Regional ecosystem details for 4.9.11
| Regional ecosystem | 4.9.11 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 4, 5, 6, (2.5), (9.5), (5.4), (10.1), (6.9), (10.4), (10.2), (5.5), (6.6), (11.26), (6.5) |
| Estimated extent1 | Pre-clearing 1814000 ha; Remnant 2021 928000 ha |
| Short description | Acacia cambagei low woodland with scattered shrubs such as Eremophila mitchellii and Geijera parviflora on Cretaceous sediments |
| Structure code | Low Woodland |
| Description | Acacia cambagei low woodland to low open woodland. Scattered shrubs particularly Eremophila mitchellii but also Santalum lanceolatum, Geijera parviflora, Flindersia maculosa, Alectryon oleifolius and Carissa ovata can be present. Occurs on flat to gently undulating plains formed on Cretaceous sediments. Soils deep to very brown - reddish brown and grey cracking clay soils, sometimes with weak gilgai development and often with scattered surface gravel or light stone cover. Not a Wetland. (BVG1M: 26a). Vegetation communities in this regional ecosystem include: 4.9.11x1: Mixed low open woodland to low woodland, with a combinations of the species Acacia tephrina (predominantly), Acacia cambagei, Atalaya hemiglauca, Ventilago viminalis, Lysiphyllum carronii and Acacia crombiei. The ground layer is tussock grasses, predominantly Astrebla spp. Occurs on undulating plains derived from Cretaceous mudstones in northern parts of the Central Downs subregion. Cracking clay soils. Not a Wetland. (BVG1M: 27a). 4.9.11x2: Acacia tephrina and/or Acacia cambagei low open woodland to woodland, occasionally with Atalaya hemiglauca. The ground layer is tussock grasses, predominantly Astrebla spp. Occurs on undulating plains derived from Cretaceous mudstones. Cracking clay soils. Not a Wetland. (BVG1M: 27a). 4.9.11x40: Acacia cambagei low open forest to low woodland, occasionally with Atalaya hemiglauca and Santalum lanceolatum. A shrub layer may occur, including Acacia cambagei and Eremophila spp. The ground layer is sparse forbs and tussock grasses. Occurs on flat to gently undulating plains of old alluvial deposits overlying Cretaceous mudstones. Red-brown to brown cracking clays soils, commonly with scattered surface gravel. Not a Wetland. (BVG1M: 26a). |
| Supplementary description | Mills (1980), G1 (LU 38), G2 (LU 39); Neldner (1984), 40c, 44b; Neldner (1991), 5a (14); Turner (1978), G1 (15), G2 (16); Turner et al. (1993), G1, G2 (8, 9); Wilson and Purdie (1990a), T1 (LU 38) |
| Protected areas | Lochern NP, Bladensburg NP, Idalia NP, Welford NP |
| Special values | 4.9.11: High fauna diversity compared to surrounding grasslands. 4.9.11x1: High fauna diversity compared to surrounding grasslands. Habitat for Acacia crombiei (Vulnerarble). 4.9.11x40: High fauna diversity compared to surrounding grasslands. |
| 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 | 4.9.11: Gidgee thickening and spread onto adjacent grasslands has occurred between 1951 and 1994 although increases have been offset by clearing during this time (Fensham and Fairfax 2005). Major threats include further clearing and the associated fragmentation. The ground layer of much of the remnant area has been invaded by buffel grass *Cenchrus ciliaris. 4.9.11x1: Gidgee thickening and spread onto adjacent grasslands has occurred between 1951 and 1994 although increases have been offset by clearing during this time (Fensham and Fairfax 2005). Major threats include further clearing and the associated fragmentation. The ground layer of much of the remnant area has been invaded by buffel grass *Cenchrus ciliaris. 4.9.11x2: Previously mapped as 4.9.7a and 4.9.7x1. 4.9.11x40: Previously mapped as 4.9.11. x40 code denotes change of land zone (land zone 4). Regional ecosystem 4.9.14x42 has been amalgamated into this regional ecosystem. Gidgee thickening and spread onto adjacent grasslands has occurred between 1951 and 1994 although increases have been offset by clearing during this time (Fensham and Fairfax 2005). Major threats include further clearing and the associated fragmentation. The ground layer of much of the remnant area has been invaded by buffel grass *Cenchrus ciliaris. |
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.
