Heard and MacDonald Islands

The Heard Island and McDonald Islands group was formed by the plume type of volcanism, a process that is poorly understood in comparison with the earth’s other two main volcanic types – subduction and seafloor spreading. This feature of the group offers an extraordinary view into the earth’s deep interior and its interactions with the lithospheric plates that resulted in the formation of the ocean basins and continents. They are the only sub-Antarctic islands that are volcanically active. The last recorded major eruption on Big Ben, which soars to an altitude of 2,745 metres, was in 1992. However, continuous activity is evident from other observations of minor steam and smoke emissions. Permanent snow and ice cover 70 per cent of Heard Island. Its steepness, combined with significant snow fall at high altitudes, makes the glaciers fast-flowing – in the order of 250 metres a year. As a result, the ice and snow in the glaciers have a relatively short turnover period of around 100 years, and the glaciers respond quickly to changes in climate by advancing or retreating. McDonald Island lies 43.5 kilometres due west of Heard Island, and is the major island in the McDonald Islands group. Satellite images taken in 2004 give evidence of significant volcanic activity over the last decade, which has seen the island increase in size from 1km2 to 2.5 km2. The previously separate Flat Island and McDonald Island are now joined by a low-lying isthmus. At its highest point, McDonald Island rises to about 230 metres. Extraordinary landforms on the islands include the flutes of Cape Pillar on Heard Island and the lonely pinnacle of Meyer Rock; the caves and other lava formations of the northern Heard Island peninsulas; the smoking caldera of Mawson Peak above the older caldera of Big Ben; the shifting sands of the Nullarbor Plain; and the extensive, dynamically changing Elephant Spit. The Heard Island and McDonald Islands group can be described as the wildest place on earth – a smoking volcano under a mantle of snow and glacial ice rising above the world’s stormiest waters. On the horizon to the west, smaller volcanic fragments rise precipitously and defiantly out of huge Southern Ocean swells. Verdant vegetation and multicoloured bird colonies contrast in sharp relief against the dazzling white of snow and ice and the grey-black of volcanic rock. The driving westerly winds above the Southern Ocean in these latitudes create unique weather patterns when they come up against the enormous bulk of Big Ben, including spectacular cloud formations around the summit and unbelievably rapid changes in winds, cloud cover and precipitation. It is the only sub-Antarctic island group believed to contain no known species directly introduced by humans. This makes it invaluable for having within one site an intact set of interrelated ecosystems – terrestrial, freshwater, coastal and marine – in which the ongoing evolution of plants and animals occurs in a natural state. The islands host a range of seabirds, and are an excellent location for investigating the effects of geographic isolation and climate on the evolution of species. Active speciation is clearly present. The beetle populations on Heard Island and McDonald Islands group show unique evolutionary adaptations to the environment, and several other invertebrate groups provide opportunities to study evolutionary processes in undisturbed populations at the southern limits of their distribution. The vast numbers of penguins (including the world’s largest macaroni penguin colony), seals and flying birds that occupy the islands are one of the great wildlife sights of the world. When the wind has died and the skies have cleared, these congregations create an incomparable cacophony of natural sound. The seal and penguin populations provide excellent opportunities to monitor the health and stability of the larger Southern Ocean ecosystem. The Heard Island and McDonald Island group is one of the best sites in the world to study the ecological and biological processes of recolonisation of the Antarctic fur seal and the king penguin populations. It is also one of the best land-based sites in the world to study the leopard seal and its role in the sub-Antarctic ecosystem. The World Heritage property is contained within the 65,000 km2 HIMI Marine Reserve, declared under the Environment Protection and Biodiversity Conservation Act 1999 in 2002. The Reserve is managed by the Antarctic Division of the Australian Government Department of the Environment, Water, Heritage and the Arts.

Government evidence of impact of climate change:

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  • Australian Government, Australian Heritage Database - Budj Bim Cultural Landscape, Portland, VIC, Australia

    The glaciers appear to be fast flowing as a result of the steep slope and high precipitation; and are likely to be particularly sensitive to climatic fluctuations.

  • Australian Government Department of Agriculture, Water and the Environment, World Heritage Places - Heard and McDonald Islands

    As a result; the ice and snow in the glaciers have a relatively short turnover period of around 100 years; and the glaciers respond quickly to changes in climate by advancing or retreating.

    Heard Island’s relatively shallow and fast flowing glaciers respond quickly to climate change; faster than any glaciers elsewhere; making them particularly important in monitoring climate change.

  • Heard and McDonald Islands Inscribed on the World Heritage List 1997

    As a result; the ice and snow in the glaciers have a relatively short turnover period of around years; and the glaciers respond quickly to changes in climate by advancing or retreating. as outstanding examples representing major stages of the earth’s history; including the record of life; significant ongoing geological processes in the development of landforms; or significant geomorphic or physiographic features Heard Island is dominated by Big Ben; Australia’s highest mountain and an active volcano; under a deep mantle of snow and glaciers.

  • Australian Government, Heard Island and McDonald Islands Marine Reserve Management Plan 2014-2024

    Climate change is likely to increase the risk of the establishment of invasive species (Chown et al. 2005).

    The effects of climate change may not be controllable or mitigated to the extent necessary to retain the Reserve’s existing natural values.

    The effects of climate change are apparent in the Reserve.

    The Reserve’s ecosystems and landscape are vulnerable to further climate change impacts; including sea level rise changes to ocean water chemistry increases in sea surface temperature and the arrival and establishment of invasive species (Australian National University 2009).

