Scotia Sea Islands Tundra

Category: Grassland, Tundra, and Human Biomes.

Geographic Location: South Atlantic and Antarctic Oceans.

Summary: This harsh environment supports significant seabird, seal, and penguin populations that have slowly recovered from losses due to the commercial sealing and whaling industries.

The Scotia Sea Islands are comprised of the South Georgia, South Sandwich, South Orkney, South Shetland, and Bouvet Islands. All are territories of the United Kingdom except for Bouvet Island, which is a Norwegian possession. The islands’ terrain ranges from cold, inhospitable rocky cliffs and ice sheets to lower, warmer areas heated by volcanic activity. These islands share environmental and biological characteristics, but also present their own unique habitats.

South Georgia Island is one of the largest and most biodiverse of all the islands. It has no permanent human settlements, but the area does have several scientific observatories. The most significant disruptions to the ecosystem have come from the commercial sealing, whaling, and fishing industries. These island groups are dispersed over a wide area, but in general are some 1,000 miles (1,600 kilometers) east of the southern tip of South America, and 600–800 miles (965–1,300 kilometers) northeast of the Antarctic Peninsula.

The Scotia Sea Islands lie in the South Atlantic and Southern (Antarctic) Oceans between South America and Antarctica. The islands are located south of the Antarctic convergence, a biological marker cordoning off the cold Antarctic waters and their harsh environments. The Scotia Sea is approximately 350,000 square miles (906,496 square kilometers) in area; it was named for a ship of the 1903 Scottish National Antarctic Expedition that visited the region.

The Scotia Sea Islands tundra is linked with the Antarctic and sub-Antarctic climate zones. Many of the islands are partially or fully covered in ice fields, snow, or glaciers either permanently or for much of the year. A cold, stormy, windy climate and widespread cloud cover dominate, with little seasonal variation.

The Scotia Sea Islands sit above the Scotia Ridge and are of mixed continental and volcanic origins; the volcanic islands here represent the Antarctic region’s only undersea volcanic arc. The South Sandwich Islands consist of 12 main islands and several smaller islets; they have experienced relatively recent volcanic activity. Bouvet Island, small and isolated, contains an inactive volcano. The South Orkney Islands consist of four main islands, several smaller islets and offshore rocks, and a few coastal freshwater lakes. The South Shetland Islands feature 11 main islands. The larger, mountainous South Georgia Island has an area of 1,450 square miles (3,755 square kilometers), as well as several offshore rocks.

Biodiversity

The harsh environment of the Scotia Sea Islands ecosystem supports only primitive flora and a few native species of land birds. South Georgia Island has one of the region’s most diverse habitats; the main flora of this tundra ecosystem consists of various mosses, lichens, algae, and liverworts. Other vegetation types include Antarctic hairgrass, fescue grass, coastal tussock grasslands, peat bogs, and feldmark.

There is an absence of native land mammals, reptiles, and amphibians. Invertebrate populations include arthropods, earthworms, mollusks, spiders, beetles, flies, and nematodes. Nonnative species successfully introduced into the ecosystem include only rats and reindeer, the latter growing to a population of several thousand since their introduction in the early 20th century. These and other, less successful, exotic species continue to alter the native habitats.

The deep ocean waters surrounding the islands support seabird, penguin, seal, and whale populations; they also harbor productive kelp beds, fish, and squid. Several species of seabirds, penguins, and seals visit the islands regularly, with some species establishing onshore breeding grounds and rookeries. Seabirds include several species of albatross, pigeon, petrel, prion, shag, and tern. Penguin species include the king, chinstrap, macaroni, gentoo, Adelie, and rockhopper penguins. Seal species include the Antarctic fur, sub-Antarctic fur, leopard, Weddell, southern elephant, and crabeater seals. South Georgia Island houses two endemic (found nowhere else) bird species: the South Georgia pintail duck and the South Georgia pipit.

Effects of Human Activity

Although the harsh environment of the Scotia Sea Islands has discouraged permanent human habitation, humans have significantly affected the ecosystem. The British and United States sealing industries flourished in the region in the 18th century, hunting the Antarctic fur seal for its hide and the elephant seal for its oil-rich blubber. The populations of both types of seals were decimated.

The whaling industry led to declining cetacean populations in the 20th century. Seal and whale populations slowly recovered, but faced new challenges and population declines in the late 20th and early 21st centuries. The commercial fishing industry threatens seals, as well as seabirds such as the albatross, through food competition, entanglement in fishing nets and lines, ocean debris and pollution, and overfishing.

Scientific interest in the region, most notably South Georgia Island, has resulted in the establishment of a British Antarctic Survey base, fisheries laboratory, and weather station on tiny Bird Island, off the tip of South Georgia. Disputes between Argentina and Great Britain over regional possessions such as the Falkland Islands led to the establishment of a British military station on South Georgia Island.

National and international legislation has protected the ecosystem’s seal populations since the mid-20th century. Examples include the Convention for the Conservation of Antarctic Seals and the Antarctic Treaty. The environmental movement of the late 20th century furthered efforts to protect the ecosystem, including the preservation of South Georgia, South Sandwich, and Bouvet Islands as nature reserves. There is limited tourism to South Georgia Island, most of which is restricted by permit.

While the climate of the region is clearly cold and inhospitable to a wide range of species—plant, fish, and mammal—warming air and sea temperatures resulting from global climate change have been recorded in this remote corner of the world. The amount and thickness of ice in the frozen waters has declined. The long-term impact as far as precipitation and temperature is unclear, but sea-level rise certainly poses challenges to the littoral, intertidal, and coastal habitats around the Scotia Sea Islands.

Bibliography

Coad, Lauren, Neil D. Burgess et al. “Progress Towards the Convention on Biological Diversity Terrestrial 2010 and Marine 2012 Targets for Protected Area Coverage.” United Nations Environment Programme World Conservation Monitoring Centre. http://www.unep-wcmc.org/progress-towards-the-cbd-terrestrial-2010-and-marine-2012-targets-for-protected-area-coverage‗272.html.

Hogg, Oliver, and Marta Soffker. "New Research Sheds Light on Marine Biodiversity of South Sandwich Islands." Marine Science Blog UK Government, 30 Aug. 2022, marinescience.blog.gov.uk/2022/08/30/new-research-sheds-light-on-marine-biodiversity-of-south-sandwich-islands/. Accessed 31 Aug. 2022.

Procter, D. and L. V. Fleming, eds. Biodiversity: The UK Overseas Territories. Peterborough, United Kingdom: Joint Nature Conservation Committee, 1999.

Watson, G. E., J. P. Angle, and P. C. Harper. Birds of the Antarctic and Sub-Antarctic. Washington, DC: American Geophysical Union, 1975.