Regional ecosystem details for 4.9.4
| Regional ecosystem | 4.9.4 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 7, 2, 1, (3), (1.1), (2.8), (1.2), (1.3), (5.2) |
| Estimated extent1 | Pre-clearing 313000 ha; Remnant 2021 313000 ha |
| Short description | Astrebla pectinata and herbs +/- Astrebla spp. tussock grassland on Cretaceous sediments |
| Structure code | Tussock Grassland |
| Description | Astrebla pectinata tussock grassland occasionally with A. lappacea and A. elymoides. Aristida latifolia and Iseilema vaginiflorum occur frequently and may be abundant in some areas. Other short lived grasses may be abundant in wet summers. A large number of forbs from the Asteraceae, Brassicaceae, Chenopodiaceae, Convolvulaceae, Euphorbiaceae, Fabaceae, Malvaceae and Zygophyllaceae may occur in this association, particularly in a wet winter. Frequent species include Abutilon malvifolium, Sclerolaena glabra, S. lanicuspis, Calotis hispidula, Crotalaria dissitiflora, Euphorbia drummondii, Salsola australis, Sida fibulifera, and S. trichopoda. Woody plants are generally absent. Occurs on flat to undulating plains formed on Cretaceous sediments. Soils deep, with a weak gilgai microrelief, stony surface, red cracking clays. Surface stone may be desert varnished. Soils are neutral to mildly alkaline with gypsum present at depth. A weak surface crust is usually present. Not a Wetland. (BVG1M: 30b). Vegetation communities in this regional ecosystem include: 4.9.4a: Astrebla pectinata, herbs +/- Astrebla spp. Occurs on undulating clay plain derived from weathered Cretaceous mudstones. Areas of gravel and lateritic surface common. Not a Wetland. (BVG1M: 30b). 4.9.4x1: Astrebla pectinata tussock grassland, commonly with Aristida latifolia (occasionally may dominate), Astrebla lappacea, Eulalia aurea and Dichanthium spp. Emergent Atalaya hemiglauca, Ventilago viminalis, Vachellia sutherlandii and Acacia georginae may occur. Occurs on undulating plains of Cambrian and Tertiary limestone. Brown cracking clays with limestone rocks. Not a Wetland. (BVG1M: 30b). 4.9.4x1a: Astrebla pectinata tussock grassland, commonly with Aristida latifolia, Astrebla lappacea and Eulalia aurea. Emergent Atalaya hemiglauca, Ventilago viminalis and Vachellia sutherlandii may occur. Occurs on undulating plains of Cambrian limestone and dolomite. Brown cracking clays with limestone rocks. Not a Wetland. (BVG1M: 30b). 4.9.4x1b: Astrebla pectinata tussock grassland, commonly with Aristida latifolia, Eulalia aurea, Astrebla spp., annual grasses and forbs. Emergent Atalaya hemiglauca, Acacia georginae and Ventilago viminalis may occur. Occurs on undulating plains of Tertiary limestone, associated with eroding surfaces around the Georgina River. Shallow brown clays with limestone and chert rocks. Not a Wetland. (BVG1M: 30b). 4.9.4x1c: Aristida latifolia, Astrebla spp., Dichanthium spp. and Eulalia aurea tussock grassland. Emergent Atalaya hemiglauca may occur. Bare areas commonly occur. Occurs on undulating plains of Tertiary limestone. Gravelly cracking clay soils with limestone and chert rocks. Not a Wetland. (BVG1M: 30b). |
| Supplementary description | Wilson and Purdie (1990a), F1 (LU 45), F2 (LU 48, 55), F4 (55); Neldner (1991), 43c (87) |
| Protected areas | Wiliyan-ngurru NP |
| Special values | 4.9.4: Potential habitat for threatened fauna species including bilby Macrotis lagotis, kowari Dasyuroides byrnei and plains-wanderer Pedionomus torquatus. 4.9.4a: Potential habitat for threatened fauna species including bilby Macrotis lagotis, kowari Dasyuroides byrnei and plains-wanderer Pedionomus torquatus. |
| 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 | 4.9.4: This regional ecosystem can include minor areas on Cainozoic sediments (land zone 4) (Wilson and Purdie 1990a). Floristic composition varies with stone cover, seasonal conditions, fertility and land use. On western plains, a dense silcrete stone cover may be present, and restricts Astrebla pectinata to gilgai situations. A. lappacea rarely occurs where a dense surface gravel is present. A. elymoides may be co-dominant in wetter situations. Density and diversity of ephemeral forbs and grasses present depends on seasonal conditions. Naturalised species associated with this regional ecosystem include *Vachellia farnesiana which is scattered along drainage lines. 4.9.4a: This regional ecosystem can include minor areas on Cainozoic sediments (land zone 4) (Wilson and Purdie 1990a). Floristic composition varies with stone cover, seasonal conditions, fertility and land use. On western plains, a dense silcrete stone cover may be present, and restricts Astrebla pectinata to gilgai situations. A. lappacea rarely occurs where a dense surface gravel is present. A. elymoides may be co-dominant in wetter situations. Density and diversity of ephemeral forbs and grasses present depends on seasonal conditions. Naturalised species associated with this regional ecosystem include *Vachellia farnesiana which is scattered along drainage lines. |
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.
