Forget
about a polar bear stranded on the ice float, the new mascot for global
warming could be a penguin turning up its beak at a diverse diet.
If you were the type of kid to pout over a
plate of broccoli, you might remember your parents saying something
like, “If you’re not going to eat this, you’ll starve.” While that was
(hopefully) an empty threat, scientists are finding that it mirrors the
unfortunate reality for at least one species coping with climate change:
chinstrap penguins.
Chinstrap penguins live on
the Antarctic Peninsula alongside the closely related Gentoo penguins.
In the last 50 years, average air temperatures in the region have
increased by about five degrees Fahrenheit. That makes it the most rapidly warming region in the Southern Hemisphere, according to the British Antarctic Survey.
(In
case you were wondering, chinstrap penguins do have the face markings
from which they get their names. Gentoo penguins, on the other hand,
have orange beaks. Both have the black backs and white stomachs that
give them that signature tuxedo look.)
When closely related species live in the same ecosystem, they tend to specialize the type of food and resources that they use, so that there is less competition between species. But that happy co-existence comes with a tradeoff.
Despite similar habitats and
diets, scientists have observed “dramatic declines” in the chinstrap
penguin population in recent years. The gentoo penguin population,
meanwhile, has expanded. A newly published study in Marine Ecology Progress Series, by lead author Michael Polito of Louisiana State University, explains the divergence.
When
closely related species live in the same ecosystem, they tend to
specialize the type of food and resources that they use, so that there
is less competition between species. But that happy co-existence comes
with a tradeoff, Polito and colleagues write: “Species with specialized
habitat or dietary requirements are likely to be highly sensitive to
environmental changes.”
From 2007 to 2011, Polito
and his colleagues analyzed stomach and feather samples of a colony of
penguins living on the Antarctic Peninsula, as well as the availability
of their main prey, a shrimp-like crustacean that’s called krill. Krill
rely on sea ice for protection and food, so when temperatures rise and
ice melts, there are fewer krill in the ocean.
Researchers
found that chinstraps were pickier penguins—they ate mostly
krill—whereas Gentoos were more adventurous, adding various types of
fish to the menu. Krill comprised nearly 100 percent of chinstrap diets
(measured by wet mass of stomach contents), whereas they only accounted
for 79 percent of Gentoo diets.
Oddly enough,
chinstraps actually forage further offshore than gentoos, in order to
reach the krill swarms. “This and other studies indicate that their
foraging choices may be a reflection of small-scale changes in prey
availability,” Polito and colleagues write.
Call
it a cautionary tale. As climate change rears its ugly head in many
ways, some of our preferred food sources may disappear. We might all be
eating organic crickets in 50 years, so start training your kids to appreciate exotic flavors now.
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