Geographic distribution of American black bears in North America

Scheick, Brian K.; McCown, J. Walter

doi:10.2192/ursus-d-12-00020.1

Cited by 109 publications

(39 citation statements)

References 13 publications

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“…American black bear ( Ursus americanus ) populations are increasingly being monitored by management agencies, as North American populations expand into developed landscapes (Scheick & McCown, ). We use a black bear population in Connecticut (CT) for which we previously estimated densities across the established range using SCR, to test the performance of SC models estimating density using camera detections of unmarked individuals.…”

Section: Methodsmentioning

confidence: 99%

Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras

Evans

Rittenhouse

2018

Journal of Applied Ecology

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Remote cameras have become a promising, cost‐effective tool for monitoring wildlife populations. Yet, for species where individuals are indistinguishable, remote cameras’ ability to provide robust and precise density estimates has been limited without the use of invasive marking. Using the American black bear as a model species, we evaluated methods for estimating wildlife densities using remote camera detections of unmarked individuals against estimates from spatial capture–recapture (SCR) models using individual detections. We also tested the effect of incorporating varying proportions of marked individuals on model accuracy and precision. Spatial count (SC) models using unmarked individuals produced estimates of bear density within 0.6% of those from SCR. We extended SC models to incorporate variation in density as a function of land use/land cover, and identified identical relationships between variation in bear densities and housing density as obtained using SCR. Incorporating individual detection data from simultaneous non‐invasive genetic sampling lead to more precise, but biased estimates. Synthesis and applications. Our results identify contexts in which camera count data can be used as an alternative to spatial capture–recapture (SCR) when individual identification is prohibitive. Spatial count models provided an accurate, but less precise replication of spatial capture–recapture density estimates and may provide consistent insights into spatial variation in density. Mixed samples of camera counts and auxiliary individual detections are likely to be of limited use, but fitting spatial count models to populations with partial visual markings could improve their precision.

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Section: Methodsmentioning

confidence: 99%

Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras

Evans

Rittenhouse

2018

Journal of Applied Ecology

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“…Studying how species modify their space use depending on landscape structure is vital for managing species such as American black bears ( Ursus americanus ), which are currently recolonizing parts of North America after major past range contractions (Scheick & McCown, ) and displaying increased conflict in human‐modified areas (Baruch‐Mordo, Breck, Wilson, & Theobald, ; McFadden–Hiller, Beyer, & Belant, ). Our objective was to evaluate black bear optimality regarding annual and seasonal home range location and size (Table ).…”

Section: Introductionmentioning

confidence: 99%

Scale‐dependent home range optimality for a solitary omnivore

Gantchoff

Wang

Beyer

et al. 2018

Ecology and Evolution

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Spatial and temporal heterogeneity are fundamental mechanisms structuring home ranges. Under optimality, an individual should structure their space use economically to maximize fitness. We evaluated support for three hypotheses related to range optimality in American black bears (Ursus americanus), predicting (a) range location on a landscape will correspond with high vegetation productivity, (b) increasing forest fragmentation will result in larger ranges, and (c) increasing proportion of forest and/or mean vegetation productivity will result in smaller ranges. We used black bear radio telemetry data from Michigan (2009–2015), Missouri (2010–2016), and Mississippi (2008–2017), USA. Annual space use excluded winter, and we separated seasonal space use into spring, summer, and fall. We collected data from 143 bears (80 females, 63 males), resulting in 97 annual and 538 seasonal ranges. We used generalized linear mixed models to evaluate productivity (estimated through Normalized Difference Vegetation Index [NDVI]) selection, and range size (km2) variation between individuals. At the annual scale, black bears consistently selected areas with greater vegetation productivity than the surrounding landscape; yet selection weakened and was more variable seasonally. Opposite to our prediction, we found that increasing fragmentation consistently resulted in smaller ranges; non‐forested land covers and forest edges might provide greater abundance or more diverse foods for bears. Ranges with a greater proportion of forest were smaller, likely reflecting an increase in food and cover which could reduce movements, yet there was no support for more productive ranges also being smaller as expected from an area minimizing strategy. Black bears displayed a scale‐dependent space use strategy: at larger spatial and temporal scales, productivity acted as the strongest limiting factor and energy maximizing was the dominant strategy, while an area minimizing strategy was exhibited seasonally. We revealed consistent, scale‐dependent responses by black bears to environmental conditions, demonstrating the intrinsic plasticity of this adaptable omnivore.

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“…In Mexico, their distribution range has decreased by 80% (SEMARNAP‐INE , Delfín‐Alfonso et al. , Scheick and McCown ). The persistence of black bears in Mexico requires the development of effective management and conservation strategies that would benefit from collection of comprehensive information on intraspecific temporal and spatial relationships (Cheyne and Macdonald , Akbaba and Ayas , Carter et al.…”

Section: Introductionmentioning

confidence: 99%

Activity and resource selection of a threatened carnivore: the case of black bears in northwestern Mexico

et al. 2018

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Abstract. Management and conservation strategies for endangered species require information on their temporal and spatial behavioral and habitat use relationships. We evaluated activity patterns and resource selection of black bears in northwestern Mexico. We surveyed 29 localities with 1450 camera traps stations from 2009 to 2013 in the states of Sonora and Chihuahua, Mexico. In each locality, we calculated the proportion of diurnal, nocturnal, and crepuscular activity through a kernel density estimator based on the time of independent photographic events, and we built a beta regression between diurnal density and annual temperature, seasonal rainfall (SR), human density, road density, daylight hours, season, and management type. To evaluate resource selection, we built a binomial logistic regression model incorporating Normalized Difference Vegetation Index (NDVI), mean and coefficient of variation of annual temperature, human population density (PD), terrain roughness, and season. Black bear activity was primarily diurnal with a bimodal tendency around sunrise and sunset. Diurnal activity (between sunrise and sunset) was positively influenced by daylight hours, SR, and private reserves and negatively influenced by anthropogenic factors. Resource selection was positively influenced by the coefficient of variation in temperature and NDVI and negatively associated with average annual temperature, PD, and terrain roughness. Activity patterns and resource use were similar to other regions in North America. However, temperature was one of the main factors influencing black bear activity and resource selection in our study areas and should be considered when developing management plans given projected increases in temperature expected under climate change scenarios. We present the first work of its kind for northwestern Mexico and considered it as an important component in future survey and management protocols for the species in the southern portion of its distribution.

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Geographic distribution of American black bears in North America

Cited by 109 publications

References 13 publications

Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras

Evaluating spatially explicit density estimates of unmarked wildlife detected by remote cameras

Scale‐dependent home range optimality for a solitary omnivore

Activity and resource selection of a threatened carnivore: the case of black bears in northwestern Mexico

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