The ongoing loss of sea-ice cover is wreaking havoc on ecosystems across the Arctic, and may spell the end of more species than previously thought.

The Scenario

Arctic sea-ice cover has shrunk this year to the second lowest summer level ever recorded, following an unprecedented winter low. “There will be winners and losers,” says Martin Renner of Tern Again Consulting in Homer, Alaska. “Species that rely directly on sea ice, like ivory gulls, will run into difficult times.”

What Researchers Have Found

But less obvious species may also be in trouble. Renner and his colleagues examined data on sea ice and zooplankton, fish and seabirds in the south-east Bering Sea between 1975 and 2014. They found that most seabird and large zooplankton species were less abundant – by 90 per cent on average for birds – when sea ice melted early in spring, suggesting that these species will decline in a warmer climate.

“Such changes will result in a very different Bering Sea ecosystem, which currently supports one of the largest remaining palatable fisheries in the world,” says Renner.

How Ice Melt Is Affecting Caribou- A Culturally Important Animal 

It’s not just sea life that’s at risk. Glenn Yannic at Université Savoie Mont Blanc in France along with his team studied the possible future effects of sea-ice loss on the Peary caribou, a culturally important animal for indigenous people, who use it for food and clothing. These animals are also a critical part of the ecosystem in the Canadian Arctic Archipelago, which has more than 36,000 islands. The caribou travel over the ice between these islands to find food and shelter, to mate and to raise their young.

“Sea ice allows caribou populations to interact and allows for genetic exchange, which influences the productivity and diversity of these populations,” says Deborah Jenkins of Trent University in Ontario, Canada, who also took part in the study.

Less Connected

According to Jenkins, connectivity among islands has declined since the 1980s and is set to get much worse by the end of this century. The loss of ice could disrupt caribou movement and gene flow. Over time, the animals may go extinct, says the study.

A lack of ice may also hamper the dispersal of plants, dooming them to extinction. Plants will need to move to colder places to track their climatic niche, says Inger Greve Alsos at the Arctic University of Norway in Tromsø. Her team used past data on sea ice and plants’ first arrival in the Arctic to show that plants are more likely to colonise new areas when sea ice is prevalent.

"For species that rely on sea ice, there may be increasingly negative and irreversible consequences, with far-reaching effects on the structure and functioning of entire ecosystems,” says Yannic.

Five Facts About Peary Caribou

1- What Are They: The smallest of all caribou subspecies having shorter faces and legs and are lighter in colour than barren-ground caribou. 

2- Where Are They Found: In small groups on the Arctic islands of the NWT and Nunavut. 

3- The Habitat: The Arctic Archipelago - where it is harsh, and treeless environment. In summer, Peary caribou forage in moist areas such as river valley slopes and upland plains. In winter, the caribou forage in more exposed areas such as hilltops and raised beach ridges where the thinner snow layer makes foraging easier. 

4- Population Size: Caribou numbers have increased and decreased on different islands since the first surveys in the early 1960s. There has been a 50% decline in its population over the years. The declines are due to several years of unusually severe winter and spring weather, hunting, predation, and competition with increased numbers of muskoxen. 

5- Biology: Female Caribou are capable of calving annually, however, depending upon whether or not they can build up adequate fat reserves over the summer to breed in mid-October. Most calves are born in the last two weeks of June. 

Do you think there is any scope to protect the culturally important Peary Caribou from extinction? How? Tell us in the comments below...