Buttongrass moorland is vegetation less than two metres in height, in which the hummock forming plant known as 'buttongrass' (Gymnoschoenus sphaerocephalus
) is usually dominant or common. Buttongrass may form almost pure swathes or be a less important component of the buttongrass moorland assemblage that includes other sedges (plants in the family Cyperaceae), cord rushes (plants in the family Restionaceae), herbs and shrubs.
A state-wide classification of this vegetation defined 25 major communities of buttongrass moorland (Jarman et al. 1988). Ten mapping units are currently used to map buttongrass moorland in Tasmania's state-wide vegetation map, TASVEG (see Forest to Fjaeldmark for descriptions). Shrubs may form a separate stratum above the layer of graminoids (sedges and cord-rushes), or they may be short and interspersed within the graminoid layer. A low cover of shrubs, and/or a modest to high cover of
Gymnoschoenus sphaerocephalus and other graminoids are useful criteria for discriminating buttongrass moorland from wet heathland, shrubland or scrub vegetation with a similar floristic composition.
Distribution of buttongrass moorland
Buttongrass moorlands are extensive in western and central Tasmania on flats, slopes, ridges and mountain plateaus below 1000 m elevation, in situations where fires are frequent and soils are infertile and poorly drained. Buttongrass moorlands are less common in eastern Tasmania and on the Australian mainland.
Buttongrass moorland is extremely well represented in Tasmania's reserve system and is relatively rare on private land.
Where to find buttongrass moorland
Buttongrass moorland can be seen from all the main roads in western Tasmania. The Peter Murrell Nature Reserve at Huntingfield, south of Hobart, contains small areas of buttongrass.
Biodiversity values of buttongrass moorland
About 272 vascular plant species are recorded from buttongrass moorland, one third of which are endemic to Tasmania. Included among these is northwest heath (Epacris curtisiae), which is listed as rare. Among the most threatened fauna species that use buttongrass moorland is the orange-bellied parrot (Neophema chrysogaster). Species such as the emu wren (Stipiturus malachuru), striated field wren (Calamanthus fuliginosus), tawny crowned honeyeater (Phylidonyris melanops), broad-toothed rat (Mastacomys fuscus), and ground parrot (Pezoporus wallicus) are other animals that depend on buttongrass moorland habitat.
Refer to the Threatened Species Link for more information on these species.
Fire management in buttongrass moorland
Buttongrass moorland vegetation is highly flammable and usually regenerates rapidly after fire. However, summer fires, or inappropriate fire intervals may cause the combustion of organic soils, leading to soil erosion and a loss of biodiversity.
The appropriate interval between fires depends on factors such as soil fertility and altitude, which affect the vegetation growth rate. In relatively fertile areas moorlands may become overgrown by shrubs or the growth of buttongrass tussocks may shade out the smaller plants. In such areas shorter fire intervals (e.g. 5 to 20 years) will help maintain buttongrass moorland patches.
Where there is no evidence that moorlands will convert to scrub, such as in high altitude and/or low fertility areas, longer fire intervals are recommended (e.g. 15 to 40 years), and particular care with fire management will be needed on slopes and where soil erosion is evident. However, even in areas where longer fire intervals are desirable it may be important to undertake more frequent management burns in strategic areas when soils are saturated in order to reduce fuel loads, thereby reducing the risk of landscape-scale summer fires.
Autumn burns are preferable to spring burns as they avoid harming ground-nesting birds such as the ground parrot. Ideally, fires should be intense enough to remove foliage, thatch and litter but not so intense that they burn the organic soils or roots. Burning in small patches, or retaining islands of unburnt vegetation will enable faster recolonisation from unburnt edges. Browsing pressure is likely to be greatest in areas close to unburnt vegetation, and in these areas less palatable plant species may have a competative advantage.
Buttongrass moorland is not suitable for domestic stock grazing. Fertilizing or draining will negatively impact the biodiversity values of the buttongrass moorland by causing the death of many plant species and increasing the opportunity for weed invasion.
Weeds and diseases of buttongrass moorland
Buttongrass moorland is relatively resistant to invasion by weeds, provided that the soil nutrient levels are not raised. However, many shrub species in this community are susceptible to dieback caused by Phytophthora cinnamomi (also known as cinnamon fungus). This pathogen is spread by the movement of infected soil, mud and water. To prevent spread of disease ensure you clean boots, machinery and vehicles before moving from an infected area into an uninfected area.
Brown, M.J. (1999) Buttongrass moorlands, Chapter 13 In J.B. Reid, R.S. Hill, M.J. Brown and M.J. Hovendon (eds) Vegetation of Tasmania, Flora of Australia supplementary Series Number 8, Australian Biological Resources Study, Hobart, pp 286–303.
Jarman, S.J., Kantvilas, G. & Brown, M.J. (1988) Buttongrass Moorland in Tasmania. Research Report No. 2. Tasmanian Forest Research Council Inc.
Balmer, J. (ed.) 2010, Proceedings of the 2007 buttongrass moorland management workshop. Nature Conservation Report 2010/4. Department of Primary Industries, Parks, Water and Environment, Hobart, Tasmania.