Regional ecosystem details for 8.12.13
| Regional ecosystem | 8.12.13 |
|---|---|
| Vegetation Management Act class | Of concern |
| Wetlands | Not a Wetland |
| Biodiversity status | Of concern |
| Subregion | 2, 1, 5, 4, (6), (11.14) |
| Estimated extent1 | Pre-clearing 5000 ha; Remnant 2021 5000 ha |
| Short description | Tussock grassland, or Xanthorrhoea latifolia shrubland, including areas recently colonised by Timonius timon var. timon shrubland, on slopes of islands and headlands, on Mesozoic to Proterozoic igneous rocks and Tertiary acid to intermediate volcanics |
| Structure code | Tussock Grassland |
| Description | Themeda triandra and/or Imperata cylindrica and/or Chionachne cyathopoda tussock grassland to closed tussock grassland (0.3-0.7m tall), or Xanthorrhoea latifolia subsp. latifolia dwarf open shrubland to open heath (0.3 - 2m tall). Includes minor areas of recent incursion by Timonius timon var. timon and/or Macaranga involucrata var. mallotoides shrubland to closed scrub (to low closed forest to low open forest) (1.5-5m tall). Themeda triandra is the most common dominant species in this ecosystem and often forms the majority of the ground cover. Other associated species may include Heteropogon triticeus, H. contortus, Lomandra longifolia, Flemingia parviflora and Sorghum nitidum forma aristatum. Includes minor areas (especially in subregions 4 and 5) of open heath to closed heath (forming a very low wind-swept canopy of 0.2 to 0.4m). May include occasional emergents or clumps of Banksia integrifolia subsp. compar, Pandanus spp. and rainforest spp. Occurs on slopes, crests and ridges of headlands and islands (especially east and south-east facing slopes and peninsulas), on undulating low hills to rolling hills of lowlands and foothills, on Mesozoic to Proterozoic igneous rocks, and Tertiary acid to intermediate volcanics. Geologies mapped include Kw (Whitsunday Volcanics), RKvp (Peninsula Range Volcanics), DCvc (Campwyn Volcanics), SDh (Mount Holly beds) and Pll (Airlie Volcanics). Early Cretaceous - Late Silurian waterlaid acid to intermediate air-fall pyroclastics and minor pyroclastic flows. Not a Wetland. (BVG1M: 32b). Vegetation communities in this regional ecosystem include: 8.12.13a: Themeda triandra and/or Imperata cylindrica and/or Chionachne cyathopoda tussock grassland to closed tussock grassland (0.3-0.7m tall), or Xanthorrhoea latifolia subsp. latifolia dwarf open shrubland to open heath (0.3 - 2m tall). Occasional emergents may include Banksia integrifolia subsp. compar, Pandanus spp. and rainforest spp. Themeda triandra is the most common dominant species in this ecosystem and often forms the majority of the ground cover. Other associated species may include Heteropogon triticeus, H. contortus, Lomandra longifolia, Flemingia parviflora, Chrysopogon fallax, Alloteropsis semialata, Panicum effusum, Glycine tomentella, Crotalaria montana, Dianella spp. and Sorghum nitidum forma aristatum. Includes minor areas (especially in subregions 4 and 5) of open heath to closed heath (forming a very low wind-swept canopy of 0.2 to 0.4m) with dominant species often including Xanthorrhoea latifolia subsp. latifolia, Grevillea banksii, Allocasuarina littoralis, Dodonaea lanceolata, Leptosema oxylobioides, Lithomyrtus obtusa, Pomaderris canescens, Pseudanthus orientalis and Chorizema parviflorum. Occurs on slopes, crests and ridges of headlands and islands (especially east and south-east facing slopes and peninsulas), on undulating low hills to rolling hills of lowlands and foothills, on Mesozoic to Proterozoic igneous rocks, and Tertiary acid to intermediate volcanics. Geologies mapped include Kw (Whitsunday Volcanics), RKvp (Peninsula Range Volcanics), DCvc (Campwyn Volcanics), SDh (Mount Holly beds) and Pll (Airlie Volcanics). Early Cretaceous - Late Silurian waterlaid acid to intermediate air-fall pyroclastics and minor pyroclastic flows. Not a Wetland. (BVG1M: 32b). 