table 3.1 changes in the extent of supporting terrestrial habitats
Source: Great Barrier Reef Marine Park Authority, 2012189 with minor updates
Supporting terrestrial habitat Saltmarshes Freshwater wetlands Forested floodplain Heath and shrublands Grass and sedgelands Woodlands Forests Rainforests
total area before european settlement (km2) 2146 1431 24,597 5351 12,364 105,123 239,602 26,886
total area remaining (km2) 1830 1237 12,655 5025 5988 64,592 145,379 16,744
proportion remaining 85 per cent 86 per cent 51 per cent 94 per cent 48 per cent 61 per cent 61 per cent 62 per cent
Figure 3.12 changes in supporting terrestrial ecosystems, pre-european and 2009
Before European settlement there were extensive areas of forests, woodlands and forested floodplain interspersed with wetlands and other aquatic habitats across much of the catchment. These habitats supported the Great Barrier Reef ecosystem. An extensive area of the catchment has been changed from forest to grassland for grazing purposes and there has been a significant increase in non-remnant vegetation. Source: Great Barrier Reef Marine Park Authority, 2012189
Some saltmarsh areas have been modified.
Saltmarshes are an important, highly productive, interface between marine and terrestrial environments in the upper intertidal area along the length of the Great Barrier Reef coast.219,220 They provide feeding and breeding areas for many marine species including many commercial fish and prawn species.163,221 Coastal development has modified saltmarshes, affecting more than 15 per cent of the habitat in the catchment.222 The impact is highest in areas with grazing and cropping, urban growth or large population centres.189
3.5.2 Freshwater wetlands
Freshwater wetlands remain intact in many areas; many are functioning poorly.
Freshwater wetlands slow the overland flow of water and capture and recycle nutrients and sediments that would otherwise enter the Great Barrier Reef.189 They are also used by some marine species for parts of their life cycle and are important dry season refuges for many species including the threatened largetooth sawfish.223 Freshwater wetlands at a whole-of-catchment scale are relatively intact, but many are functioning poorly due to a range of factors, including loss of connectivity, sediment and nutrient overload,