Emperor penguins – call for classification as “threatened” species | Polarjournal
Emperor penguins have synchronized their breeding precisely with the rhythm of the sea ice. If it breaks up too early, the chicks cannot yet swim with their downy plumage. Photo: Dr. Michael Wenger

Emperor penguins are the icons of Antarctica – and they are increasingly endangered because their habitat, the sea ice, is shrinking due to global warming. Therefore, the U.S. Fish and Wildlife Service proposed listing the species as “threatened” under the U.S. Endangered Species Act this past August, based on decades of research.

Emperor penguins (Aptenodytes forsteri) are imperatively dependent on fast ice – sea ice attached to the Antarctic continent – and its punctual seasonal rhythm for their breeding and molting. Populations are therefore extremely sensitive to changes in the spatial and temporal extent and thickness of sea ice. For example, a colony in Halley Bay in the Weddell Sea suffered a catastrophic breeding failure in 2016 because the sea ice broke up before the chicks had developed their waterproof plumage and were able to swim. Scientists believe that 10,000 chicks drowned at the time.

“The reason it’s important to have a thick, stable platform of sea ice is that the chicks that are raised during the breeding season in winter, they have this downy plumage, but they need to acquire waterproof plumage to be able to survive at sea in the cold water,” explains Stephanie Jenouvrier, a research associate and seabird ecologist at Woods Hole Oceanographic Institution (WHOI) in Massachusetts. “If the sea ice breaks up too early in the season, they will not have acquired their waterproof plumage, and they will drown and die in the Antarctic water, so it will be a complete breeding failure.”

Life cycle of emperor penguins. Graphic: Zina Deretsky/National Science Foundation

For decades, scientists from around the world have been studying the effects of climate change on emperor penguin colonies in Antarctica, including a team from WHOI. Long-term studies have shown that climate protection measures are urgently needed to protect the emperor penguins. The disappearance of sea ice is driving them towards extinction. Emperor penguins are considered indicator species whose population trends can illustrate the consequences of climate change.

In some regions of the Antarctic Peninsula, according to WHOI, sea ice cover has declined by 60 percent in 30 years, resulting in the virtual disappearance of one colony already. Jenouvrier and other scientists found in a study published in 2019 that there is still hope for emperor penguins if humans can limit the Earth’s temperature rise to 1.5 or 2 degrees Celsius above pre-industrial levels. However, if warming continues at the current rate, more than 80 percent of emperor penguin colonies are expected to become virtually extinct by 2100. However, a recent study from earlier this year by Jenouvrier et al. calling for the classification of emperor penguins as an endangered species paints an even bleaker picture, predicting the extinction of 98 percent of emperor penguin colonies if climate change continues at the same pace.

The alarming studies by scientists, as well as the urging of the Center for Biological Diversity, which first called for protection status for the emperor penguin in 2011, prompted the U.S. Fish and Wildlife Service in August to draft a proposal that would include listing the emperor penguin as “threatened” under the Endangered Species Act.

The U.S. Fish and Wildlife Service’s proposal to list the emperor penguins as “threatened” is an important conservation measure, as the animals’ habitat is expected to continue shrinking in the coming decades. Photo: Heiner Kubny

“This proposal is an important step for raising awareness about the impact of climate change,” Jenouvrier says. “Emperor penguins, like many species on earth, face a very difficult climate future.”

Philip Trathan, head of conservation biology at the British Antarctic Survey (BAS), added: “This is just one important step forward for the emperor penguin. Additional conservation actions including increased protection at breeding sites and foraging grounds are also necessary.”

Listing the emperor penguin under the Endangered Species Act also means that action must be taken against all aspects that threaten the species, including greenhouse gas emissions and industrial overfishing of important prey species such as krill and squid. Federal agencies would have to ensure that their activities, including those that produce high carbon emissions, do not threaten the penguin or its habitat. The Endangered Species Act is the world’s strongest environmental law aimed at preventing the extinction of endangered species and facilitating their recovery, and is increasingly being used to protect species threatened primarily or in part by climate change, WHOI said in a press release. In 2008, the polar bear was the first species to be listed primarily due to global warming.

Julia Hager, PolarJournal

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