Climate Presses and Pulses Impact Magellanic Penguin Populations
Presses and pulses — long-term trends versus short-term extreme events — affect animal species differently, yet understanding their combined effects is essential for conservation. Researchers at the University of Washington studied nearly four decades of data on Magellanic penguins at Punta Tombo, Argentina, to determine how these climate phenomena influence survival and reproduction.
Analyzing data from 1982 to 2019 for nearly 54,000 penguins, the team examined:
- Survival and reproductive success of penguins at Punta Tombo, historically one of the largest breeding sites
- Climate conditions during each breeding season
- Ocean conditions off the coast and along migration routes
Using an integrated population model, researchers found that both presses and pulses significantly affected penguin populations. For example:
- Climate pulses like heat waves can cause mass mortality, illustrated by a 2019 heat wave that killed over 350 penguins in a single day.
- Climate presses, such as increased rainfall, also negatively affect chicks through exposure during storms.
- Conversely, the gradual weakening of the Río de la Plata silt plume — a press — improved winter feeding conditions for adult penguins, supporting better survival.
Despite some positive effects, negative impacts from warming and wetter conditions dominated. The Punta Tombo breeding population declined from roughly 400,000 pairs in the early 1980s to about 150,000 in 2019. Penguins are moving north to find more abundant food and establishing new breeding sites.
“For conservation to be most effective, we need to know where, when and how to apply our limited resources,” said co-author Briana Abrahms. Long-term, detailed data allowed the team to evaluate both long-term trends and extreme events together, providing crucial insights for predicting future impacts of climate change on Magellanic penguins and other long-lived species globally.
