Potential distribution of Ursus americanus in Mexico and its persistence: Implications for conservation

Monroy‐Vilchis, Octavio; Castillo-Huitrón, Nathalia M.; Zarco‐González, Martha M.; Rodríguez‐Soto, Clarita

doi:10.1016/j.jnc.2015.11.003

Cited by 11 publications

(9 citation statements)

References 33 publications

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“…Black bears are considered a population of conservation concern in the Southwestern United States and endangered in Northern Mexico (Monroy‐Vilchis et al, 2016 ), where they continue to be persecuted to protect livestock (Bravo & Davis, 2017 ; Varas, 2007 ). Black bears also face threats from landscape fragmentation, militarization of the United States–Mexico border, and potentially from poaching for gall bladders used in Eastern Traditional Medicine (Delfín‐Alfonso et al, 2012 ; Espinoza et al, 1993 ; McCracken et al, 1995 ; Onorato et al, 2004 ; Varas, 2007 ).…”

Section: Discussionmentioning

confidence: 99%

“…American black bears are considered forest habitat specialists. In the Southwestern United States and Northwestern Mexico, forests are primarily restricted to higher elevation, montane habitats, which experience cooler temperatures and higher precipitation relative to lowland deserts (Delfín‐Alfonso et al, 2012 ; LeCount, 1980 ; Monroy‐Vilchis et al, 2016 ). Alternative forested habitats in this region are provided by riparian systems, where abundant water enables distinct forested habitats even in hyper‐arid desert landscapes.…”

Section: Introductionmentioning

confidence: 99%

“…However, deserts are generally considered unsuitable bear habitat (Costello et al, 2001 ) and black bears are thought to only venture through lower elevation deserts when dispersing (Onorato et al, 2004 ), with little recorded about their utilization of desert riparian systems. American black bears have lost as much as 80% of their range in Mexico and were historically extirpated from large parts of the Southwestern United States (Monroy‐Vilchis et al, 2016 ), suggesting that these species may have once occurred more frequently in other habitat types (Lackey et al, 2013 ). Likewise, habitat loss from widespread alterations of riparian systems from historic and current dewatering, damming, and conversion to agriculture has led to many dramatic changes in these ecosystems and potentially the extirpation of many of their historic animal constituents (Leopold, 1970 ).…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…We identified the most important variables related to the species' distribution and downloaded them as digital maps (Table 1). We unified the data for extreme coordinates, projection and resolution (1 km) 56 using IDRISI Selva 17.0 57 and verified the possible correlations between them in Biomapper4. 58…”

Section: Predictive Variablesmentioning

confidence: 90%

Potential distribution of Aquila chrysaetos in Mexico: Implications for conservation

D’Addario

Monroy‐Vilchis

Zarco‐González

et al. 2019

Avian Biology Research

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The golden eagle (Aquila chrysaetos) has been poorly studied in Mexico. Even though it is listed as threatened in this country, partly because of habitat fragmentation and direct persecution, little is known of its distribution. We assessed the potential distribution of this species in Mexico using ecological niche modelling (ecological niche factor analysis, artificial neural network, genetic algorithm for rule-set production, environmental distance, support vector machine, MaxEnt) and the weighted average ensemble method. The models were evaluated using the area under the curve of the receiver operating characteristics. We applied a threshold of 50% probability to obtain high-suitability areas and considered marginality and specialization calculated by ecological niche factor analysis and the most important variables to the model. We assessed and evaluated the percentage of high-suitability area occurring in all Mexican natural protected areas. The performance of the ensemble model was high (area under the curve = 0.93) and the most important variables contributing to the model were grasslands and tree cover percentage. The resulting high-suitability area is considerably fragmented, it comprises 16% of the country and just 8% of it is located in natural protected areas. We propose some urgent actions and conservation measures to face the main problems that are threatening the species in Mexico.

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“…However, new occurrences of bears have since been reported far south of that model's predicted suitable habitat [223,224]. Another model, restricted to more recent presence points (being more accurately associated with current habitat conditions) and variables related to land cover, elevation and human density, but not climatic variables yielded better predictions relative to these points at the current southern limit of the range (21 • N) [225]. On the other hand, the presence of wandering black bears well outside their primary range is not necessarily indicative of a population expansion nor of what constitutes suitable habitat [226].…”

Section: American Black Bearsmentioning

confidence: 99%

Understanding Species–Habitat Associations: A Case Study with the World’s Bears

Garshelis¹

2022

Land

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Habitat modeling is one of the most common practices in ecology today, aimed at understanding complex associations between species and an array of environmental, bioclimatic, and anthropogenic factors. This review of studies of seven species of terrestrial bears (Ursidae) occupying four continents examines how habitat models have been employed, and the functionality of their predictions for management and conservation. Bear occurrence data have been obtained at the population level, as presence points (e.g., sign surveys or camera trapping), or as locations of individual radio-collared animals. Radio-collars provide greater insights into how bears interact with their environment and variability within populations; they are more commonly used in North America and Europe than in South America and Asia. Salient problematic issues apparent from this review included: biases in presence data; predictor variables being poor surrogates of actual behavioral drivers; predictor variables applied at a biologically inappropriate scale; and over-use of data repositories that tend to detach investigators from the species. In several cases, multiple models in the same area yielded different predictions; new presence data occurred outside the range of predicted suitable habitat; and future range projections, based on where bears presently exist, underestimated their adaptability. Findings here are likely relevant to other taxa.

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Potential distribution of Ursus americanus in Mexico and its persistence: Implications for conservation

Cited by 11 publications

References 33 publications

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

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

Potential distribution of Aquila chrysaetos in Mexico: Implications for conservation

Understanding Species–Habitat Associations: A Case Study with the World’s Bears

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