Buchanan in Queensland. Tarrabool Lake, the largest wooded swamp in tropical Australia, when completely filled, is located in the west of the Tablelands. Other important water sources on the downs are the artesian springs such as those of the Edgbaston Reserve. The Barkly region, with a population of just over 5,900 people, has the lowest population of any region in the Northern Territory. Most live in the main town of Tennant Creek. Barkly has a diverse economy including agriculture, fishing, and defence but the main source of income is cattle ranching as the area includes some of the best beef cattle grazing country in Australia. Some of the very large cattle stations located on the Tableland include Alexandria Station, Alroy Downs, Anthony Lagoon, Austral Downs, Avon Downs, Banka Banka, Brunette Downs, Creswell Downs, Eva Downs, Helen Springs, Newcastle Waters and Lake Nash Station. The region attracts more than 140,000 tourists average each year. Ecology The dominant flora of the Tableland is semi-arid savanna of Mitchell grass. The Tableland forms the western portion of the Mitchell Grass Downs ecoregion, which covers an area running 1500 km from here southeast into the Channel Country of Queensland. The Carpentaria tropical savanna ecoregion lies to the north in the lowlands around the Gulf of Carpentaria. The Victoria Plains tropical savanna lies to the west. The central Australian desert lies south of these savannas and grasslands. The grasslands are mostly used for cattle grazing and are home to some threatened species of plants and animals. The higher areas of Mount Isa and the Selwyn Range, known as the Mount Isa Inlier, have their own unique wildlife. Biogeographic Region The Barkly Tableland (MGD02), with an area of , is an IBRA biogeographic subregion of the Mitchell Grass Downs (MGD) IBRA region (or bioregion). The Mitchell Grass Downs bioregion, together with the Mount Isa Inlier and Desert Uplands bioregions, constitute the larger Mitchell Grass Downs ecoregion. See Interim Biogeographic Regionalisation for Australia Flora Mitchell grass is hardy with long roots so is well adapted to dry soils and periods of drought. The grasslands support other distinctive plants alongside the grasses but there are no areas of thick woodland, only acacia trees scattered across the plain, and red river gum along watercourses. Fauna The habitat of the Mitchell Grass Downs is mostly a uniform cover of grassland and therefore does not support a great variety of wildlife. The