“Each winter, thousands of Emperor Penguins leave the ocean and start marching to a remote place in Antarctica for their breeding season. Blinded by blizzards and strong winds, only guided by their instincts, they march to an isolated region, that does not support life for most of the year…”
The famous documentary March of the Penguins, directed by Luc Jacquet, earned the emperor penguin fanfare and admiration around the world. With their charismatic shape and loving nature, emperor penguins reside on the ice and in the ocean waters of Antarctica for the entirety of their lifespan, living on average from 15 to 20 years.
Satellite data has been used to help researchers better understand emperor penguin populations and how they respond to environmental variability, including the threat of a rapidly warming planet. But the information gleaned so far remains too limited to significantly help conservation efforts. Enter André Ancel, a researcher who led a team on a mission to study the remaining areas where emperor penguins might breed. His team recently published their findings in the journal Global Ecology and Conservation.
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“The climate of our planet is undergoing regional and global changes, which are driving shifts in the distribution and phenology of many plants and animals,” Ancel writes in his paper. “We focus on the southern polar region, which includes one of the most rapidly warming areas of the planet. Among birds adapted to live in this extreme and variable environment, penguin species are the best known.”
Even with their extreme adaption capabilities, emperor penguin breeding colonies are impacted by the fact that chicks often succumb to Antarctic elements. “Though they are one of the tallest and heaviest birds in the world, the survival rate of newborn emperor penguins is really low, only about 19 percent,” Shun Kuwashima, a PhD student at UCSC and self-declared penguin lover, explained. The purpose of Ansel et al.’s research was to predict how the species responds to climate change and to better understand the penguins’ biogeography, or geographical distribution.
“There are only about 54 known breeding colonies,” notes Ancel, “many of which have not yet been comprehensively studied.”
But finishing the research was a problem, considering that access to emperor penguin colonies remains limited. Getting accurate measurements on the size and location of the colonies relies on ground mapping and aerial photographs, which is “laborious, time consuming and costly,” according to Ancel. Even with the help of satellites, heavy cloud cover in the winter degrades the quality of images. Not to mention, the lack of light further complicates the collection of accurate data. In addition, the break-out of sea ice at the end of the breeding season can reduce the probability of detecting breeding colonies.
Although the authors did not actually conduct any exploration or examine remote sensing data to locate new emperor penguin colonies, they used data on the location of known colonies to make their findings. Based on the behavioral patterns of penguins, including movement and dispersal, and on the availability of food, the researchers found “six regions potentially sheltering colonies of emperor penguins.”
It is true that scientists have looked for emperor penguin colonies with satellite data in the past, but the method was limited. To make improvements and find potentially missing colonies, the team developed an approach for calculating separation distance between colonies.
The approach determined the loxodromic separation distance (the shortest distance between two points on the surface of a sphere) between each pair of geographically adjacent colonies. Then, based on the fact that a breeding adult can travel 100 km from the colony during the breeding period, assuming a circumpolar distribution, the researchers pinpointed the potential areas where emperor penguin colonies might exist or could settle.
“Based on distances between existing colonies, we found six regions potentially sheltering colonies of emperor penguins,” Ancel explained to GlacierHub. “Some of the regions are located near glaciers.”
The regions identified by Ancel et al. do not fundamentally differ from the areas of other known colonies, which makes it possible that there are more than 54 colonies. It is similarly plausible that emperor penguins are adapting to new conditions through behavioral changes, Ancel indicated.
He expressed anxiety about climate change, noting that emperor penguins do not appear to show much flexibility in this regard. Emperor penguins live on sea ice off the coast, with some living near glaciers, including by Taylor Glacier, Mertz Glacier and Dibble Glacier. They require a proper amount of ice: not too much, so they can walk to the sea and hunt for food, but also not too little, so they can stay away from predators.
“Emperor penguins, like many other sea animals, are critically influenced by the harmful effects of global warming,” Kuwashima told GlacierHub in a recent interview. “The entire emperor penguin population could decrease by a third by the end of the century due to the inadvertent effect of climate change.”
It is heartbreaking to imagine that we may no longer be able to see the adorable emperor penguin chicks in Antarctica, but emperor penguins are in danger. As research conducted by Trathan et al. in 2011 showed, “In the Antarctic Peninsula region, one of the most rapidly warming parts of the planet during the latter part of the 20th century, one emperor colony has disappeared.”
Ancel concluded, “Our analysis highlights a fundamental requirement, that in order to predict how species might respond to regional climate change, we must better understand their biogeography and the factors that lead to their occupation of particular sites.” Armed with this knowledge, we might still be able to protect this beautiful species.