Arctic fauna

The Arctic is the northernmost region of the Earth, centered on the North Pole. The arctic landscape is mainly tundra. This frozen ground lies above the tree line and is covered with hearty plants, such as moss and lichen, from which caribou and musk ox feed. Arctic temperatures can be as low as -30 degrees Fahrenheit in the winter and as warm as 54 degrees Fahrenheit in the summer. Some interior regions can become much warmer. Due to its extreme northern latitude, the Arctic gets varying amounts of sunlight at different times of the year. Precipitation is very low, with an average annual rainfall of only between 5 and 10 inches.

Besides extreme fluctuations between summer and winter temperatures, the arctic landscape contains permanent snow and ice in the high country; grasses, sedges, and low shrubs in the lowlands; and permafrost in almost all locations. The permafrost limits drainage and retains moisture for plant growth within the active layer. This can result in wetland formation, as occurs in level areas of the coastal plains of the Arctic. Here, extensive wetlands are home to aquatic vegetation, invertebrate fauna, waterfowl, and shorebirds. The plant growth season is usually around 105 days. However, plants take advantage of constant sunlight in the summer months, enabling them to optimize photosynthesis without the usual nighttime respiration cost.

Arctic Fauna

Arctic ecosystems lack the diversity and richness of species that characterize temperate or tropical ecosystems. Animal and plant species decline in number with increasing latitude. Vertebrate species of the Arctic are limited to around twenty species of mammals and more than one hundred species of birds. Most are closely related species, such as the caribou of North America and the reindeer of Eurasia. This similarity in arctic mammalian fauna results from the lower sea levels of the Pleistocene glaciations, when a broad land connection, known as the Bering Land Bridge, connected present-day Alaska and Siberia. Some arctic mammalian fauna, primarily herbivores and carnivores, rarely occur outside the Arctic and have adapted to life in this environment. Other fauna, such as species of ground squirrels, voles, shrews, red fox, ermine, wolverine, wolf, and brown bear, are common to other ecosystems but are distributed widely throughout the Arctic.

Wet sedge meadows often associated with lake margins, estuaries, and seacoasts are favored nesting habitats for millions of migrating waterfowl and shore birds during the summer months in arctic regions. In addition to shorebirds and waterfowl, finches, buntings, and sparrows are the most abundant species nesting in the Arctic. Terrestrial, avian fauna of the Arctic include only a few resident species, among them the ptarmigan, snowy owl, gyrfalcon, and raven. Nonresident species include raptorial birds that commonly nest in the Arctic, such as the peregrine falcon, rough-legged hawk, short-eared owl, the golden eagle, and the white-tailed eagle. These remaining species are present in the Arctic only in summer to breed and rear young, migrating to southern latitudes during winter.

A wide range of marine mammals and fish live in the severe conditions of the Arctic Ocean. Whales, dolphins, walruses, and six species of seals make their home in this northern polar region, which is covered by ice most of the year.

Threats to the Arctic

Human activity has exercised a strong influence on the wildlife of arctic regions. Polar bears, walrus, musk ox, and caribou have been greatly reduced in numbers through hunting alone. This danger was recognized in 1973 when protective legislation was approved for the polar bear. Still, species diversity continues to decrease at an alarming rate in the twenty-first century, and measures to protect the wildlife of the Arctic must be taken. Other threats to the health and biodiversity of the Arctic include anthropogenic global climate change due to oil and gas drilling, mining, overfishing, and shipping routes. These human-induced threats have put the Arctic ecosystem and its inhabitants at risk. Invasive species have also threatened the delicate balance of fauna in the Arctic region. Organizations, such as Greenpeace and the World Wildlife Fund, advocate for global treaties, conservation frameworks, and increased public awareness of the threats to the Arctic. The Arctic Council is an intergovernmental body that focuses on protecting the Arctic environment with the cooperation of Arctic states and Indigenous peoples. 

Principal Terms

Adaptation: The processes of change in a living organism that enable it to adjust to the conditions of the environment in which it lives

Arctic: The surface of Earth lying above 66.5 degrees North latitude, including the Arctic Ocean between North America and Russia

Permafrost: Any soil in the arctic regions in which temperatures below freezing have existed continuously for a long time

Tundra: A treeless, level, or gently rolling plain of the Arctic region; characterized by a marshy surface from which mosses, lichens, and low shrubs grow

Bibliography

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