“Losing large numbers of adults from a single event like this, that’s a major concern.”

Climate change is having far-reaching consequences not just for humans, but for wildlife and ecosystems, a new report has shown.

According to a study conducted by the University of Washington (UW) and published in the journal Ornithological Applications, a massive 2019 heatwave in Argentina, which led to a mass die-off of Magellanic penguins could possibly threaten the survival of the species in the future.

The official conservation status of these penguins is Near Threatened. The IUCN Red List of Threatened Species estimates the population of Magellanic penguins to be somewhere around 1.5 million.

UW researchers warn that with heatwaves forecast to become increasingly intense and more frequent due to the continuing rise of anthropogenic greenhouse gas emissions, heat-death mortalities will rise even further.

Study

The researchers made the comments after studying the impact of a January 2019 heatwave in Punta Tombo (Argentina’s southern coast) on one of the world’s largest breeding colonies of Magellanic penguins.

They recorded temperatures at the site during the breeding season, which typically rise from around 10C (50F) to 37C (100F). However, on 19 January 2019 temperatures spiked to 44C (111F) in the shade.

The extreme heat wave killed at least 354 penguins in the days following the record high temperature, the Independent reported.

“This extreme event fell near the tail end of the breeding season for Magellanic penguins, so it killed a large number of adults, as well as chicks,” lead author Katie Holt, a UW doctoral student in biology told the publication.

“It’s the first time we’ve recorded a mass mortality event at Punta Tombo connected to extreme temperatures.”

Nearly three-quarters of the penguins that died were adults, many of which likely died of dehydration, based on postmortem analyses.

Researchers found 27% of adult penguin corpses along paths heading out of the breeding colony to the ocean, where they could get a drink – penguins have glands that can filter salt out of the water.

The dead birds were often found on their stomachs with their feet and flippers extended and mouth open, a common panting and cooling pose for Magellanic penguins.

‘Major concern’

While UW researchers have previously documented mass mortality events at Punta Tombo caused by severe rainstorms that primarily killed chicks, the 2019 event is of ‘particular concern’ because it led to the loss of a large number of adults in a single event.

“Any mass die-off like this is a concern,” Holt said.

“But what is most concerning about heat-death mortality is that it has the potential to kill a lot of adults.”

She added: “The population viability of long-lived seabirds like Magellanic penguins relies on long lifespans. Adult Magellanic penguins can live more than 30 years, so they typically have many opportunities to successfully raise chicks. If we’re losing large numbers of adults from a single event like this, that’s a major concern.”

Coping mechanisms

Among other findings, the scientists noted that while global warming is going to produce more extreme weather events of all types globally, the consequences of their effects will help scientists determine the limits that some species can endure.

For instance, the team found that to avoid events such as this heat wave, penguins “could have the ability to cope, like moving breeding sites.”

But Holt said:  “It will take time to investigate whether those adaptations are effective.”

A separate study highlighted that climate change is also causing animals to witness ‘shapeshifting’. This means their bodies are evolving in order to adapt to the continually warming planet.

The study is published in the biomedical journal, Cell Press. 

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