Oecologia

, Volume 184, Issue 1, pp 87–99 | Cite as

Habitat degradation affects the summer activity of polar bears

  • Jasmine V. Ware
  • Karyn D. Rode
  • Jeffrey F. Bromaghin
  • David C. Douglas
  • Ryan R. Wilson
  • Eric V. Regehr
  • Steven C. Amstrup
  • George M. Durner
  • Anthony M. Pagano
  • Jay Olson
  • Charles T. Robbins
  • Heiko T. Jansen
Behavioral ecology –original research

Abstract

Understanding behavioral responses of species to environmental change is critical to forecasting population-level effects. Although climate change is significantly impacting species’ distributions, few studies have examined associated changes in behavior. Polar bear (Ursus maritimus) subpopulations have varied in their near-term responses to sea ice decline. We examined behavioral responses of two adjacent subpopulations to changes in habitat availability during the annual sea ice minimum using activity data. Location and activity sensor data collected from 1989 to 2014 for 202 adult female polar bears in the Southern Beaufort Sea (SB) and Chukchi Sea (CS) subpopulations were used to compare activity in three habitat types varying in prey availability: (1) land; (2) ice over shallow, biologically productive waters; and (3) ice over deeper, less productive waters. Bears varied activity across and within habitats with the highest activity at 50–75% sea ice concentration over shallow waters. On land, SB bears exhibited variable but relatively high activity associated with the use of subsistence-harvested bowhead whale carcasses, whereas CS bears exhibited low activity consistent with minimal feeding. Both subpopulations had fewer observations in their preferred shallow-water sea ice habitats in recent years, corresponding with declines in availability of this substrate. The substantially higher use of marginal habitats by SB bears is an additional mechanism potentially explaining why this subpopulation has experienced negative effects of sea ice loss compared to the still-productive CS subpopulation. Variability in activity among, and within, habitats suggests that bears alter their behavior in response to habitat conditions, presumably in an attempt to balance prey availability with energy costs.

Keywords

Activity Behavioral plasticity Climate change Sea ice loss Ursus maritimus 

Notes

Acknowledgements

This work was supported by U.S. Geological Survey’s Changing Arctic Ecosystems Initiative and the U.S. Fish and Wildlife Service. Additional support was provided by the Detroit Zoological Association; a Coastal Impact Assessment Program grant through the State of Alaska (Grant No. M11AF00060); and the National Fish and Wildlife Foundation. Teck Alaska Inc, BP Exploration Alaska, Inc.; ARCO Alaska Inc.; Conoco-Phillips, Inc.; and the ExxonMobil Production Company provided in-kind support. We would like to thank the reviewers for their time and comments on this manuscript. This paper was reviewed and approved by USGS under their Fundamental Science Practices policy (http://www.usgs.gov/fsp). The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Author contribution statement

KDR, EVR, RRW, SCA, GMD, and AMP conducted the fieldwork, KDR developed original idea for manuscript, DCD, RRW, JO, and JVW compiled, organized, and coded aspects of the data, JFB, KDR, and JVW designed statistical models and analyzed the data, CTR, HTJ, and KDR provided mentorship, project guidance and manuscript feedback to JVW, and JVW, KDR, and JFB wrote the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare there are no conflicts of interest.

Supplementary material

442_2017_3839_MOESM1_ESM.docx (359 kb)
Supplementary material 1 (DOCX 359 kb)

