Conservation Genetics

, Volume 16, Issue 6, pp 1359–1373 | Cite as

Conservation genetics of Magnolia acuminata, an endangered species in Canada: Can genetic diversity be maintained in fragmented, peripheral populations?

Research Article


The genetic diversity of peripheral populations is potentially important to the future adaptive capacity of species, although may be difficult to predict. A large number of species-at-risk in Canada are at the northern edge of their distribution, and many of these live in fragmented habitat. We used nuclear and chloroplast markers to assess patterns of genetic diversity and differentiation within and among populations of Canadian Magnolia acuminata (Cucumber tree), an endangered species in Canada that extends as far north as the fragmented Carolinian forest in southern Ontario. We also compared the genetic composition of Canadian M. acuminata to populations sampled throughout its central distribution in the USA. We found a high proportion of shared microsatellite alleles, plus a single cpDNA haplotype, distributed throughout the entire M. acuminata range. We also found that despite occupying fragmented habitat at their range periphery, Canadian populations showed little reduction in genetic diversity relative to the USA populations, and we attribute this to effective historical dispersal in a long-lived, polyploid species. However, a combination of private alleles, genetic substructuring, and lower levels of genetic diversity in seedlings compared to mature trees, suggests that current levels of gene flow are relatively low among Canadian populations. Therefore, despite high levels of genetic diversity in Canadian M. acuminata, managers should be aware that without intervention, populations will likely become increasingly isolated and experience a reduction in genetic diversity which in turn may threaten their long-term survival in Canada.


Magnolia acuminata Genetic diversity Habitat fragmentation Core populations Peripheral populations Genetic differentiation 



Many thanks to Graham Buck and Donald Kirk of the Ontario Ministry of Natural Resources for assistance with permits and location information; Danny Bernard of the Big Creek Conservation Authority for providing access to, and knowledge about, trees within the National Wildlife Area; Dave Holmes of the Long Point Conservation Authority; Deborah Dale of the North American Native Plant Society; Jennifer Paul and Adam Wilford for assistance with fieldwork; Richard Figler and members of the Magnolia Society for collecting plant tissue from USA sites. Sampling in Ontario was conducted under Permit GU-B-018-11 issued under the Endangered Species Act. Financial support was provided by an Ontario Ministry of Natural Resources Species at Risk Research Fund awarded to JF, an Ontario Ministry of Natural Resources Species at Risk Stewardship Fund awarded to JF, the Natural Sciences and Engineering Research Council (JF Discovery Grant), and Trent University.


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Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • Cara Budd
    • 1
  • Elizabeth Zimmer
    • 2
  • Joanna R. Freeland
    • 3
  1. 1.Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughCanada
  2. 2.Department of BotanySmithsonian National Museum of Natural HistoryWashingtonUSA
  3. 3.Department of BiologyTrent UniversityPeterboroughCanada

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