Grasslands of the World.pdf - Disasters and Conflicts - UNEP

J.G. McIVOR
Australian grasslands 357
and the introduction of exotic species. They were originally composed of
taller, warm-season grasses (Themeda triandra , T. avenacea , Stipa bigeniculata ,
S. aristiglumis , Poa labillardieri ) but with higher grazing pressures since
European settlement these have been replaced by short , cool-season species
(Danthonia spp., Stipa variabilis , Chloris spp.) and exotic annuals (Hordeum
leporinum , Bromus spp. , Trifolium spp., Medicago spp., Erodium spp. and
Arctotheca calendula ).
Sub-alpine sodgrass
Small areas of this community occur as treeless grasslands or the understorey
of subalpine woodlands on acid soils with annual rainfall above 750 mm in the
southeastern highlands. The principal grasses are Poa spp. , Danthonia nudiflora
and Themeda triandra . Historically, these grasslands were used for summer
grazing , often after burning during early summer, but grazing has declined as
emphasis is now placed on water supply, tourism and conservation .
Saltbush-xerophytic mid -grass
These communities are often treeless and are characterized by chenopod
shrubs, usually less than one metre tall , from the genera Atriplex , Maireana ,
Sclerolaena , Rhagodia and Enchylaena . They are important in New South
Wales, South Australia (Plate 9.2) and Western Australia, with smaller amounts
in Queensland and the Northern Territory in areas with 125 to 400 mm
rainfall . The space between the shrubs is covered with annual grasses and forbs
Plate 9.2
Saltbush community in South Australia .