Queensland tropical rain forests
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The Queensland tropical rain forests are a terrestrial ecoregion located in northeastern Australia.
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[edit] Setting
The ecoregion covers 32,700 square kilometers (12,600 square miles) of northeastern coastal Queensland, from the coast up a series of plateaus and tablelands to the mountains behind the coast. The ecoregion comprises three separate sections. The northern area, which includes Cairns, is the largest, from 15°30’ to 19°25’ south latitude. This northern section is also known as the Wet Tropics bioregion.
The second section extends from the Whitsunday group to Carmila, including Mackay, and the third section includes the Warginburra Peninsula, extending inland to include portions of the Normanby Range. The two southern sections are also known as the Central Mackay Coast bioregion.
[edit] Flora
The Queensland tropical rain forests are designated one of the Global 200 ecoregions. The ecoregion is the largest remnant of Australia's rain forest flora, home to ancient assemblage of plants, called the Antarctic flora, presently characteristic of New Zealand and southern Chile, and that once covered much of Australia and Antarctica until about 15 million years ago.
Conifers of the southern hemisphere family Araucariaceae are the characteristic tree species. In the northern section of the ecoregion, Kauri commonly form the forest canopy, with Agathis robusta most common at lower elevations, and A. microstachya and A. atropurpurea predominant at higher elevations. In the southern sections, Araucaria cunninghamii is predominant, with Araucaria bidwillii dominant in two small areas. Conifers in the family Podocarpaceae are also present, including genera Podocarpus and Sundacarpus. The forests are thick with vines, ferns, epiphytes, and palms.
These forests are limited to areas of high rainfall and good soils. In waterlogged soils, the rainforest flora gives way to Melaleuca thickets, and on poor soils and in drier areas Eucalyptus becomes dominant. The rainforest flora is intolerant of fire, and where periods of drought have allowed devastating fires, the rainforest flora has retreated, allowing fire-tolerant Eucalyptus to become established. If a relatively wet period persists, the rainforest flora may reestablish itself. It is thought that the land management practices of the aboriginal Australians, which involve setting regular fires to keep the eucalyptus woodlands open, may have encouraged the expansion of eucalyptus forests at the expense of the rainforest flora. These rainforests seem to have retreated considerably since the arrival of the aboriginals' ancestors 50,000 years ago, and are presently limited to isolated pockets comprising less than 2% of the continent's area.
[edit] Conservation
These forests are particularly interesting because of their southern location and the high degree of endemism of their plant and animal species.
Deforestation has led to habitat fragmentation and diminushing populations of species such as spotted-tailed quoll (Dasyurus maculatus), cassowary (Casuarius casuarius), and ring-tail possum (Hemibelideus lemuroides).
Introduced species also pose a serious threat to many native species.
