Regional ecosystem details for 4.3.9
| Regional ecosystem | 4.3.9 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 1, 7, 4, 5.1, (5), (1.3), (5.2), (6), (10.4), (5.4), (2.5), (1.1), (5.3), (2), (10.2) |
| Estimated extent1 | Pre-clearing 119000 ha; Remnant 2021 110000 ha |
| Short description | Acacia cambagei and/or A. georginae low woodland on alluvial plains |
| Structure code | Low Woodland |
| Description | Acacia cambagei and/or A. georginae low open forest to tall open shrubland. A shrub layer commonly occurs, typically dominated by A. cambagei or A. georginae. The ground layer is dominated by tussock grasses, including Eragrostis setifolia, Astrebla spp., Aristida latifolia and Bothriochloa ewartiana. A variety of forbs from the families Asteraceae, Chenopodiaceae, Fabaceae and Malvaceae may be seasonally abundant. Occurs on alluvial plains (commonly in braided systems). Soils vary from deep, red and brown cracking clays to alluvial texture contrast soils and non-cracking clays. Not a Wetland. (BVG1M: 26a). Vegetation communities in this regional ecosystem include: 4.3.9a: Acacia georginae tall open shrubland, occasionally with Corymbia terminalis, Atalaya hemiglauca and Eucalyptus coolabah. A lower shrub layer may occur, including Acacia georginae, Senna spp. and Eremophila spp. The ground layer is sparse tussock grasses. Occurs on narrow alluvial plains associated with minor watercourses in Tertiary clay plains and limestone landscapes in the far west of the bioregion. Systems are commonly braided. Stripped cracking clay soils with surface gravel lag. Not a Wetland. (BVG1M: 26a). 4.3.9b: Acacia georginae and/or Acacia cambagei low open woodland, occasionally with Atalaya hemiglauca and Eucalyptus coolabah. A lower shrub layer of Acacia georginae and/or Acacia cambagei commonly occurs. The ground layer is patchy tussock grasses. Occurs on narrow, active Quaternary alluvial plains with a mixture of sand and clay material in the west of the bioregion. Loams and clays. Surface gravel commonly occurs. Not a Wetland. (BVG1M: 26a). 4.3.9c: Acacia cambagei low woodland to low open forest. A shrub layer may occur, including Acacia cambagei, Eremophila spp. and Myoporum acuminatum. The ground layer is patchy tussock grasses and forbs. Occurs on active Quaternary alluvial plains in the east of the bioregion. Silty clay soils, commonly gravelly. Not a Wetland. (BVG1M: 26a). |
| Supplementary description | Neldner (1991), 28c (23); Wilson and Purdie (1990a), W2 (11) |
| Protected areas | Lochern 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 | 4.3.9: In many areas 30-50% of tall shrubs stand dead, although regeneration of Acacia georginae present in some areas (Neldner, 1991). |
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.
