Mitchell Grass Downs


The Mitchell Grass Downs is a tropical and subtropical grasslands, savannas, and shrublands ecoregion in northeastern Australia. It is a mostly treeless grassland, characterised by Mitchell grasses.

Location and description

The ecoregion is bounded on the north and east by tropical savanna ecoregions – the Victoria Plains tropical savanna to the northeast, the Carpentaria tropical savanna to the north, the Einasleigh Uplands savanna to the northeast, and the Brigalow tropical savanna to the east. More arid ecoregions lie to west and south – the Great Sandy-Tanami desert to the southwest, the Simpson Desert to the south, and the Eastern Australia mulga shrublands to the southeast.
The ecoregion includes three IBRA regions – Mitchell Grass Downs, Mount Isa Inlier, and Desert Uplands.

Climate

The climate is tropical and semi-arid. Average annual rainfall varies across the ecoregion, from 350 mm to 750 mm. In much of the ecoregion rainfall is seasonal, coinciding with the summer monsoon. Rainfall becomes less seasonal towards the southeast.

Flora

The vegetation consists mostly of grasses along with wildflowers and low shrubs, including Queensland bluebush. There are scattered dry acacia woodlands, predominantly of gidgee. Watercourses support woodlands of red river gum, coolibah, and paperbark.
The Desert Uplands has dry woodlands of Eucalyptus populnea, E. melanophloia, and E. similis. Low open woodlands of snappy gum, Cloncurry box, and silver box grow in the Mount Isa Inlier.