References

  1. Amstrup SC (1995) Movements, distribution, and population dynamics of polar bears in the Beaufort Sea. PhD dissertation, University of Alaska, Fairbanks, AK, USAGoogle Scholar
  2. Amstrup SC, Marcot BG, Douglas DC (2008) A Bayesian network modeling approach to forecasting the 21st century worldwide status of polar bears. American Geophysical Union Geophysical Monograph Series, Washington, pp 213–268Google Scholar
  3. Atkinson SN, Nelson RA, Ramsay MA (1996) Changes in body composition of fasting polar bears (Ursus maritimus): the effect of relative fatness on protein conservation. Physiol Zool 69:304–3016CrossRefGoogle Scholar
  4. Atwood TC, Marcot BG, Douglas DC, Amstrup SC, Rode KD, Durner GM, Bromaghin JF (2015a) Evaluating and ranking threats to the long-term persistence of polar bears. US Geological Survey open-file report. doi: 10.3133/ofr20141254
  5. Atwood TC, Peacock E, McKinney MA, Lillie K, Wilson R, Miller S (2015b) Demographic composition and behavior of polar bears summering on shore in Alaska. US Geological Survey, administrative reportGoogle Scholar
  6. Auld JR, Agrawal AA, Relyea RA (2009) Re-evaluating the costs and limits of adaptive phenotypic plasticity. Proc R Soc B. doi: 10.1098/rspb.2009.1355 PubMedPubMedCentralGoogle Scholar
  7. Bates D, Maechler M, Bolker B, Walker S, Christensen RHB, Singmann H, Dai B, Grothendieck G, Eigen C, Rcpp L (2015) Package ‘lme4’. R Foundation for Statistical Computing, Vienna Google Scholar
  8. Beever EA, Ray C, Mote PW, Wilkening JL (2010) Testing alternative models of climate-mediated extirpations. Ecol Appl 20:164–178. doi: 10.1890/08-1011.1 CrossRefPubMedGoogle Scholar
  9. Beever EA, Dobrowski SZ, Long J, Mynsberge AR, Piekielek NB (2013) Understanding relationships among abundance, extirpation, and climate at ecoregional scales. Ecology 94:1563–1571. doi: 10.1890/12-2174.1 CrossRefPubMedGoogle Scholar
  10. Bellard C, Bertelsmeier C, Leadley P, Thuiller W, Courchamp F (2012) Impacts of climate change on the future of biodiversity. Ecol Lett 15:365–377. doi: 10.1111/j.1461-0248.2011.01736.x CrossRefPubMedPubMedCentralGoogle Scholar
  11. Bromaghin JF, McDonald TL, Stirling I, Derocher AE, Richardson ES, Regehr EV, Douglas DC, Durner GM, Atwood T, Amstrup SC (2015) Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline. Ecol Appl 25:634–651. doi: 10.1890/14-1129.1 CrossRefPubMedGoogle Scholar
  12. Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach, 2nd edn. Springer, New YorkGoogle Scholar
  13. Cavalieri D, Parkinson C, Gloersen P, Zwally H (1996) Sea ice concentrations from Nimbus-7 SMMR and DMSP SSM/I passive microwave data. Digital Media, National Snow and Ice Data Center, Boulder (updated 2006) Google Scholar
  14. Cherry SG, Derocher AE, Thiemann GW, Lunn NJ (2013) Migration phenology and seasonal fidelity of an Arctic marine predator in relation to sea ice dynamics. J Anim Ecol 82:912–921CrossRefPubMedGoogle Scholar
  15. Chevin LM, Lande R, Mace GM (2010) Adaptation, plasticity, and extinction in a changing environment: towards a predictive theory. PLoS Biol 8(4):e1000357. doi: 10.1371/journal.pbio.1000357 CrossRefPubMedPubMedCentralGoogle Scholar
  16. Crawford JA, Frost KJ, Quakenbush LT, Whiting A (2012) Different habitat use strategies by subadult and adult ringed seals (Phoca hispida) in the Bering and Chukchi Seas. Polar Biol 35:241–255. doi: 10.1007/s00300-011-1067-1 CrossRefGoogle Scholar
  17. Cushing DH, Dickson RR (1976) The biological response in the sea to climatic changes. Adv Mar Biol 14:1–122CrossRefGoogle Scholar
  18. Derocher AE, Andriashek D, Stirling I (1993) Terrestrial foraging by polar bears during the ice-free period in western Hudson Bay. Arctic 46:251–254. doi: 10.14430/arctic1350 CrossRefGoogle Scholar