8.12.13b: Timonius timon var. timon and/or Macaranga involucrata var. mallotoides shrubland to closed scrub (to low closed forest to low open forest) (1.5-5m tall). Pittosporum ferrugineum is sometimes a codominant or prominent canopy species. Other occasional canopy species may include Acacia spirorbis subsp. solandri, Bursaria tenuifolia, Neolitsea brassii, Glochidion lobocarpum and Macaranga tanarius. Other rainforest pioneering species may occasionally be present. A lower shrub layer is sometimes present, consisting of similar species to the upper layer. The ground layer is grassy, and dominated by species such as Chionachne cyathopoda, Imperata cylindrica and Sorghum nitidum forma aristatum. Occurs on slopes, ridges and crests (of headlands and islands) on rolling low hills, steep low hills and rolling hills of lowlands and foothills, on Mesozoic to Proterozoic igneous rocks, and Tertiary acid to intermediate volcanics. The main geology types are Kw (Whitsunday Volcanics), Kg and Pll (Airlie Volcanics). Early Cretaceous - Early Permian waterlaid acid to intermediate air-fall pyroclastics, minor pyroclastic flows and lavas. Includes leucocratic alkali granite, granophyre and quartz syenite. Not a Wetland. (BVG1M: 28e). 8.12.13x1: Bare rock with scattered shrubs and low trees. Occurs on slopes, ridges and crests (of headlands and islands) on Mesozoic to Proterozoic igneous rocks, and Tertiary acid to intermediate volcanics. The main geology types are Kw (Whitsunday Volcanics), Kg and Pll (Airlie Volcanics). Early Cretaceous - Early Permian waterlaid acid to intermediate air-fall pyroclastics, minor pyroclastic flows and lavas. Includes leucocratic alkali granite, granophyre and quartz syenite. Not a Wetland. (BVG1M: 29a). |
| Supplementary description | Bailey et al. (2003), 8HG-12, R-1-7412; Batianoff, Dillewaard and Franks (1997), Vegetation unit 21, 22 (in part); Brushe et al. (in prep), Map units 80, c74-12; Cumming (1997), Vegetation type 30; Kemp (2009) Ga, Gal, Sx, Gim, Gam, Gi, Gil, Gila, Fli, Fl |
| Protected areas | Northumberland Islands NP, South Cumberland Islands NP, Molle Islands NP, Whitsunday Islands NP, Percy Isles NP, Brampton Islands NP, Smith Islands NP, Gloucester Island NP, Lindeman Islands NP, Broad Sound Islands NP, Cape Palmerston NP, Repulse Islands |
| Special values | 8.12.13: Habitat for vulnerable plant flora species Comesperma oblongatum. There is no evidence that any of the grasslands had a tree cover in pre-clearing times. Important habitat for ground orchids. 8.12.13a: Habitat for vulnerable plant species Comesperma oblongatum. Also habitat for several species which are poorly known from the Central Qld Coast area including, Caladenia catenata, Chorizema parviflorum, Digitaria diffusa, Ophioglossum reticulatum and Zornia areolata. Also habitat for a number of species at the northern limit of their range including Hovea clavata, Phyllota phylicoides, Pseudanthus orientalis and Zornia areolata. This ecosystem most likely owes its existence to a combination of extreme windshear/salt-spray effects and a low surface rock content ensuring that it is not fire protected (Brennan 1986). It is therefore naturally restricted to exposed parts of islands and headlands. It is possible that burning by people in the Whitsundays may have maintained some of the grasslands for thousands of years. Some areas of grasslands on islands are being colonised by either Timonius timon var. timon shrubland, or vine thicket, however most grassland boundaries appear to be stable. There is no evidence that any of the grasslands had a tree cover in pre-clearing times. 8.12.13b: Habitat for Dichanthium setosum which is listed as "Vulnerable" under the Environment Protection and Biodiversity Conservation Act 1999. |
