Edition 2 From Forest to Fjaeldmark The Vegetation Communities Scrub, heathland and coastal complexes Correa alba Edition 2 From Forest to Fjaeldmark 1 Scrub, heathland and coastal complexes Community (Code) Page Acacia longifolia coastal scrub (SAL) 12 Banksia marginata wet scrub (SBM) 14 Broad-leaf scrub (SBR) 16 Coastal heathland (SCH) 18 Coastal scrub (SSC) 21 Coastal scrub on alkaline sands (SCA) 23 Eastern riparian scrub (SRE) 25 Eastern scrub on dolerite (SED) 28 Heathland on calcareous substrates (SCL) 30 Kunzea ambigua regrowth scrub (SKA) 32 Leptospermum glaucescens heathland and scrub (SLG) 34 Leptospermum lanigerum scrub (SLL) 37 Leptospermum scoparium heathland and scrub (SLS) 39 Leptospermum with rainforest scrub (SRF) 41 Melaleuca pustulata scrub (SMP) 43 Melaleuca squamea heathland (SMM) 45 Melaleuca squarrosa scrub (SMR) 47 Rookery halophytic herbland (SRH) 49 Scrub complex on King Island (SSK) 51 Spray zone coastal complex (SSZ) 53 Subalpine heathland (SHS) 55 Western regrowth complex (SWR) 57 Western subalpine scrub (SSW) 59 Western wet scrub (SWW) 61 Wet heathland (SHW) 63 Edition 2 From Forest to Fjaeldmark 1 General description The communities in this section are structurally and floristically variable and are divided into mapping Scrubs, heathlands and the diverse complexes that units on the basis of the nature or identity of the they may form are, with a few notable exceptions, dominant or most common species, and to a lesser dominated by scleromorphic species. The canopy extent on structure and habitat. structure of the woody plants in these communities varies from 30 to 100% solid crown cover and is usually 5 m or less in height. While this height is the Ecological theory arbitrary divide between forest (including woodland) Scrub and heathland communities may represent and scrub (Specht 1970), taller vegetation is included either biotic climax or a particular stage in vegetation in these mapping units when it maintains a dense development within a sere, depending on where scrubby structure and/or a floristic composition they occur. Climax vegetation is capable of indistinguishable from communities typically 5 m or remaining floristically and structurally stable for long less in height. periods in the absence of disturbance. Vegetation representing stages in a sere change floristically and Scrub and heathland communities typically have only structurally over time in the absence of disturbance. two strata; a dominant layer of shrubs comprising Where vegetation changes rapidly in its structural one to many species; and a ground layer of herbs, and/or floristic form, it will present a challenge for orchids, prostrate shrubs, ferns and occasionally mapping due to its temporal instability. grasses and/or sedges. Some heath and scrub vegetation also includes emergent trees, but where Trees are excluded from areas of biotic climax present, these never form more than 5% solid vegetation by the presence of climatic, hydrologic, or crown cover. soil factors that prevent tree growth or survival. Examples of habitats where heathland and scrub The ground layer is often sparse in vegetation cover may form stable biotic climax communities include and species richness, although it may be diverse mature vegetation in coastal habitats subject to salt- and/or dense in the more open-canopy spray and wind-pruning, where shrub species are communities. If shrubs form less than a 30% solid rarely able to reach heights in excess of 5 m. crown cover over a ground layer dominated by grasses, sedges or rushes, then the vegetation is not Large areas of heathland and scrub occur in areas considered part of Scrub, heathland and coastal where natural successional processes which would complexes. normally lead to the development of forest have been deflected by disturbance. Fire frequency is the Areas mapped in TASVEG by units described in most common driver of vegetation succession in Scrub, heathland and coastal complexes occur from Tasmania. Fire in combination with other factors sea level to about 1200 m and on a range of rock such as infertile substrates, frequent water-logging or types in all climates. desiccation, and/or frost leads to the development Not all heath and scrub vegetation is mapped in of scrub and heathland by excluding trees. Areas units described in this section. Heathland and scrub with frequent fire are most commonly occupied by in alpine areas are dealt with in the section Highland sedgeland or grassland while forests occur where treeless vegetation. Scrub forming vegetation with a fires are relatively infrequent (Jackson 1968, Brown prominent component of rainforest species (sensu and Podger 1982, Ellis 1985). Scrub is common in Jarman et al. 1984) is classified in the section areas with an intermediate fire frequency. Rainforest and related scrub. Also excluded from Vegetation characteristics, climate, topographic this section are floristic communities which in factors and human behaviour all affect the restricted situations have a mature height of less disturbance regimes. Different combinations of than 5 m but elsewhere commonly develop