Natural recolonization by large carnivores has rarely been documented. American black bears (Ursus americanus) recently (1988-present) recolonized portions of their former range in western Texas. We used mtDNA sequence data (n = 144 bears) from 7 populations of southwestern black bears in New Mexico, Texas, and northern Mexico to test predictions regarding metapopulation structure of the species in this region and the source of recolonization in western Texas. Six variable nucleotides were detected, resulting in 5 mtDNA haplotypes. Although within-site diversity of haplotypes (h) and nucleotides (π) was low, a high degree of genetic partitioning among sites was detected (ϕST = 0.6301). Analyses pinpointed northern Mexico as the source of black bears for western Texas. Female-mediated gene flow is proceeding slowly in this system (Nfm = 0.4961 individuals/generation), but its occurrence was inferred via field observations. Nested clade analyses indicated that populations of bears in the Mexico–Texas region (area that encompasses mountain ranges within Nuevo Leon and Coahuila, Mexico, northward to smaller ranges located in the Trans-Pecos region of western Texas) were connected via restricted gene flow due to isolation by distance. Long-distance colonization is the likely cause of extant geographical associations between New Mexican and Mexico–Texas populations. The naturally fragmented, xeric environment of the Chihuahuan Desert impedes colonization, but is not a complete barrier to this process. Conservation initiatives concerning recolonization by black bears within the Mexico–Texas mainland–island metapopulation should focus on preventing human–bear interactions and maintaining corridors for dispersal between the mainland populations in Mexico and the island populations in western Texas.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.