580 Pflanzen (Botanik)
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Wallum is widespread on coastal dunefields, beach ridge plains and associated sandy flats in northern NSW and southern Queensland. These sand masses contain large aquifers, and the wallum ecosystem is considered to be generally groundwater-dependent. This study describes the floristic composition and environmental relations of wallum on a Pleistocene barrier system at Nabiac (32˚ 09’S 152˚ 26’E), on the lower North Coast of NSW. Despite their minimal elevation and degraded relief, the Nabiac barriers maintain floristic patterns related to topography and hence groundwater relations. Comparative analyses identified the Nabiac wallum as representative of the ecosystem throughout large parts of its range in eastern Australia. The Nabiac wallum and nearby estuarine and alluvial vegetation supports species and communities of conservation significance. A borefield is proposed for development on the Nabiac barriers, thereby providing a valuable opportunity for research into mechanisms of groundwater utilisation by the wallum ecosystem.
Floristic variation in Sphagnum-dominated peatland communities of the Central Highlands, Victoria
(2007)
The floristic composition of Sphagnum-dominated peatlands in the Central Highlands region of Victoria was surveyed (37º 25´ S; 145º 50´ E). NMDS ordination and cluster analysis divided the peatland sites into two broad groups with altitude being the most important factor separating these groups. Other important factors were aspect, slope and the amount of shade. Group 1 included subalpine sites that are similar to those found at higher altitudes further east in Victoria. Important species included Empodisma minus, Epacris paludosa, Richea continentis and Baeckea gunniana. The two species of Sphagnum present were Sphagnum cristatum and the more inundation-tolerant Sphagnum novozelandicum. Group 2 included montane peatlands with abundant Sphagnum cristatum. These sites range from broad wet heaths dominated by Richea victoriana and Carex appressa, to narrower cool temperate rainforest and riparian systems. The ‘rainforest’ peatlands are characterised by Leptospermum grandifolium, Nothofagus cunninghamii, Carex appressa and Blechnum penna-marina, and are in varying stages of post-fire succession regulated by sitespecific microclimate. The conservation status and catchment function of these peatlands are briefly discussed.
Soil and vegetation data were collected from a sodic-scald near Yelarbon in southern Queensland. The surface of the landscape includes relatively light textured pedestals of the A-horizon with slightly alkaline pH and slopes leading down to scalded basement representing the surface of the strongly alkaline B-horizon. The strongest gradient within the floristic patterns was associated with wetland vegetation in drainage lines, but a secondary and orthogonal gradient was related to soil pH, which was probably a function of lower alkalinity on the more stable and weathered A-horizons. There were few significant differences between soil or vegetation characteristics from plot data comparing parts of the landscape with differing historical grazing regimes. Sites included stock routes heavily grazed between the 1920s and 1970s, and subsequently almost ungrazed; and grazed paddocks that have had moderate use throughout this period. There is clear evidence that the area is naturally active in terms of erosion and deposition during flooding regardless of grazing.
Haloragis exalata F. Muell. subspecies exalata (family Haloragaceae), a perennial forb, is currently listed as Vulnerable, under both national and New South Wales threatened species conservation legislation. Very few herbarium records existed until recently. Recent discoveries of Haloragis exalata subsp. exalata in new sites on the NSW South Coast and Southern Tablelands prompted us to carry out surveys for the two varieties of the taxon, var. exalata and var. laevis. Our surveys in 2004– 2007 aimed to relocate historical collection sites and target areas of potentially suitable habitat in these areas. Our work has substantially increased the number of known localities for Haloragis exalata subsp. exalata var. exalata. It can be locally abundant. Ecologically it appears to function as a gap species whose populations are almost invariably found at sites where disturbance through temporary inundation, physical disturbance, or fire, has exposed bare earth with higher levels of light at ground level than would be present when the local vegetation community is intact. There are morphological differences between populations in disjunct areas. Haloragis exalata subsp. exalata var. laevis is much more restricted. As a result, the conservation status of Haloragis exalata subsp. exalata may need revision, considering that a) var. exalata is more widespread than previously known, but that b) there is only one known extant population of var. laevis, and that c) the population from Geehi area may be a distinct taxon.
