consequence of the interactions between its large area, several biologically significant climatic gradients, the biogeographic effects of eight river basins, and the importance of landscape form driving water and soil redistribution in semi-arid environments of inland Australia. This diversity is expressed through the presence of 31 subregions of the Interim Biogeographic Regionalisation for Australia and 46 major vegetation subgroups of the National Vegetation Information System. The most common terrestrial vegetation NVIS subgroups are (i) Mitchell grass (Astrebla) tussock grasslands, (ii) Eucalyptus open woodlands with a grassy understorey, and (iii) cleared, non-native vegetation. Other vegetation subgroups occur with lower frequency and form a complex mosaic that gradually changes from north-east to south-west across the Galilee Basin. The woody components of these vegetation types have been subject to clearance over 16% of the Galilee Basin, mainly to the east, with the aim of improving pasture productivity. The annual rate of clearance has declined since 2005. Pasture components are reported to have stable condition, except for a recent decline in the north-east corner. As rivers and streams are all intermittent, the durations of flow and non-flow periods, and the depth of water, together determine the number of species locally per unit area and degree of species sharing amongst rivers and residual waterholes. The ecology of rockholes (shallow depressions that collect local rainwater) and outcrop springs (springs of water that has percolated through rock layers in the immediately surrounding area) is poorly studied, as is the ecology of the species that occur within aquifers below ground level (stygobiota). However, discharge springs (springs of water that had percolated through rock layers over long distances and from which water emanates under pressure) are better studied, and numerous locally endemic species of plant, mollusc and fish have been identified. The ecology of both discharge springs and stygobiota is understood to depend on relatively stable water regimes, compared with the highly intermittent character of other aquatic habitats in the region. As a result of water drawdown for agriculture, discharge springs have been subject to significant degradation over the last century. Only 36% of the 300 springs complexes (local clusters of springs) identified in the Great Artesian Basin in 1900 are still active. There are no data on impacts of agricultural drawdown on stygobiota. Discharge springs have also been subject to invasion by exotic plants and disturbance by sheep, pigs, horses and donkeys. Riverbanks and waterholes are generally assessed