Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 11, Issue 4 (2010)
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This fourth paper in the NSW Vegetation Classification and Assessment series covers the Brigalow Belt South-/1(BBS) and Nandewar (NAN) Bioregions and the western half of the New England Bioregion (NET), an area of 9.3 million hectares being 11.6% of NSW. It completes the NSWVCA coverage for the Border Rivers-Gwydir and Namoi CMA areas and records plant communities in the Central West and Hunter–Central Rivers CMA areas. In total, 585 plant communities are now classified in the NSWVCA covering 11.5 of the 18 Bioregions in NSW (78% of the State). Of these 226 communities are in the NSW Western Plains and 416 are in the NSW Western Slopes. 315 plant communities are classified in the BBS, NAN and west-NET Bioregions including 267 new descriptions since Version 2 was published in 2008. Descriptions of the 315 communities are provided in a 919 page report on the DVD accompanying this paper along with updated reports on other inland NSW bioregions and nine Catchment Management Authority areas fully or partly classified in the NSWVCA to date. A read-only version of Version 3 of the NSWVCA database is on the DVD for use on personal computers. A feature of the BBS and NAN Bioregions is the array of ironbark and bloodwood Eucalyptusdominated shrubby woodlands on sandstone and acid volcanic substrates extending from Dubbo to Queensland. This includes iconic natural areas such as Warrumbungle and Mount Kaputar National Parks and the 500,000 ha Pilliga Scrub forests. Large expanses of basalt-derived soils support grassy box woodland and native grasslands including those on the Liverpool Plains; near Moree; and around Inverell, most of which are cleared and threatened. Wetlands occur on sodic soils near Yetman and in large clay gilgais in the Pilliga region. Sedgelands are rare but occupy impeded creeks. Aeolian lunettes occur at Narran Lake and near Gilgandra. Areas of deep sand contain Allocasuarina, eucalypt mallee and Melaleuca uncinata heath. Tall grassy or ferny open forests occur on mountain ranges above 1000m elevation in the New England Bioregion and on the Liverpool Range while grassy box woodlands occupy lower elevations with lower rainfall and higher temperatures. The vegetation classification and assessment is based on over 100 published and unpublished vegetation surveys and map unit descriptions, expert advice, extra plot sampling and data analysis and over 25 000 km of road traverse with field checking at 805 sites. Key sources of data included floristic analyses produced in western regional forest assessments in the BBS and NAN Bioregions, floristic analyses in over 60 surveys of conservation reserves and analysis of plot data in the western NET Bioregion and covering parts of the Namoi and Border Rivers- Gwydir CMA areas. Approximately 60% of the woody native vegetation in the study area has been cleared resulting in large areas of “derived” native grasslands. As of June 2010, 7% of the area was in 136 protected areas and 127 of the 315 plant communities were assessed to be adequately protected in reserves. Using the NSWVCA database threat criteria, 15 plant communities were assessed as being Critically Endangered, 59 Endangered, 60 Vulnerable, 99 Near Threatened and 82 Least Concern. 61 of these communities are assessed as part of NSW or Commonwealth-listed Threatened Ecological Communities. Current threats include expanding dryland and irrigated cropping on alluvial plains, floodplains and gently undulating topography at lower elevations; over-grazing of steep hills; altered water tables and flooding regimes; localized mining; and the spread of exotic species, notably Coolatai Grass (Hyparrhenia hirta).
Changes in vegetation structure and composition over a 28 year period (1978–2006) following removal of human-induced disturbances, were examined in a calcareous coastal dune system in Point Nepean National Park (380 19’S, 1440 41’E) in south-eastern Victoria, Australia. In the early 1980s human habitation of Point Nepean was abandoned and disturbance regimes such as burning, slashing and land clearing were altered or removed, providing an opportunity to study the recovery of disturbed coastal vegetation. Broad-scale and community-level vegetation changes were assessed by comparing quadrat and GIS mapping data from 1978 with data collected in 2006. Results indicate a change in broad vegetation patterns; shrubland vegetation has replaced hind dune grasslands and disturbed areas and there has been a decrease in exposed coastal areas (such as blowouts, dunes and cliffs), and an increase in woody native species and highly invasive woody weeds. The changes highlight the importance of incorporating vegetation states in planning management actions in dynamic coastal vegetation.
