Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 10, Issue 4 (2008)
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This third paper in the NSW Vegetation Classification and Assessment series covers the NSW South-western Slopes Bioregion of 8.192 million hectares being 10% of NSW. A total of 135 plant communities, comprising 97 new communities and 38 previously described communities, are classified. Their protected area and threat status is assessed. A full description of the 135 plant communities is provided in a 400 page report, generated from the NSWVCA database, on the CD accompanying this paper. Eucalyptus-dominated grassy or shrubby woodlands and open forests are the main types of vegetation in the bioregion. The CD also contains a read-only version of Version 2 of the NSWVCA database that includes updated information on the plant communities previously published in Version 1 of the NSWVCA covering the NSW Western Plains. Six new communities are added to the Western Plains. The vegetation classification and assessment is based on published and unpublished vegetation surveys and map unit descriptions that are listed in the NSWVCA Bibliography on the CD, expert advice and extensive field checking. Over 80% of the native vegetation in the NSW South-western Slopes Bioregion has been cleared making it the most cleared and fragmented of the 18 IBRA Bioregions in NSW. Exotic plant species dominate the ground cover outside conservation reserves, state forests, roadsides and travelling stock reserves. As of September 2008 about 1.9% of the Bioregion was in 105 protected areas and 28 of the 135 plant communities were assessed to be adequately protected in reserves. Using NSWVCA Threat Criteria, 18 plant communities were assessed as being Critically Endangered, 33 Endangered, 29 Vulnerable, 25 Near Threatened and 30 Least Concern. Current threats include over-grazing, especially during drought, exotic species dominance of the ground cover, impacts of fragmentation on species persistence and genetic diversity and impacts of lower rainfall due to climate change. To address these threats, linking and enlarging vegetation remnants through revegetation (including regenerating native ground cover) is required. Some progress is being made through re-vegetation schemes driven by the NSW 2003 Natural Resource reforms, however, more incentive funding for landholders would accelerate the re-vegetation program.
The floristic composition and environmental relations of wetland vegetation in the Wallis Lake catchment (32˚ 09’S; 152˚ 20’E), area 1292 km2, on the lower North Coast of NSW are described. The catchment supports wetlands listed as Endangered Ecological Communities (NSW Threatened Species Conservation Act 1995) and plant species of high conservation value. A methodology of air photo interpretation, site-based sampling (114 quadrats) and landscape differentiation was developed. A total of 393 vascular plant taxa were recorded (including 10% exotics). Wetland vegetation formations and subformations including mangrove forest, swamp sclerophyll forest, wet heathland, chenopod shrubland, tussock grassland, sedgeland and rushland are described using numerical classification. 31 plant species of national or regional conservation significance are identified. Four Endangered Ecological Communities are discussed – Coastal Saltmarsh, Swamp Oak Floodplain Forest, Swamp Sclerophyll Forest on Coastal Floodplains, and Freshwater Wetlands on Coastal Floodplains. A key recommendation is the completion of reliable wetland vegetation and soil landscape mapping for all land tenures in the catchment – to assess wetland condition and conservation significance, and representation in formal conservation reserves, thereby directing future priorities for the protection of wetland biodiversity on both public and private lands. The methodology developed can be applied to the survey and conservation of wetland biodiversity in other parts of coastal NSW.
Guidelines and core attributes for site-based vegetation surveying and mapping developed for the Northern Territory, are relevant to botanical research, forestry typing, rangeland monitoring and reporting on the extent and condition of native and non-native vegetated landscapes. These initiatives are consistent with national vegetation guidelines and the National Vegetation Information System (NVIS) framework. This paper provides a synopsis of vegetation site data collection, classification and mapping in the Northern Territory, and discusses the benefits of consistency between the guidelines, core attributes and the NVIS framework; both of which has an emphasis on the NVIS hierarchical classification system for describing structural and floristic attributes of vegetation. The long-term aim of the NVIS framework is that national attributes are adopted at regional levels to enable comparability of vegetation information within survey and jurisdictional boundaries in the Northern Territory and across Australia. The guidelines and core attributes are incorporated in current and future vegetation survey and mapping programs in the Northern Territory.
