Российская часть ареала белого медведя – это около 4 млн квадратных километров воды, островов и арктического материкового побережья от архипелага Земля Франца-Иосифа на западе до Берингова пролива на востоке. Исторически полевые исследования белого медведя ограничены районами, досягаемыми на вертолете с нескольких аэропортов на побережье, что неизбежно искажает наше знание о виде. В 2014-2016 гг. географический охват таких работ был кардинально расширен за счет включения группы специалистов по белому медведю в состав комплексных морских экспедиций, организованных в интересах ПАО НК «Роснефть». Об этом материал, подготовленный нами для The Circle - WWF Global Arctic Programme Magazine.
Автор фото Максим Деминов
In the Russian Arctic, thousands of polar bears range over almost 4 million square kilometres of water, islands and mainland coast—all the way from Franz Josef Land in the west to the Bering Strait in the east. Historically, the study of polar bears in Russia was restricted to coastal areas accessible by helicopters from a few airports, resulting in a biased understanding of these animals. But as Andrei Boltunov tells us, a new approach has dramatically expanded research coverage of the polar bear range in Russia.
According to the International Union for the Conservation of Nature, the Russian Arctic is host to four polar bear subpopulations, each named after the seas they inhabit: Barents, Kara, Laptev and Chukchi. An interesting research question is: Does this subdivision reflect the natural structure of polar bear populations in the region?
From 2014 to 2016, polar bear studies were a part of four large-scale, complex expeditions organized by Rosneft, a Moscow-based oil company. The studies covered all four seas of the Russian Arctic and lasted a total of about six months. The aim was to provide up-to-date insights into the biological and environmental background of the species in its natural habitat—which is within an area of the Arctic shelf being considered for development—as well as a basis for monitoring bears in the area as an indicator of sustainable Arctic marine ecosystems.
To study the polar bears, researchers tranquillized 32 of them to obtain samples. They also tagged 20 using satellite transmitters. In addition, they set up 78 autonomous photo recorders on Wrangel Island, Novaya Zemlya and Novosibirskie Islands. Laboratory studies analyzed the bears’ DNA, toxicology and microbiology.
Although some of the results of these field expeditions and lab studies are still being analyzed, we can draw some general preliminary conclusions about polar bear life in the Russian Arctic.
Everywhere the species ranges, there is a balance between local resident bears and large-scale nomads in the overall population. (A resident species is one that inhabits an area throughout the year.) This finding is suggested by a number of factors: the geographic features of various parts of the Russian Arctic; regional patterns of sea ice cover; the distribution of the main polar bear prey species; and the results of recent polar bear studies. In this context, the Kara Sea likely has the biggest proportion of bears who are present year-round. This conclusion is supported by the considerably low variability of haplotypes (groups of genes inherited from a single parent) in the area compared with bears in the Chukchi Sea region. The Chukchi Sea is a rich feeding area, so it attracts a fair number of bears from nearby areas seasonally, leading to high variability in haplotypes. The vast marine area between the Kara Sea and Chukchi Sea habitats serves as a kind of buffer zone.
The levels of persistent organic pollutants (POPs) found in the polar bears reveal two major clusters of bears. The Kara Sea bears have a higher POPs burden. This sets them apart from the rest of the Russian Arctic bears.
There is evidence of exposure to antibiotics in some of the polar bears. We can infer that these bears live closer to coastal settlements, unlike their counterparts who inhabit more remote Arctic areas.
Overall, the polar bear population in the Russian Arctic has a complex, patchy structure where populations differ by haplotype diversity, pollution burden and habitat use features. Recent large-scale studies provide an extensive amount of new information on the species and raise new questions.
However, conserving these polar bears against the backdrop of a changing environment and increasing economic activity requires further studies aimed at helping us develop and apply measures to ensure their long-term survival.
Andrei Boltunov is a member of the International Union for the Conservation of Nature/Species Survival Commission Polar Bear Specialist Group. He works with the Marine Mammal Research and Expedition Center Ltd.
This article originally appeared in The Circle: Arctic biodiversity in the spotlight. The Circle shares perspectives from across the Arctic, and the views expressed here are not necessarily those of WWF.