How and Why are Penguins Disappearing?
When searching online I came across the article An Emperor Penguin Colony in Antarctica Vanishes by Karen Weintraub for the New York Times and published in April 2019. This immediately intrigued me because I had never heard about this news story. The title drew me in because how can a large thriving population just disappear in only three years?
Background:
The second-largest Emperor Penguin (Aptenodytes forsteri) colony is located at Halley Bay in Antarctica on the northern side of the Brunt Ice Shelf. For the last two decades, they have resided in a bay known to the locals as Windy Creek. No organized research had ever been conducted on the colony, but it had been visited by staff of The Halley Research Station intermittently from 1956 to 2012. The estimates on the size of the population varied between about 14,300–23,000 pairs. Although the recorded population among the penguins varied, it was consistently the largest in the Weddell Sea. There also had been no recorded instances of breeding failure among their colony.
What Happened?:
Recent monitoring by the British Antarctic Survey has shown that recently the colony of emperor penguins Halley Bay has suffered a terrible breeding failure, while their neighbors the Dawson-Lambton colony which can be found 55m South of Halley Bay, have only increased in size. The team of the British Antarctic Survey (BAS) used (VHR) satellite imagery to estimate population changes. They found that since 2015 the colony has had almost no successful breeding attempts.
Why?:
Emperor penguins are unique to other birds because their habitat for breeding relies critically on seasonal fast ice. This ice must remain solid almost the whole year in order for penguins to find mates, breed and then raise their chicks. Late fast ice formation, early breaking, or complete failure of ice formation strongly reduces the likelihood of successful breeding in any location. Previously the colony had bred without a problem, but in 2015 a powerful El Nino system arrived, which is the periodic warming of the Pacific Ocean that alters global weather patterns. This caused strong storms to hit Antarctica.
When BAS refers to “breeding failure” they mean since the ice broke up the young chicks consequently drowned because they were too young to swim. In 2016 satellite observations by BAS found short-lasting sea ice and early breakage during Spring resulted in almost complete breeding failure. This observation was confirmed by ground observation by staff at the Halley VI research stations in November 2016. In 2017 early breakage of fast ice in mid-November caused another year of breeding failure. Year after year the sea ice broke up drowning another year’s worth of chicks.
Interestingly between 2016 and 2018, BAS’s satellite imagery found an abnormally large increase in the number of penguins found at the Dawson-Lambton Glacier colony which is about 55 km south of the Halley Bay Colony. Through satellite, BAS found that the colony has decreased from 3,690 pairs in 2010 to 1,280 pairs in 2015. Suddenly out of the blue numbers increase in 2016 to 5,315 pairs, 11,117 pairs in 2017 and 14,612 pairs in 2018, which is an increase of 1000% from the 2015 estimate.
So how did the numbers grow so drastically?
BAS found that many of the birds in the Halley Bay colony successfully relocated to Dawson-Lambton. The population of Halley Bay decreases annually with more failed breeders moving to Dawson Lambton.
What does this mean?:
Climate change is extremely complex and differs drastically based on the context, meaning that scientists don’t know how or if this Emperor Penguin colony was impacted by climate change. What scientists can infer from this case is how sensitive emperor penguin colonies are to their environment. This would suggest they would be under the category of vulnerable species or animals that are likely to become endangered unless the circumstances that threaten it improve. Vulnerability is mainly caused by habitat loss which the emperor penguin colony has already shown to suffer from.
Volume 241 of the Biological Conservation Journal includes a review on The Emperor Penguin’s vulnerability to climate change. It touches on the fact that in the current era of environmental change that the formation or persistence of sea ice (especially fast ice) is predicted to change drastically. Since the majority of emperor penguin colonies reside on fast ice it can be inferred that is a key aspect of the species’ lifestyle. This means that alternative habitats for the fast ice reliant species are out of the question.
PBS News used a climate model linked to our population what is likely to happen if greenhouse gas emissions continue on their current trend. They found that all known 54 Emperor Penguin colonies would be in decline by the year 2100 and 80% would be quasi-extinct. They estimate that the total number of Emperor Penguins would decrease by 86% compared to its current size. However, there still is a bit of hope if the world works together to reduce greenhouse gas emissions and succeeds in stabilizing the average global temperature to 3 degrees Fahrenheit above pre-industrial levels. If the world is able to do so PBS estimates that Emperor Penguins would decline by 31% which is drastic but much better than the 86% option.
Ecology:
Emperor Penguins are what’s considered a mesopredator in the Antarctic ecosystem or a predator that preys on smaller animals in the food in a specific food chain system. They prey on fish, krill, and squid and are preyed on by leopard seals, sea lions, fur seals, and orcas. Taking a mesopredator like the Emperor Penguin out of the ecosystem would likely cause a trophic cascade. This means the prey of the Emperor Penguin such as squid, fish, and krill would experience “predator release” where their numbers significantly increase since nothing is keeping them in check anymore. Breeding penguins also enrich the land with their droppings that contain nitrogen, carbon and phosphorus this is called an “ornithogenic impact”. Taking penguins away would decrease the enrichment of the soil.
References
Amos, J. (2019, April 25). Antarctica: Thousands of emperor penguin chicks wiped out. Retrieved March 29, 2020, from https://www.bbc.com/news/science-environment-48041487
British Antarctic Survey. (n.d.). Distribution of Penguins in Antarctica [Image; jpdg]. Retrieved from https://mongabay.s3.amazonaws.com/12/0414penguins.jpg
Byrnes, H. (2019, January 16). Why Penguins Are So Much More Important Than You Think. Retrieved March 29, 2020, from https://247wallst.com/special-report/2019/01/16/why-penguins-are-so-much-more-important-than-you-think/
Fretwell, P., & Trathan, P. (2019). Emperors on thin ice: Three years of breeding failure at Halley Bay.Antarctic Science, 31(3), 133–138. doi:10.1017/S0954102019000099
Jenouvrier, S. (2019, November 13). Emperor Penguin extinction graph [Image; png]. Retrieved from https://d3i6fh83elv35t.cloudfront.net/static/2019/11/emperor-penguin_file-20191107-10901-p3dyta-1200x675.png
Jenouvrier, S. (2019, November 13). Emperor Penguins could march to extinction if nations fail to halt climate change. Retrieved March 29, 2020, from https://www.pbs.org/newshour/science/emperor-penguins-could-march-to-extinction-if-nations-fail-to-halt-climate-change
NOAA. (n.d.). What are El Niño and La Niña? Retrieved March 29, 2020, from https://oceanservice.noaa.gov/facts/ninonina.html
Trathan, P.N., Wienecke, B., Barbraud, C., Jenouvrier, S., Kooyman, G., Le Bohec, C., et al. 2019. The emperor penguin — vulnerable to projected rates of warming and sea ice loss. Biological Conservation, 10.1016/j.biocon.2019.108216.
Wilkinson, B. (2019, April 26). The world’s second-largest emperor penguin colony has nearly disappeared. Retrieved March 29, 2020, from https://www.cnn.com/2019/04/25/weather/penguins-antarctic-halley-scn-scli-intl/index.html