DARLING RIVERINE PLAINS BIOREGION Background Report

16/08/02 Darling Riverine Plains Bioregion Background Report
3.3 PLANT COMMUNITY DESCRIPTIONS
The distribution of plant communities in the DRP is influenced by climate, landform,
drainage and soil/substrate attributes. This distribution has been extensively modified as a
result of European settlement and land use, the introduction of rabbits and other pest species,
and modification of drainage regimes due to the rapid expansion of irrigation since the 1930s.
In particular, distribution and floristic composition of grassy or herbaceous communities has
been profoundly affected by disturbance, particularly from grazing by domestic stock and
rotational cropping (Walker & Hodgkinson 1999; Kirkpatrick 1997; Lewer, S., DLWC, pers.
com. Dec. 2001).
In this section, broad descriptions of vegetation types from reports covering the DRP have
been integrated in an attempt to provide an overview of the dominant vegetation communities
and the changes across the landscape resulting from landform variation, increasing aridity
from east to west and north-south climatic influences. These descriptions generally include
the dominant species in the overstorey, shrub layer and grass cover and while they are too
broad to indicate local variation and subtle habitat changes, they provide a general picture of
the landscape. The vegetation descriptions are taken from Plants of Western NSW
(Cunningham et al. 1992); land systems descriptions by Walker (1991); vegetation
descriptions provided by Morgan and Terrey (1992); the eight communities defined for the
northern floodplains (Smith et al 1998); and descriptions of the riverine plains of the Namoi
catchment (NWCMC 1996). The province diagrams taken from Morgan and Terrey (1992)
(Figure 3.1 through to Figure 3.11) indicate in more detail some of the plant communitylandform
associations throughout the DRP. The key conservation areas are described in
section 8.4.1.
co-dominant co-dominant sub-dominant
Land Profile
Geology Medium and coarse Quaternary alluvials Fine Quaternary alluvials. Quaternary alluvials
Landform and Soils Low, gently undulating rises. Red Plains with shallow depressions and Creek and river channels, levees
texture contrast soils
channels. Brown and grey clays. and immediate flood plain.
Vegetation Woodland to open woodland of Open woodland and grasslands,
Alluvial soils.
River cooba, eurah, black box,
leopardwood, wilga, budda, native includes myall, black box, belah, belah, lignum with coolabah
orange, warrior bush with bimble box eurah, leopardwood, whitewood and becoming common in the west.
woodland on higher areas and occasional wilga, lignum, flowering River red gum lines larger
occasional white cypress on deeper lignum. May be prominent channels, cumbungi on
soils. Understorey includes salt bushes understorey of old man saltbush. waterlogged areas. White cypress
and copper burrs. Occasional rosewood Occasional areas of curly Mitchell and bimble box on coarse
and whitewood, and, in the south, grey
box, yellow wood and Blakely’s red
gum.
grass.
textured levee deposits
Condition Usually heavily thinned with severe Usually heavily thinned and heavily Heavily grazed. Some cropping.
scalding. Some cropping on coarser
soils.
grazed. Cropping in the south. Dieback in river red gums.
Reservation None Minor areas in Macquarie Marshes Macquarie Marshes NR
NR
(18 211ha)
Key Areas 1, 2, 3
Figure 3.1 Profile of the Bogan-Macquarie Province
(adapted from Morgan & Terrey 1992)
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