Fauna of Antarctica
The fauna of Antarctica is characterized by its extreme conditions and limited biological diversity, shaped by a long history of geological change and isolation. Once a fully vegetated land, Antarctica has transformed into a largely ice-covered continent that supports only a few hardy terrestrial species, primarily invertebrates like nematodes, tardigrades, and some moss-dwelling protozoans. In contrast, the surrounding seas teem with life, including seals, whales, and a variety of seabirds that rely on marine food chains. The sub-Antarctic and cool temperate islands offer greater biodiversity due to their milder climates and more complex ecosystems, which include higher plant life leading to a richer array of animal species.
However, the Antarctic ecosystem faces significant threats from human activities, such as the introduction of invasive species and the impacts of climate change, including rising temperatures and melting ice. These challenges further complicate the survival of native species and the delicate balance of this unique environment. Overall, while Antarctica presents a harsh habitat for its fauna, the adaptations of its species and the richness of its surrounding marine life highlight the continent's ecological significance.
Subject Terms
Fauna of Antarctica
The history of life in the Antarctic is fascinating, largely because, in geologic terms, Antarctica has been very different from the way it is in the twenty-first century. For much of Antarctic history, the continent was fully vegetated and carried all the animal life that depends on plants for a living. This is very different from its state in the twenty-first century. Antarctica’s gradual glaciations and long isolation from other continental landmasses have impeded the establishment and development of land-based flora and fauna. Other significant factors have hampered terrestrial biotic evolution in Antarctica, including the harsh climate, the ice cover, and the limited number of ice-free land areas. Consequently, the terrestrial flora and fauna of Antarctica are few.
The Antarctic is an extreme environment for any organism to survive in. Yet, both marine and terrestrial habitats of the Antarctic contain fauna that have adapted to the extreme conditions to utilize available resources effectively. Generally speaking, Antarctic regions lack a wide array of faunal diversity due to a lack of habitat. The sub-Antarctic and cool temperate islands have much greater diversity, including shrubs and trees. With this higher plant life comes a correspondingly complex array of animal life. The sub-Antarctic and cool temperate islands also possess high levels of endemism due to their long-standing geographical and ecological isolation from each other and the surrounding continental landmasses.
Antarctic Fauna
The terrestrial fauna consists of a few invertebrate species of protozoans, rotifers, nematodes, tardigrades, collembola, and a species of mite. These life forms are restricted mainly to moist beds of moss. The diversity of marine mammals and birds in the coastal areas and associated pack ice is dependent on marine food chains in the adjacent seas. Because of the vast ice, the continent supports only a small population of cold-adapted land plants and animals. The surrounding sea is as rich in life as the land is barren. The marine life in the seas surrounding Antarctica include seals, sea lions, whales, and orcas.
The resources of Antarctic and sub-Antarctic waters also support vast numbers of various seabirds, which play an essential role in the marine ecosystem. Nesting grounds are limited, confined to the scattered sub-Antarctic islands and ice-free localities during the summer on the Antarctic continent and Antarctic Peninsula.
Few terrestrial vertebrates are resident in Antarctica, and those that do occur are limited to sub-Antarctic islands. There are no naturally occurring mammals, reptiles, or amphibians. However, humans have deliberately or accidentally introduced a range of animals, such as rats, mice, fish, chickens, rabbits, cats, pigs, sheep, cattle, and reindeer, to the sub-Antarctic, many impacting native species. Terrestrial animals of the sub- and maritime Antarctic include arthropods, earthworms, and mollusks. Higher insects include spiders, beetles, and flies, most confined to the less severe areas. Microinvertebrate groups, such as nematodes, tardigrades, and rotifers, are also numerically well represented. The terrestrial fauna of the severe areas of the Antarctic continent are even more simplified. No higher insects are present; the smallest arthropods are restricted to limited areas of vegetation. Instead, groups such as nematodes become dominant. In the most extreme continental cold deserts, simple food webs consist of as few as one to three nematode species, only one of which may be predatory.
Threats to the Antarctic
Much of the Antarctic bears the distinctive imprint of human modification, particularly by deliberately introducing animal pests and predators. The introduced mammals, notably rodents, cats, rabbits, sheep, cattle, and reindeer, are of particular concern as they are invasive species. There have been several cases of successful eradication of alien mammals from islands, and such efforts continue in the twenty-first century. This is important since islands are vital breeding and resting grounds for seabirds. The fauna of Antarctica faces additional threats as well. Global climate change has caused warming temperatures, melting sea ice, and ocean acidification, altering the environment of native species. Human activities have also caused pollution and habitat destruction.
Principal Terms
Antarctica: The continent surrounding the South Pole, almost entirely covered by an ice sheet
Collembola: Primitive, wingless insects
Higher Insects: Generally larger insects with increasing levels of morphological complexity
Pack Ice: Floating islands of ice that form flows measuring from a few feet wide to ice islands miles across
Sub-Antarctic: Antarctic landmasses of lesser southern latitude exhibiting more moderate climatic conditions
Bibliography
Boyall, Laura. "Wildlife of Antarctica." Antarctic Glaciers, www.antarcticglaciers.org/antarctica-2/introductory-antarctic-resources/wildlife-of-antarctica. Accessed 20 Aug. 2024.
Di Prisco, G., E. Pisano, and A. Clarke Milano. Fishes of Antarctica: A Biological Overview. Springer, 1998.
Mohammad, Arif. "Animal Life in the Antarctic: The Seventh Continent." Journal of Applied Zoological Research, vol. 4, no. 1, 1993, pp. 13-20.
Lohan, Tara. "Antarctica's Looming Threat." The Revelator, 4 Jan. 2024, therevelator.org/antarctica-invasive-species. Accessed 20 Aug. 2024.
Murphy, E., and J. King. "Icy Message from the Antarctic." Nature, vol. 389, no. 6646, 1997, pp. 20-21.
Phillips, Lauren, and Rachel Leihy. "Toughness Has Limits: More than 1,100 Species Live in Antarctica, but They're at Risk from Human Activity." Phys.org, 4 May 2022, phys.org/news/2022-05-toughness-limits-species-antarcticabut-theyre.html. Accessed 25 June 2023.
Sayre, A. P. Antarctica. Twenty-First Century Books, 1998.
Stone, L. M. Birds of Antarctica. Rourke, 1995.