Regional ecosystem details for 5.9.3
| Regional ecosystem | 5.9.3 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 2, 4, 6, (5), (7), (4.2), (8), (4.4), (1), (3), (12), (6.10), (11), (13), (9), (4.3), (10), (4.1), (6.9) |
| Estimated extent1 | Pre-clearing 3389000 ha; Remnant 2021 3383000 ha |
| Short description | Astrebla spp. +/- short grasses +/- forbs open tussock grassland to herbland on Cretaceous sediments |
| Structure code | Open Tussock Grassland |
| Description | Astrebla spp. +/- short grasses +/- forbs open tussock grassland to herbland. Astrebla pectinata typically predominates but locally Astrebla lappacea may dominate, a Sclerolaena spp. sparse-forbland may at times predominate, other tussock grasses may be present occupying the spaces between the tussocks of Astrebla spp. Dactyloctenium radulans, Brachyachne convergens and Iseilema spp. may predominate in some areas. Forbs such as Atriplex spp., Sclerolaena spp., Trianthema triquetra, *Portulaca oleracea and Salsola australis occur and in less favourable seasons tend to predominate forming a sparse ground cover (<10%). Isolated shrubs including Senna artemisioides subsp. oligophylla, Senna phyllodinea and Acacia victoriae may be conspicuous, but trees are absent. Occurs on flat to gently undulating plains with slopes usually less than 3% (sometimes up to 5%). Soils stony, deep to moderately deep, red and brown cracking clays, or rarely desert loams. Occurs on mantled pediments and fresh Cretaceous sediments. Not a Wetland. (BVG1M: 30b). Vegetation communities in this regional ecosystem include: 5.9.3a: Astrebla lappacea and/or Sclerolaena spp. open tussock grassland/herbland. Either Astrebla lappacea open tussock grassland or an open to sparse-forbland of Sclerolaena bicornis and/or Sclerolaena calcarata and/or Sclerolaena lanicuspis and/or Sclerolaena spp. may be dominant depending on seasonal conditions. Dactyloctenium radulans, Brachyachne convergens and Iseilema spp. may predominate in some areas. Other forbs such as Atriplex spp., Trianthema triquetra, *Portulaca oleracea and Salsola australis are common. Occurs on flat to gently undulating plains with shallow to moderately deep alkaline self mulching cracking clay soils, fresh Cretaceous sediments. Not a Wetland. (BVG1M: 30b). 5.9.3b: Variable herbland on fresh Cretaceous sediments. Dominant species varies considerably depending on seasonal conditions and may include variable combinations of; Astrebla spp., Aristida latifolia, Dactyloctenium radulans, Iseilema vaginiflorum, Atriplex spp., Sclerolaena spp. A large number of forb species may occur, many of them ephemeral and seasonally abundant. In less favourable seasons ground cover can be very sparse with Dactyloctenium radulans and Iseilema vaginiflorum dominating, especially in areas with significant grazing. Occurs on flat to gently undulating plains (< 1%) of fresh Cretaceous sediments. Shallow to moderately deep brown cracking clay soils with self-mulching surface. Not a Wetland. (BVG1M: 30b). 5.9.3c: [RE not in use]²: This vegetation community is now mapped as 5.3.9x1. Acacia cyperophylla var. cyperophylla low woodland with Acacia cambagei sometimes co-dominant. Scattered Atalaya hemiglauca may be present while in some areas Senna artemisioides subsp. Oligophylla and Eremophila freelingii for a prominent low shrub layer. The ground layer is generally sparse and comprising a variety of grass and forb species such as Eriachne mucronata, Salsola australis or Zygophyllum ammophilum. Occurs on drainage lines within stony plains. Soils are generally deep gravelly massive to weakly structured sandy loams to sandy clay loams. Not a Wetland. (BVG1M: 24a). 5.9.3x1: [RE not in use]²: This vegetation community is now mapped as 5.9.3b. Astrebla squarrosa usually predominates with Astrebla pectinata being codominant, and together form a tussock grassland. Iseilema vaginiflorum and Aristida latifolia are frequent and abundant in heavily grazed areas. Shrubs are very sparse and infrequent. A number of forbs occur and may become abundant after winter rain. Occurs on flat clay plains of Winton plateau. Associated soils are moderately deep grey cracking clays, strongly self-mulching surface. Not a Wetland. (BVG1M: 30b). 