Fire is an integral component of many ecosystems worldwide. Many plant species require fire-related cues, primarily heat and smoke, to trigger germination. Despite the importance of this process, the responses of many Australian species to these cues are unknown. Without this knowledge fire management strategies may be developed that are inappropriate for individual species and vegetation communities. In this study we examined the responses of a dry sclerophyll forest seed bank to heat and smoke germination cues. Analysis was possible for 48 taxa within the soil seedbank with 34 of these showing a response to one or both of the germination cues. 10 species responded to the heat treatment, 11 species responded to the smoke treatment and 13 species responded to both the heat and smoke treatments. Germination cues acted independently for all species considered. Results in this study were consistent with published reports for most species, although some differences were seen at the species and genus level. The study highlights the importance of fire-related cues in enhancing germination of a large proportion of the species occurring in dry sclerophyll forests.
Introduced perennial grasses are capable of altering the habitat of native species, causing reductions in population size and vigour, and potentially affecting life-history processes such as survival, pollination and seedling recruitment. We examined the utility of herbicide treatment on two exotic grasses, Pennisetum clandestinum (Kikuyu) and Stenotaphrum secundatum (Buffalo grass) to restore the habitat of Calystegia affinis, a critically endangered species endemic to Lord Howe and Norfolk Islands. Using two herbicides, Asset (designed to affect only grasses) and Glyphosate (a general herbicide), we compared effectiveness in reducing grass cover on a population of Calystegia affinis. We protected Calystegia plants from the herbicides by ensuring their leaves were covered by plastic bags during herbicide application. Both herbicides were similarly effective in reducing grass cover after four weeks and had no noticeable adverse affect on Calystegia (suggesting the plastic bag protection was effective). After 26 weeks, Glyphosate was more effective in maintaining a reduced grass cover. Plots treated with either herbicide had a greater relative increase in abundance of Calystegia stems compared to untreated controls. The Glyphosate treatment resulted in the greatest relative increase in stem abundance, but this was not significantly greater than in the Asset treatment. We consider that spraying with Glyphosate treatment, with follow-up monitoring and spot-spraying, will assist the recovery of the Calystegia affinis population. Ultimately, the maintenance of a weed-free zone at the forest edge will provide suitable habitat for additional recruitment of this and other native species.
The Peak Range (22˚ 28’ S; 147˚ 53’ E) is an archipelago of rocky peaks set in grassy basalt rolling-plains, east of Clermont in central Queensland. This report describes the flora and vegetation based on surveys of 26 peaks. The survey recorded all plant species encountered on traverses of distinct habitat zones, which included the ‘matrix’ adjacent to each peak. The method involved effort comparable to a general flora survey but provided sufficient information to also describe floristic association among peaks, broad habitat types, and contrast vegetation on the peaks with the surrounding landscape matrix. The flora of the Peak Range includes at least 507 native vascular plant species, representing 84 plant families. Exotic species are relatively few, with 36 species recorded, but can be quite prominent in some situations. The most abundant exotic plants are the grass Melinis repens and the forb Bidens bipinnata. Plant distribution patterns among peaks suggest three primary groups related to position within the range and geology. The Peak Range makes a substantial contribution to the botanical diversity of its region and harbours several endemic plants among a flora clearly distinct from that of the surrounding terrain. The distinctiveness of the range’s flora is due to two habitat components: dry rainforest patches reliant upon fire protection afforded by cliffs and scree, and; rocky summits and hillsides supporting xeric shrublands. Plants endemic to the Peak Range are mainly associated with the latter of these habitats.
Species area curves from 37 sites spanning the diversity of native vegetation in Queensland were examined. For the majority of sites investigated a 500 m2 plot captured about 80–90% of the vascular plant species present at the time of sampling. Floristic data collected for grassland, heathland, acacia shrublands and most eucalypt woodlands using a 500 m2 plot is appropriate for floristic analysis and adequately represent the vascular plants present at the site at the time. Using a larger plot would only slightly increase the species capture at a site but it would generally be more efficient to increase the number of sites sampled to more adequately capture the diversity across the extent of the vegetation type. However for many Queensland rainforest communities, a much larger sample size is required to capture the full species richness of a site.