The vegetation of Imbota Nature Reserve (30° 35’S, 151° 45’E) (218 ha in area), 10 km south-east of Armidale, and Yina Nature Reserve (30° 29’S, 151° 45’E), (101 ha in area), 10 km east of Armidale, on the Northern Tablelands, NSW, is described. Based on classification analyses, air photo interpretation and ground-truthing, seven vegetation communities are described and mapped : 1. Eucalyptus caliginosa (Broad-leaved Stringybark) Grassy Forest and Woodland on deep soils at Imbota; 2. Eucalyptus viminalis (Manna Gum) Grassy Forest and Woodland, Community; 3. Eucalyptus caliginosa (Broad-leaved Stringybark) Grassy Forest and Woodland on shallow soils at Imbota; 4. Eucalyptus caliginosa (Broad-leaved Stringybark) Grassy Forest and Woodland at Yina; 5. Eucalyptus blakelyi (Blakely’s Red Gum) – Eucalyptus melliodora (Yellow Box) Woodland; 6. Eucalyptus viminalis (Manna Gum) – Eucalyptus nova-anglica (New England Peppermint) Grassy Forest and Woodland and 7. Riparian Herbfields 252 vascular plant taxa (from 59 families) were recorded from the two reserves, 179 species in Imbota NR, the larger reserve and 209 in Yina NR. The lower species richness at Imbota is likely to have resulted human disturbance rather than from overall habitat heterogeneity.
Wollemia nobilis Jones et al. (Wollemi Pine) is restricted to four sites growing in warm temperate rainforest typical of the canyons in the Blue Mountains and Wollemi National Parks. 88 vascular plant species were recorded from four sites. The tree canopy at all sites is dominated by Wollemia nobilis, Ceratopetalum apetalum, Doryphora sassafras and Acmena smithii. A large number of fern and vine species dominate the forest floor. Site 1 contains more species than the other sites, possibly due to its diversity of topographic features. Similarity analysis indicates that sites 2 and 3 are the most similar and sites 1 and 4 are least similar in floristic composition. 54% of plant species were recorded at one site only. Ceratopetalum apetalum, Blechnum cartilagineum and Wollemia nobilis were found to contribute most to the similarity between sites.
The aim of this study was to assess the role of currents in the dispersal of seashore species with buoyant propagules. Four introduced species which have now attained a wide distribution in southern and eastern Australia were used as indicators: Cakile edentula, Cakile maritima (Brassicaceae), Euphorbia paralias (Euphorbiaceae) and Arctotheca populifolia (Asteraceae). None arrived in Australia unaided, as all early collection localities are near ports and early long-distance dispersal within Australia was often due to shipping. Buoyancy and viability of propagules were tested to assess dispersal and colonisation potential. Propagule spread was analysed using information from herbarium specimens and fieldwork. A progression of herbarium specimen collection dates could often be explained by regional current regimes, as revealed by stranding locations of drift bottles and drift cards. The eastward spread of Euphorbia paralias from King George Sound, Western Australia, correlated well with stranding patterns of drift bottles released south of the Sound. The colonisation by Arctotheca populifolia of the southern extremity of the Eyre Peninsula and the south-east of South Australia was achieved through fruits carried from Western Australia by the Leeuwin Current. These and other congruencies between patterns of spread and the results of drifter releases are analysed and discussed.
The assumption that ‘soils’ and ‘vegetation’ are closely associated was tested by describing soils and vegetation along a Travelling Stock Reserve west of Grenfell, New South Wales (lat 33° 55’S, long 147° 45’E). The transect was selected on the basis of (a) minimising the effects of non-soil factors (human interference, climate and relief) on vegetation and (b) the presence of various soil and vegetation types as indicated by previous mapping. ‘Soils’ were considered at three levels: soil landscapes (a broad mapping unit widely used in central western NSW), soil types (according to a range of classifications) and soil properties (depth, pH, etc.). ‘Vegetation’ was considered in three ways: vegetation type (in various classifications), density/floristic indices (density of woody species, abundance of native species, etc.) and presence/absence of individual species. Sites along the transect were grouped according to soil landscapes or soil types and compared to vegetation types or indices recorded at the sites. Various measures indicated low associations between vegetation types and soil landscapes or soil types. Except for infrequent occurrences of a soil type or landscape, any one soil type or landscape was commonly associated with a number of vegetation types and any one vegetation type was associated with a number of soil landscapes or soil types. However, significant associations between some vegetation indices, mainly density or numbers of woody species, and some soil landscapes and soil types were evident. Although many species were relatively ubiquitous, some groups of species that were restricted to one or two soil types were identified. Canonical Correspondence Analysis provided some suggestions as to which properties (e.g. texture) of these soils were associated with the presence of particular species.
