Scotia Sanctuary - Ecosystems / Plants
Mallee-spinifex habitat – Scotia Sanctuary
Eight ecosystems have been mapped for Scotia , although substantial ground-truthing is still required. Community distribution is largely determined by the influence of minor changes in topography and associated soil type on soil water relations, and history of disturbance: Eucalyptus shrublands are confined to sandy soils on the dunes and sandy swales, while Casuarina woodlands are found in the swales and calcareous plains of loamy solonised brown soils.
Sandy soils have a lower field capacity for water storage than soils with a higher clay content due to larger average soil particle size and larger pore spaces within the soil matrix. However, larger soil particle size also results in increased water infiltration in sandy soils, and reduced evaporation rate due to poor capillary development and a lower matrix potential for extraction of water from the pore spaces. Combined with greater potential rooting depth, these factors appear to compensate for reduced field capacity, resulting in greater year round water availably on dunes than in swales or on heavier soils. The eight ecosystems are:
1. Casurina Pauper Woodland
Casuarina pauper , growing to 10 - 12 m, occurs as a dominant species on the brown loamy sands of interdune areas. It is frequently associated with Alectryon oleifolius ssp. canescens and/or Myoporum platycarpum. Commonly associated understorey shrubs include Enchylaena tomentosa, Chenopodium curvispicatum, Maireana pentatropis, Maireana georgei, Sclerolaena obliquicuspis, Eremophila sturtii, Olearia muelleri, Senna artemisioides ssp. filiformis, Senna aretemisioides ssp. petiolaris and Senne artemisioides nothosp. coriacea. Frequently occurring grasses and herbs include Stipa spp., Vittadinia cuneata and Dissocarpus paradoxus.
2. Eucalyptus Open-Shrubland
Eucalyptus open-shrubland dominated by Eucalyptus oleosa, Eucalyptus gracilis and Eucalyptus dumosa to 8 m occurs on interdune plains of sandy-loam solonised soils. Associated understorey shrubs include Enchylaena tomentosa, Chenopodium curvispicatum, Chenopodium desertorum, Atriplex stipitata, Maireana pentatropis, Maireana georgei, Sclerolaena obliquicuspis, Eremophila sturtii, Olearia muelleri, Senna artemisioides subspecies, Myoporum platycarpum, Dodonea viscosa ssp. angustissima and Acacia colletioides. Frequently occurring grasses and herbs include Stipa sp., Vittadinia cuneata, Dissocarpus paradoxa and Chenopodium cristatum.
3. Eucalyptus Open-Shrubland Of Eucalyptus Gracilis
A Eucalyptus gracilis mallee community, growing to 8 m and in which Melaleuca lanceolata is a prominent component, occurs in association with salt lakes. Associated shrubs confined to this community include Leptospermum coriaceum, Acacia rigens and Hibbertia virgata. Disphyma crassifolium ssp. clavellatum is a common component of the ground layer.
4. Eucalyptus Open-Shrubland With Triodia Understorey
On low dune ridges Eucalyptus open-shrubland to 8 m occurs and is characterised by the presence of Triodia scariosa as the dominant component of the understorey. The most frequent dominants are Eucalyptus socialis, Eucalyptus dumosa and Eucalyptus gracilis, with Eucalyptus oleosa, Eucalyptus costata and Eucalyptus leptophylla as more occasional associates. Commonly associated shrubs include Dodonea viscosa ssp. angustissima, Maireana pentatropis, Eremophila glabra and Grevillea huegelii. Associated grasses and herbs include Stipa spp., Podolepis capillaries and Vittadinia cuneata.
5. Low Open-Shrubland
A vegetation community dominated by varying proportions of Halosarcia pergranulata, Halosarcia indica, Halosarcia halocnemoides ssp. halocnemoides, Frankenia spp. and Osteocarpum acropterum ssp. diminutum is found in association with an ephemeral salt lake.
6. Atriplex Versicaria Low Open-Shrubland
An open shrub community dominated by Atriplex versicaria is generally associated with salt lakes. Frequently associated species include Lycium australe, Disphyma crassifolium ssp. calvellatum, Maireana pentratropis, Sclerolaena obliquicuspis and Stipa spp.
7. Mixed Shrubland
In a number of areas Dodonea viscosa ssp. angustissiam and/or Eremophila sturtii form stands of varying density to approximately 2 m. The understorey consists of a variety of grasses and herbs. This community has resulted from past clearing of Eucalyptus open shrubland or Casuarina pauper woodland.
An artificial community consisting of largely exotic grasses and herbs with no associated shrubs. This community generally occurs around the more reliable ground water tanks.
Despite previous disturbance, Scotia supports some of the most intact examples of Eucalyptus spp. open shrubland and Casuarina pauper woodland in New South Wales.