Emperor penguins are struggling to survive as sea ice vanishes

New research from Australia, using satellite imagery to track emperor penguin colonies in East Antarctica, reveals that these iconic birds are struggling to cope with the rapid changes in their environment. 

The study, led by the Australian Antarctic Division, highlights that emperor penguins, which have adapted to environmental shifts for nearly a million years, are now facing unprecedented challenges due to the rapid loss of their breeding habitat.

Fast-ice for penguin breeding

Barbara Wienecke, a seabird researcher at the Australian Antarctic Division, explained that emperor penguins have historically responded to changes in their preferred breeding grounds, the Antarctic fast-ice zone, by relocating when conditions became unsuitable. 

However, in 2022 and 2023, the untimely loss of fast-ice habitat, combined with record low sea-ice extent, led to significant breeding failures in some colonies. 

Scientists fear these recent events could indicate worsening ice conditions, leaving the penguins with little time or capacity to adapt.

“Emperor penguins need stable fast-ice for about 10 months a year to breed successfully and rear their chicks,” Wienecke said. 

“If their breeding platform disintegrates before early December, when the chicks still have their downy plumage, it’s likely they will all perish. If it disintegrates before the end of December, chicks without waterproof plumage will die.”

Limited capacity to adapt to rapid changes

As long-lived seabirds, emperor penguins can handle occasional disruptions to their environment, but Wienecke warned that they have limited ability to adjust to the accelerating pace of environmental changes. 

The penguins cannot shorten the time it takes for their chicks to develop, making it difficult for them to adapt to a shorter fast-ice season.

Wienecke and her team – including sea-ice scientist Jan Lieser and seabird experts Julie McInnes and Jonathon Barrington – used satellite imagery from the European Space Agency’s Sentinel-2 program to examine shifts in breeding habitats and ice conditions from 2018 to 2023.

Monitoring penguins with satellite imagery

Satellite imagery has proven invaluable for monitoring the variability in fast-ice habitat, according to Lieser. “From this, we can assess the adaptability of emperor penguins to rapid change, and the impacts of habitat change on breeding success,” he said. 

The research team studied satellite images covering 6,000 kilometers of East Antarctica’s coastline between September and December, the crucial time for chick rearing and fledging.

They manually tracked the locations of penguin colonies each year and measured the distance between the colonies and the fast-ice edge. 

This distance is critical, as adult penguins need to be close to the edge to access open water for feeding, but if the colony is too close, the ice may break up before the chicks are ready to survive at sea.

Rising breeding failures due to habitat loss

The study found that 13 of the 27 colonies examined are at risk of reduced or complete breeding failure due to habitat loss. Nine of these colonies experienced such failures at least once during the six-year study period. 

One colony disappeared entirely, although some individuals may have joined other nearby colonies. 

While some penguin colonies moved to new types of habitats, such as ice shelves or ice tongues, these areas are also vulnerable to iceberg calving events that can alter local conditions.

Previous population modeling studies have projected that up to 65% of emperor penguin colonies could become “quasi-extinct” (on the path to extinction) by 2050. 

However, Wienecke noted that the variability in colony locations relative to sea ice makes it difficult to model these trends accurately.

Importance of ongoing monitoring

The new study highlights the importance of medium and high-resolution satellite imagery as a tool for annual monitoring of emperor penguin colonies and their fast-ice habitats across Antarctica. 

According to Weinecke, ongoing, continent-wide monitoring is essential to quantify the effects of changing ice conditions on penguin populations and assess the cumulative impacts of other threats, such as disease.

“Satellite imagery enables us to identify the locations of emperor penguin colonies each year and assess the local environmental conditions,” explained Weinecke. 

This combination of satellite data with ground and aerial counts of penguins where possible will provide a clearer picture of how local populations are affected by these environmental changes.

In conclusion, the study, published in the journal Endangered Species Research, stresses the need for continued monitoring and research to better understand the consequences of rapid ice loss on emperor penguins and their breeding success. 

Without stable fast-ice, these iconic seabirds face an uncertain future as they struggle to adapt to the rapidly changing conditions in Antarctica.

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