Modelling polar bear maternity den habitat in east Svalbard

  • Benjamin Merkel Norwegian Polar Institute, Fram Centre, Tromsø, Norway
  • Jon Aars Norwegian Polar Institute, Fram Centre, Tromsø, Norway
  • Glen E Liston Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO, USA
Keywords: Climate change, reproduction, SnowDens-3D, snowdrift model, terrain model, topograpy


We evaluated a novel tool that predicts possible maternity den habitat of the polar bear (Ursus maritimus) based on a physical snow transport model, a digital terrain model and weather data. We observed and compared den locations in three important denning areas in east Svalbard (Kongsøya, n = 288; Svenskøya, n = 86; Hopen, n = 115) with modelled snowdrift distributions for 24 years. Accounting for a likely position uncertainty of 100 m, 69% of all dens were located within year-specific modelled snowdrifts. These covered on average 1.8%, 2.1% and 24.7% of the three study islands, respectively. Our snowdrift model accurately predicted maternity den positions (R2 = 0.42, area under the receiving operating characteristic curve [AUC] = 0.85). A model based on slope and altitude, also predicted den positions reasonably well (R2 = 0.35, AUC = 0.88). Habitat maps identifying both current and future areas for maternity denning will become important in managing the Barents Sea population as well as other Arctic populations where changes in sea-ice conditions alter the accessibility to traditional denning areas.


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Aars J. 2013. Variation in detection probability of polar bear maternity dens. Polar Biology 36, 1089–1096, doi: 10.1007/s00300-013-1331-7.

Aars J., Marques T.A., Buckland S.T., Andersen M., Belikov S., Boltunov A. & Wiig Ø. 2009. Etimating the Barents Sea polar bear subpopulation size. Marine Mammal Science 25, 35–52, doi: 10.1111/j.1748-7692.2008.00228.x.

Amstrup S.C. 2003. The polar bear, Ursus maritimus. In G.A. Feldhamer et al. (eds.): Wild mammals of North America: biology, management, and conservation. Pp. 587–610. Baltimore, MD: Johns Hopkins University Press.

Amstrup S.C. & Gardner C. 1994. Polar bear maternity denning in the Beaufort Sea. The Journal of Wildlife Management 58, 1–10, doi: 10.2307/3809542.

Andersen M., Derocher A.E., Wiig O. & Aars J. 2012. Polar bear (Ursus maritimus) maternity den distribution in Svalbard, Norway. Polar Biology 35, 499–508, doi: 10.1007/s00300-011-1094-y.

Barbet-Massin M., Jiguet F., Albert C.H. & Thuiller W. 2012. Selecting pseudo-absences for species distribution models: how, where and how many? Methods in Ecology and Evolution 3, 327–338, doi: 10.1111/j.2041-210X.2011.00172.x.

Barton´ K. 2013. MuMIn: multi-model inference: R package version 1.9.13. Accessed on the internet at

Clarkson P.L. & Irish D. 1991. Den collapse kills female polar bear and two newborn cubs. Arctic 44, 83–84, doi: 10.14430/arctic1522.

Derocher A.E., Andersen M., Wiig O., Aars J., Hansen E. & Biuw M. 2011. Sea ice and polar bear den ecology at Hopen Island, Svalbard. Marine Ecology Progress Series 441, 273–279, doi: 10.3354/meps09406.

Derocher A.E., Lunn N.J. & Stirling I. 2004. Polar bears in a warming climate. Integrative and Comparative Biology 44, 163–176, doi: 10.1093/icb/44.2.163.

Durner G.M., Amstrup S.C. & Ambrosius K.J. 2001. Remote identification of polar bear maternal den habitat in northern Alaska. Arctic 54, 115–121, doi: 10.14430/arctic770.

Durner G.M., Amstrup S.C. & Fischbach A.S. 2003. Habitat characteristics of polar bear terrestrial maternal den sites in northern Alaska. Arctic 56, 55–62, doi: 10.14430/arctic602.

Durner G.M., Simac K.S. & Amstrup S.C. 2013. Mapping polar bear maternal denning habitat in the National Petroleum Reserve–Alaska with an IfSAR digital terrain model. Arctic 66, 197–206, doi: 10.14430/arctic4291.

Fielding A.H. & Bell J.F. 1997. A review of methods for the assessment of prediction errors in conservation presence/absence models. Environmental Conservation 24, 38–49, doi: 10.1017/s0376892997000088.

Fischbach A.S., Amstrup S.C. & Douglas D.C. 2007. Landward and eastward shift of Alaskan Polar bear denning associated with recent sea ice changes. Polar Biology 30, 1395–1405, doi: 10.1007/s00300-007-0300-4.

Furevik B.R. & Haakenstad H. 2012. Near-surface marine wind profiles from rawinsonde and NORA10 hindcast. Journal of Geophysical Research—Atmospheres 117, article no. D23106, doi: 10.1029/2012jd018523.

Hansen B.B., Grotan V., Aanes R., Saether B.-E., Stien A., Fuglei E., Ims R.A., Yoccoz N.G. & Pedersen Å.O. 2013. Climate events synchronize the dynamics of a resident vertebrate community in the High Arctic. Science 339, 313–315, doi: 10.1126/science.1226766.

Hansson R. & Thomassen J. 1982. Isbjørnbinner med unger i Bogen hiområde, Kongsøya, Svalbard—en etologisk grunnstudie. (Polar bears with cubs in the Bogen denning area, Kongsøya, Svalbard—an ethological base study.) Rapportserie 12. Oslo: Norwegian Polar Institute.