| Fire management guidelines | SEASON: 8.12.13a: Any time providing sufficient soil moisture is available. 8.12.13b: Storm burning season. INTENSITY: 8.12.13a: Low to moderate. 8.12.13b: High. INTERVAL: 8.12.13a: 2 - 4 years. 8.12.13b: 5 to 10 years. Allow to burn if fires carry from adjacent communities. INTERVAL_MIN: 2. INTERVAL_MAX: 10. STRATEGY: Aim to retain at least 50 % during any given year. ISSUES: 8.12.13a: In some areas threatened by encroachment of Timonius timon and other rainforest emergents, although the dynamics of this process are poorly understood. Need for monitoring of the geographical extent of these areas (re/- encroachment of woodland). It is likely that the extent of this system is maintained more by geology, and levels of exposure than fire. 8.12.13b: There is evidence to suggest that this ecosystem is a successional stage of ecosystem 8.12.13a. However, it should also be noted that in many areas, the later appears stable even in absence of any significant fire events (i.e. some of the Mackay coast islands). Timonius timon flowers during the period July to November, when fire is most likely to be applied. |
| Comments | 8.12.13a: Structurally similar to 8.11.9, but often with substantial floristic differences, and occurring on land zone 12. Distinguished from all other regional ecosystems and vegetation communities on Land Zone 12 by the combination of occurrence on islands and headlands, and the structure (grassland, or shrubland of Xanthorrhoea, or a very low dwarf heathland < 0.4m tall). (Heath examples are closely related to 8.12.29c, but are included in 8.12.13a when they are less than 0.4m tall at which point they are usually indistinguishable from 8.12.13a on aerial photography.). Occurs on many islands throughout the bioregion. Also found on the mainland at Grimston Point north of Airlie Beach, Blacks Beach at Mackay, Freshwater Point east of Sarina, Cape Palmerston and on the coast between Island Head Ck and Cape Manifold. Some of the island and headland grasslands remain in excellent condition, however, many have been heavily impacted by cattle, sheep, horses and especially goats. Heavy grazing appears to be directly linked to changes in species dominance, for example, many parts of 8.12.13a on St. Bees Island (grazed heavily by feral goats) are now dominated by the grasses Aristida personata, A. spuria and A. queenslandica var. dissimilis. Several weeds are a serious threat to this ecosystem, including *Stachytarpheta jamaicensis, *Lantana camara, *Centrosema molle, *Bidens pilosa, *Megathyrsus maximus and *Melinis repens. *Themeda quadrivalvis is known to occur on the Lindeman Island airstrip and is potentially a serious threat. Other currently less serious but often prominent weeds include *Ageratum conyzoides subsp. conyzoides, *Opuntia stricta, *Passiflora foetida, *Tridax procumbens, *Triumfetta rhomboidea and *Dichanthium annulatum. 8.12.13b: This vegetation community usually represents a recent (within the last few decades or years) woody incursion into grasslands. It is possible that certain burning regimes would return this community to 8.12.13a. Distinguished from all other regional ecosystems on the same land zone by the dominance of Timonius timon var. timon and Macaranga involucrata var. mallotoides. Occurs on islands from Saddleback Island near Dingo Beach in the north to Digby Island (45km east of Cape Palmerston), in the south. Also mapped on the mainland at Grimston Point north of Airlie Beach. Compromised by weed invasion on some islands. Common problem weeds include *Centrosema molle, *Lantana camara, *Bidens pilosa, *Melinis repens, *Ageratum conyzoides subsp. conyzoides and *Stachytarpheta jamaicensis. 8.12.13x1: Often close to seaward zone on continental islands. May form extensive area on some exposed islands e.g. High Peak Island. Occurs on many islands throughout the bioregion. Also found on the mainland at Grimston Point north of Airlie Beach, Blacks Beach at Mackay, Freshwater Point east of Sarina, Cape Palmerston and on the coast between Island Head Ck and Cape Manifold. |
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.
