The warming world has disrupted the timing for plant and animal reproduction, and it's usually bad news for species that depend on each other – like flowers blooming too early and pollinating bees arriving too late. But researchers have found the rare critter that's getting a boost from the change: king penguins.
A new study of 19,000 king penguins in a sub-Antarctic island chain found their breeding is starting 19 days earlier than it did in 2000. Mating earlier has increased the breeding success rate by 40%, according to a study in Wednesday's journal Science Advances.
The study of timing in nature is called phenology. It's been a major concern for biologists because predators, prey, pollinators and plants are mostly adapting to warmer climates at different rates. And that means crucial mismatches in timing.
It's especially common in birds and pollinating species such as bees. Most birds, especially in North America, aren't keeping pace with changes in phenology, according to Clemson University biological sciences professor Casey Youngflesh, who wasn't part of the study.
Having a species like the king penguin adapt so well to seasonal shifts and timing changes "is unprecedented,” said study co-author Celine Le Bohec, a seabird ecologist at the French science agency CNRS. "It's quite striking.”
Unlike other penguins, which are threatened with dwindling numbers because of earlier breeding, the king penguin has the ability to breed from late October to March. And they are taking advantage of that flexibility, Le Bohec said.
They are succeeding even though the water is warming and the food web that they rely on is changing with it, said Le Bohec and study lead author Gael Bardon, a seabird ecologist at the Scientific Centre of Monaco.
"They can adjust really well their foraging behavior,” Bardon said. "We know that some birds are going directly to the south, to the polar front. Some are going to the north. Some are staying around the colony and so they can adjust their behavior and that’s what makes king penguins cope really well with such changes for the moment.”
Le Bohec added that it may only be a temporary adjustment to an environment that is changing quickly. "So that’s why, for the moment, the species is able to cope with this change, but till when? This, we don’t know, because it’s going very, very fast.”
Other penguins that have limited diets are more threatened by changes coming from a warming ocean and the makeup of the food chain. But king penguins – which are so abundant they are considered a species of least concern – can eat other prey besides the lanternfish that makes up their primary diet, researchers said.
"The king penguin may have a bit of flexibility as a trick up its sleeve and may be in a good position to adapt as their environment changes,” said Michelle LaRue, a professor of Antarctic marine science at the University of Canterbury in New Zealand who was not part of the study. But she said she wonders what happens after breeding because king penguins live 20 or more years in the wild and this study looks at only a small part of their lifespan.
Outside scientists are just as cautious as Le Bohec and Bardon over whether to declare the king penguins a rare good-news climate change story.
"Winning for this species might mean losing for another species if they are competing for resources,” Clemson's Youngflesh said.
Ignacio Juarez Martinez, a biologist at Oxford University in the United Kingdom, who conducted a study of different penguins with earlier breeding, said: "This study shows that king penguins might be a winner for now, which is excellent news, but climate change is ongoing and future changes to currents, precipitation or temperatures can undo these gains.”
