This indicator assesses Black Bear genetic diversity and genetic differentiation at the provincial scale, providing an indication of the genetic health of the species in Ontario.
Figure 1. Map representing the 3 genetic groups of American Black Bears identified in Ontario. Blue: northwestern regional population; Green: southeastern regional population; Red: Bruce Peninsula population. The scale on the right indicates the probability that an individual would genetically correspond to the population it was sampled in. The two shades of blue and green respectively indicate the subgroups identified within the northwestern and southeastern populations (Source: Pelletier et al. 2012).
Figure 1. Map representing the 3 genetic groups of American Black Bears identified in Ontario. Blue: northwestern regional population; Green: southeastern regional population; Red: Bruce Peninsula population. The scale on the right indicates the probability that an individual would genetically correspond to the population it was sampled in. The two shades of blue and green respectively indicate the subgroups identified within the northwestern and southeastern populations (Source: Pelletier et al. 2012).
Figure 2. Heterozygosity level (scale 0 to 1) for each American Black Bear genetic group identified in Ontario (n = 2839 individuals; error bars represent Standard Deviation) (Source: Pelletier et al. 2012)
Figure 2. Heterozygosity level (scale 0 to 1) for each American Black Bear genetic group identified in Ontario (n = 2839 individuals; error bars represent Standard Deviation) (Source: Pelletier et al. 2012)
Figure 3. Number of different alleles for each American Black Bear genetic group identified in Ontario (n = 2839 individuals; error bars represent Standard Deviation) (Source: Pelletier et al. 2012).
Figure 3. Number of different alleles for each American Black Bear genetic group identified in Ontario (n = 2839 individuals; error bars represent Standard Deviation) (Source: Pelletier et al. 2012).
Figure 4. Number of haplotypes present within each American Black Bear genetic group in Ontario. Note: Analyses were conducted on a subset of individuals: n = 230, 392, and 38 for the northwestern, southeastern, and Bruce Peninsula populations, respectively (Source: Pelletier et al. 2011).
Figure 4. Number of haplotypes present within each American Black Bear genetic group in Ontario. Note: Analyses were conducted on a subset of individuals: n = 230, 392, and 38 for the northwestern, southeastern, and Bruce Peninsula populations, respectively (Source: Pelletier et al. 2011).
Status:
- Three distinct genetic groups of Black Bears were identified in Ontario: the northwestern regional population, the southeastern regional population, and the Bruce Peninsula population.
- While overall genetic differentiation among the three groups was generally low, the Bruce Peninsula population showed a level of differentiation with the larger northwestern and southeastern populations (FST = 0.13 and 0.12, respectively) more than 10 times as high as the level detected between the northwestern and southeastern populations (FST = 0.01). This indicates a lack of Black Bear movement between the Bruce Peninsula and the other regions of Ontario.
- The northwestern and southeastern Ontario Black Bear populations show high levels of historical (# of haplotypes = 17 and 26, respectively) and contemporary genetic diversity (heterozygosity = 0.76 and 0.77, respectively; # of alleles = 14.2 and 14.4, respectively).
- In contrast, the Bruce Peninsula population shows reduced historical (# of haplotypes = 2) and contemporary genetic diversity (heterozygosity = 0.55 and # of alleles = 4.6), likely related to geographic isolation resulting from habitat fragmentation. This population may be at risk of inbreeding depression and reduced population viability.
Information on the genetic differentiation and genetic diversity of Black Bears in Ontario is based on results detailed in Pelletier et al. (2011 and 2012). Genetic data were obtained from hair collected via baited barbed wire hair traps placed throughout Ontario between 1997 and 2012, as well as from samples obtained opportunistically (livetrapping, hunting, or road kills). A total of 2839 individual Black Bears were sampled from 61 sites throughout Ontario. This initiative was part of the Ontario’s Enhanced Black Bear Management Program, whose goal is to monitor the number of Black Bears in the province over time to support Ontario’s Enhanced Black Bear management Framework.
Following collection of hair samples, DNA was extracted, amplified and sequenced to obtain individual genotypes and sequences of maternal DNA. As such, individual genotypes provided information about the current genetic diversity of Black Bears in the province. Diversity was assessed by i) looking at the differences between the paternal and maternal genetic information within each individual (“heterozygosity”), and ii) looking at the overall number of potential genetic types (or, “alleles”). Both of these measures were averaged across all individuals in the population, providing an indication of overall genetic diversity.
Sequences of maternal DNA (“haplotypes”) provided information on the historical genetic diversity of Black Bear populations in Ontario. Haplotypic diversity (number of haplotypes) was measured for each sampling site as an indication of historical genetic diversity. Analyses were conducted on a subset of individuals (n = 660).
Finally, genetic differentiation was examined using a measure called FST, where 1 indicates complete differentiation and 0 indicates no differentiation between two populations. FST was calculated among all possible pairs of identified genetic groups. These genetic groups were delineated based on the geographical distribution of similar haplotypes and similar alleles.
Related Target(s)
Web Links:
Ontario Black Bear Density Map https://www.ontario.ca/document/bear-density-map
References:
Dixon, J.D., M.K. Oli, M.C. Wooten, T.H. Eason, J.W. McCown, and D. Paetkau. 2006. Effectiveness of a regional corridor in connecting two Florida Black Bear populations. Conservation Biology 20: 155–162.
Frankham, R., J.D. Ballou, and D.A. Briscoe. 2002. Introduction to conservation genetics. Cambridge University Press. Cambridge, U.K.
Onorato, D.P., E.C. Hellgren, R.A. Van Den Bussche, D.L. Doan-Crider, and J.R. Skiles. 2007. Genetic structure of America Black Bears in the desert southwest of North America: conservation implications for recolonization. Conservation Genetics 8:565–576.
Pelletier, A., M.E. Obbard, B.N. White, C. Doyle, and C.J. Kyle. 2011. Small-scale genetic structure of American Black Bears illustrates potential postglacial recolonization routes. Journal of Mammalogy 92:629–644.
Pelletier, A., M.E. Obbard, K. Mills, E. J. Howe, F.G. Burrows, B.N. White, and C.J. Kyle. 2012. Delineating genetic groupings in continuously distributed species across largely homogeneous landscapes: a study of American Black Bears (Ursus americanus) in Ontario, Canada. Canadian Journal of Zoology 90:999-1014.
Puckett, E. E., T.V. Kristensen, C.M. Wilton, S.B. Lyda, K.V. Noyce, P.M. Holahan, and L.S. Eggert. 2014. Influence of drift and admixture on population structure of American Black Bears (Ursus americanus) in the Central Interior Highlands, USA, 50 years after translocation. Molecular Ecology 23:2414-2427.
Scheick, B. K., and W. McCown. 2014. Geographic distribution of American Black Bears in North America. Ursus 25: 24-33.
Statistics Canada. 2011. Census of Canada, population density by census division. Produced by the Demography Division, Ottawa, ON. [Available at: http://www.statcan.gc.ca/pub/91-214-x/2010000/m003-eng.htm]
Warrillow, J., M. Culver, E. Hallerman, and M. Vaughan. 2001. Subspecific affinity of Black Bears in the White River National Wildlife Refuge. Journal of Heredity 92:226–233.
Genetic diversity is the combination of different genes found within a population and the pattern of variation found within different populations of the same species (Frankham et al. 2002). It is shaped by past population processes and affects the viability of species and populations in the future. Genetically diverse organisms are thought to be better able to withstand and adapt to environmental changes, to pass on those traits to descendants and to contribute positively to the persistence of s…
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