|Biosphere Reserve Information|
|General Description||Macquarie Island is a fully protected area under Tasmanian jurisdiction in the southern ocean/sub-Antarctic/Antarctic region. The terrestrial flora and fauna of the biosphere reserve, together with the marine flora and fauna of the surrounding ocean have similarities with species ranging in distribution from Antarctica through to the Australasian region. Its isolation and the short geological time (600,000 years) since its emergence above sea level demonstrate the colonization of a site by long distance dispersal and ongoing evolution with several endemic species. Many of the island’s marine mammals and seabirds spend most of their lives at sea, in areas ranging from the Antarctica coast to the North Pacific Ocean. The Reserve together with other breeding sites provides a rare opportunity to monitor the status of these wide-ranging species, and indirectly the health of the oceans in which they forage. Programme are being carried out to monitor the status of albatross, penguin and seal species and to link findings with other remote breeding locations. Work is also being carried out to control and or eradicate exotic species in order to protect endemic species. The Macquarie Island Biosphere Reserve has no resident population and is remote from population centers, a factor common to all sub-Antarctic and Antarctic locations.|
|Major ecosystem type||Tundra communities and barren arctic desert; island; coastal component|
|Major habitats & land cover types||
Five main vegetation formations have been described, tall-tussock grassland, short tussock grassland (herbfield), fen, bog and feldmark. While the distribution of these formations generally reflects the island’s topography introduced European rabbits have severely modified some of them. There being no trees tall-tussock grassland is the tallest vegetation on the island, up to 2m in places, and provides considerable shelter to breeding birds of several species, as well as microclimates for other organisms. Rabbit grazing destroyed large areas of this formation, resulting in modified short tussock grassland formations. The latter has also been greatly modified although several of its vascular flora species have benefited from rabbit grazing. It is dominant in moderately exposed sites which are not wet enough to produce fen and bog formations.
Tall-tussock grassland occupies less exposed, drained sites on coastal flats and slopes as well as inland valley bottoms and sides to over 200 m a.s.l.; short tussock grassland (herbfield) dominant in moderately exposed sites which are not wet enough to produce fen and bog formations. Several salt tolerant vascular species become dominant along the coastal margins and on offshore seastacks around the high-energy shoreline, while fen and bog formations dominate wet valley bottoms and raised beach terraces along some coastal margins. Feldmark formations on the exposed summit plateau, cover around 50% of the island, the ground cover varies from 5% to over 50% and is dominated by the endemic, cushion forming Azorella macquariensis in the more sheltered sites and increasingly by cushion forming mosses as the wind exposure increases; lakes, pools and mires are abundant. Some smaller species of burrow-nesting seabirds breed in the larger cushions.
In the closed fen and bog formations decomposition rates are slow with peat beds being over 6m deep in places. An endemic orchid is found in these formations. Small patches of sphagnum moss have been rapidly increasing in area in recent years, which has been attributed to global warming.
Introduced vertebrate pests have greatly modified habitats on the island since its discovery in 1810. Rabbits have modified the vegetation (above) while the decimation of burrow-nesting seabird colonies by feral cats has greatly reduced massive, localised nutrient inputs. The impacts which ship rats, house mice and Wekas (a flightless New Zealand bird) have had on nutrient cycles, by feeding extensively on the indigenous vertebrate fauna, is unknown.
Soil types have been classified as highmoor, fen, and bog peats, and dry land cover types: tundra soils. However the Macquarie Island soils differ from these groups elsewhere in that they have been formed under extreme oceanic, as opposed to continental, climatic conditions. Lakes, pools and mires are abundant, but large areas of the island, especially along western stretches of the plateau, are dry. The ionic composition of most lakes reflect oceanic influences on the reserve. Many lakes lack streams to feed them and/or outflowing streams, explained by the porous nature of the rock and dipping rock strata.
|Location||54°30' to 54°47'S; 158°48' to 158°57'E|
|Transition area(s) when given|
|Altitude (metres above sea level)||0 to +433|
|Administrative authorities||Tasmanian Department of Primary Industries, Water and Environment|
|Last updated: 12/1/2010|