Heard Island

  • overview
  • geography
  • history
  • fauna & flora
  • further reading

OVERVIEW

Lying deep in the South Indian Ocean, Heard Island and McDonald Island are closer to Antarctica than any other major landmass, and have traditionally been the preserve of researchers and scientists. Their remoteness and status as a Federal Nature Reserve and World Heritage site have ensured the islands are visited only by the fortunate few.

Heard Island is the home of Big Ben, Australia's highest mountain and only active volcano. At 2,745 metres, this snow covered monolith is an impressive 517 metres higher than Mt Kosciuszko. Heard also enjoys the unique human history associated with discovery, sealing and Australia's first Antarctic Research Station. Fortunately the human impact of these few visitors was minimal, and today the island is one of the few in the world that is largely as nature intended.

Penguins are by far the most abundant birds. King, Gentoo, Macaroni and Rockhopper Penguins all breed there in large, noisy colonies. In the skies above there are prions, petrels and the kings of the wind, several species of albatross. Other wildlife highlights include Antarctic Fur Seals, Southern Elephant Seals and Subantarctic Fur Seals.

 

GEOGRAPHY

Heard Island and the McDonald Islands are located on the relatively shallow (less than 1000m deep) central part of the submarine Kerguelen Plateau. The islands collectively comprise one of two (with the Isles of Kerguelen) surface exposures of the plateau which, with an area of approximately two million square kilometres, is one of the largest submarine plateaus on earth. The Kerguelen Plateau began to form approximately 115 million years ago. Recent geological investigations suggest a formative period extending over 80 million years, with the formation of Heard Island commencing approximately 45-50 million years ago and continuing to this day.

Heard Island essentially consists of two oval shaped regions connected by an extensive, low gravel isthmus near Atlas Cove. The main part of the island is dominated by Big Ben, a massive volcanic cone between 18 and 20 km in diameter that rises to a height of 2745m at Mawson Peak, and sits above a large ice covered plateau. The smaller oval of Laurens Peninsula (about 8km long and 6km wide) rises to 715m at Anzac Peak and contains three main snow capped peaks. The eastern end of the island terminates in Elephant Spit, a changeable sand and gravel feature affected by the prevailing easterly ocean currents, which extends offshore for approximately 10km.

The McDonald Islands appear to be an uplifted and eroded portion of a shallow submarine volcano and is composed of phonolitic lava, very different from that which characterises Heard Island.

The substantial glaciation of Heard Island and periods of glacial advance and retreat, in keeping with climate change, have resulted in the occurrence of widespread erosional and depostional landforms. Erosional features include glacial valleys, ice-abraded bedrock surfaces, trough heads, rock bars, cirques, cols and horns.

The islands are constantly exposed to vigorous westerly ocean waves generated by the 'furious fifties', resulting in the presence of wide spread erosional and depositional coastal landforms. Persistent wave action has produced the steep cliffs found around much of Heard Island, with the coastline in some areas punctuated by steep beaches of sand, shingle, cobbles and boulders, as well as bars and spits resulting from the drift alongshore of substantial quantities of glacial and volcanic sediment.

 

HISTORY

Although the nearby Iles Kerguelen were frequently visited by sealing vessels from the 1770s and there was shipping activity in the southern Indian Ocean since before 1800, Heard Island and the McDonald Islands remained unknown until the mid 1800s. Captain Peter Kemp of the sealing vessel Magnet may have sighted land in the vicinity of Heard Island in 1833. However the discovery of Heard Island is attributed to Captain John Heard on the merchant vessel Oriental. Captain Heard made a confirmed sighting of the island on 25 November 1853 when travelling from Boston to Melbourne on a newly recommended, more southerly, 'great circle' route. The McDonald Islands were discovered on 4 January 1854 by Captain W. McDonald on the Samarang.

Within a few years of discovery, sealing operations had commenced at numerous locations around the Heard Island coast. The first landing was by a sealing expedition at Try Pot Beach on 15 February 1855. More than 40 vessels made over 100 voyages to Heard Island seeking 'sea-elephant' (Southern Elephant Seal) oil in the three decades following the island's discovery. The highest level of human activity ever at the island occurred during the sealing period from 1855-1882, with production of seal oil and visitation peaking in 1857-1859 and declining thereafter.