  19. Derocher AE, Wiig Ø, Andersen M (2002) Diet composition of polar bears in Svalbard and the western Barents Sea. Polar Biol 25:448–452. doi: 10.1007/s00300-002-0364-0 Google Scholar
  20. Derocher AE, Aars J, Amstrup SC, Cutting A, Lunn NJ, Molnar PK, Obbard ME, Stirling I, Thiemann GW, Vongraven D, Wiig O, York G (2013) Rapid ecosystem change and polar bear conservation. Conserv Lett 6:368–375. doi: 10.1111/conl.12009 Google Scholar
  21. DeWitt TJ, Sih A, Wilson DS (1998) Costs and limits to phenotypic plasticity. Trends Ecol Evol 13:77–81. doi: 10.1016/s0169-5347(97)01274-3 CrossRefPubMedGoogle Scholar
  22. Durner GM, Douglas DC, Nielson RM, Amstrup SC, McDonald TL, Stirling I, Mauritzen M, Born EW, Wiig Ø, DeWeaver E, Serreze MC, Belikov SE, Holland MM, Maslanik J, Aars J, Bailey DA, Derocher AE (2009) Predicting 21st-century polar bear habitat distribution from global climate models. Ecol Monogr 79:25–58. doi: 10.1890/07-2089.1 CrossRefGoogle Scholar
  23. Feng Z, Rubao J, Campbell RG, Ashjian CJ, Zhang J (2016) Early ice retreat and ocean warming may induce copepod biogeographic boundary shifts in the Arctic Ocean. J Geophys Res 121:6137–6158. doi: 10.1002/2016JC011784 CrossRefGoogle Scholar
  24. Ferguson SH, Taylor MK, Messier F (2000) Influence of sea ice dynamics on habitat selection by polar bears. Ecology 81:761–772. doi: 10.1890/0012 CrossRefGoogle Scholar
  25. Frost KJ, Lowry LF, Pendleton G, Nute HR (2004) Factors affecting the observed densities of ringed seals, Phoca hispida, in the Alaskan Beaufort Sea, 1996–99. Arctic 57:115–128. doi: 10.14430/arctic489 CrossRefGoogle Scholar
  26. Fuller A, Dawson T, Helmuth B, Hetem RS, Mitchell D, Maloney SK (2010) Physiological mechanisms in coping with climate change. Physiol Biol Zool 83:713–720. doi: 10.1086/652242 CrossRefGoogle Scholar
  27. Gormezano LJ, Rockwell RF (2013) What to eat now? Shifts in polar bear diet during the ice-free season in western Hudson Bay. Ecol Evol 3:3509–3523. doi: 10.1002/ece3.740 PubMedPubMedCentralGoogle Scholar
  28. Harwood L, Smith TG, George JC, Sandstrom SJ, Walkusz W, Divoky GJ (2015) Change in the Beaufort Sea ecosystem: diverging trends in body condition and/or production in five marine vertebrate species. Prog Oceanogr 136:263–273. doi: 10.1016/j.pocean.2015.05.003 CrossRefGoogle Scholar
  29. Jay CV, Fischbach AS, Kochnev AA (2012) Walrus areas of use in the Chukchi Sea during sparse sea ice cover. Mar Ecol Prog Ser 468:1–13. doi: 10.3354/meps10057 CrossRefGoogle Scholar
  30. Hoffmann AA, Sgrò CM (2011) Climate change and evolutionary adaptation. Nature 470:479–485. doi: 10.1038/nature09670 CrossRefPubMedGoogle Scholar
  31. Johnson DS (2013) Crawl: fit continuous-time correlated random walk models to animal movement data. R package version 3.1.4. http://cran.r-project.org/package=crawl
  32. Kahry M, Zhongping L, Mitchell BG, Nevison CD (2016) Effects of sea ice cover on satellite-detected primary production in the Arctic Ocean. Biol Lett 12:20160223. doi: 10.1098/rsbl.2016.0223l CrossRefGoogle Scholar
  33. Kelly BP, Badajos OH, Kunnasranta M, Moran JR, Martinez-Bakker M, Wartzok D, Boveng P (2010) Seasonal home ranges and fidelity to breeding sites among ringed seals. Polar Biol 33:1095–1109. doi: 10.1007/s00300-010-0796-x CrossRefGoogle Scholar
  34. Knudsen B (1978) Time budgets of polar bears (Ursus maritimus) on North Twin Island, James Bay, during summer. Can J Zool 56:1627–1628. doi: 10.1139/z78-224 CrossRefGoogle Scholar
  35. Kochnev A (2002) Autumn aggregations of polar bears on Wrangel Island and their importance to the population. In: Proceedings of the marine mammals of the holarctic 2002, Moscow, RussiaGoogle Scholar
