Reindeer in South Georgia are an example of an animal which has been introduced outside its native range. The reindeer

Reindeer

The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one has already gone extinct.Reindeer vary considerably in color and size...

, a species of deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 adapted to arctic

Climate of the Arctic

The climate of the Arctic is characterized by long, cold winters and short, cool summers. There is a large amount of variability in climate across the Arctic, but all regions experience extremes of solar radiation in both summer and winter...

 and subarctic climate

Subarctic climate

The subarctic climate is a climate characterized by long, usually very cold winters, and short, cool to mild summers. It is found on large landmasses, away from the moderating effects of an ocean, generally at latitudes from 50° to 70°N poleward of the humid continental climates...

s, was introduced to the subantarctic

Subantarctic

The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...

 island of South Georgia by Norwegian

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 whalers in the early 20th century. The reason for the introduction was to provide both recreational hunting

Hunting

Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...

 and fresh meat for the numerous people working in the whaling

Whaling

Whaling is the hunting of whales mainly for meat and oil. Its earliest forms date to at least 3000 BC. Various coastal communities have long histories of sustenance whaling and harvesting beached whales...

 industry on the island at the time. Since then, although the people have departed, the reindeer population, in two geographically separated wild herds, has increased to the point where their presence is causing environmental damage and has led to a decision to eradicate them.

History

The first introduction was made by the brothers C.A.

Carl Anton Larsen

Carl Anton Larsen was a Norwegian Antarctic Explorer, who made important contributions to the exploration of Antarctica, the most significant being the first discovery of fossils, for which he received the Back Grant from the Royal Geographical Society...

 and L.E. Larsen in November 1911. Three males and seven females from Hemsedal

Hemsedal

Hemsedal is a municipality in Buskerud county, Norway. It is part of the traditional region of Hallingdal. The administrative centre of the municipality is the village of Trøym. In 1897, Hemsedal was separated from the municipality of Gol to become a municipality of its own.Hemsedal is the...

 in southern Norway were released at Ocean Harbour

Ocean Harbour

Ocean Harbour is a deeply indented bay on the north coast of South Georgia which is entered west-northwest of Tijuca point. It was an active whaling station between 1909–1920...

 (then the site of an active whaling station) on the Barff Peninsula

Barff Peninsula

Barff Peninsula is a peninsula forming the east margin of Cumberland East Bay, South Georgia, extending northwest from Sörling Valley to Barff Point. It was probably first seen by the British expedition under James Cook in 1775. The peninsula takes its name from its northern extremity, Barff Point....

, on the northern coast of South Georgia. These formed the basis of what came to be called the Barff herd which, by 1958, had increased to 3000 animals. A 1976 population estimate of 1900 head indicated subsequent decrease, though with some range expansion to Royal Bay

Royal Bay

Royal Bay is a bay, 4 miles wide and indenting 5 miles , entered between Cape Charlotte and Cape Harcourt along the north coast of South Georgia....

.

A second introduction was made in 1912 by the Christian Salvesen Company. Two male and three female reindeer were left at Leith Harbour

Leith Harbour

Leith Harbour , also known as Port Leith, was a whaling station up on the northeast coast of South Georgia, established and operated by Christian Salvesen Ltd, Edinburgh. The station was in operation from 1909 until 1965. It was the largest of seven whaling stations, situated near the mouth of...

 on the Busen Peninsula in Stromness Bay

Stromness Bay

Stromness Bay is a bay wide, entered between Cape Saunders and Busen Point on the north coast of South Georgia.Stromness Bay, like Leith Harbour takes its name from a location in Scotland, Stromness, on the Orkney Mainland...

, also on the north coast of the island. By 1918 they had increased to 20 animals, but the entire herd was killed by an avalanche

Avalanche

An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...

 that year.

The third introduction took place in 1925; three males and four females were released at Husvik Harbour

Husvik

Husvik is a former whaling station on the north-central coast of South Georgia Island. It was one of three such stations in Stromness Bay, the other two being Stromness and Leith Harbour. Husvik initially began as a floating, offshore factory site in 1907. In 1910, a land station was constructed...

 in Stromness Bay. These became the nucleus of the Busen herd, the numbers of which increased slowly to 40 in 1953 before climbing rapidly to about 800 head by the early 1990s. The source of the animals was the same as that of the Barff herd.

The Barff herd was relatively isolated from human access and increased rapidly in size before it outgrew its resources and declined in numbers. The Busen herd, however, was much more accessible to the human population of South Georgia; its size was kept relatively low by regular hunting until whale processing declined and came to an end.

