Coolibah - Black Box Woodlands of the Darling Riverine Plains and the Brigalow Belt South Bioregions - profile

Distribution

Coolibah-Black Box Woodlands are limited to the Darling Riverine Plains (DRP) and Brigalow Belt South (BBS) bioregions, situated in northern NSW and southern Queensland. The southern limit of the ecological community is the southern boundary of the Darling Riverine Plains bioregion in NSW. This equates with the southern distribution limit for Coolibah. The northern limit is the northern boundary of the Brigalow Belt South bioregion in Queensland. While Coolibah and Black Box extend outside the above bioregions, the national ecological community is limited to the two bioregions noted above.
Coolibah-Black Box Woodlands are associated with many major wetlands, primarily linked to the Darling Basin. In many cases the ecological community extends up to the fringes of the wetlands. The ecological community is likely to occur in the Local Government Areas of Bogan, Bourke, Brewarrina, Central Darling, Cobar, Coonamble, Gwydir, Inverell, Moree Plains, Narrabri, Walgett and Warren in NSW.

Habitat and ecology

• The Coolibah-Black Box Woodlands are found on the grey, self-mulching clays of periodically waterlogged floodplains, swamp margins, ephemeral wetlands and stream levees.
• The structure of the ecological community may vary from tall woodland in riparian zones to very open woodland with a sparse mid-layer of shrubs and saplings and a grassy ground layer. The structure and composition varies depending on topography and flooding or disturbance history.
• States in which Coolibah-Black Box Woodlands exist include: structurally intact old growth with mature trees and native ground layer; structurally intact mature stands (thinned stands where trees may have been naturally thinned or ringbarked and coppiced approximately 50-100 years ago); dense regrowth with or without mature trees with intact groundcover (typically after flood events); tree canopy removed but native groundcover intact; isolated paddock trees with relictual groundcover and native trees and ground cover removed or almost so.
• Eucalyptus coolabah subsp. coolabah (Coolibah) must be present in the tree canopy and is typically a dominant or subdominant tree species. Where Coolibah is not the dominant tree species present on its own, then Coolibah together with E. largiflorens (Black Box) make up the dominant tree species in the canopy.
• Other tree species may occur in the tree canopy but are not dominant in the ecological community, except as small localised stands within patches of the ecological community. These include Acacia salicina (Cooba), Acacia stenophylla (River Cooba), Casuarina cristata (Belah), Eremophila bignoniiflora (Eurah), E. camaldulensis (River Red Gum) and E. populnea (Poplar Box).
• Medium to tall shrubs are sparse to absent in many areas of this ecological community. At other sites, shrubs may form clumps. Where a mid-layer is present it may include one or more of the following: Alectryon oleifolius (Western Rosewood), Alstonia constricta (Bitterbark), Chenopodium nitrariaceum (Nitre Goosefoot), Eremophila mitchellii (Budda), Geijera parviflora (Wilga), Duma florulenta (Lignum) and Rhagodia spinescens (Spiny Saltbush).
• The native species in the ground layer may include the graminoids: Astrebla lappacea (Curly Mitchell Grass), Cyperus victoriensis (Yelka), Dactyloctenium radulans (Button Grass), Dichanthium sericeum (Queensland Bluegrass), Eleocharis spp. (Spike-rushes), Eragrostis setifolia (Neverfail), Panicum decompositum (Native Millet), Paspalidium distans and Paspalidium jubiflorum (Warrego Summer Grass); and the herbs: Daucus glochidiatus (Native Carrot), Marsilea drummondii (Common Nardoo), Plantago cunninghamii (Sago-weed), Pycnosorus globosus (Drumsticks), Tetragonia tetragonioides (New Zealand Spinach) and Tribulus spp. (Caltrop). Chenopods include Atriplex spp, Einadia nutans subsp. (Climbing Saltbush) and Sclerolaena spp. The composition of the ground layer will vary depending on past and present grazing pressure as well as the drought and water regime.
• National listing focuses legal protection on remaining patches of the ecological community that are functional, relatively natural and in relatively good condition. Very degraded patches are not part of the national ecological community listed under the EPBC Act.
• The key diagnostic attributes for the ecological community are as follows: Distribution is limited to the Darling Riverine Plains and the Brigalow Belt South bioregions; It typically occurs on grey, self-mulching clays of periodically waterlogged floodplains, swamp margins, ephemeral wetlands and stream levees; a tree canopy is present and shows these features: Eucalyptus coolabah subsp. coolabah (Coolibah) must be present in the tree canopy / where Coolibah and E. largiflorens (Black Box) co-occur, together they make up the dominant species in the tree canopy (>50% of tree crown cover) / hybrids of Coolibah or Black Box with each other and other eucalyptus species (typically Bimble Box) are included as dominant tree species. The mid or shrub layer may or may not be present. When present it is typically sparse or clumped and is of variable composition; The ground layer is of variable composition and cover ranging from sparse to dense. Ground cover lifeforms typically comprise native graminoids, other herbs, chenopods and other low shrubs that are typically under 50cm tall.
• The listed ecological community is limited to patches that meet the following condition thresholds: Patch size - the minimum patch size is 5ha. This may include native vegetation that may be naturally open or contain regrowth AND tree canopy layer - the crown cover of trees in the patch must be >8% AND Coolibah and/or Black Box in the tree canopy must be present in the patch that are either mature trees with a main stem that has a dbh of >30cm OR hollow-bearing trees (live or dead) OR coppiced trees with a main stem that has a dbh of >20cm AND ground layer - 10% or more of the ground cover comprises native graminoids, other herbs, chenopods and/or native low shrubs (ie woody plants typically lesss than 50cm tall) AND exotic species - in the ground layer, the percentage cover of non-native perennial plant species does not exceed the percentage cover of native plant species (annual or perennial).
• The ecological community has a number of characteristic habitat features of value to particular fauna such as a grassy understorey with scattered fallen logs, areas of deep-cracking clay soils, patches of thick regenerating Eucalyptus saplings and large trees containing a diverse bark and foliage resource and an abundance of small and large hollows.
• The association of the woodland ecological community with floodplains indicates its particular importance for birds both as woodland habitat as as nesting sites for colonial breeding waterbirds that rely on occasional wetlands in addition to woodland habitats.
• Coolibah-Black Box woodlands are important habitat for reptiles and amphobians and may support more of these fauna than surrounding ecological communities such as grasslands as a result of increased structural layers.
• The ecological community provides important habitat to many terrestrial invertebrates, particularly centipedes, scorpions, slaters land snails, wolf spiders, crickets and ground-dwelling beetles. The community also provides ephemeral habitat for aquatic macro-invertebrates following inundation or where gilgai are present. Characteristic groups include crustaceans (fairy shrimps, clam shrimps, seed shrimps, shield shrimps), molluscs (eg. Planorbidae), water spiders, dragonflies and aquatic insects.

Regional distribution and habitat

• Brigalow Belt South
• Broken Hill Complex
• Cobar Peneplain
• Darling Riverine Plains
• Mulga Lands
• Murray Darling Depression
• Nandewar
• New England Tablelands
• NSW North Coast
• NSW South Western Slopes
• Riverina
• South Eastern Queensland
• Sydney Basin