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  • Ponganis, P.J.  (4)
  • 1
    Online Resource
    Online Resource
    Cambridge University Press (CUP) ; 2017
    In:  Antarctic Science Vol. 29, No. 3 ( 2017-06), p. 201-208
    In: Antarctic Science, Cambridge University Press (CUP), Vol. 29, No. 3 ( 2017-06), p. 201-208
    Abstract: There are seven emperor penguin ( Aptenodytes forsteri ) colonies distributed throughout the traditional boundaries of the Ross Sea from Cape Roget to Cape Colbeck. This coastline is c. 10% of the entire coast of Antarctica. From 2000 to 2012, there has been a nearly continuous record of population size of most, and sometimes all, of these colonies. Data were obtained by analysing aerial photographs. We found large annual variations in populations of individual colonies, and conclude that a trend from a single emperor penguin colony may not be a good environmental sentinel. There are at least four possibilities for census count fluctuations: i) this species is not bound to a nesting site like other penguins, and birds move within the colony and possibly to other colonies, ii) harsh environmental conditions cause a die-off of chicks in the colony or of adults elsewhere, iii) the adults skip a year of breeding if pre-breeding foraging is inadequate and iv) if sea ice conditions are unsatisfactory at autumn arrival of the adults, they skip breeding or go elsewhere. Such variability indicates that birds at all Ross Sea colonies should be counted annually if there is to be any possibility of understanding the causes of population changes.
    Type of Medium: Online Resource
    ISSN: 0954-1020 , 1365-2079
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2017
    detail.hit.zdb_id: 2104104-0
    detail.hit.zdb_id: 1009128-2
    SSG: 12
    SSG: 13
    SSG: 14
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    Cambridge University Press (CUP) ; 2008
    In:  Antarctic Science Vol. 20, No. 1 ( 2008-02), p. 3-11
    In: Antarctic Science, Cambridge University Press (CUP), Vol. 20, No. 1 ( 2008-02), p. 3-11
    Abstract: The emperor penguin ( Aptenodytes forsteri ) is extremely dependent on the extent and stability of sea ice, which may make the species particularly susceptible to environmental change. In order to appraise the stability of the emperor penguin populations at six colonies in the western Ross Sea, we used linear regression analysis to evaluate chick abundance trends (1983–2005) and Pearson's r correlation to assess their relation to two local and two large-scale climate variables. We detected only one significant abundance trend; the Cape Roget colony increased from 1983 to 1996 ( n = 6). Higher coefficients of variation in chick abundances at smaller colonies (Cape Crozier, Beaufort Island, Franklin Island) suggest that such colonies occupy marginal habitat, and are more susceptible to environmental change. We determined chick abundance to be most often correlated with local Ross Sea climate variables (sea ice extent and sea surface temperature), but not in consistent patterns across the colonies. We propose that chick abundance is most impacted by fine scale sea ice extent and local weather events, which are best evaluated by on-site assessments. We did not find sufficient evidence to reject the hypothesis that the overall emperor penguin population in the Ross Sea was stable during this period.
    Type of Medium: Online Resource
    ISSN: 0954-1020 , 1365-2079
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2008
    detail.hit.zdb_id: 2104104-0
    detail.hit.zdb_id: 1009128-2
    SSG: 12
    SSG: 13
    SSG: 14
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Cambridge University Press (CUP) ; 2014
    In:  Antarctic Science Vol. 26, No. 1 ( 2014-02), p. 33-37
    In: Antarctic Science, Cambridge University Press (CUP), Vol. 26, No. 1 ( 2014-02), p. 33-37
    Abstract: The emperor penguin colony at Coulman Island is reputedly the largest known. This reputation is based on intermittent ground and aerial surveys performed since 1958. From an aerial survey obtained on 28 October 2010 we discovered that the total number of chicks was 56% of the lowest previous estimate of 2006 and only 41% of the most recent estimate in 2008. All of the counts tallied since 1983 were determined either by ground counts or from aerial film or digital photographs, or estimates from adult counts. We also determined the sea ice conditions in autumn, which is close to the time the adults arrive to breed. We present three hypotheses of what might have happened from 2008–10 to cause the step change in chick production, the small recovery of chick numbers in 2011, and the complete recovery of number of adults from 2010–11. We conclude that local circumstances may have strongly influenced the breeding behaviour of the emperor penguins in 2010 and to a lesser degree in 2011 when many adults elected not to breed.
    Type of Medium: Online Resource
    ISSN: 0954-1020 , 1365-2079
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2014
    detail.hit.zdb_id: 2104104-0
    detail.hit.zdb_id: 1009128-2
    SSG: 12
    SSG: 13
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Online Resource
    Online Resource
    Elsevier BV ; 1997
    In:  Respiration Physiology Vol. 109, No. 1 ( 1997-7), p. 73-80
    In: Respiration Physiology, Elsevier BV, Vol. 109, No. 1 ( 1997-7), p. 73-80
    Type of Medium: Online Resource
    ISSN: 0034-5687
    Language: English
    Publisher: Elsevier BV
    Publication Date: 1997
    detail.hit.zdb_id: 2010715-8
    Location Call Number Limitation Availability
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