Researchers map emperor penguin habitats under climate extremes

A group of researchers has constructed guano indices of emperor penguins to reveal the changes in the species' breeding habitats over the past 11 years.

For every one degree Celsius rise in temperature, emperor penguins shift their breeding site an average of 73 meters further, while each additional centimeter of snowfall adds another 66 meters to the move, according to the researchers.

Emperor penguins serve as early-warning sentinels for the Antarctic ecosystem and climate change, as noted in a recent research article in the journal Remote Sensing of Environment.

Understanding how climate change influences their habitat use provides insights into the fragile polar ecosystem, supporting climate actions under the United Nations Sustainable Development Goals (SDGs).

However, it remains unclear how the gradual climate change and extreme climatic events affect the dispersal of emperor penguin breeding habitats due to the lack of a systematic and long-term dataset documenting their habitat use.

Researchers from Sun Yat-sen University and the University of Montana developed guano indices. They presented an automated approach to map emperor penguin breeding habitats from 2013 to 2023 at a 30-meter spatial resolution using Earth observation satellite imagery.

"Our findings showed that, under the pressure of climate change, emperor penguins are now having to relocate their breeding grounds frequently," said Lin Hong, the paper's first author and a PhD student of Sun Yat-sen University School of Geospatial Engineering and Science.

"Unlike most birds, emperor penguins cannot fly, nor do they build nests," said Lin. "Instead, they rely on a stable sea-ice surface to breed."

The study found that some emperor penguins are comparatively fortunate because their breeding sites are shielded by nearby islands, towering ice cliffs or grounded icebergs, and they are within easy reach of open waters rich in prey. In these locations, the penguins rarely change their breeding sites, which are often reused for up to seven years.

Yet where no such protective barriers exist, emperor penguins' ice homes are far more vulnerable to break-up, underscoring that climate change, coastal topography, and prey availability all interact to shape emperor-penguin survival.

The researchers further revealed that habitat dispersal is sensitive to four extreme events, including heat, blizzards, storms, and low sea ice concentration. Specifically, colonies exposed to intense climate extremes generally exhibit more fragmented distributions.

(Cover: Emperor penguin chicks. /VCG)