Regional ecosystem details for 4.9.17
| Regional ecosystem | 4.9.17 |
|---|---|
| Vegetation Management Act class | Of concern |
| Wetlands | Not a Wetland |
| Biodiversity status | Of concern |
| Subregion | 4, 6.4, (6.3), (11.26), (6.5), (6.6) |
| Estimated extent1 | Pre-clearing 80000 ha; Remnant 2021 10000 ha |
| Short description | Acacia harpophylla +/- A. cambagei low woodland on undulating Cretaceous sediments |
| Structure code | Low Woodland |
| Description | Acacia harpophylla low woodland, commonly with Acacia cambagei. Eucalyptus thozetiana is sometimes an emergent on upper slopes. Scattered Atalaya hemiglauca may occur. Trees such as Flindersia maculosa and Brachychiton rupestris trees and tall shrubs such as Eremophila mitchellii, Geijera parviflora, Hakea leucoptera and Alectryon oleifolius subsp. elongatus are usually present and may form a well-defined layer. The ground layer is often sparse although grasses and forbs are seasonally abundant. Dominant grasses include the perennials Paspalidium constrictum and Enteropogon acicularis and the short grass Sporobolus caroli. The forbs Abutilon oxycarpum, Sida fibulifera and Portulaca spp. occur frequently while the sub shrubs Chenopodium desertorum and Enchylaena tomentosa may be abundant. Occurs on labile Cretaceous shales. Soils are usually deep to very deep, brown to reddish brown cracking clays with soft self-mulching surfaces with variable gilgai development. Stone cover is usually light although may be heavy in scarp retreat zones. Not a Wetland. (BVG1M: 25a). |
| Supplementary description | Neldner (1984), 42a, 42b; Turner (1978), G3 (LU 17); Mills and Lee (1990), G2 (LU33) |
| Fire management guidelines | SEASON: Wet to early dry season when soil is moist. INTENSITY: Low. INTERVAL: Brigalow should be left long unburnt often for >10 years. INTERVAL_MIN: 10. INTERVAL_MAX: 50. STRATEGY: Patchy, within the 20-30% range of area burnt. ISSUES: Acacias (e.g., brigalow) 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 | 4.9.17: This was described in Sattler and Williams (1999) under 4.4.2 but has been reallocated to the correct land zone. Extensively cleared. The understorey of many remaining areas has been invaded by buffel grass *Cenchrus ciliaris. |
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.