  36. Koski WR, George JC, Sheffield G, Galginaitis MS (2005) Subsistence harvests of bowhead whales (Balaena mysticetus) at Kaktovik, Alaska (1973–2000). J Cetacean Res Manag 7:33–37. doi: 10.1007/s00300-007-0300-4 Google Scholar
  37. Laidre KL, Stern H, Kovacs KM, Lowry L, Moore SE, Regehr EV, Ferguson SH, Wiig Ø, Boveng P, Angliss RP (2015) Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century. Conserv Biol 29:724–737. doi: 10.1111/cobi.12474 CrossRefPubMedPubMedCentralGoogle Scholar
  38. Lane JE, Kruuk LEB, Charmantier A, Murie JO, Dobson FS (2012) Delayed phenology and reduced fitness associated with climate change in a wild hibernator. Nature 489:554–557. doi: 10.1038/nature11335 CrossRefPubMedGoogle Scholar
  39. Latour PB (1981) Spatial relationships and behavior of polar bears (Ursus maritimus Phipps) concentrated on land during the ice-free season of Hudson Bay. Can J Zool 59:1763–1774. doi: 10.1139/z81-242 CrossRefGoogle Scholar
  40. Lavergne S, Mouquet N, Thuiller W, Ronce O (2010) Biodiversity and climate change: integrating evolutionary and ecological responses of species and communities. Annu Rev Ecol Evol Syst 41:321–350. doi: 10.1146/annurev-ecolsys-102209-144628 CrossRefGoogle Scholar
  41. Lunn N, Stirling I (1985) The significance of supplemental food to polar bears during the ice-free period of Hudson Bay. Can J Zool 63:2291–2297. doi: 10.1139/z85-340 CrossRefGoogle Scholar
  42. Lunn N, Servanty S, Regehr EV, Converse SJ, Richardson E, Stirling I (2016) Population dynamics of an apex predator at the edge of its range—impacts of changing sea ice on polar bears in Western Hudson Bay. Ecol Appl. doi: 10.1890/15-1256 Google Scholar
  43. Messier F, Taylor M, Ramsay M (1992) Seasonal activity patterns of female polar bears (Ursus maritimus) in the Canadian Arctic as revealed by satellite telemetry. J Zool 226:219–229. doi: 10.1111/j.1469-7998.1992.tb03835.x CrossRefGoogle Scholar
  44. Messier F, Taylor MK, Ramsay MA (1994) Denning ecology of polar bears in the Canadian Arctic Archipelago. J Mammal 75:420–430. doi: 10.2307/1382563 CrossRefGoogle Scholar
  45. Obbard ME, Thiemann GW, Peacock E, Debruyn TD (2010) Polar bears: proceedings of the 15th working meeting of the Iucn/Ssc Polar Bear Specialist Group, Copenhagen, Denmark: IUCN. 29 June–3 July 2009. Gland, Switzerland and Cambridge, UK. IUCNGoogle Scholar
  46. Olson J (2015) Identifying maternal denning of polar bears using temperature: denning distribution in relation to sea ice in the southern Beaufort Sea. M.S. thesis, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, USAGoogle Scholar
  47. Ovsyanikov N, Menyushina I (2010) Number, condition, and activity of polar bears on Wrangel Island during ice free autumn seasons of 2005–2009. In: Proceedings of the marine mammals of the holarctic meeting, Oct. 11–15, 2010, Kaliningrad, Russia, pp 445–450Google Scholar
  48. Parmesan C (2006) Ecological and evolutionary responses to recent climate change. Annu Rev Ecol Evol Syst 37:637–669. doi: 10.1146/annurev.ecolsys.37.091305.110100 CrossRefGoogle Scholar
  49. Paul MJ, Zucker I, Schwartz WJ (2008) Tracking the seasons: the internal calendars of vertebrates. Philos Trans R Soc B 363:341–361. doi: 10.1098/rstb.2007.2143 CrossRefGoogle Scholar
  50. Peacock E, Sonsthagen SA, Obbard ME, Boltunov A, Regehr EV, Ovsyanikov N, Aars J, Atkinson SN, Sage GK, Hope AG (2015) Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic. PLoS ONE 10:e0136126. doi: 10.1371/journal.pone.0112021 CrossRefPubMedPubMedCentralGoogle Scholar
  51. Pilfold NW, Derocher AE, Richardson E (2014) Influence of intraspecific competition on the distribution of a wide-ranging, non-territorial carnivore. Glob Ecol Biogeogr 23:425–435. doi: 10.1111/geb.12112 CrossRefGoogle Scholar
  52. Pongracz JD, Derocher AE (2016) Summer refugia of polar bears (Ursus maritimus) in the southern Beaufort Sea. Polar Biol. doi: 10.1007/s00300-016-1997-8 Google Scholar
