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Migration phenology and seasonal fidelity of an Arctic marine predator in relation to sea ice dynamics.

https://arctichealth.org/en/permalink/ahliterature259225
Source
J Anim Ecol. 2013 Jul;82(4):912-21
Publication Type
Article
Date
Jul-2013
Author
Seth G Cherry
Andrew E Derocher
Gregory W Thiemann
Nicholas J Lunn
Source
J Anim Ecol. 2013 Jul;82(4):912-21
Date
Jul-2013
Language
English
Publication Type
Article
Keywords
Animal Migration - physiology
Animals
Arctic Regions
Climate change
Ice Cover
Seasons
Ursidae - physiology
Abstract
Understanding how seasonal environmental conditions affect the timing and distribution of synchronized animal movement patterns is a central issue in animal ecology. Migration, a behavioural adaptation to seasonal environmental fluctuations, is a fundamental part of the life history of numerous species. However, global climate change can alter the spatiotemporal distribution of resources and thus affect the seasonal movement patterns of migratory animals. We examined sea ice dynamics relative to migration patterns and seasonal geographical fidelity of an Arctic marine predator, the polar bear (Ursus maritimus). Polar bear movement patterns were quantified using satellite-linked telemetry data collected from collars deployed between 1991-1997 and 2004-2009. We showed that specific sea ice characteristics can predict the timing of seasonal polar bear migration on and off terrestrial refugia. In addition, fidelity to specific onshore regions during the ice-free period was predicted by the spatial pattern of sea ice break-up but not by the timing of break-up. The timing of migration showed a trend towards earlier arrival of polar bears on shore and later departure from land, which has been driven by climate-induced declines in the availability of sea ice. Changes to the timing of migration have resulted in polar bears spending progressively longer periods of time on land without access to sea ice and their marine mammal prey. The links between increased atmospheric temperatures, sea ice dynamics, and the migratory behaviour of an ice-dependent species emphasizes the importance of quantifying and monitoring relationships between migratory wildlife and environmental cues that may be altered by climate change.
PubMed ID
23510081 View in PubMed
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Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity.

https://arctichealth.org/en/permalink/ahliterature295310
Source
Glob Chang Biol. 2018 01; 24(1):410-423
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
01-2018
Author
Karyn D Rode
Ryan R Wilson
David C Douglas
Vanessa Muhlenbruch
Todd C Atwood
Eric V Regehr
Evan S Richardson
Nicholas W Pilfold
Andrew E Derocher
George M Durner
Ian Stirling
Steven C Amstrup
Michelle St Martin
Anthony M Pagano
Kristin Simac
Author Affiliation
U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA.
Source
Glob Chang Biol. 2018 01; 24(1):410-423
Date
01-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Animals
Arctic Regions
Caniformia
Climate change
Diet
Food chain
Ice Cover
Population Dynamics
Reproduction
Seasons
Ursidae - blood
Abstract
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (=7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.
PubMed ID
28994242 View in PubMed
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