Since the whaling industry ended in the 1960s, and those employed by it departed, South Georgia has been largely depopulated except for a small military presence, visiting scientists and occasional tourists from cruise ships or private yachts. Little hunting or any other human control of the reindeer has occurred. The two herds, separated by glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

s terminating in the ocean and isolated from other ice and snow free areas, comprise some 2600 animals occupying 318 km², one third of the total vegetated area, and thus potential grazing habitat, of the island.

Biology

Rutting

Rut (mammalian reproduction)

The rut is the mating season of ruminant animals such as deer, sheep, elk, moose, caribou, ibex, goats, pronghorn and Asian and African antelope....

 peaks between the 20th and 30th of March, with calves being born in November. Males become sexually mature at 4-8 months old and females can first conceive at 16-17 months. The mean generation length is 4.2 years, with males having an average 7-8 year, and females an 11-12 year, lifespan, with annual mortality of 30-40%. The main limiting factor in the population is the availability of winter forage; as well as starvation, a significant cause of mortality is falls from cliffs while trying to access ungrazed areas.

Environmental impact

The population density of the reindeer in South Georgia is generally much higher than in their native range. In the Svalbard

Svalbard

Svalbard is an archipelago in the Arctic, constituting the northernmost part of Norway. It is located north of mainland Europe, midway between mainland Norway and the North Pole. The group of islands range from 74° to 81° north latitude , and from 10° to 35° east longitude. Spitsbergen is the...

 archipelago in the Arctic, reindeer density is about 5/km², while 7/km² is considered a safe stocking rate for winter range. In South Georgia, although densities vary, values ranging from 40/km² to 85/km² have been recorded.

The areas occupied by reindeer on South Georgia are the most vegetated and biologically diverse on the island. The impact of the animals has been severe, resulting in overgrazing

Overgrazing

Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, or by overpopulations of native or non-native wild animals.Overgrazing reduces the...

 of the native Tussac Grass

Poa flabellata

Poa flabellata , called Tussac Grass, is a species of tussock grass native to southern South America and the Falkland Islands. It has been introduced into Scotland as a source of fodder because of its ability to grow in hostile conditions...

 and Greater Burnet

Acaena magellanica

Acaena magellanica, commonly called Buzzy Burr or Greater Burnet , is a species of flowering plant whose range includes southern South America and many subantarctic islands....

, soil erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

, loss of plant community biodiversity

Biodiversity

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

 and the spread of invasive

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 weed

Weed

A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...

s, such as the introduced grass Poa annua

Poa annua

Poa annua, or annual meadow grass , is a widespread low-growing turfgrass in temperate climates. Though P. annua is commonly considered a solely annual plant due to its name, perennial bio-types do exist. 'Poa' is Greek for fodder. It is one of the sweetest grasses for green fodder, but less ...

which is better able to sustain grazing than the native flora.

Because of the environmental damage caused by the reindeer, and the danger that glacial retreat

Retreat of glaciers since 1850

The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and in the longer term, the level of the oceans...

 caused by global warming

Global warming

Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...

 will allow the reindeer to extend their range to other areas of the island, their permanent eradication has been proposed, with an announcement of intention being made on 19 February 2011. In order to preserve their genetic resources, and in order to help diversify agriculture in the Falkland Islands

Falkland Islands

The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...

, a translocation of 59 South Georgian reindeer calves (26 males and 33 females) from the Busen herd to the Falklands was undertaken in 2001 by the Falkland Island Government to establish a commercial herd there. Their first offspring were produced in 2003.

Other southern introductions

Few introductions of reindeer to places in the southern hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 have been carried out. An attempted introduction in the late 1940s to southern Argentina failed when the animals were subsequently killed. An attempt to translocate animals from South Georgia to Isla Navarino, Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, failed when seven of the eight animals being transported died on the sea voyage. Apart from South Georgia, the only other successful introduction was in 1954 to the subantarctic Kerguelen Islands

Kerguelen Islands

The Kerguelen Islands , also known as the Desolation Islands, are a group of islands in the southern Indian Ocean constituting the emerged part of the otherwise submerged Kerguelen Plateau. The islands, along with Adélie Land, the Crozet Islands and the Amsterdam and Saint Paul Islands are part of...

, a French territory in the southern Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

, with ten reindeer from Swedish Lapland, which had increased by the 1970s to a population of about 2,000.