Brown Bear

Brown bear female with two cubs in the Pasvik River Valley (Photo: Steinar Wikan)

This formerly widespread and common species in Fennoscandia was almost exterminated in the early 20th century due to excessive hunting. Nowadays, ~150 individuals are found in Norway and close annual monitoring of the population is conducted to assess the recovery status. Brown bears are an elusive species and it is difficult to obtain demographic data with conventional means.

With the advancements of molecular tools, a scat collection program was initiated in 2006 and demographic data like individual identification and sex are determined by genetic methods. This approach is also advantageous because no handling of animals is involved (i.e., non-invasive) and hence, bears are not disturbed.

In addition, regular hair snare projects are undertaken to non-invasively collect hairs from brown bears in Pasvik.

Bear going under barbed wire leaving hair behind. (Drawing: Leif Ollila)

The research group and genetic lab at NIBIO Svanhovd has been instrumental in advancing monitoring methods and research on brown bears in Norway and Fennoscandia. Today, the Department of Ecosystems in the Barents Region at Svanhovd houses a collection that contains scat and hair samples with sampling efforts ongoing.

This detailed sampling scheme combined with the application of molecular tools (Andreassen et al. 2012, Bidon et al. 2013) has also enabled research in the recovering Fennoscandian brown bear populations (Hagen et al. 2015, Schregel et al. 2012, 2015, 2017) describing spatial connectivity and differentiation patterns. Brown bears in Fennoscandia belong to two different populations, with the population in northern Norway being more closely related and connected to the Russian bear populations (Kopatz et al. 2014). Finally, the recent recolonization event allows for the testing of theoretical biological models that help to understand dynamics in recovering natural populations (Hagen et al. 2015).

Relevant Literature

Schregel, J., Kopatz, A., Eiken, H. G., Swenson, J. E. & Hagen, S. B. 2017. Sex-specific genetic analysis indicates low correlation between demographic and genetic connectivity in the Scandinavian brown bear (Ursus arctos). PLoS ONE 12: e0180701. [Pdf]

Kopatz, A., Eiken, H. G., Aspi, J., Kojola, I., Tobiassen, C., Tirronen, K. F., Danilov, P.I. & Hagen, S.B. 2014. Admixture and gene flow from Russia in the recovering northern European brown bear (Ursus arctos). PLoS ONE 9: e97558. [Pdf]

Hagen, S. B., Kopatz, A., Aspi, J., Kojola, I. & Eiken, H. G. 2015. Evidence of rapid change in genetic structure and diversity during range expansion in a large terrestrial carnivore. Proceedings of the Royal Society B: Biological Sciences 282: e20150092. [Pdf]

Andreassen, R., Schregel, J., Kopatz, A., Tobiassen, C., Knappskog, P. M., Hagen, S. B., Kieven, O., Schneider, M., Kojola, I., Aspi, J., Rykov, A., Tirronen, K. F., Danilov, P. I. & Eiken, H. G. 2012. A forensic DNA profiling system for Northern European brown bears (Ursus arctos). Forensic Science InternationalGenetics 6: 798–809. [Pdf]

Schregel, J., Eiken, H. G., Grondahl, F. A., Hailer, F., Aspi, J., Kojola, I., Tirronen, K. F., Danilov, P. I., Rykov, A., Poroshin, E., Janke, A., Swenson, J. E. & Hagen, S. B. 2015. Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery. Molecular Ecology 24: 6041–6060. [Pdf]

Schregel, J., Kopatz, A., Hagen, S. B., Brøseth, H., Smith, M. E., Wikan, S., Wartiainen, I., Aspholm, P. E., Aspi, J., Swenson, J. E., Markarova, O., Polikarpova, N., Schneider, M., Knappskog, P. M., Ruokonen, M., Kojola, I., Tirronen, K. F., Danilov, P. I. & Eiken, H. G. 2012. Limited gene flow among brown bear populations in far Northern Europe? Genetic analysis of the east-west border population in the Pasvik Valley. Molecular Ecology 21: 3474–3488. [Pdf]

Bidon, T., Frosch, C., Eiken, H. G., Kutschera, V. E., Hagen, S. B., Aarnes, S. G., Fain, S. R., Janke, A. & Hailer, F. 2013. A sensitive and specific multiplex PCR approach for sex identification of ursine and tremarctine bears suitable for non-invasive samples. Molecular Ecology Resources 13: 362–368. [Pdf]

Bidon, T., Janke, A., Fain, S. R., Eiken, H. G., Hagen, S. B., Saarma, U., Hallström B. M., Lecomte, N. & Hailer, F. 2014. Brown and polar bear Y chromosomes reveal extensive male-biased gene flow within brother lineages. Molecular Biology and Evolution 31: 1353–1363. [Pdf]