Key Habitats
Great Barrier Reef
Covering an area of 348,000 square kilometers, the Great Barrier Reef contains the world’s largest collection of coral reefs, with 400 types of coral, 1,500 species of fish and 4,000 types of mollusk. The greatest threat to the reef is climate change, which causes massive bleaching events. Coastal development, land-based run-off pollution, and unsustainable fishing practices also exacerbate these issues befalling the already stressed corals.
The Outback (Deserts & Shrublands)
Australia’s desert and dry shrublands—commonly called the Outback—are found in the center of the continent stretching to the west coast. These lands contain the largest intact tropical savanna on Earth, covering nearly 2 million km2. The most pervasive threats to these shrublands are related to invasive species, changes in fire management regimes, and declining rainfall.
Wetlands and swamps
Australia is home to a variety of wetlands, from tidal mangroves and billabongs, to salt lakes and freshwater springs. Australian wetlands are critical to the survival of birds that migrate across the globe each year, and are also permanent habitats to numerous unique plants and animals. Many wetlands in Western Australia are threatened by alteration of natural water systems, invasive species, mining activities, and pollution.
Eastern Temperate forests
Temperate forests are found along the eastern coast of Australia from Queensland to New South Wales. These forests remain vulnerable to clearing for ranching and agriculture. The Cumberland plain woodland system near Sydney has been cleared for grazing and cropping to the just 10% of its original area.
Most Pressing Issues
Climate Change
Climate change compounds existing threats to Australia’s ecosystems. An increase in the number and size of fires throughout Australia has been linked to a warming climate, which in the last year killed or displaced nearly three billion animals. Massive coral bleaching events caused by warming seas have destroyed more than half of the Great Barrier Reef’s corals since 1995.
Agriculture Clearing and Overgrazing
Extensive land clearing and grazing continues to degrade land and decrease biodiversity; in temperate ecosystems, less than 2% of the original grasslands remain. Overgrazing promotes erosion and desertification, and contributes to the spread of invasive plants. Wet tropics have also become fragmented due to land alteration for cane sugar farming and other industries. Methane emissions and ammonia runoff from livestock farming has caused algal bloom and fish die-offs in Queensland’s Great Barrier Reef.
Invasive Species
Invasive animals and plants have a major impact on Australian ecologies. Historically, feral cats, foxes and rabbits have been a cause of local extinctions and significant reductions in range for native species through a combination of habitat modification and predation. Other well-known examples include cane toads, willows and—more recently—black striped mussels and red fire ants.
Water Pollution
Common contaminants found in coastal rivers and estuaries around Australia include metals, pesticides, fertilizers, erosion sediments, and plastic debris. The current state of coastal river and estuary pollution has been deteriorating since 2011, particularly due to agriculture; it is estimated that each year almost 19,000 tonnes of phosphorus and 141,000 tonnes of nitrogen are discharged to rivers flowing to the coast.