into disturbance regimes, climate and edaphic situations forest. For example, Melaleuca ericifolia dominated result in the development of different vegetation vegetation is always mapped as Melaleuca ericifolia communities. Thus there are complex feedbacks swamp forest (NME) within the Non-eucalypt forest between vegetation, micro-climate, soil and and woodland section even when it forms a low disturbance regimes, which reinforce the presence of dense shrubbery in coastal areas. The Intersectional particular vegetation stages and prevent succession Key and keys to each section will redirect users to to climax vegetation communities. the appropriate section and mapping unit. Edition 2 From Forest to Fjaeldmark 2 The vegetation community resulting from a leaf scrub (SBR). The description for SBR was particular and persistent disturbance regime is broadened to include forest forms of the assemblage referred to as ‘meta-stable’, since it usually re- previously described by NNP. establishes quickly after disturbance and is disturbed Three of the five complexes described previously again before later-stage succession can take place. were discontinued and have been replaced by finer- scale mapping of areas previously covered by these Mapping scrub and heathlands units. The units Heathland scrub mosaic on Flinders In general, TASVEG mapping attempts to represent Island (SHF) and Heathland scrub complex at the vegetation as it appears from the most current Wingaroo (SCW) have been differentiated into their source imagery. However in some instances it is component communities which include Freshwater obvious that a recent disturbance has given rise to a aquatic sedgeland and rushland (ASF) and Wet pioneer community likely to persist for a short heathland (SHW). The unit Seabird rookery duration only. Where there is evidence that the complex (SRC) has also been differentiated into its pioneering vegetation will be replaced quickly by a major component communities by fine-scale meta-stable vegetation community, then it is the mapping. Where tussock grasses dominated rookery meta-stable vegetation type (usually the pre- vegetation, these are now mapped (where of disturbance community) that is mapped. This can be sufficient size) to the most appropriate grassland achieved using information from earlier imagery or unit, while the taller heathy vegetation is likely to deduced from undisturbed remnants. have become Coastal heathland (SCH). However a new unit has been erected to distinguish the Classification review herbaceous-halophytic shrubland component of A recent review of the mapping units in the Scrub, rookery vegetation. The new unit, Rookery heathland and coastal complexes section led to halophytic herbland (SRH), has only the superficial changes in the TASVEG classification at the end of resemblance to any of the other heathlands and 2012. The unit descriptions, the key for the section scrubs, but it is included here because of its and the Intersectional Key were all revised to proximity to coastal heathlands and scrub with describe more accurately the vegetation that is which it has at least some species in common. The included in each unit and how they are distinguished new unit will not be confined to mapping of seabird in the new classification. Several units were rookery areas but will be used to map any areas of discontinued. These units will continue to appear in vegetation with this floristic composition. TASVEG only until the mapping of these areas can Coastal complex on King Island (SCK) has been be revised and reallocated to other units. For revised and renamed Spray zone coastal complex descriptions to these discontinued units consult the (SSZ). The redefined unit excludes coastal scrub and first edition of Forest to Fjaeldmark (Harris and heathland although inevitably some will be Kitchener 2005). Several new units have been incorporated unintentionally due to the constraints erected and will map at least part of the extent of of mapping scale. SSZ still includes a complex of these communities for the first time in version 3.0 of vegetation formations, but will no longer be the TASVEG data set. More accurate and complete restricted to mapping King Island vegetation. SSZ has coverage of new units will be provided in later been broadened to map spray zone vegetation in versions of TASVEG as the mapping is revised. exposed coastal areas of Tasmanian and its off-shore As part of the change in classification two units were islands. Vegetation not matching the description for removed from other sections and placed into the this new unit on King Island will be placed in the best Scrub, heathlands and coastal complexes section. matching coastal unit available, most commonly One of these was Leptospermum with rainforest Coastal heathland (SCH). scrub (RLS) which was moved into this section from The other two complexes were retained—Scrub the Rainforest and related scrub section because complex on King Island (SSK) and the Queenstown rainforest species do not dominate the community. regrowth mosaic (SQR), although the latter has The new code is for this unit is SRF.