Ice dependent species in the arctic

The arctic is home to many beloved species including our adored polar bear. Arctic species depend on sea ice for their survival. This is where these animals live, hunt and rear their off-sping. Sea ice habitats are critical to the survival of these species and are now in a state of crisis.

For more than 30 years, sea ice has been in a steady and rapid decline. This is in part due to the temperature at the arctic rising more than twice as quickly as the rest of the earth due to arctic amplification. Arctic or polar amplification is the phenomenon that any change in the net radiation balance tends to produce a larger change in temperature near the poles than in the planetary average. This is commonly referred to as the ratio of polar warming to tropical warming. And, this magnification of temperature has caused sea ice to thin, recede and melt much earlier in the year. As the sea ice shrinks so do the habitats of ice-dependent species.

Polar bears

Ice has many uses for polar bears, but they primarily use it to hunt. When sea ice is plentiful in the winter, it gives them access to seals. Once ice melts and polar bears retreat to land, bears must use their energy reserves to survive until sea ice reforms. When ice forms late or is too thin for seals to make their dens, food becomes scarce and polar bears run the risk of starvation during summer months. And while many won’t necessarily starve, a lack of food could hinder a female’s ability to bring a cub to term.

Studies show that polar bears at the southern point of their range are giving birth less frequently and fewer cubs are surviving. In these areas it was quite common to see a mother with three cubs. Today, researchers are observing more and more mothers with a single cub.

Narwhals

When they’re not swimming in open sea, deep-diving narwhals get air from small cracks in the ice, which also keep them safe from predators. When cracks widen and ice disappears, narwhals become vulnerable to predation.

A warmer, ice-free Arctic is attractive to curious marine species. Killer whales are showing up in the region in increasing numbers, which means trouble for the whale. This population of killer whales likes to gorge on narwhal, so when the apex predator is around, narwhals tend to cower close to shorelines where food is scarce. Since this is a new phenomenon, scientists are still learning how the growing number of predators are affecting the overall health and behaviour of narwhals.

Arctic caribou

Arctic caribou are known for their epic long-distance migrations so it’s no surprise ice serves as a migratory habitat for some caribou.

Peary caribou, found in the high Arctic Archipelago and Ellesmere Island, need to travel on ice in search of the limited amount of forage between high Arctic islands. The absence of sea ice would be disastrous for these groups, completely disrupting their migrations. Less reliable sea ice that is thin or forms later in the year could result in a population decline for both groups.

Walrus

The Pacific walruses prefer to spend their time on ice in groups known as haul-outs. It’s here they socialize, rest and reproduce. This ice-based habitat also provides access to food.

When sea ice shrinks or melts entirely, it forces walruses to haul out on land where food availability is limited. Instead of gathering in smaller groups, land-based haul outs are much larger. This can result in a stampede, which you can see in a shocking scene of Our Planet. Meanwhile, Atlantic walruses are found in Canadian haul outs on land in late summer and early fall, when sea ice is at its minimum. As the Arctic warms, the push for industrial development is on the rise, increasing the risk of disturbances to this critical habitat.