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

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Grasslands of the world
after rain – in the south they are Danthonia caespitosa , Stipa variabilis , Chloris
truncata and species of Calandrinia , Ptilotus and Sclerolaena. In the north,
Enneapogon spp., Eragrostis spp., Aristida spp. and Dactyloctenium radulans
are important. Grazing animals show marked preferences for different species in
these communities. Studies in southern New South Wales (Leigh and Mulham,
1966a,b, 1967) showed animals prefer green grasses and forbs, then dry grass
and forbs, followed by annual and short -lived perennial chenopods, with the
perennial Atriplex and Maireana shrubs least preferred. The perennial saltbush
plants confer stability to the soils and vegetation and serve as an important
drought reserve ; during droughts , saltbush may be a major part of the diet. The
combination of drought and overgrazing has led to loss of saltbush, with the
palatable Atriplex and Maireana species disappearing.
Acacia shrub–short -grass
Acacia shrublands are widespread in arid Australia on lighter textured infertile
soils in all states except Victoria. Mulga (Acacia aneura ) is the major shrub,
but other Acacia, Cassia and Eremophila species are also important, plus
chenopods in southern areas. These shrubs provide important “top feed” and
mulga in particular is lopped or pushed over to provide feed for stock during
droughts . The herbage layer is dominated by annual and short -lived perennial
grasses and forbs. The principal grasses are Eragrostis spp., Monachather
paradoxus , Eriachne spp. , Aristida contorta , Thyridolepsis mitchelliana , Stipa
spp. , Neurachne spp. and Enneapogon spp. Common forbs are species of
Calotis, Helipterum and Ptilotus .
Plate 9.3
Acacia nilotica thicket and seedlings (foreground) in a Mitchell grass
community.
J.G. McIVOR