This is the determined battle of polar bears to seek out meals in a melting Arctic | Science | EUROtoday
In a world the place local weather change is altering pure habitats at a speedy tempo, polar bears have develop into one of many symbols of the combat for survival. Summers are lengthening, planet temperatures are rising and there’s much less and fewer ice. When the frozen blocks of the Arctic disappear, bears spend extra time on land, the place it’s tough to seek out meals, as their conventional searching methods that make the most of the ocean ice are much less efficient. A research revealed in the present day in Nature Communications presents a portrait of the challenges that the 25,000 polar bears left on the planet face so as to not die of starvation.
In the interval of late spring and early summer season, polar bears use sea ice as a searching platform. They feed primarily on seals which can be giving start and weaning their pups in the identical season. When the ice melts, the Arctic giants need to decelerate as a lot as doable to preserve vitality. A crew of scientists, led by wildlife biologist Anthony Pagano of the United States Geological Survey, noticed polar bears up shut for 3 weeks over the summer season. To obtain this, they positioned collars outfitted with cameras and GPS on twenty bears in western Hudson Bay, Manitoba (Canada). In this space the inhabitants has decreased by round 30% since 1987 and the ice-free interval has elevated by three weeks since 1979, protecting bears on land for about 130 days within the final decade.
After analyzing the pictures, they found that the bears tried completely different techniques to feed and preserve vitality reserves, together with scavenging and resting at related ranges as grizzly bears once they enter hibernation. 70% of those that have been lively ate terrestrial meals reminiscent of berries, herbs and fowl carcasses. Three bears ventured to swim lengthy distances to seek out meals within the water and though two of them discovered stays of belugas and seals, they have been unable to eat whereas swimming or deliver them to land.
Regardless of their consuming or relaxation technique, there was a constant lower in physique mass and 19 of the 20 misplaced a mean of 1 kilogram per day. “A continued increase in the length of summer on land will be associated with an increased risk of starvation,” says Pagano. “Neither strategy will allow polar bears to exist on land beyond a certain amount of time. Even those bears that were foraging lost weight at the same rate as those that were lying down,” provides Charles Robbins, director of the Bear Center at Washington State University and co-author of the research.
It has been speculated that polar bears may adapt to ice-free seasons by looking for terrestrial meals, however the research reveals that it isn’t really easy to seek out it and that it doesn’t present them with the vitamins or vitality they want, in order that they find yourself affected by famine. David Nogués Bravo, a macroecologist on the Center for Macroecology, Evolution and Climate on the University of Copenhagen who has not participated within the research, explains that the dearth of meals “reduces the probability of maintaining generational replacement” and provides that “terrestrial foods gave them some energy benefit, but ultimately they had to spend more energy to access those resources.”
The ice that covers the Arctic reaches its minimal each September and annually is lower than the earlier. According to NASA information, based mostly on a number of of its satellites, the extent of the polar cap has decreased at a fee of 12.6% every decade since 1980. A 2023 research supported by observations from NASA and ESA satellites predicts that between 2030 and 2050 the primary ice-free September will arrive. And if greenhouse emissions are usually not diminished, by 2100 the Arctic area will spend as much as half a yr with out ice.
The research's findings have vital implications for the conservation of polar bears, but additionally invite us to analyze the repercussions it has for the marine and terrestrial ecosystems of the Arctic. The presence of those animals trying to find longer in terrestrial areas has oblique impacts on different species reminiscent of birds, in response to Nogués. “Bears are capable of eating dozens of eggs in a short time and reduce the probability that these bird populations have to survive,” he provides.
That polar bears are in severe hazard of extinction is nothing new. What is shocking is the huge decline in hatchlings and the hunger confronted by adults as a consequence of melting sea ice. “I have seen polar bears in the Arctic and it is darkening to witness the path of this species towards its probable functional extinction in the not too distant future,” says Nogués, who emphasizes that it is very important consider that “the biodiversity crisis and the climate crisis are not two different crises, but two sides of the same coin.”
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