape permeability for grizzly bear movements in Washington and southwestern British Columbia

Providing opportunities for grizzly bears (Ursus arctos) to move between blocks of habitat is important for the long-term conservation of grizzly bear populations. While the particulars of grizzly bear habitat selection during long-distance movements are poorly understood, some landscape characteristics such as road density and land cover type are correlated with grizzly bear habitat use at various scales. We compiled digital maps of roads, human population density, land cover class, and topography to evaluate the resistance of the year 2001 landscape to grizzly bear movement in Washington State and adjacent portions of Idaho and British Columbia (BC). We developed habitat association and dispersal habitat suitability models based on published literature and used geographic information system (GIS) weighted-distance and least-cost analysis techniques to evaluate landscape permeability for grizzly bear movement. Our analysis identified 5 blocks of potential grizzly bear habitat in Washington and adjacent areas, including the Columbia–Selkirk Mountains, the North Cascades, the Central Cascades, the South Cascades, and the Coast Range. We evaluated landscape permeability between these habitat blocks and highlighted potential linkage areas. Our models indicated the Stevens Pass fracture zone between the North and Central Cascades blocks was the most permeable, followed (in order of relative permeability) by the Fraser–Coquihalla fracture zone between the North Cascades and the Coast Range, the Okanogan–Kettle fracture zone between the North Cascades and the Columbia Mountains, and the Snoqualmie Pass fracture zone between the Central and South Cascades. This evaluation provides a consistent measure of the expected potential for grizzly movement across a broad landscape that can be used to target areas for finer-scale evaluation and help identify landscape management priorities at a regional scale.

Grizzly bear selection of managed and unmanaged forests in the Selkirk Mountains

We tested the commonly held hypotheses that grizzly bears (Ursus arctos) select against clearcuts and young forests and select for natural openings and old forests in the Selkirk Mountains from 1986 to 1991. We compared use versus availability using χ2 goodness-of-fit for 11 bears (five females, six males) in a south study area containing both open roads (public use allowed) and closed roads (no public use allowed) and 11 bears (seven females, four males) in a north study area containing restricted roads (forestry use only). Zero of 11 females and 1 of 11 males (1/22 bears) selected against (P < 0.05) clearcuts. Five of 11 females and 2 of 11 males (7/22 bears) selected against (P < 0.05) young forests. The apparent selection against young forests appeared to be due to selection against associated open roads, not against young forests themselves. Forestry activities alone (managed forests and restricted roads) appeared to have no negative impact on grizzly bear habitat use. Because of small sample sizes, pooling of seasonal data, and lack of experimental replication, our results should not be extrapolated until similar studies are conducted elsewhere.

Functional responses in polar bear habitat selection

Habitat selection may occur in situations in which animals experience a trade‐off, e.g. between the use of habitats with abundant forage and the use of safer retreat habitats with little forage. Such trade‐offs may yield relative habitat use conditional on the relative availability of the different habitat types, as proportional use of foraging habitat may exceed proportional availability when foraging habitat is scarce, but be less than availability when foraging habitat is abundant. Hence, trade‐offs in habitat use may result in functional responses in habitat use (i.e. change in relative use with changing availability). We used logistic and log‐linear models to model functional responses in female polar bear habitat use based on satellite telemetry data from two contiguous populations; one near shore inhabiting sea ice within fjords, and one inhabiting pelagic drift ice. Open ice, near the ice edge, is a highly dynamic habitat hypothesised to be important polar bear habitat due to high prey availability. In open ice‐polar bears may experience a high energetic cost of movements and risk drifting away from the main ice field (i.e. trade off between feeding and energy saving or safety). If polar bears were constrained by ice dynamics we therefore predicted use of retreat habitats with greater ice coverage relative to habitats used for hunting. The polar bears demonstrated season and population specific functional responses in habitat use, likely reflecting seasonal and regional variation in use of retreat and foraging habitats. We suggest that in seasons with functional responses in habitat use, polar bear space use and population distribution may not be a mere reflection of prey availability but rather reflect the alternate allocation of time in hunting and retreat habitats.