  53. Post E, Forchhammer MC (2008) Climate change reduces reproductive success of an Arctic herbivore through trophic mismatch. Philos Trans R Soc B 363:1355–1358. doi: 10.1098/rstb.2007.2207 CrossRefGoogle Scholar
  54. R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org
  55. Réale D, McAdam AG, Boutin S, Berteaux D (2003) Genetic and plastic response of a northern mammal to climate change. Proc R Soc B 270:591–596. doi: 10.1098/rspb.2002.2224 CrossRefPubMedPubMedCentralGoogle Scholar
  56. Reeves RR (1998) Distribution, abundance and biology of ringed seals (Phoca hispida): an overview. NAMMCO Sci Publ 1:9–45. doi: 10.7557/3.2979 CrossRefGoogle Scholar
  57. Regehr EV, Lunn NJ, Amstrup SC, Stirling I (2007) Effects of earlier sea ice breakup on survival and population size of polar bears in Western Hudson Bay. J Wildl Manag 71:2673–2683. doi: 10.2193/2006-180 CrossRefGoogle Scholar
  58. Regehr EV, Hunter CM, Caswell H, Amstrup SC, Stirling I (2010) Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice. J Anim Ecol 79:117–127. doi: 10.1111/j.1365-2656.2009.01603.x CrossRefPubMedGoogle Scholar
  59. Rode KD, Amstrup SC, Regehr EV (2010) Reduced body size and cub recruitment in polar bears associated with sea ice decline. Ecol Appl 20:768–782. doi: 10.1890/08-1036.1 CrossRefPubMedGoogle Scholar
  60. Rode KD, Peacock E, Taylor M, Stirling I, Born EW, Laidre KL, Wiig Ø (2012) A tale of two polar bear populations: ice habitat, harvest, and body condition. Popul Ecol 54:3–18. doi: 10.1007/s10144-012-0304-y CrossRefGoogle Scholar
  61. Rode KD, Pagano AM, Bromaghin JF, Atwood TC, Durner GM, Simac KS, Amstrup SC (2014a) Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population. Wildl Res 41:311–322. doi: 10.1071/WR13225 CrossRefGoogle Scholar
  62. Rode KD, Regehr EV, Douglas DC, Durner G, Derocher AE, Thiemann GW, Budge SM (2014b) Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations. Glob Change Biol 20:76–88. doi: 10.1111/gcb.12339 CrossRefGoogle Scholar
  63. Rode KD, Wilson RR, Regehr EV, StMartin M, Douglas D, Olson JW (2015) Increased land use by Chukchi Sea polar bears in relation to changing sea ice conditions. PLoS ONE 10:e0142213. doi: 10.1371/journal.pone.0142213 CrossRefPubMedPubMedCentralGoogle Scholar
  64. Rogers MC, Peacock E, Simac K, O’Dell MB, Walker JM (2015) Diet of female polar bears in the southern Beaufort Sea of Alaska: evidence for an emerging alternative foraging strategy in response to environmental change. Polar Biol 38:1035–1047. doi: 10.1007/s00300-015-1665-4 CrossRefGoogle Scholar
  65. Root TL, Price JT, Hall KR, Schneider SH, Rosenzweig C, Pounds JA (2003) Fingerprints of global warming on wild animals and plants. Nature 421:57–60. doi: 10.1038/nature01333 CrossRefPubMedGoogle Scholar
  66. Scheiner SM, Berrigan D (1998) The genetics of phenotypic plasticity. VIII. The cost of plasticity in Daphnia pulex. Evolution 52:368–378CrossRefGoogle Scholar
  67. Schliebe S, Rode K, Gleason J, Wilder J, Proffitt K, Evans T, Miller S (2008) Effects of sea ice extent and food availability on spatial and temporal distribution of polar bears during the fall open-water period in the Southern Beaufort Sea. Polar Biol 31:999–1010. doi: 10.1007/s00300-008-0439-7 CrossRefGoogle Scholar
  68. Steinger T, Roy BA, Stanton ML (2003) Evolution in stressful environments II: adaptive value and costs of plasticity in response to low light in Sinapis arvensis. J Evol Biol 16:313–323. doi: 10.1046/j.1420-9101.2003.00518.x/full CrossRefPubMedGoogle Scholar
  69. Stirling I, Derocher AE (2012) Effects of climate warming on polar bears: a review of the evidence. Glob Change Biol 18:2694–2706. doi: 10.1111/j.1365-2486.2012.02753.x CrossRefGoogle Scholar
