Regional ecosystem details for 4.9.14
| Regional ecosystem | 4.9.14 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 7, 3, 1, 2, 5, (1.1), (1.3), (5.1), (5.4), (5.3), (1.2), (2.3) |
| Estimated extent1 | Pre-clearing 476000 ha; Remnant 2021 465000 ha |
| Short description | Acacia georginae or A. cambagei low open woodland with Astrebla spp. on limestone |
| Structure code | Low Open Woodland |
| Description | Acacia georginae or A. cambagei low open woodland to tall open shrubland. Scattered Senna artemisioides subsp. oligophylla shrubs are usually present. The ground stratum is dominated by Astrebla pectinata with Aristida latifolia, Eragrostis setifolia and the ephemerals Enneapogon avenaceus, Iseilema vaginiflorum, and Tripogon loliiformis occurring frequently. A variety of ephemeral and some perennial forbs may be present, the former often becoming seasonally prominent. Frequent species include Sclerolaena lanicuspis, Crotalaria dissitiflora, Goodenia fascicularis, Rhynchosia minima, Salsola australis, Sida fibulifera, S. trichopoda and Zygophyllum ammophilum. Species from Asteraceae, Chenopodiaceae, Malvaceae and other families occurs infrequently. Occurs on flat to gently undulating plains formed from Cainozoic deposits overlying limestone. Soils are moderately deep-to-deep, red cracking clays with self-mulching surfaces. Weak gilgai micro relief and surface crusts are common. Soils are moderately to very strongly alkaline usually with lime present throughout the profile and small amounts of gypsum at depth. Scattered siliceous and ironstone gravel occurs at the surface. Not a Wetland. (BVG1M: 26a). Vegetation communities in this regional ecosystem include: 4.9.14x1: Acacia cambagei grassy tall open shrubland (Ht 5-7m; density 50-150/ha) becoming a shrubby open tussock grassland in some areas. Occurs on gently undulating plains (0-1%) formed on alluvial clay plains overlying a wide range of geological beds. Not a Wetland. (BVG1M: 26a). 4.9.14x40: Acacia georginae and/or Acacia cambagei low open woodland to tall open shrubland, occasionally with Atalaya hemiglauca, Corymbia terminalis and Acacia excelsa subsp. angusta. A shrub layer of Acacia georginae and/or Acacia cambagei commonly occurs. The ground layer is patchy tussock grasses. Occurs on Tertiary clay plains and early Quaternary clay deposits in the west of the bioregion. Cracking clay soils, commonly with surface gravel lag. Not a Wetland. (BVG1M: 26a). 4.9.14x40a: Acacia cambagei and/or Acacia georginae low open woodland, occasionally with Atalaya hemiglauca, Corymbia terminalis and Acacia excelsa subsp. angusta. A lower shrub layer of Acacia cambagei and/or Acacia georginae commonly occurs. The ground layer is patchy tussock grasses. Occurs on eroding margins of Tertiary clay plains and high-level, old alluvial deposits east of the Georgina River. Cracking clay soils, commonly with surface gravel lag. Not a Wetland. (BVG1M: 26a). 4.9.14x40b: Acacia georginae tall open shrubland, occasionally with Atalaya hemiglauca, Corymbia terminalis and Acacia excelsa subsp. angusta. A lower shrub layer of Acacia georginae commonly occurs. The ground layer is patchy tussock grasses. Occurs on eroding margins of Tertiary clay plains and high-level, old alluvial deposits west of the Georgina River. Cracking clay soils, commonly with surface gravel lag. Not a Wetland. (BVG1M: 26a). 4.9.14x40c: Acacia georginae and/or Acacia cambagei low open woodland, occasionally with Atalaya hemiglauca, Corymbia terminalis and Acacia excelsa subsp. angusta. A lower shrub layer of Acacia georginae and/or Acacia cambagei commonly occurs. The ground layer is patchy tussock grasses. Occurs on early Quaternary clay deposits associated with the edges of broad sand sheets of the Northwest Highlands bioregion. Cracking clay soils, commonly with surface gravel lag. Not a Wetland. (BVG1M: 26a). 4.9.14x41: Mixed low open woodlands, with combinations of the species Atalaya hemiglauca, Ventilago viminalis, Grevillea striata, Acacia cambagei and Vachellia sutherlandii. Occurs on Tertiary clay plains. Cracking clay soils, commonly with surface gravel lag. Not a Wetland. (BVG1M: 27b). 4.9.14x42: [RE not in use]²: This regional ecosystem is now mapped as 4.9.11x40. Acacia cambagei low open woodland. A shrub layer dominated by Acacia cambagei may occur. The ground layer is sparse tussock grasses. Occurs on Tertiary high-level clay alluvial deposits near the Thomson River. Commonly gravelly. Not a Wetland. (BVG1M: 26a). 4.9.14x43: Acacia cambagei tall open shrubland to low open woodland. The ground layer is dominated by Astrebla spp. Occurs on gently undulating plains of wind-blown clay (parna) overlying Tertiary limestones/mudstones. Red powdery clays. Not a Wetland. (BVG1M: 26a). 4.9.14x44: Acacia cambagei low open woodland, occasionally with Atalaya hemiglauca. A shrub layer of Acacia cambagei commonly occurs. The ground layer is bare to very sparse tussock grasses and forbs. Occurs on high-level, Tertiary alluvial deposits associated with the Kynuna Plateau subregion. Red-brown clay soils, usually with a thick gravelly or cobbly surface. Not a Wetland. (BVG1M: 26a). |
| Supplementary description | Wilson and Purdie (1990a), T2 (40); Neldner (1991), 10a, 10b (20) |
| Protected areas | Diamantina NP |
| Fire management guidelines | SEASON: Wet to early dry season when soil is moist. INTENSITY: Low. INTERVAL: Broad interval range of 6-10 years for open acacia with grassy understorey. INTERVAL_MIN: 6. INTERVAL_MAX: 10. STRATEGY: Patchy, within the 20-30% range of area burnt. ISSUES: Acacias (e.g., gidgee) germinate infrequently following high rainfall events, mature slowly and are long-lived. Acacias are vulnerable to frequent and high-severity fires. Fire in surrounding fire-adapted communities can be used to mitigate against wildfire. Fuel loads within Acacia communities can sometimes also require infrequent patchy burns, particularly following years of good rain, to protect them from wildfire and promote diversity at the ground layer. Long absence of fire can result in canopy closure by Acacias and lead to self-protection of these communities. Introduced invasive grasses (e.g., buffel Cenchrus ciliaris) may increase the risk and severity of fires. |
| Comments | 4.9.14: Ephemeral herbs occur seasonally, grasses in summer and forbs in winter. This regional ecosystem occurs on Cainozoic deposits (land zone 4). Ephemeral herbs occur seasonally, grasses in summer and forbs in winter. 4.9.14x1: Occurs on alluvial clay plains (land zone 3). 4.9.14x40: Was previously partly mapped as 4.4.1x3. 4.9.14x41: 4.4.1a has been amalgamated into this RE. |
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.
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.