We examined differences in floristics among three regionally-threatened woodland communities in the western Riverina: Blackbox (Eucalyptus largiflorens), Bimble box-Pine (Eucalyptus populnea-Callitris glaucophylla) and Boree (Acacia pendula) between 2001 and 2004. Our aim was to examine possible relationships between the diversity and biomass of groundstorey vegetation, and remnant condition and rainfall both among communities and across years. The three woodland communities varied widely in their plant species composition, with only 22% of the 358 species common to all communities. Seven species, mainly exotic grasses and forbs, contributed 25% of the total cover across all sites and times. Blackbox communities had the greatest number of exotic and annual species. There were poor relationships between condition and diversity, richness, evenness or abundance of groundstorey plant species within 400 m2 quadrats. Overall, sites in better condition tended to support a greater cover of native plants and a lower cover of exotic plants (Blackbox only). There were only weak relationships between rainfall and biomass. The marked variation in species diversity in relation to changing seasonal conditions and within similar condition classes highlights the difficulties of developing benchmarks for separating the effects of management, and seasonal and longer-term climate change.
Information is provided on the taxonomy and distribution of 71 taxa of naturalised or naturalising plants newly recorded for the state of New South Wales during the period 1 January 2002 to 31 December 2003. Of these taxa, 32 are new records for Australia (prefaced with a †). These species are: Abutilon pictum, Acanthus mollis, †Aesculus indica (naturalising), Agapanthus praecox subsp. orientalis, Ajuga reptans, †Anigozanthos flavidus, Aquilegia vulgaris, Arbutus unedo, †Athertonia diversifolia (naturalising), †Bergenia x schmidtii (naturalising), Bromus catharticus subsp. stamineus, Bryophyllum daigremontianum, Bryophyllum fedtschenkoi, Calyptocarpus vialis, †Ceiba speciosa (naturalising), Cereus uruguayanus, †Cestrum x cultum, †Chamaecyparis lawsoniana, Cistus salviifolius, †Clematis montana, †Coprosma x cunninghamii, Coprosma robusta, Cornus capitata, Cotoneaster simonsii, Cotoneaster x watereri group, Crinum moorei, Cupressus lusitanica, †Cylindropuntia fulgida var. mamillata forma monstrosa, †Cylindropuntia prolifera, Cylindropuntia tunicata, Desmanthus virgatus, Drosanthemum candens, †Elaeagnus umbellata (naturalising), †Eragrostis trichophora, †Eupatorium lindleyanum, †Gibasis pellucida, Glechoma hederacea, †Hesperis matronalis, Hieracium aurantiacum subsp. carpathicola, †Inga edulis (naturalising), †Juniperus conferta (naturalising), †Justicia caudata, Lamium galeobdolon, Lathyrus tingitanus, †Lysimachia fortunei, †Maackia amurensis, †Monstera deliciosa, †Murdannia keisak, Odontonema tubaeforme, Oxalis vallicola, Phoenix canariensis, †Physostegia virginiana, Pinus patula, Pittosporum eugenioides, †Pittosporum ralphii, Pittosporum tenuifolium, Plectranthus ecklonii, †Potentilla vesca, †Prunus campanulata, †Rhododendron ponticum, Rosa luciae, Rubus rugosus, Ruellia squarrosa, †Senna multijuga, Stapelia gigantea, Stephanophysum longifolium, Strobilanthes anisophylla, †Tabebuia chrysotricha, †Tabebuia impetiginosa, †Tradescantia pallida and Ulmus x hollandica. Additional notes and name changes are recorded for plants first recognised as naturalised for New South Wales over the period 2000–2001. The identification of several naturalised taxa occurring in New South Wales has been corrected. Plants formerly identified as Pinus nigra var. corsicana are now considered to be Pinus halepensis; Cylindropuntia arbuscula is Cylindropuntia kleiniae, Cylindropuntia tunicata is Cylindropuntia rosea, Abrus precatorius subp. precatorius is now Abrus precatorius subsp. africanus and Cotoneaster ?horizontalis is Cotoneaster microphyllus. Further field studies have revealed that Cylindropuntia leptocaulis, Cylindropuntia spinosior, Hypericum kouytchense and Chamaesyce ophthalmica are more widespread than previously thought.