Regional ecosystem details for 11.9.3
| Regional ecosystem | 11.9.3 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 26, 15, 29, 6, (11), (6.4), (23), (10), (24), (21) |
| Estimated extent1 | Pre-clearing 269000 ha; Remnant 2021 152000 ha |
| Short description | Dichanthium spp., Astrebla spp. grassland on fine-grained sedimentary rocks |
| Structure code | Tussock Grassland |
| Description | Dichanthium sericeum and/or Astrebla spp. (A. lappacea, A. elymoides and A. squarrosa) tussock grassland. May contain high cover of short-lived perennial grasses, annual grasses and annual forbs, depending on seasonal conditions. Other frequently occurring species may include the grasses Aristida leptopoda, A. latifolia, Bothriochloa erianthoides, Digitaria brownii, D. divaricatissima, Enneapogon spp., Eriochloa crebra, Heteropogon contortus, Panicum decompositum, P. queenslandicum, Paspalidium globoideum, Themeda triandra and Thellungia advena and the forbs Abelmoschus ficulneus, Boerhavia dominii, Corchorus trilocularis, Cyperus bifax, Glycine latifolia, Ipomoea lonchophylla, Phyllanthus maderaspatensis, Tribulus micrococcus and Rhynchosia minima. Isolated low shrubs and trees and open woodland occur in some areas. Typical species include Eucalyptus melanophloia, E. orgadophila, Corymbia erythrophloia, Lysiphyllum carronii, Atalaya hemiglauca, Acacia pendula, A. omalophylla and Geijera parviflora. Occurs on gently undulating to undulating plains and rises with cracking clay soils derived from fine-grained sediments. Not a Wetland. (BVG1M: 30b). Vegetation communities in this regional ecosystem include: 11.9.3a: Eucalyptus spp., and/or Acacia spp. open woodland. Typical species include Eucalyptus melanophloia, E. populnea, E. orgadophila, Corymbia erythrophloia, Lysiphyllum carronii, Atalaya hemiglauca, Acacia pendula, A. omalophylla and Geijera parviflora. The ground layer is dominated by a similar range of species listed under 11.9.3. Occurs on gently undulating to undulating plains and rises with cracking clay soils derived from fine-grained sediments. Not a Wetland. (BVG1M: 30b). |
| Supplementary description | Galloway et al. (1974), LU14; Neldner (1984), 66, 67; Speck et al. (1968), Kiddell; Fensham (1999), bluegrass on sediments |
| Protected areas | Tregole NP, Carnarvon NP, Chesterton Range NP |
| Special values | 11.9.3: Potential habitat for NCA listed species: Cymbonotus maidenii, Swainsona murrayana. |
| 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 | 11.9.3: This regional ecosystem is known locally as 'downs'. Areas with mixed species open woodland, which often occur on rises and referred to locally as wooded downs, are mapped as 11.9.3a. Presence of dominant grass species varies with grazing and seasonal conditions. Includes areas on lightly folded older sediments in western parts of bioregion (e.g. Mantuan Downs area). Extensively cultivated and converted to pasture or cropping lands or modified by total grazing. Subject to invasion by the exotic species *Cenchrus ciliaris across its range and, in northern parts, Parthenium hysterophorus. Naturalised species associated with this regional ecosystem include *Hibiscus trionum var. trionum and *Malvastrum americanum. |
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.
