King penguins could be wiped out by climate change

  February 12, 2008 – One of the emblems of the Antarctic, the king
penguin, could be driven to extinction by climate change, a French study
published on Monday warned.
   In a long-term investigation on the penguins’ main breeding grounds,
investigators found that a tiny warming of the Southern Ocean by the El Nino
effect caused a massive fall in the birds’ ability to survive.
   If predictions by UN scientists of ever-higher temperatures in coming
decades prove true, the species faces a major risk of being wiped out, they
say.
   Second in size only to the emperor penguin, king penguins (Aptenodytes
patagonicus) live on islands on the fringes of Antarctica in the southern
Indian Ocean, with an estimated population of two million breeding pairs.
   The species is unusual in that it takes a whole year for all the birds to
complete their breeding cycle — the ritual of courtship, egg laying,
incubating and chick rearing.
   This extreme length, spanning the Antarctic winter and summer, means the
birds are vulnerable to downturns in seasonal food resources for incubating
their eggs and nurturing their chicks.
   Their main diet, small fish and squid, depends on krill. These minute
crustaceans are in turn extremely sensitive to temperature rise.
   The team, led by Yvon Le Maho of France’s National Centre for Scientific
Research (CNRS), marked 456 penguins with subcutaneous electronic tags at a
big breeding ground on Possession Island on the Crozet archipelago in the
southern.
   They buried radio antennas on pathways used by the penguins on the island
and connected them to a computer that automatically recorded when the birds
came and went.
   The surveillance programme ran from November 1997 to April 2006, a period
that included an El Nino, the cyclical warming event that is not linked to
climate change.
   During the El Nino, penguins that were early breeders did well, but those
that bred later were badly hit, as the progressively warmer seas made food
rarer.
   But the overall impact on population only became visible two years later,
because of the penguins’ long reproductive cycle.
   An increase of just 0.25 degrees Celsius (0.45 degrees Fahrenheit) in
surface sea temperature translated into a nine-percent decline in an adult
bird’s chance of survival, Le Maho calculates.
   According to the UN’s Nobel-winning panel of climate scientists, the mean
global temperature is already set to rise by around 0.2 C (0.35 F) per decade
over the next two decades as part of a longer warming trend this century.
   "Our findings suggest the king penguin populations are at heavy extinction
risk under the current global warming predictions," the scientists say.
   Their paper is published on Monday by the US journal, Proceedings of the
National Academy of Sciences (PNAS).

AFP