Colonies of Adélie penguins could see their numbers decimated with as many as two-thirds of the population in Antarctic set to be wiped out by the end of the century, according to a new study published this week in the journal Scientific Reports.
Penguin(s) like the cold, but not weather that is too cold
Penguins do well in the cold but can’t deal with the extreme cold. On the other side of the coin, they won’t do well if Antarctica gets too warm either. The West Antarctic Peninsula (WAP), where Adélie, as well as Emperor penguins thrive, is warming as fast as anywhere on earth and threatens the penguins’ ability to rear chicks and could see a decline of almost 70% by 2099.
“It is only in recent decades that we know Adélie penguins population declines are associated with warming, which suggests that many regions of Antarctica have warmed too much and that further warming is no longer positive for the species,” said lead author Dr Megan Cimino.
The sea surface around Antarctic are on the rise and have already reduced the Adélie penguin population by about 80% in the last 2.5 decades. “These two things seem to be happening in the WAP at a higher rate than in other areas during the same time period,” Dr Cimino said. And unfortunately, for the tuxedo-ed birds, there is no signs of this trend slowing.
To undergo their research, the team behind the study used satellite data of penguins, which can be counted from space as well as climate change models to tell a tale of the penguins’ plight. While it’s certainly not good news, it’s not all dire news as Adélie penguin numbers are “steady or increasing” in other areas where climate change is less rapid than Antarctic.
“The Cape Adare region of the Ross Sea is home to the earliest known penguin occupation and has the largest known Adélie penguin rookery in the world,” Dr Cimino said.
“Though the climate there is expected to warm a bit, it looks like it could be a refugium in the future, and if you look back over geologic time it was likely one in the past.”
45,000 year history in jeopardy
Adélie penguins (Pygoscelis adeliae) have a history of almost 45,000 years in Antarctica and have survived past climate changes including the expansion of glaciers and sea ice changes.
Penguins spend most of their time inland in the summer and move to the waters edge for feeding in the colder months, this is now at risk. The researchers studied numerous colonies and some were doing alright for now, something that is not expected to last. Other colonies that weren’t growing saw losses as high as 80% in the most affected colonies.
Warming seas will likely see the penguins’ diet cast into to doubt when they have less prey to feast on if temperatures continue to rise.
“Changes in [sea] ice and temperature can cause changes in the food, krill and fish,” said Cimino. Elsewhere she continued, “the fish populations have gone down a ton, so their major diet in those areas is krill. In other areas, these penguins eat more fish, which are a more nutritious food source.”
Warming temperatures will melt ice and this doesn’t help penguins.
“For penguins who lay their eggs on the ground… rain and puddles are bad because eggs can’t survive when they’re lying in a pool of water. Chicks that don’t have waterproof feathers can become wet and die from hypothermia.”