Harington C.R. 1968. Denning habits of the polar bear (Ursus maritimus Phipps). Canadian Wildlife Service Report 5, 1–30.

Johnson C.J., Nielsen S.E., Merrill E.H., McDonald T.L. & Boyce M.S. 2006. Resource selection functions based on use-availability data: theoretical motivation and evaluation methods. Journal of Wildlife Management 70, 347–357, doi: 10.2193/0022-541x.

Laidre K.L., Stirling I., Lowry L.F., Wiig Ø., Heide-Jørgensen M.P. & Ferguson S.H. 2008. Quantifying the sensitivity of Arctic marine mammals to climate-induced habitat change. Ecological Applications 18, 97–125, doi: 10.1890/06-0546.1.

Larsen T. 1972. Air and ship census of polar bears in Svalbard (Spitsbergen). Journal of Wildlife Management 36, 562–570, doi: 10.2307/3799089.

Larsen T. 1985. Polar bear denning and cub production in Svalbard, Norway. Journal of Wildlife Management 49, 320–326, doi: 10.2307/3801524.

Larsen T. 1986. Population biology of the polar bear (Ursus maritimus) in the Svalbard area. Norsk Polarinstitutt Skrifter 184. Oslo: Norwegian Polar Institute.

Lentfer J.W. 1975. Polar bear denning on drifting sea 
ice. Journal of Mammalogy 56, 716–718, doi: 10.2307/

Liston G.E. & Elder K. 2006. A distributed snow-evolution modeling system (SnowModel). Journal of Hydrometeorology 7, 1259–1276, doi: 10.1175/jhm548.1.

Liston G.E., Perham C.J., Shideler R.T. & Cheuvront A.N. 2016. Modeling snowdrift habitat for polar bear dens. Ecological Modelling 320, 114–134, doi: 10.1016/j.ecolmodel.2015.09.010.

Lone K., Aars J. & Ims R.A. 2013. Site fidelity of Svalbard polar bears revealed by mark-recapture positions. Polar Biology 36, 27–39, doi: 10.1007/s00300-012-1235-y.

Lønø O. 1970. The polar bear (Ursus maritimus Phipps) in the Svalbard area. Norsk Polarinstitutt Skrifter 149. Oslo: Norwegian Polar Institute.

Maindonald J. & Braun W.J. 2010. Data analysis and graphics using R. 3rd edn. Cambridge: Cambridge University Press.

Mauritzen M., Derocher A.E. & Wiig Ø. 2001. Space-use strategies of female polar bears in a dynamic sea ice habitat. Canadian Journal of Zoology—Revue Canadienne de Zoologie 79, 1704–1713, doi: 10.1139/cjz-79-9-1704.

Messier F., Taylor M.K. & Ramsay M.A. 1994. Denning ecology of polar bears in the Canadian Arctic Archipelago. Journal of Mammalogy 75, 420–430, doi: 10.2307/1382563.

Nagelkerke N.J.D. 1991. A note on a general definition of the coefficient of determination. Biometrika 78, 691–692, doi: 10.1093/biomet/78.3.691.

Pearce J. & Ferrier S. 2000. Evaluating the predictive performance of habitat models developed using logistic regression. Ecological Modelling 133, 225–245, doi: 10.1016/S0304-3800(00)00322-7.

Ramsay M.A. & Stirling I. 1986. On the mating system of polar bears. Canadian Journal of Zoology 64, 2142–2151, doi: 10.1139/z86-329.

R Development Core Team 2018. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing.

Reistad M., Breivik Ø., Haakenstad H., Aarnes O.J., Furevik B.R. & Bidlot J.-R. 2011. A high-resolution hindcast of wind and waves for the North Sea, the Norwegian Sea, and the Barents Sea. Journal of Geophysical Research—Oceans 116, C05019, doi: 10.1029/2010jc006402.

Reistad M., Haakenstad H., Furevik B. & Haugen J.E. 2015. NORA10—final report 2015. The atmospheric part. Oslo: Norwegian Deepwater Programme.

Stien A., Ims R.A., Albon S.D., Fuglei E., Irvine R.J., Ropstad E., Halvorsen O., Langvatn R., Loe L.E., Veiberg V. & Yoccoz N.G. 2012. Congruent responses to weather variability in High Arctic herbivores. Biology Letters 8, 1002–1005, doi: 10.1098/rsbl.2012.0764.

Stocker T.F., Qin D., Plattner G.K., Tignor M., Allen S.K., Boschung J., Nauels A., Xia Y., Bex B. & Midgley B. (eds.) 2013. Climate change 2013. The physical science basis. Contribution of Working Group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press.

Van Pelt W.J.J., Kohler J., Liston G.E., Hagen J.O., Luks B., Reijmer C.H. & Pohjola V.A. 2016. Multidecadal climate and seasonal snow conditions in Svalbard. Journal of Geophysical Research—Earth Surface 121, 2100–2117, doi: 10.1002/2016JF003999.

Wiig Ø. 1998. Survival and reproductive rates for polar bears at Svalbard. Ursus 10, 25–32, doi: 10.2307/3873105.

Wood S.N. 2006. Generalized additive models: an introduction with R. Boca Raton, FL: Chapman and Hall.

Zeyl E., Aars J., Ehrich D. & Wiig Ø. 2009. Families in space: relatedness in the Barents Sea population of polar bears (Ursus maritimus). Molecular Ecology 18, 735–749, doi: 10.1111/j.1365-294X.2008.04049.x.

How to Cite
Merkel, B., Aars, J., & Liston, G. E. (2020). Modelling polar bear maternity den habitat in east Svalbard. Polar Research, 39.
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