  70. Stirling I, Lunn NJ, Iacozza J (1999) Long-term trends in the population ecology of polar bears in Western Hudson Bay in relation to climatic change 52:294–306. doi: 10.14430/arctic935 Google Scholar
  71. Stirling I, Richardson E, Thiemann GW, Derocher AE (2008) Unusual predation attempts of polar bears on ringed seals in the Southern Beaufort Sea: possible significance of changing spring ice conditions. Arctic 61:14–22CrossRefGoogle Scholar
  72. Stirling I, McDonald TL, Richardson E, Regehr EV, Amstrup SC (2011) Polar bear population status in the northern Beaufort Sea, Canada, 1971–2006. Ecol Appl 21:859–876. doi: 10.1890/10-0849.1 CrossRefPubMedGoogle Scholar
  73. Stroeve J, Holland MM, Meier W, Scambos T, Serreze M (2007) Arctic sea ice decline: faster than forecast. Geophys Res Lett 34:L09501. doi: 10.1029/2007GL029703 CrossRefGoogle Scholar
  74. Stroeve J, Markus T, Boisvert L, Miller J, Barrett A (2014) Changes in Arctic melt season and implications for sea ice loss. Geophys Res Lett 41:1216–1225. doi: 10.1002/2013GL058951 CrossRefGoogle Scholar
  75. Suydam RS, George JC (2004) Subsistence harvest of bowhead whales (Balaena mysticetus) by Alaskan Eskimos, 1974–2003. Presented to the 56th International Whaling Commission. SC/56/BRG12Google Scholar
  76. Thiemann GW, Iverson SJ, Stirling I (2008) Polar bear diets and Arctic marine food webs: insights from fatty acid analysis. Ecol Monogr 78:591–613. doi: 10.1890/07-1050.1 CrossRefGoogle Scholar
  77. Valladares F, Gianoli E, Gomez JM (2007) Ecological limits to plant phenotypic plasticity. New Phytol 176:749–763. doi: 10.1111/j.1469-8137.2007.02275.x CrossRefPubMedGoogle Scholar
  78. Vedder O, Bouwhuis S, Sheldon BC (2013) Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations. PLoS Biol 11(7):e1001605. doi: 10.1371/journal.pbio.1001605 CrossRefPubMedPubMedCentralGoogle Scholar
  79. Vors LS, Boyce MS (2009) Global declines of caribou and reindeer. Glob Change Biol 15:2626–2633. doi: 10.1111/j.1365-2486.2009.01974.x CrossRefGoogle Scholar
  80. Wang J, Cota GF, Comiso JC (2005) Phytoplankton in the Beaufort and Chukchi Seas: distribution, dynamics, and environmental forcing. Deep-Sea Res Part II 52:3355–3368. doi: 10.1016/j.dsr2.2005.10.014 CrossRefGoogle Scholar
  81. Ware J, Rode K, Pagano A, Bromaghin J, Robbins C, Erlenbach J, Jensen S, Cutting A, Nicassio-Hiskey N, Hash A, Owen M, Jansen H (2015) Validation of mercury tip-switch and accelerometer activity sensors for identifying resting and active behavior in bears. Ursus 26:86–96. doi: 10.2192/ursus-d-14-00031.1 CrossRefGoogle Scholar
  82. Whiteman JP, Harlow HJ, Durner GM, Anderson-Sprecher R, Albeke SE, Regehr EV, Amstrup SC, Ben-David M (2015) Summer declines in activity and body temperature offer polar bears limited energy savings. Science 349:295–298. doi: 10.1126/science.aaa8623 CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg (Outside the USA) 2017

Authors and Affiliations

  • Jasmine V. Ware
    • 1
  • Karyn D. Rode
    • 2
  • Jeffrey F. Bromaghin
    • 2
  • David C. Douglas
    • 3
  • Ryan R. Wilson
    • 4
  • Eric V. Regehr
    • 4
  • Steven C. Amstrup
    • 5
  • George M. Durner
    • 2
  • Anthony M. Pagano
    • 2
  • Jay Olson
    • 6
  • Charles T. Robbins
    • 7
  • Heiko T. Jansen
    • 1
  1. 1.Department of Integrative Physiology and NeuroscienceWashington State UniversityPullmanUSA
  2. 2.Alaska Science CenterU.S. Geological SurveyAnchorageUSA
  3. 3.Alaska Science CenterU.S. Geological SurveyJuneauUSA
  4. 4.U.S. Fish and Wildlife ServiceAnchorageUSA
  5. 5.Polar Bears InternationalBozemanUSA
  6. 6.Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUSA
  7. 7.School of the Environment and School of Biological SciencesWashington State UniversityPullmanUSA

Personalised recommendations