    Issues Climate change is likely to affect many aspects of the Reserve; including its physical landscape (i.e. glacial retreat and the formation of lagoons and freshwater lakes) biodiversity (i.e. changes in distribution and abundance of flora and fauna and an increased risk of the arrival and establishment of invasive species) and Background Waste generated by human activities may deleterious impact upon the Reserve’s values. have a cultural values (i.e. exposure or immersion of low lying cultural heritage sites).

    Research and monitoring activities may be impeded by severe weather and sea conditions. (c) will be conducted by a researcher with appropriate credentials and experience . (d) gives due consideration to the likely impact on the conservation status of any fauna or fora species .

  • IUCN World Heritage Outlook, Heard and McDonald Islands, 2014

    Avalanches and landslides at least partly attributable to glacier retreats from global climate change (other component from lava flows).

    Chemical changes in oceanic waters; Temperature changes High Threat Inside site Climate change artificially accelerating ecological processes and interaction in terrestrial and marine ecosystems.

    Pronounced climate change is expected to result in the establishment of new species; and changes to species’ distributions.

  • IUCN World Heritage Outlook, Heard and McDonald Islands, 2017

    Ongoing climate change poses an increasing risk to fundamental alterations in biodiversity.

    Climate change; non native species incursions and the presence of P. annua are the greatest threats to the natural values on the islands.

    Global processes such as climate change; plastic production and off shore fishing can impact on the local biota.

    The biggest and current threat to the island is sustained global climate change.

    Climate change will also increase this invasion.

    Potential biosecurity breaches (coupled with climate change) are significant threats to the natural values biodiversity and ecosystems on the islands efforts to prevent the introduction of rats and mice have been successful to date.

    Pronounced climate change is likely to increase the introduction and or spread of non native species; including disease causing organisms.

    Avalanches and landslides at least partly attributable to glacial retreats from global climate change (other component from lava flows).

    Ocean acidification; Temperature extremes High Threat Inside site Climate change is artificially accelerating ecological processes and interaction in terrestrial and marine ecosystems.

    Climate warming; changes in rainfall patterns and changes in glacial meltwater threaten the structure of the terrestrial ecosystem.

    Climate change threatens the extensive cushion carpets.

    Climate change threatens the dominant and keystone plant species on the island as well as wetlands at Spit Bay.

    Ongoing climate change poses an increasing risk to fundamental alterations in biodiversity.

    Solid Waste Data Deficient Inside site; extent of threat not known Outside site Containers; such as fuel drums and gas cylinders that have washed up on the island as marine debris; may rust and leak contents causing local contamination (IUCN Consultation; 2017).

    Coupled with known föhn winds that generate high temperatures; drought conditions are likely to occur.

    Ocean acidification High Threat Inside site; widespread(15 50 ) Outside site cean acidification is likely to adversely affect marine ecosystems more directly than terrestrial (Kawaguchi et al.; 2013).

    Indirectly; ocean acidification may alter food sources for bird and marine mammal species on the islands.

  • IUCN World Heritage Outlook, Heard and McDonald Islands, 2020

    The biggest and current threat to the island is sustained global climate change.

    The alien grass species Poa annua may be displacing native vegetation on Heard Island; especially colonising newly deglaciated landscapes; which are increasing in frequency and area under climate change.

    Potential biosecurity breaches (coupled with climate change) are significant threats to the natural values; biodiversity and ecosystems on the islands.

    Invasive Non Native Alien Species High Threat (Presence and expansion of invasive grass (Poa annua)) Inside site; localised( 5 ) Poa annua is a non native species established; and now expanding; on ice free areas on the eastern and southeastern ice free areas of Heard Island (where there is a significantly milder climate than western areas); which are occurring more frequently under climate change.

    Temperature extremes (Climate Change) Very High Threat Inside site; throughout( 50 ) Outside site Climate change and sea level rise poses a significant threat to World Heritage values of the site.

    Climate warming; changes in rainfall patterns and changes in glacial meltwater threaten the structure (and potentially; ecosystem functions) of the terrestrial ecosystem.

    Avalanches and landslides at least partly attributable to glacial retreats from global climate change (other component from lava flows).

    Temperature extremes High Threat (Regional warming of air and sea surface temperatures) Inside site; throughout( 50 ) Climate change will alter glacial dynamics on the island; the majority of which is capped in ice (from the peak to c. 300m a.s.l).

    Climate change is altering ecological processes and interaction in terrestrial and marine ecosystems.

    Pronounced climate change will also increase the likelihood of the introduction and or spread of non native species (IUCN Consultation; 2017).

    Climate change; the introduction of non native species and the potential expanding extent of Poa annua are the greatest threats to the natural values on the islands.

    Global processes such as climate change; plastic pollution and off shore fishing can further impact on the local biota.

    Altered hydrological regime due to climate change also threatens Heard Island’s dominant and keystone plant species as well as wetlands at Spit Bay.

    Ongoing and accelerating climate change poses an increasing risk of fundamental alterations in biodiversity.

    Its glaciers and largely unmodified flora and fauna communities are important markers of climate change (IUCN Consultation; 2017).

    Solid Waste (Contamination from washed up containers; toxic waste) Very Low Threat Inside site; localised( 5 ) Outside site Containers; such as fuel drums and gas cylinders that have washed up on Heard island as marine debris; may rust and leak contents causing local contamination (IUCN Consultation; 2017).

    Coupled with known föhn winds that generate high temperatures; drought conditions are likely to occur in locations around the island.

    Ocean acidification (Ocean acidification) High Threat Inside site; widespread(15 50 ) Outside site Ocean acidification is likely to adversely affect marine ecosystems more directly than terrestrial ecosystems (Kawaguchi et al.; 2013).

    Indirectly; ocean acidification may alter the distribution and abundance (and at worst; remove) prey species for bird and ne mammal species on the islands.