Influence of drift and admixture on population structure of American black bears (Ursus americanus) in the Central Interior Highlands, USA, 50 years after translocation.
Bottlenecks, founder events, and genetic drift often result in decreased genetic diversity and increased population differentiation. These events may follow abundance declines due to natural or anthropogenic perturbations, where translocations may be an effective conservation strategy to increase population size. American black bears (Ursus americanus) were nearly extirpated from the Central Interior Highlands, USA by 1920. In an effort to restore bears, 254 individuals were translocated from Minnesota, USA, and Manitoba, Canada, into the Ouachita and Ozark Mountains from 1958 to 1968. Using 15 microsatellites and mitochondrial haplotypes, we observed contemporary genetic diversity and differentiation between the source and supplemented populations. We inferred four genetic clusters: Source, Ouachitas, Ozarks, and a cluster in Missouri where no individuals were translocated. Coalescent models using approximate Bayesian computation identified an admixture model as having the highest posterior probability (0.942) over models where the translocation was unsuccessful or acted as a founder event. Nuclear genetic diversity was highest in the source (AR = 9.11) and significantly lower in the translocated populations (AR = 7.07-7.34; P = 0.004). The Missouri cluster had the lowest genetic diversity (AR = 5.48) and served as a natural experiment showing the utility of translocations to increase genetic diversity following demographic bottlenecks. Differentiation was greater between the two admixed populations than either compared to the source, suggesting that genetic drift acted strongly over the eight generations since the translocation. The Ouachitas and Missouri were previously hypothesized to be remnant lineages. We observed a pretranslocation remnant signature in Missouri but not in the Ouachitas.
Division of Biological Sciences, University of Missouri, 226 Tucker Hall, Columbia, MO, 65211, USA.
Emily E
EE
Puckett
Thea V
TV
Kristensen
Clay M
CM
Wilton
Sara B
SB
Lyda
Karen V
KV
Noyce
Paula M
PM
Holahan
David M
DM
Leslie
Jeff
J
Beringer
Jerrold L
JL
Belant
Don
D
White
Lori S
LS
Eggert
D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D018703:Founder Effect; D040961:Genetic Drift; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D018895:Microsatellite Repeats; D008957:Models, Genetic; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014481:United States; D001503:Ursidae / Q000235:genetics*
D004272:DNA, Mitochondrial
approximate Bayesian computation; founder effect; genetic drift; reintroduction