5.9.3x2: Astrebla pectinata and/or Astrebla lappacea and/or Aristida latifolia open herbland. In some areas Dactyloctenium radulans, Brachyachne convergens and Iseilema spp. may be seasonally common. Forbs such as Atriplex spp. and Sclerolaena spp. occur, and in less favourable seasons tend to predominate. Isolated shrubs of Acacia tetragonophylla or Senna spp. may occur. Occurs on level to gently undulating plains formed by superficial Cainozoic clay deposits overlying a range of geologies. Soils shallow to deep, crusted red and minor brown medium to heavy clays. Small to moderate amounts of ironstone, chalcedony, laterite, and silcrete gravel occur in the profile and on the surface. Not a Wetland. (BVG1M: 30b). 5.9.3x3: Seasonally variable sparse to open tussock grassland/herbland, dominant grasses include Astrebla pectinata, Aristida spp., Enneapogon avenaceus and Sporobolus actinocladus. Annual grasses such as Dactyloctenium radulans, Iseilema vaginiflorum and Brachyachne ciliaris may be seasonally abundant. Forbs such as Atriplex spp., Sclerolaena spp., Osteocarpum acropterum, Maireana spp., *Portulaca oleracea, Salsola australis and Neobassia proceriflora are common and in less favourable seasons tend to predominate forming a sparse ground cover (<10%). Isolated shrubs may be conspicuous, but trees are absent. Occurs on flat to gently undulating plains with abundant ironstone surface gravel cover. Soils moderately deep to deep, may be weakly gilgaied or strongly gilgaied with depressions parallel to the contour, crusted, red cracking clays. Ground cover always sparse, varies with amount of stone cover and seasonal conditions. Not a Wetland. (BVG1M: 30b). |
| Supplementary description | Neldner (1991), 47a (92); Boyland (1984), 27; Dawson (1974), F1-4 (84, 85); Wilson and Purdie (1992), F4 (55); Mills (1980), F2 (69) |
| Protected areas | Diamantina NP, Pullen Pullen SWR, Bladensburg NP, Astrebla Downs NP |
| Fire management guidelines | INTERVAL: Fire return interval not relevant. INTERVAL_MIN: 100. INTERVAL_MAX: 100. STRATEGY: Do not burn deliberately. The grasses and forbs of Astrebla spp. dominated communities do not require fire for regeneration. Protection relies on management of fire in the surrounding country to prevent running fires entering Astrebla spp. communities, particularly at times of low soil moisture. ISSUES: Fire can sometimes be used as a tool to control woody thickening and woody weeds in grasslands. Moderate intensity fire is required for a successful kill of the woody species but good moisture levels are required to ensure recovery of the ground layer. Large scale germination of woody species is most likely to occur in high rainfall years. The best management opportunity is usually after storms at the end of the subsequent dry season, although exclusion of grazing pressure may still be required to ensure sufficient fuel loads. |
| Comments | 5.9.3: Surface stone (gibbers) may be desert varnished (Dawson, 1984; Wilson and Purdie, 1992). Composition of flora depends on seasonal conditions and past land use. Astrebla elymoides and A. squarrosa associated with infrequent gilgai. A fluctuating climax with Astrebla pectinata and short grasses dominating in favourable years, and Atriplex spp. And Sclerolaena spp. Dominating in poorer seasons. It is not unusual for Astrebla spp. To be inconspicuous for considerable periods, particularly under grazing. 5.9.3b: RE 5.9.3x1 was amalgamated into this RE. 5.9.3x2: Created to differentiate Cainozoic residual and colluvial clays (Landzone 4) from in situ clays (Landzone 9). These Cainozoic clays have a weak potassic signature indicating either leaching of potassium during deep weathering or mixing with leached material during transport, as opposed to fresh Cretaceous clays which retain a strong Potassic signature. |
1 Estimated extent is from version 13 pre-clearing and 2021 remnant regional ecosystem mapping. Figures are rounded for simplicity. For more precise estimates, including breakdowns by tenure and other themes see remnant vegetation in Queensland.
2 Superseded: Revision of the regional ecosystem classification removed this regional ecosystem code from use. It is included in the regional ecosystem description database because the RE code may appear in older versions of RE mapping and the Vegetation Management regulation.
