Global warming has altered the reproduction schedule of plants and animals, which is usually bad news for species that depend on each other, such as flowers that bloom too early and pollinating bees arriving too late. But researchers have discovered a rare creature that benefits from the change: king penguins.
A new study of 19,000 king penguins from a subantarctic island chain reveals that their reproduction begins 19 days earlier than in 2000. According to a study published Wednesday in the journal Science Advances, earlier mating has increased the reproductive success rate by 40%.
The study of the calendar in nature is called phenology. It has been a major concern of biologists because predators, prey, pollinators and plants adapt to warmer climates at different rates. And that means crucial calendar mismatches.
It is especially common in birds and pollinator species such as bees. Most birds, especially in North America, are not keeping pace with phenological changes, according to Casey Youngflesh, a professor of biological sciences at Clemson University, who was not involved in the study.
That a species like the king penguin adapts so well to seasonal and calendar changes “is unprecedented,” says Celine Le Bohec, co-author of the study and seabird ecologist at the French scientific agency CNRS. “It’s pretty amazing.”
Unlike other penguins – whose numbers are threatened by the advance of reproduction – the king penguin can reproduce from the end of October to March. And they are taking advantage of that flexibility, says Le Bohec.
They are achieving this even though the water is warming and the food web on which they depend is changing with it, say Le Bohec and the study’s lead author, Gaël Bardon, a seabird ecologist at the Monaco Scientific Centre.
“They can adjust their foraging behavior very well,” Bardon said. “We know that some birds go directly south, towards the polar front. Others go north. Others stay around the colony, so they can adjust their behavior and that is what makes the king penguins cope very well with these changes at the moment.”
Le Bohec added that this may only be a temporary adaptation to a rapidly changing environment. “Therefore, for the moment, the species is capable of coping with this change, but for how long? We do not know this, because it is going very, very fast.”
Other diet-limited penguins are more threatened by changes from ocean warming and food chain composition. But king penguins – so abundant that they are considered a species of least concern – can eat other prey besides the lanternfish that make up their main diet, according to researchers.
“The king penguin may have an ace up its sleeve in adapting to changes in the environment,” says Michelle LaRue, professor of Antarctic Marine Sciences at the University of Canterbury in New Zealand, who was not involved in the study. But he wonders what happens after breeding, because king penguins live 20 years or more in the wild and this study only looks at a small part of their life.
Other scientists are as cautious as Le Bohec and Bardon about declaring king penguins to be rare positive news about climate change.
“Winning for this species may mean losing for another if they compete for resources,” says Clemson’s Youngflesh.
Ignacio Juárez Martínez, a biologist at the University of Oxford (United Kingdom), who led a study on different penguins with earlier breeding, stated: “This study shows that king penguins may come out ahead for now, which is excellent news, but climate change is underway and future changes in currents, precipitation or temperatures could undo these gains.”