دانلود رایگان مقاله انگلیسی حرکات خرس قطبی ماده Ursus maritimus در دریای کارا در تابستان، زمان شکستن یخ دریایی - اشپرینگر 2017

Abstract

The polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the Taimyr Peninsula, eastern part of the Kara Sea, using as an example a female polar bear tagged by a radio collar with an Argos satellite transmitter. Analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that direction of the polar bear movement depends precisely on the direction of the sea-ice cover break-up.

The life features of many arctic mammals depend on sea ice. For the polar bear (Ursus maritimus), early ice melting and late seasonal ice formation increases duration of the adverse period. Ice melting is accompanied by a shift of the ice–water boundary towards the deepwater Arctic basin, where food accessibility is lower and polar bears are forced to go to land.

In 1994–1997, female polar bear ice habitats in the western Russian Arctic, the Kara Sea, were studied using the Ocean-01 synchronous satellite to determine the ice type and concentration preferences of these animals [1]. The data of this report suggest that in the Kara Sea, in summer, polar bears are moving in the northeastern direction. The same is supported by the results of our interviewing in 2010 of the Cape Sterlegov station staff, who observed the polar bear movement along the Kara Sea coast from west to east. However, there is no comprehensive survey of reasons for such a movement of polar bears.

Much attention is paid to the polar bear strategy of space use, especially in connection with changes in ice habitats [2–4]. The polar bear female displacements during different seasons have been discussed in a number of reports [5–7] and even the average speed has been estimated for an individual female bear on the way from northern Alaska to Greenland [8]. But it is still unclear how migration of an individual animal depends on the ice break-up timing.