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

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Grasslands of the world
or loams. A variety of other woody species also occur (Eucalyptus , Acacia,
Casuarina , Terminalia ). The native understoreys are sparse and unproductive,
with major grasses being species of Paspalidium , Bothriochloa , Aristida and
Chloris . These communities have been extensively cleared for development
to exploit their natural fertility by sown introduced pastures (mainly based
on the grasses Cenchrus ciliaris , Chloris gayana and Panicum maximum var.
trichoglume ) and cropping.
Xerophytic mid-grass
These grasslands form the herbaceous layer of semi -arid low woodlands
on a wide range of light soils of poor to moderate fertility in both northern
and southern Australia . In northern Australia they occur in a subcoastal arc
inland from the tropical tall -grass communities , in Western Australia, the
Northern Territory and Queensland in areas with 350–750 mm annual rainfall .
They have variable composition, with a range of dominant species including
Aristida spp. , Chloris spp., Bothriochloa decipiens , B. ewartiana , Eriachne spp. ,
Digitaria spp. and Chrysopogon fallax . Annuals are also important (Sporobolus
australasicus, Aristida spp., Dactyloctenium radulans ). The southern component
is widespread in western New South Wales, where Danthonia spp., Chloris
truncata , C. acicularis , Stipa variabilis , S. setacea , S. aristiglumis and species of
Eragrostis , Aristida, Enneapogon and Enteropogon are important.
These woodlands have variable tree and shrub layers. Tree clearing has been
important in central and southern Queensland and New South Wales. Major
increases in the density of the shrub layer (species of Eremophila , Cassia ,
Dodonaea and Acacia ) have reduced grass production and threaten the viability
of grazing in some areas.
Temperate tall -grass
Dichelachne spp. , Poa labillardieri and Themeda triandra give sparse grazing
in the wetter forest and heath areas of eastern New South Wales, Victoria and
Tasmania, and also in the dry sclerophyllous forests, where Danthonia pallida is
also important. These pastures are of low grazing value and animal production
in these areas depends on clearing and the development of sown pastures.
Temperate short -grass
Apart from small areas of treeless grassland , these communities form the
herbaceous layer of temperate woodlands growing on a range of soils
extending from southern Queensland through New South Wales and Victoria
to southeast South Australia , with other areas near Adelaide, in Tasmania
and in the southwest of Western Australia. Annual rainfall varies from 400 to
650 mm, with summer dominance in the north and winter dominance in the
south. These woodlands were among the first areas used for domestic livestock
and have been extensively modified by clearing , grazing , fertilizer application