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Variation in non-metrical skull traits of polar bears (Ursus maritimus) and relationships across East Greenland and adjacent subpopulations (1830–2013)

  • Øystein Wiig
  • Poul Henrichsen
  • Torstein Sjøvold
  • Erik W. Born
  • Kristin L. Laidre
  • Rune Dietz
  • Christian Sonne
  • Jon Aars
Original Paper
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Abstract

Knowledge of subpopulation identity including substructure is a prerequisite for sound management of polar bears (Ursus maritimus). It is not known whether the present catch of polar bears in the East Greenland subpopulation (EG) is sustainable. We used the Mean Measure of Divergence (MMD) to examine geographical variation in non-metrical traits from 1414 polar bear (Ursus maritimus) skulls collected in East Greenland (EG), Svalbard (SVA), Franz Josef Land (FJL), Davis Strait (DS), Baffin Bay (BB), and Kane Basin (KB), between 1830 and 2013. We focused on East Greenland with the goal of examining substructuring in the subpopulation. We did not find significant differences among samples across four areas of the EG subpopulation (i.e., offshore Fram Strait, NE, SE, and SW Greenland) using data from 1830 to 1983. Our analyses did not lend support to substructuring. However, we draw our conclusions with caution because skulls were sampled over a long time period and had low power due to small sample sizes. Also, comparisons were limited to pre-1980s skulls. The decrease in sea ice in EG since the 1990s due to climate change may have led to substructuring not detected with MMD. This study contributes to the current efforts by Greenland authorities to quantify connectivity of polar bears between southeast and northeast Greenland which is important information for the evaluation of the sustainability of the catch of bears from the EG subpopulation.

Keywords

Polar bear Ursus maritimus Non-metrical traits Skulls Population substructure East Greenland 

Notes

Acknowledgements

We thank Frédéric Santos for help and discussions related to the use of the AnthropMMD program and Karsten Sund for taking the photographs of the polar bear skull (Fig. 2). The Danish Cooperation for Environment in the Arctic (DANCEA) and local hunters are acknowledged for financial and logistic support for sampling skulls in East Greenland. We are grateful to the following institutions for providing access to their historic polar bear skull collections for this study: American Museum of Natural History, New York; Canadian Museum of Natural History, Ottawa; Canadian Wildlife Service, Edmonton; Carnegie Museum of Natural History, Pittsburgh; Göteborg Natural History Museum, Gothenburg; Museum of Comparative Zoology, Cambridge Mass.; Museum Man and Nature, Munich; Natural History Museum, Berlin; Natural History Museum, London; Natural History Museum, University of Oslo, Oslo; Natural History Museum, Vienna; Natural History Museum of Denmark, Copenhagen; National Museum of Natural History, Washington DC; Swedish Museum of Natural History, Stockholm; The Academy of Natural Sciences, Philadelphia; University Museum of Bergen, Bergen; Zoological Museum of Moscow University, Moscow; Zoological Museum of the Zoological Institute of the Russian Academy of Sciences, Saint Petersburg. Two of the coauthors (PH and TS) had permission from each of the museums to investigate polar bear skulls in their collection.

Conflict of interest

The authors declare that they have no conflict of interest.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Natural History MuseumUniversity of OsloOsloNorway
  2. 2.IdestrupDenmark
  3. 3.Osteology UnitStockholm UniversityStockholmSweden
  4. 4.Greenland Institute of Natural ResourcesNuukGreenland
  5. 5.Polar Science Center, Applied Physics LaboratoryUniversity of WashingtonSeattleUSA
  6. 6.Department of Bioscience, Arctic Research Centre, Faculty of Science and TechnologyAarhus UniversityRoskildeDenmark
  7. 7.Fram CentreNorwegian Polar InstituteTromsøNorway

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