‘Hidden’ colony of emperor penguins discovered in Antarctica (from space)

It was animal droppings, clearly visible on the snows of Antarctica, that revealed their presence. colony of emperor penguins (Aptenodytes forsteri) were previously unknown to scientists by about 500 adults; The relatively small breeding site adds to the 65 groups of emperor penguins already identified on the coasts of the White Continent.

study It was recently published in Biology PLUS He asserts that despite conservation efforts, Antarctica’s biodiversity is seriously threatened by climate change. The emperor penguin is known as the most vulnerable of the species: without reducing greenhouse gas emissions, “up to 80% of emperor penguin colonies should be extinct by 2100,” the researchers warn.

Therefore, the discovery of this new colony can be seen as good news, but Dr Peter Fretwell, Head of Geographic Information at the British Antarctic Survey, remains pessimistic: “ Like many of the recently discovered sites, this settlement is small and located in an area that has been hit hard by the recent melting of sea ice. “, Confirms In a press release from BAS. Emperor penguins need sea ice to reproduce; However, current climate projections indicate that this habitat is likely to decline. So, it was kind Listed as an endangered species in October 2022 by the Fish and WildLife Service.

Half of the colonies were spotted by satellite

Like half of the penguin colonies known to date, this new one was discovered through satellite imagery. Many groups are already located in inaccessible areas and can only be studied in this way. Scientists discovered the new site thanks to images from Sentinel-2, a series of observational satellites of the European Space Agency, developed under the Copernicus programme. The discovery was confirmed thanks to high-resolution images from the Maxar WorldView-3 satellite.

While assessing the loss of sea ice from satellite imagery, Peter Fretwell discovered the colony’s presence: it was revealed thanks to bird guano, which showed up very clearly against the landscape’s whites. It is located on the west coast of the continent at Verleger Point. The resolution of the WorldView-3 images made it possible to estimate the number of individuals in this population.

Emperor penguins are the largest and heaviest of all penguins, reaching a height of 1 meter and weighing up to 45 kg. They breed throughout the winter in Australia. They arrive in their colonies from late March to April and lay eggs from May to June (females lay one egg per year). The chicks leave the colony after about 150 days and return when they are four years old to breed. Emperor penguins feed mainly on fish, krill, and crustaceans. To date, the species includes approximately 600,000 to 650,000 individuals.

Vulnerability due to heavy reliance on sea ice

” According to the best available science, by 2050, their global population size is likely to decline from 26% (to about 185,000 breeding pairs) to 47% (to about 132,500 breeding pairs) under low and high carbon scenarios, respectively. », US Fish and Wildlife Service warns.

Their heavy reliance on sea ice—whether for reproduction or to escape predators like killer whales and leopard seals—makes the species extremely vulnerable. If the ice breaks before the offspring are strong enough, the chicks fall into the water, drown, or freeze. ” Last year we had the lowest sea ice ever recorded in Antarctica, and this year it’s even worse, two years in a row. », Fretwell said Live Science.

Not only is global warming causing their habitat to melt rapidly, but it is also increasing the acidity of the oceans, threatening some of the crustaceans these birds feed on.

If greenhouse gas emissions continue to rise, almost 80% of colonies should be extinct by the year 2100. On the other hand, of the researchers counted in 2019 that if the goals of the Paris Agreement are met, the emperor penguin’s viable refuge will be located in Antarctica, and only 19% or 31% of the colonies are expected to be extinct by 2100 – depending on scenarios in which warming is limited to 1.5°C or 2°C. respectively.

According to the Intergovernmental Panel on Climate Change, the goal is to limit global warming to +1.5°C by the end of the century. out of reach now. However, any effort to limit the increase in temperatures can contribute to the conservation of endangered species; The goal of +2°C is still achievable. As a reminder, climate change is currently affecting approximately 11,000 species on the International Union for Conservation of Nature (IUCN) Red List, increasing the likelihood of their extinction.

Source : British Antarctic Survey