Two types of climate events are steadily reshaping Earth’s climate and ecosystems. “Pulses” are short-term climate events such as shifting ocean currents, while “presses” are prolonged events like heat waves.
In a recent study from the University of Washington, researchers set out to investigate how different presses and pulses have impacted Magellanic penguins. The experts studied the effects of climate events on these migratory marine predators at a large breeding site in Punta Tombo, Argentina.
The study showed that pulses and presses are affecting Magellanic penguins in different ways, yet are equally important for the survival of the species. The researchers also determined that the combination of these two types of climate events has taken a major toll on the size of the penguin population at Punta Tombo.
“We found that penguin survival doesn’t rest solely – or even largely – on one or a few climate effects,” explained study lead author T.J. Clark-Wolf. “Instead, many different presses and pulses impact penguin reproduction and survival over time.”
The research was focused on data collected at Punta Tombo from 1982 to 2019 by study co-author Dee Boersma. The information included details on reproductive success for nearly 54,000 penguins at the site, climate conditions during each breeding season, and ocean conditions off the coast of Punta Tombo.
The experts integrated the data into a population model that provided details of the effects of separate climate events. The model showed that each type of climate event had distinct effects on the penguin population at Punta Tombo.
Heat waves have been perhaps the most detrimental of the various climate presses and pulses, killing both adults and chicks. In 2019, for example, a single-day heat wave killed more than 350 penguins at the site.
According to the experts, the number of breeding pairs at Punta Tombo dropped from about 400,000 in the 1980s to about 150,000 in 2019.
“This colony will be 100 years old in 2024, but we finished another on-the-ground survey in late October at Punta Tombo and its numbers continue to decline,” said Boersma. “The penguins are instead moving north to be closer to their food.”
The researchers noted that understanding how these presses and pulses shape this population is crucial for informing conservation efforts.
“For conservation to be most effective, we need to know where, when and how to apply our limited resources,” said senior author Briana Abrahms. “Information generated by this study tells us which climate effects we need to worry about and which ones we don’t – and therefore can help us focus on measures that we know will have a positive impact.”
The study is published in the journal Proceedings of the National Academy of Sciences.
By Chrissy Sexton, Earth.com Editor
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