Warming seas mean King Penguins have to travel further to forage, limiting their reproductive success
Scientists have confirmed that global warming is a severe threat to the King Penguin population, having an effect on their survival and breeding patterns. A recent study led by Yvon Le Maho, from the CNRS Institut Pluridisciplinaire Hubert Curien in Strasbourg, tracked 456 individual penguins over a nine year period. They found that even a small increase in temperature, reflecting existing climate change predictions, poses an enormous danger and significant extinction risk for these charismatic creatures. The results were published in the February 11th Issue of PNAS.
Many consider climate change to be the most significant environmental challenge facing mankind at this moment in time. Its effects include extreme weather patterns, rising sea levels and in some areas a reduction in food resources. Importantly Earth’s warming patterns take affect most strongly in polar regions with temperatures seen to have risen five times faster than the global average over the past 50 years. It’s this warming which makes climate change as much of a challenge for penguins as mankind.
Penguins are marine predators, positioned at the top of the Antarctic food chain and hence studying their population dynamics can reflect the evolution of marine supplies such as krill, which nestle at the bottom of the food chain. The adult penguins commute to and from their colony to collect food for themselves and their offspring, with the distance travelled being directly correlated with the temperature of the ocean surface. Organisms at the low trophic levels are only able to thrive at a narrow temperature range. The warmer the surface of the water, the less marine life there is close to the colony and hence the further the penguin has to go in order to fish. During the summer months, the penguins have been seen to travel between 300-600km away from the colony, as the warmer Southern Ocean sea surface has hindered the development of marine life forms near the colony.
Counterintuitively, this warming doesn’t only occur in the summer: during the winter period, the ocean surface temperature has been shown to increase by around 0.26°C, which leads to a population collapse of marine organisms then too, explaining why the King Penguins have been seen to travel up to 2000km away during this period.
Unsurprisingly, as well as a decrease in marine life forms, warmer Southern Ocean sea surface temperatures are also connected with an abrupt decline in the penguin population’s reproductive success. With less food available for consumption and to bring back to the young, the little chicks have an abridged likelihood of survival. Using the data collected, a mathematical model was produced, which was used to predict a subsequent 9% drop in the penguin’s survival two years later. The Intergovernmental Panel on Climate Change has predicted the Earth to warm by 0.2°C per decade for the next two decades – the threat to the penguin population can clearly be inferred. The investigation was carried out on the sub Antarctic species, Aptenodytes patagonicus, found on the Possession Island in the Crozet Archipelago, located in the southern Indian Ocean. It is in this area where around two-thirds of the world’s King Penguin population reproduce, a staggering two million birds.
The penguins were monitored in their natural environment via an electronic tag, which was implanted under their skin. Maho and his colleagues were the first group to carry out this method of research. In past studies numbered rings were attached to the bird’s wing. However, this method of tracking was shown to hinder the penguin’s swimming ability. Furthermore, penguins fitted with these rings have been shown to have a reduction in reproductive success and a reduced life expectantly. Fitting the individual with an electronic tag was shown not to have an impact on how they go about their daily life.
This key study does not only reflect the effect of global warming on biodiversity but importantly its additional wider effect on marine food chains, which can lead to an imbalance of organisms throughout the trophic levels.
The penguin population has limited options, with an increase in the temperature of the ocean sea surface being inevitable. Will they adapt to the changing global environment and survive? Or will they fall as a defenseless victim of climate change?
King Penguin feeding its young – the
adults make epic foraging journeys of
up to 2000km
(Photo credit: Oceanwide Expeditions)
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Tags: Climate Change, Global Warming, King Penguin
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