Dr. Susan Crockford
December is late fall within the Arctic: winter situations are gearing up however aren’t in full swing in all places. Sea ice is growing rapidly over Hudson Bay and transferring slowly in the direction of the Bering Sea however the Svalbard archipelago remains to be devoid of pack ice.
Such situations north of Norway have existed most years since 2005: it’s definitely not a brand new improvement for Svalbard to be freed from surrounding pack ice in December (though there was plenty of ice in 2019 and 2021 by late November). This implies conventional denning areas on the japanese islands once more can’t be utilized by pregnant polar bear females, as a result of they should be ensconced of their dens by at the very least late November or so.
Some appear to assume it is a calamity: that such ‘lack of habitat’ is a big concern for the survival of the subpopulation, if not your complete species. Nonetheless, the identical situations existed in 2011 and didn’t end in a dramatic decline within the inhabitants as measured in 2015 (Aars et al. 2017) as a result of the bears knew find out how to reply. They’ve apparently moved north to make maternity dens on the ocean ice or east to the Franz Josef Land archipelago in Russia (Aars 2015). These areas are nonetheless throughout the Barents Sea subpopulation boundaries and researchers have identified for twenty years that bears have moved round inside it (Andersen et al. 2012; Derocher 2005; Maurizen et al. 2002).
Sea ice replace
Observe that for the previous couple of weeks, the Canadian Ice Service charts for many of Hudson Bay ice have solely been updating as soon as every week (on Wednesday). This appears to be a perennial drawback about this time of yr. It might have one thing to do with glitches within the satellite tv for pc information, though they provide no rationalization for the problem.
Svalbard ice situations
The picture beneath is from Andersen and colleagues, together with Derocher (2012) displaying tiny King Karls Land (Kongsoya or Kong Karis Land) maternity dens as they had been greater than a decade in the past. These islands aren’t used for denning if the pack ice doesn’t attain them by about mid- to late November.
Whereas it’s definitely true that the Svalbard/Barents Sea area has misplaced extra ice than some other subpopulation space (Regehr et al. 2016), additionally it is true that polar bear haven’t been negatively impacted by this modification. Opposite to expectations, research since then have proven the bears are thriving: partly, as a result of ice round Svalbard has nonetheless been accessible in the course of the important spring feeding and mating interval (Aars et al. 2017; Lippold et al. 2019).
Furthermore, the response of polar bears to this modification in sea ice situations is just not unprecedented. There’s proof of an analogous motion of ringed seals and polar bears out of the Beaufort Sea when spring ice situations had been particularly heavy in 1974/1975, as they had been the earlier yr (1973/1974).
Marine mammal biologist John Burns famous the next in 1975 (Burns et al. 1975:77 pdf beneath):
“In the course of the interval 9 to 19 June [1975] intensive aerial surveys of ringed seals had been undertaken in areas of land quick ice between Barter Island and Level Lay. ..The need of conducting these surveys was based mostly on observations in the course of the winter of 1974-1975, which indicated unusually excessive densities of ringed seals within the Chukchi Sea and the reverse within the Beaufort Sea. Observations for the Beaufort Sea had been obtained by [Jack] Lentfer (private communication).
Briefly, polar bears have methods to take care of pretty dramatic modifications in sea ice habitat as a result of such modifications have all the time existed of their world: most bears don’t simply persist with a inflexible plan if it threatens their survival, even when some biologists assume they might.
References
Aars, J. 2015. Analysis on polar bears at Norwegian Polar Institute. On-line seminar (‘webinar”), January 14. pdf right here.
Aars, J., Marques,T.A, Lone, Ok., Anderson, M., Wiig, Ø., Fløystad, I.M.B., Hagen, S.B. and Buckland, S.T. 2017. The quantity and distribution of polar bears within the western Barents Sea. Polar Analysis 36:1. 1374125. doi:10.1080/17518369.2017.1374125
Andersen, M., Derocher, A.E., Wiig, Ø. and Aars, J. 2012. Polar bear (Ursus maritimus) maternity den distribution in Svalbard, Norway. Polar Biology 35:499-508.
Burns, J.J., Fay, F.H., and Shapiro, L.H. 1975. The relationships of marine mammal distributions, densities, and actions to sea ice situations (Quarterly report for quarter ending September 30, 1975, initiatives #248 and 249). In Environmental Evaluation of the Alaskan Continental Shelf, Principal Investigators’ Studies, July-September 1975, Quantity 1. NOAA Environmental Analysis Laboratories, Boulder, Colorado. pp. 77-78. Pdf right here.
Derocher 2005. Inhabitants ecology of polar bears at Svalbard, Norway. Inhabitants Ecology 47:267-275.
http://www.springerlink.com.ezproxy.library.uvic.ca/content material/765147518rp35613/fulltext.pdf
Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, J.L., Bytingsvik, J., Jenssen, B.M., Derocher, A.E., Welker, J.M. and Routti, H. 2019. Temporal developments of persistent natural pollution in Barents Sea polar bears (Ursus maritimus) in relation to modifications in feeding habits and physique situation. Environmental Science and Technology 53(2):984-995.
Mauritzen, M., Derocher, A.E., Wiig, Ø., Belikov, S.E., Boltunov, A.N., Hansen, E. and Garner, G.W. 2002. Utilizing satellite tv for pc telemetry to outline spatial inhabitants construction in polar bears within the Norwegian and western Russian Arctic. Journal of Utilized Ecology 39:79-90. http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2664.2002.00690.x/summary
Regehr, E.V., Laidre, Ok.L, Akçakaya, H.R., Amstrup, S.C., Atwood, T.C., Lunn, N.J., Obbard, M., Stern, H., Thiemann, G.W., & Wiig, Ø. 2016. Conservation standing of polar bears (Ursus maritimus) in relation to projected sea-ice declines. Biology Letters 12: 20160556. http://rsbl.royalsocietypublishing.org/content material/12/12/20160556
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