Publisher :
Place of publication :
Publication year : 2009
Thematic : Climate Change and Biodiversity
Language : English
Note
Penguins are adapted to live in extreme environments, but they can be highly sensitive to
climate change, which disrupts penguin life history strategies when it alters the weather,
oceanography and critical habitats. For example, in the southwest Atlantic, the distributional
range of the ice-obligate emperor and Ade´lie penguins has shifted poleward and
contracted, while the ice-intolerant gentoo and chinstrap penguins have expanded their
range southward. In the Southern Ocean, the El Nin˜ o-Southern Oscillation and the
Southern Annular Mode are the main modes of climate variability that drive changes in
the marine ecosystem, ultimately affecting penguins. The interaction between these
modes is complex and changes over time, so that penguin responses to climate change are
expected to vary accordingly, complicating our understanding of their future population
processes. Penguins have long life spans, which slow microevolution, and which is
unlikely to increase their tolerance to rapid warming. Therefore, in order that penguins
may continue to exploit their transformed ecological niche and maintain their current
distributional ranges, they must possess adequate phenotypic plasticity. However, past
species-specific adaptations also constrain potential changes in phenology, and are
unlikely to be adaptive for altered climatic conditions. Thus, the paleoecological record
suggests that penguins are more likely to respond by dispersal rather than adaptation.
Ecosystem changes are potentially most important at the borders of current geographic
distributions, where penguins operate at the limits of their tolerance; species with low
adaptability, particularly the ice-obligates, may therefore be more affected by their need
to disperse in response to climate and may struggle to colonize new habitats. While
future sea-ice contraction around Antarctica is likely to continue affecting the iceobligate
penguins, understanding the responses of the ice-intolerant penguins also
depends on changes in climate mode periodicities and interactions, which to date remain
difficult to reproduce in general circulation models.
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Keywords : Sacalia quadriocellata
Encoded by : Pauline Carmel Joy Eje