Living on the edge: a process for redesigning campgrounds in grizzly bear habitat

The North Fork of the Shoshone Highway Corridor contains 52% of the developed recreation sites within the Shoshone National Forest. The highway is a popular access route for visitors traveling from Cody, WY to Yellowstone National Park. This river corridor is also an important habitat for a growing population of grizzly bears. The Shoshone National Forest is currently proposing a major reconstruction of recreation facilities along the highway corridor. This has presented the Forest with an excellent opportunity to recreate facilities that encourage more appropriate human behavior in grizzly habitat. This concept for campground design is a composite of many design strategies currently used internationally in bear habitat designs and information derived from current research in bear/human conflict, grizzly bear behavior and bear habitat use and habitat assessment. The application of this concept to recreational facilities in the North Fork Corridor is the product of an interagency design team of landscape architects and biologists from the US Forest Service, Wyoming Game and Fish Department, US Fish and Wildlife Service, and the National Park Service in the Greater Yellowstone Area. The design process involves identifying local grizzly bear use patterns and zoning campground components to accommodate these patterns. The most vulnerable facilities (tent pads), are located furthest from bear travel corridors and food preparation areas. Buffer zones, leave strips, trails and barriers are used to help direct bear travel around the campground. Food storage facilities, garbage facilities, cooking sites, and other attractants are consolidated. Human access into bear travel zones is structurally controlled. A major focus of the design is to emphasize the presence of the bear through the actual layout of campground facilities and to capitalize on the unique experience of camping in the grizzly bear's domain.

Black Bear Habitat Use in Relation to Food Availability in the Interior Highlands of Arkansas

A black bear (Ursus americanus) food value index (FVI) was developed and calculated for forest cover type classifications on Ozark Mountain (White Rock) and Ouachita Mountain (Dry Creek) study areas in western Arkansas. FVIs are estimates of bear food production capabilities of the major forest cover types and were calculated using percent cover, mean fruit production scorings, and the dietary percentage of each major plant food species as variables. Goodness-of-fit analyses were used to determine use of forest cover types by 23 radio-collared female bears. Habitat selection by forest cover type was not detected on White Rock but was detected on Dry Creek. Use of habitats on Dry Creek appeared to be related to food production with the exception of regeneration areas, which were used less than expected but had a high FVI ranking. In general, pine cover types had low FVI rankings and were used less than expected by bears. Forest management implications are discussed. Int. Conf. Bear Res. and Manage. 9(1):309-318 Black bear populations in the eastern United States are much reduced, largely due to land conversion that resulted in habitat loss and fragmentation (Maehr 1984). Schoen (1990) stated that part of our task in managing bear habitats is to identify what habitats are important to bears and determine the optimal or sometimes minimal habitat mix necessary for maintaining populations at desired or viable population levels. Although food is only one component of an organism's habitat requirements, it is especially important for bears because of their large size and relatively inefficient digestive system (Pritchard and Robbins 1990). It is important to determine what foods are most critical to bears and the forest management practices that produce those foods. Although a number of habitat use studies have been conducted on black bears in North America (Beeman and Pelton 1977, Warburton 1984, Brody and Pelton 1989, Unsworth et al. 1989, Hellgren etal. 1991), few studies have attempted to link habitat use with food availability (Kansas and Raine 1990, Noyce and Coy 1990). It is not only important to determine the habitats that are selected for by bears, but it is perhaps more important to determine why those habitats are selected. The objective of this study was to quantify food production and relative value assoeiated with a variety of silvicultural practices and forest cover types and compare that to black bear habitat use for 2 study areas in the Interior Highlands of Arkansas. This study was funded under provisions of the Federal Aid in Wildlife Restoration Act (PittmanRobertson Act), administered by the Arkansas Game and Fish Commission. Additional funding was provided by the Ozark National Forest (NF), the Arkansas Cooperative Fish and Wildlife Research Unit, and Environmental Systems Company, Inc. C.J. Amlaner, P.S. Gipson, M.R. Pelton, and T.B. Wigley provided advice on study design and, along with D.L. Garshelis, R.L. Kirkpatrick, and T.E. Martin, helped edit earlier manuscripts. Special thanks go to graduate student S.G. Hayes and a number of technicians for their assistance in the field. Appreciation is also extended to W.F. Limp, J.A. Farley, and J.J. Lockhart from the Arkansas Archaeological Survey for their valuable assistance in using the Geographic Information System (GIS).

Transmitter Drops as a Technique for Detecting Black Bear Habitat Use

Transmitter Drops as a Technique for Detecting Black Bear Habitat Use

The Effects of Developments and Primary Roads on Grizzly Bear Habitat Use in Yellowstone National Park, Wyoming

The Effects of Developments and Primary Roads on Grizzly Bear Habitat Use in Yellowstone National Park, Wyoming

Brown Bear Movements and Habitat Use at Karluk Lake, Kodiak Island

Brown Bear Movements and Habitat Use at Karluk Lake, Kodiak Island