Mountain Heathlands

In Tasmania and Australia heaths are not dominated by members of the Ericaceae as in the northern hemisphere, but by members of the closely related family Epacridaceae and other taxa particularly Leptospermum (Myrtaceae). Heaths in the more, demanding, alpine conditions found on the plateaus are composed of various combinations of mainly endemic species such as Bellendena montana, Orites acicularis, O. revolute, Persoonia gunnii (Proteaceae), Cyathodes petiolaris, Monotoca empetrifolia, Richea scoparia (Epacridaceae), Helichrysum backhousei and Olearia ledifolia (Asteraceae). The plateaus also have a number of gymnosperm dominated heath-like communities, which are unique to Tasmania. Microcachrys tetragona (Podocarpaceae) is a decumbent or semi-erect species that forms tangled heaths either carpeting the ground in pure stands or in association with Pentachondra pumila and the endemic Cyathodes dealbata (Epacridaceae). Other heath-forming endemic conifers on the plateaus are Diselma archeri (Cupressaceae) and Microstrobus niphophilus (Podocarpaceae). These can form very dense heath-like communities either individually as local dominants or in association. In more sheltered habitats they can assume shrub proportions. At slightly lower altitudes, in the sub alpine belt, heath also occurs within woodlands, especially on talus slopes or in areas affected by cold air drainage. Species more typically found in these situations are again largely represented by endemics such as Lomatia polymorpha (Proteaceae), Richea sprengeloids (Epacridaceae) and Westringia rubrifolia (Lamiaceae).

Mountain Sedgefields

Sedgefields dominated by Carpha alpina, Oreobolus oumilio and Uncinnia flaccida (Cyperaceae) occur on all of the higher mountains of Tasmania. They occupy soils that are occasionally waterlogged but may dry out during dry summers.  Their swards may be closed or open but are often dotted with various dwarf shrubs such as Hakea lissocarpus, Lissanthe montana, Olearia algida and the endemic Pernettya tasmanica (Ericaceae). Cushion plants may also be present especially Pimelea pygmea and the endemic Abrotanella fostorioides (Asteraceae). At lower altitudes, sedges may be less dominant and, in fact, Astelia alpina of the Liliaceae is the dominant species over extensive areas of waterlogged soils often forming pure stands.

Fjellfields

The term ‘fjell’ was originally used to describe a hill or mountain, a rocky or barren hill or a moor. It was first used in Australia to describe the rock-strewn areas of the Tasmanian plateaus. It has since become the basis of the word ‘feldmark (or Fjaeldmark)’ used by southern hemisphere botanists to describe exposed, often spectacular, upland communities of dwarf flowering plants mosses and lichens usually dominated by cushion plants (chamaeophytes). Paradoxically many of the plants are draught resistant despite the fact that these areas often experience high levels of precipitation. However, the explanation is that most of the water falls as snow and in some of the more exposed areas this simply gets blown away, while any water from melting snow or rain is shed as surface runoff or percolates rapidly through the fragmented substratum. On Tasmania the four main cushion plants, all endemic, is Donatia novae-hollandiae (Donatiaceae), Dracophyllum minimum (Epacridaceae), Ewartia meredithae (Asteraceae) and Pterygeropappus lawrencii (Asteraceae). Other cushion plants may include Abrotanella forsterioides, Centrolepis monogyna and Phyllachne colensoi, but, in addition, there are a number of mosses that form cushion such as Dicranium billardieri and Racomitrium pruinosum.  These plants are covered by snow during winter and in some cases may be exposed only for a few months during summer. Their growth rates can therefore be extremely slow, but despite this they often achieve diameters of a metre or more, and often coalesce with neighbouring plants to form a tight mosaic of different species. The cushion also provide seed beds for other species and are the main habitat for certain specialist species such as Prasophyllum alpinum, one variety of Sprengelia incarnata, and the endemic Plantago gunnii (Plantaginaceae).

Tasmanian Alpine Sand Dunes

Associated with Lake Augusta on the Central Plateau of Tasmania there are large parabolic dunes. This is an extremely rare feature of alpine zones and has considerable conservation value. Beyond the foredunes zonation was not particularly strong but the vegetation could be divided in to nine vegetation types. These included Orites revoluta open shrubland, Olearia algida open shrubland, Grevillea australis open shrubland, Richea acerosa-Orites revoluta shrubland, Richea acerosa heath, Helichrysum hookeri heath, Helichrysum hookeri open shrubland, fen and marsupial lawn. However, most of these vegetation types have species in common.

Orites revoluta Open Shrubland
This vegetation, dominated by the Tasmanian endemic Orites revoluta, occurred in areas where fresh sand was being deposited on previously stable areas. Other relatively common species include Acaena novae-zelandiae and Senecio gunnii.  

Olearia algida Open Shrubland
This vegetation, dominated by the Tasmanian endemic Olearia algida, represented one of the foredune communites and characterisic some of the steeper slopes.  With its sand binding abilities it was helping to form and maintain the foredunes. Other relatively common species include Grevillea australis, Helichrysum hookeri and Lissanthe montana.

Grevillea australis Open Shrubland
Occurring on some of the less steep parts of the foredunes, this community also played a role in maintaining the stability of these dunes. Other relatively common species include Asperula gunnii, Carex gaudichaudiana, Leptorhynchos squamatus, Microseris scapigera, Oreomyrrhis ciliata, Restia australis, Velleia montana and the Tasmanian endemic Cyathodes nitida. In fact, this latter species is Central Plateau  endemic mainly confined to dunes.

Richea acerosa-Orites revoluta Shrubland
Occurring on the driest parts of stable dunes this vegetation intergrades with Richea acerosa heath where the water table comes closer to the surface. Both of the dominant species are endemic to Tasmania.  Other relatively common species include Deyeuxia monticola, Epacris gunnii and the Tasmanian endemic Monotoca empetrifolia.

Richea acerosa Heath
Heath dominated by the Tasmanian endemic Richea acerosa occurs on relatively humid, stable dunes where the water table comes close to the surface. Other relatively common species include Craspedia alpina, Empodisma minus, Epacris petrophila, Erigeron pappochromus, Leucopogon pilifer, Lycopodium fastigiatum and the Tasmanian endemic Pimelea pygmaea.

Helichrysum hookeri heath
Confined to stable dunes this community intergrades with the Richea acerosa heath in the more humid areas. Other relatively common species include Carpha alpina, Cotula alpina, Gnaphalium traversii, Hypericum japonicum and Plantago glabrata.  

Helichrysum hookeri open shrubland
This community is a feature of remobilised sand derived from well-dveloped soils. Other species include Brachyscome radicata and Schoenus calyptratus.

Fen
This vegetation, which is heavily grazed by marsupials and can have a bowling green-like surface, is characteristic of fertile, shallow, sandy clays. Many of the species found associated with other vegetation types can be found here including the Tasmanian endemic Abrotanella forsteroides.

Marsupial Lawn
Heavily grazed by marsupials, the vegetation is characteristic of deep, less fertile sands.  Typical species include Agrostis venusta, Brachyscome radicata, Gonocarpus micranthus, Hypericum japonicum, Isotoma fluvialis, Ranunculus nanus, Schoenus calyptratus, and Velleia montana.

 

References

Beadle, N. C. W. 1981. The Vegetation of Australia. Gustav Fischer Verlag.

Curtis, W. 1967. The endemic flora of Tasmania. The Ariel Press, London.

Pharo, E, J, & Kirkpatrick, J. B. 1994. Vegetation of the alpine dunes at Lake Augusta, Tasmania. Australian Journal of Ecology, 19: 319-227.