Potential distribution of American black bears in northwest Mexico and implications for their conservation

Delfín-Alfonso, Christian Alejandro; López‐González, Carlos A.; Equihua, Miguel

doi:10.2192/ursus-d-11-00007.1

Cited by 49 publications

(14 citation statements)

References 34 publications

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“…Most localities ( n = 24) were selected because black bears were potentially present at elevations over 1500 m and mixed forest occurred at these sites (Delfín‐Alfonso et al. ). The remaining selected localities were sites where bears were unlikely to occur.…”

Section: Methodsmentioning

confidence: 99%

“…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%

“…Black bear (Ursus americanus, Pallas 1780) is considered in the category of least concern by the IUCN due to their widespread distribution and abundance in Canada and the United States; however, the southernmost populations in Mexico are considered endangered with local extinction ❖ www.esajournals.org (DOF 2015). In Mexico, their distribution range has decreased by 80% (SEMARNAP-INE 1999, Delf ın-Alfonso et al 2012, Scheick and McCown 2014. 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 2011, Akbaba and Ayas 2012, Carter et al 2012.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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“…The presence of the species in the southern area of its distribution range in Mexico is characterized by a low number of records, and the precise limits of this range are still unknown (Delfín-Alfonso et al 2011;Delfín-Alfonso et al 2012;Scheick and McCown 2014). On April 2014, one black bear specimen was captured by local inhabitants in Felipe Carrillo Puerto, a town located in the municipality of Guadalupe Victoria, state of Durango.…”

Section: Introductionmentioning

confidence: 99%

“…On April 2014, one black bear specimen was captured by local inhabitants in Felipe Carrillo Puerto, a town located in the municipality of Guadalupe Victoria, state of Durango. Durango is one of the states where there is a high uncertainty about the presence of the black bear (Delfín-Alfonso et al 2012;Juárez-Casillas and Varas 2013); prior to this capture, there had been no recent records of the species in the area (Delfín-Alfonso et al 2011). The presence of the specimen in this locality raise questions about its geographical origin, whether associated with the Sierra Madre Occidental or the Sierra Madre Oriental.…”

Section: Introductionmentioning

confidence: 99%

One black bear (Ursus americanus) connects the great sierras: Genetic evidence

Camargo-Aguilera

Lara‐Díaz

Coronel‐Arellano

et al. 2017

Therya

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The black bear has inhabited North America for three million years. Two clades diverged during this period: coastal and continental; the continental clade includes two subclasses (western and eastern). The contact between both is a recent event. Because there is a high genetic differentiation between subclasses, the genetic flow of populations between Sierra Madre Oriental and Sierra Madre Occidental is considered as restricted to nonexistent; also, desert environments and human settlements act as a barrier. There are no recent records of black bears in Durango, so the capture of an individual from there presents the opportunity to test whether there is a possible connection between the populations of Sierra Madre Occidental and Sierra Madre Oriental. Our objective was to determine the geographic origin of this individual and validate whether there is a likely connection between populations from both mountain ranges. A black bear specimen was captured in Felipe Carrillo Puerto, municipality of Guadalupe Victoria, Durango. This specimen was sedated. Tissue samples from ear, hair and excrement were collected; samples of mtDNA were extracted and amplified, and two 418-bp sequences were obtained. The haplotype was characterized by a neutrality test of the control region. To determine the origin of the specimen, GenBank was searched for matches with haplotypes previously described and geographically characterized. Six 418-bp sequences were successfully amplified. The neutrality test yielded a single haplotype, with a 99.32 % agreement with haplotype C. Haplotype C has been previously described for the Trans-Pecos region in Texas; accordingly, this haplotype belongs to the eastern subclade. The origin of the black bear specimen captured was Sierra Madre Oriental, based on the presence of haplotype C. This bear traveled at least 250 km to reach the municipality of Guadalupe Victoria. This displacement event indicates that connectivity between black bear populations from both Sierras Madres has been maintained. This distance is similar to displacements previously reported in fragmented environments where a suitable habitat is surrounded by arid zones. However, this displacement took place between two large mountain ranges, rather than within a single mountain range. Genetic diversity, frequency of displacement events between the Sierras, time and distance between displacements, dispersal routes and presence of patches of suitable habitat, are all factors that should be evaluated in order to understand the current dispersal and genetic-flow patterns between the subspecies of bears in Mexico.El oso negro ha estado presente en Norteamérica desde hace tres millones de años; durante este periodo divergieron dos clados: el costero y el continental. Dentro del clado continental existen dos subclados (occidental y oriental), y el contacto entre ambos se considera un evento reciente. Debido a la alta diferenciación genética entre subclados, se considera que el flujo genético de las poblaciones entre la Sierra Madre Oriental y Oc...

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Cicada nymphs dominate American black bear diet in a desert riparian area

Lundgren

Moeller

Clyne

et al. 2022

Ecology and Evolution

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American black bears are considered dependent on high‐elevation forests or other montane habitats in the drylands of western North America. Black bear sign, including that of cubs, was observed throughout the summers of 2015, 2016, and 2018 along a perennial desert river in the Sonoran Desert of Arizona. We analyzed the contents of 21 black bear scats, collected from May to October of 2016 and 2018. Apache cicada nymphs ( Diceroprocta apache ) were the dominant food item, occurring in 90% of scats and comprising an average of 59% of scat contents. In the process of excavating these nymphs, bears created large areas of turned‐over soil, a form of ecosystem engineering with potential implications for soils, vegetation, and fluvial geomorphology. Given that species distributions are shaped by physiological and ecological contexts, as well as anthropogenic legacies, it is possible that black bears once occurred more commonly in desert riparian systems prior to widespread agricultural development, hunting, and dewatering. Although more research is necessary, we suggest that desert riparian systems may be an alternative habitat for black bears. Better understanding the diet and habitat breadth of American black bears is important in the context of increasing landscape fragmentation and militarization in the U.S.‐Mexican borderlands.

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Potential distribution of American black bears in northwest Mexico and implications for their conservation

Cited by 49 publications

References 34 publications

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

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

One black bear (Ursus americanus) connects the great sierras: Genetic evidence

Cicada nymphs dominate American black bear diet in a desert riparian area

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