State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.
At a glance
The physical and chemical components of the Antarctic environment are changing on a region-specific basis. Recent studies suggest that rate of change is increasing, and East Antarctica, so long thought of as safe from climate change, is undergoing measurable change and may contribute significantly to sea level rise in the future.
The complex Antarctic food web is based on vast numbers of marine microorganisms, including bacteria, phytoplankton and zooplankton. Changes to the marine environment, including ocean acidification, will have a significant impact on these organisms, and since they are at the base of the food web, these changes will have profound effects throughout the Antarctic ecosystems.
Climate change and warming conditions are also supporting the movement of alien species into the region, where they may outcompete endemic species. For example, there is already evidence that king crabs are expanding their range and are moving south, where they will be a new predator for the local soft-shelled and no-shelled invertebrates.
Many subantarctic islands already harbour alien plant species, which often thrive and outcompete endemic species. Many also carry the legacy of introduced vertebrates, such as rabbits or pigs that were released onto the islands during the sealing years as food sources. Rats and mice also abound and can cause havoc among seabird colonies.
Some populations of seals and penguins that were slaughtered in huge numbers in the late 19th and early 20th centuries have recovered while others, especially the seabirds, still suffer great losses in commercial fishing operations. The greatest threat, however, may well be the bycatch in illegal, unregulated and unreported fisheries. Most whale species that visit the Southern Ocean are still on the Red List of Threatened Species of the International Union for Conservation of Nature.
In a rapidly changing world, environmental assessment requires long-term data to enable a comparison of the different states a natural ecosystem can achieve, and to determine trends of various parameters or indicators sensitive to possible change. For example, many vertebrate populations need to be monitored for two or three generations to establish the extent of natural fluctuations.35 Moreover, because of the local differences in environmental conditions, it is important to monitor comparable indicators at more than one site to study the abilities of systems or organisms to adapt to changing conditions. It is also important to establish the processes that regulate and sustain a system. However, long-term data are often lacking; when they are available, they may be limited in their spatial scales and quality. The following section provides information on a number of key indicators important to the Antarctic environment, based on the available data.
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