Regional ecosystem details for 5.9.4
| Regional ecosystem | 5.9.4 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 2, 4, 1, 12, (8), (5), (10), (4.2), (11), (3), (4.1) |
| Estimated extent1 | Pre-clearing 940000 ha; Remnant 2021 939000 ha |
| Short description | Aristida contorta sparse tussock grassland on fresh Cretaceous sediments with dense gravel cover |
| Structure code | Sparse Tussock Grassland |
| Description | Aristida contorta usually predominates forming an open to sparse tussock grassland. Other short grasses including Oxychloris scariosa, Enneapogon avenaceus, Sporobolus actinocladus and Tripogon loliiformis are common. Annual grasses such as Brachyachne prostrata and Eriachne pulchella occur frequently, while the perennial Aristida latifolia and Eragrostis xerophila may be locally common. Forbs such as Gnephosis arachnoidea, Rhodanthe floribunda, Maireana dichoptera and Sclerolaena lanicuspis may predominate after winter rain. Sparsely scattered shrubs may occur in places. Short grasses build up after wet summers, while forbs common after winter rainfall. Occurs on flat to gently undulating plains with abundant surface gravel cover of ironstone, chalcedony, laterite, silcrete or silicified sandstone. Soils shallow to deep, desert loams, with gravelly, sandy clay loams overlying structured medium clays. Ground cover always sparse, varies with amount of stone cover and seasonal conditions. Not a Wetland. (BVG1M: 31b). Vegetation communities in this regional ecosystem include: 5.9.4x1: Aristida contorta sparse to open tussock grassland +/- Oxychloris scariosa +/- Enneapogon avenaceus +/- Sporobolus actinocladus. Ephemeral forbs may predominate after winter rain. Sparsely scattered shrubs such as Senna spp. And Acacia tetragonophylla may occur in places. Local shallow deposits of windblown sand support ephemeral forbs such as Calotis plumulifera, Gnephosis eriocarpa, Rhodanthe moschata and Polycalymma stuartii, and less commonly isolated patches of Senna spp. Shrubland. Sparsely scattered trees, such as Corymbia terminalis, Hakea eyreana, and Grevillea striata may occur in places. Floristic composition varies with seasonal conditions, density of stone pavement and gilgai micro relief. Occurs on level to gently undulating plains formed by Cainozoic colluvial and residual deposits overlying deeply weathered Cretaceous sediments. Associated soils shallow to deep gravely to sandy desert loams. Not a Wetland. (BVG1M: 31b). 5.9.4x2: Astrebla pectinata sparse to open herbland commonly with Sporobolus actinocladus, Brachyachne ciliaris, Atriplex spp., Sclerolaena spp., Salsola australis and Osteocarpum spp. Mosaic of sparse to open tussock grassland in gilgai depressions dominated by Astrebla pectinata, and sparse herbland on benches and dense gravels dominated by Sporobolus actinocladus, Brachyachne ciliaris, Enneapogon avenaceus, Sclerolaena spp., Atriplex spp., Salsola australis, Osteocarpum spp., *Portulaca oleracea. Occurs on level to gently undulating plains formed by Cainozoic colluvial and residual deposits overlying deeply weathered Cretaceous sediments. Deep stony often gilgaied soils with depressions sometime parallel to contour, soils range from desert loams to moderately deep crusted red-brown cracking clays. Moderate to large amounts of ironstone gravel on surface. Not a Wetland. (BVG1M: 30b). |
| Supplementary description | Wilson and Purdie (1990a), P1 (56), P2 (60); Neldner (1991), 47b (96) |
| Protected areas | Diamantina NP, Pullen Pullen SWR, Munga-Thirri NP |
| Special values | 5.9.4: Habitat for threatened fauna species including kowari Dasyuroides byrnei. 5.9.4x2: Habitat for threatened fauna species including kowari Dasyuroides byrnei. |
| Fire management guidelines | INTERVAL: Fire return interval not relevant. INTERVAL_MIN: 100. INTERVAL_MAX: 100. STRATEGY: Exclude fire. ISSUES: Unlikely to burn due to generally sparse nature. Rarely enough fuel load to burn in any case. |
| Comments | 5.9.4: Some localised sheet erosion and associated change in floristic composition evident (Wilson and Purdie 1990b; F4). 5.9.4x1: 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. 5.9.4x2: 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. Some localised sheet erosion and associated change in floristic composition evident (Wilson and Purdie 1990b; F4). |
1 Estimated extent is from version 13.1 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.
