Overview
Australia’s semi-arid zone occurs in the interior of the continent, where average rainfall is less than 500mm per year, but more than 250mm. It covers one-third of New South Wales and although water is limiting, there is enough to support sclerophyllous tree-dominated vegetation and an understorey of drought-resistant shrubs and ephemeral grasses and herbs. There are two subformations: grassy and shrubby.
Communities of the grassy subformation are comparatively luxuriant, with larger trees and a predominantly grassy understorey. Chenopod shrub may be common in some locations. They occur on floodplains that are only occasionally flooded, which contrasts to the more frequently inundated Inland Riverine Forests. Some grassy semi-arid woodlands resemble grassy woodland communities and together may form a transitional boundary on the eastern edge of the semi-arid zone. Grassy semi-arid woodlands tend to have more ephemeral ground cover and a predominance of trees and shrubs.
Parrots and cockatoos are diverse and conspicuous inhabitants of semi-arid woodlands, as is the charismatic though reclusive ground-dwelling mallee fowl. Mammalian fauna was originally rich and diverse, however many species have disappeared since European settlement. Medium-sized animals were the worst affected and some species are now extinct in New South Wales.
The semi-arid zone presented a tough and wild frontier for settlers and was the setting for famous expeditions by Oxley, Sturt and Mitchell. Squatters ventured into the zone in the 1840’s, and the discovery of artesian water lead to a rapid expansion and intensification of pastoralism across the region. Widespread overstocking soon exhausted resources, leading to massive soil erosion. Feral goats and rabbits have further compounded this, and controlling their numbers continues to be a challenge for management of semi-arid woodlands.
Threatened species in this vegetation formation
See a
list of species, populations and ecological communities associated with
the Semi-arid woodlands (grassy sub-formation) formation.
Find species in a more specific vegetation class
The Semi-arid woodlands (grassy sub-formation) formation can be divided into the following classes. Select a vegetation class
on the list below to see a list of species associated with it: