Genetic structure of American black bears in the desert southwest of North America: conservation implications for recolonization

American black bears (Ursus americanus) have recolonized parts of their former range in the Trans-Pecos region of western Texas after a >40-year absence. Assessment of genetic variation, structuring, gene flow, and dispersal among bear populations along the borderlands of Mexico and Texas is impo...

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Bibliographic Details
Published in:Conservation genetics 2007-06, Vol.8 (3), p.565-576
Main Authors: Onorato, Dave P, Hellgren, Eric C, Van Den Bussche, Ronald A, Doan-Crider, Diana L, Skiles, J. Raymond Jr
Format: Article
Language:English
Subjects:
Animal populations
Bayesian analysis
Bears
Carnivores
Chihuahuan Desert
Clustering
Conservation genetics
Corridors
Deserts
Dispersal
Gene flow
Genetic analysis
Genetic diversity
Genetic structure
Metapopulations
Populations
Recolonization
Sampling
Subpopulations
Ursus americanus
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Summary:American black bears (Ursus americanus) have recolonized parts of their former range in the Trans-Pecos region of western Texas after a >40-year absence. Assessment of genetic variation, structuring, gene flow, and dispersal among bear populations along the borderlands of Mexico and Texas is important to gain a better understanding of recolonization by large carnivores. We evaluated aspects of genetic diversity and gene flow for 6 sampling areas of black bears in southwestern North America using genotypic data from 7 microsatellite loci. Our results indicated that genetic diversity generally was high in the metapopulation of black bears in northern Mexico and western Texas. The episodic gene flow occurring via desert corridors between populations in northern Mexico and those in western Texas has permitted the establishment of only moderate levels of genetic structuring. Bayesian clustering analyses and assignment testing depicted the presence of 3 subpopulations among our 6 sampling areas and attested to the generally panmictic nature of bear populations in the borderlands region. The potentially ephemeral nature of the small populations in western Texas and genotypic characteristics of bears recolonizing these habitats attest to the importance of linkages along this portion of the borderlands of the United States and Mexico to effectively conserve and manage the species in this part of its range.
ISSN:1566-0621
1572-9737
DOI:10.1007/s10592-006-9192-z