Defining indigenous species may at first appear straight forward; most botanical texts provide similar definitions. The consistent requirement of such definitions is the lack of human intervention in the occurrence of the species within the area under consideration. Islands around the world have been invaded by plant species brought to their shores by humans. They are also places where self-introduced species can be continually arriving, as they have done for millennia. Scrutiny of the situation on Norfolk Island (1200 km east of Australia) finds that the distinction between indigenous and introduced taxa is sometimes unclear. There is also inconsistency regarding the acceptance of self-introduced species as indigenous. This paper explores these issues and notes that they are more important than idle botanical curiosity, because control of introduced (weed) species is a major area of activity in managing protected natural areas.
Eucalyptus largiflorens (Black Box) is the most common tree in the Chowilla anabranch system on the Murray River floodplain. It typically has dull, glaucous, grey-green leaves. Occasional trees with smaller, glossy green leaves (Green Box) occur scattered amongst the Black Box. In areas with increasing salinity, they usually appear much healthier than adjacent, normal Black Box trees. Green Box plants are intermediate between normal Eucalyptus largiflorens plants and Eucalyptus gracilis plants in many morphological and allozyme characters, strongly suggesting that they are hybrids between those species. Green Box plants tolerate salinity better and use water more conservatively than normal Black Box plants, traits that they have probably inherited from Eucalyptus gracilis. In 1994, the Botanic Gardens of Adelaide used tissue culture and micropropagation to produce nearly 9,000 cloned Green Box plants which were planted out on Riverland floodplains. Since the 1990s, the high cost of producing clonal plants has meant that no further such plantings have occurred. Because Green Box plants can be a considerable distance from the nearest plants of one putative parent (Eucalyptus gracilis), more detailed studies could contribute to the existing work on such phantom hybrids.
The arid and semi-arid southwest of New South Wales has received disproportionately less attention from botanists than other similar-sized geographic regions of the state. Recent work has extended our knowledge of three extremely rare plant taxa from this part of the state. Zygophyllum compressum (Zygophyllaceae) and Elachanthus glaber (Asteraceae) are restricted to gypseous rises within active saline groundwater discharge complexes with limited distribution in southwest New South Wales and occur within the plant community “Gypseous shrubland on rises and semi-arid plains” (ID253) which is listed as threatened (vulnerable) within the state. Eremophila crassifolia (Myoporaceae) is restricted to a few plants on a roadside and adjacent mallee vegetation approximately 35 km east of Wentworth. Based on IUCN criteria it is suggested that Eremophila crassifolia is critically endangered and Zygophyllum compressum and Elachanthus glaber endangered in New South Wales and all should be listed under the NSW Threatened Species Conservation Act 1995.
The Greater Blue Mountains World Heritage Area (GBMWHA), immediately west of Sydney (33° 53’S; 151° 13’E), on the east coast of Australia was listed as World Heritage for its outstanding natural values, a major component of which is the high number of eucalypt species and eucalypt-dominated communities present, some 13 per cent of all eucalypt species in the world. They grow in a great variety of plant communities, from tall closed forests, through open forests and woodlands, to stunted mallee shrublands. This paper provides a definitive list of the 96 eucalypts (species of the genera Eucalyptus, Angophora and Corymbia in the family Myrtaceae), that have been recorded there (55 widespread, 41 restricted), together with the distribution of the eucalypts in the eight reserves that make up the GBMWHA, and information on the classification and habitat of the different species. The information is based on records held at the National Herbarium of New South Wales and the results of surveys by the NSW Department of Environment, Climate Change and Water (DECCW) over the past 20 years. The majority of species have components of both stress-tolerator and competitor ecological strategies and this has probably been a main contributor to their success. However details of the ecology of the majority of taxa are poorly-known and more research is needed to provide guidance for conservation management in the face of changing climate conditions.