Five scientific visits are known from the late 19th and early 20th centuries, with brief visits by the Challenger and the Arkona in 1874, the German South Polar Expedition in 1902, and in 1929 by a French mineral prospecting expedition and the British, Australian and New Zealand Antarctic Research Expedition (BANZARE) led by Douglas Mawson.

No further visits to Heard Island are known until the establishment of the Australian National Antarctic Research Expedition (ANARE) station at Atlas Cove in December 1947. The station was occupied between December 1947 and March 1955, providing a base for extensive scientific activities on the island throughout that period.

The United Kingdom formally established its claim to Heard Island in 1910, marked by the raising of the Union Jack and the erection of a beacon by Captain Evensen, master of the Mangoro. Effective government, administration and control of Heard Island and the McDonald Islands was transferred to the Australian Government on 26 December 1947 at the commencement of this ANARE to Heard Island, with a formal declaration that took place at Atlas Cove. The transfer was confirmed by an exchange of letters between the two governments on 19 December 1950.

Three summer expeditions by the Australian Antarctic programme occurred between 1985 and 1989. There was a brief midwinter visit in 1990, an overwinter expedition in 1992 and summer expeditions in 2000/01 and 2003/04.

The first recorded landing on the McDonald Islands occurred by helicopter in 1971 with the second almost a decade later in 1980.

 

 

FAUNA & FLORA

Low growing herbaceous flowering plants and bryophytes are the major components of vegetation on Heard Island. The vascular flora is comprised of the smallest number of species of any major subantarctic island group, reflecting its isolation, small ice-free area and severe climate. Twelve vascular species are known from Heard Island of which five have also been recorded on McDonald Island. Bryophytes (mosses and liverworts) and lichen contribute substantially to overall biodiversity to Heard Island with 62 bryophyte species and 71 lichen species recorded. The low plant diversity most likely reflects the island's isolation, small size, severe climate, the short, cool growing season, and for Heard Island in particular, permanent ice cover. Ongoing volcanic activity regularly alters the distribution and abundance of the vegetation dramatically.

Heard and McDonald Islands are free from introduced predators and provide a crucial breeding habitat in the middle of the vast Southern Ocean for a range of birds. The surrounding waters are important feeding areas for birds and some scavenging species also derive sustenance from their co-habitants on the islands.

Penguins are by far the most abundant birds on the islands, with four breeding species present, comprising of king, gentoo, macaroni and rockhopper penguins. The penguins mostly colonise the coastal tussock and grasslands of Heard Island and have previously been recorded as occupying the flats and gullies on McDonald Island.

Other seabirds recorded as breeding at Heard Island include three species of albatross (wandering, black-browed and light-mantled sooty), southern giant petrels, cape petrels, four species of burrowing petrels (Antarctic and fulmar prions, common and South Georgian diving petrels), Wilson's storm petrels, kelp gulls, subantarcic Skuas, Antarctic terns and Heard Island cormorant. Although not a true seabird, the Heard Island sheathbill also breeds on the island.

There are three breeding species of seals on these islands: the Antarctic and Subantarctic fur seals and the southern elephant seal. The breeding population of Antarctic fur seals has increased dramatically since their decimation at the hands of sealers in the nineteenth century. Their predominant diet is fish and in particular mackerel icefish. Southern elephant seals are the largest seals in the world; males can weigh up to 4000 kg while females may reach 900 kg and their life expectancy may exceed 20 years. They are by far the most abundant seal on Heard Island, coming ashore to breed and moult. Leopard seals are the most commonly occurring non-breeding seal species visiting the island which serves as a major wintering area for the species.

Cetacean records for the region are sparse due to lack of survey effort, but the waters are known to be of high productivity and importance to these animals. Species observed at sea around Heard and McDonald Islands include the blue whale, orca, humpback whale, long-finned pilot whale, southern bottlenose whale, sperm whale, Minke whale, dusky dolphin and southern right whale.

 

FURTHER READING

Meyer, L., Constable, A. & Williams, R. 2000. Conservation of marine habitats in the region of Heard Island and the McDonald Islands. Australian Antarctic Division, Department of the Environment and Heritage, Kingston.

Downes, M. 2002. First Visitors to Heard Island. ANARE Research Notes. Australian Antarctic Division, Department of the Environment and Heritage.

Quilty, P.G. & Wheller, G. 2000. Heard Island and the McDonald Islands: a window into the Kerguelen Plateau. Pap. Proc. R. Soc. Tasm, 133

 

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