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Nungar Plain is a large, naturally treeless area in the northern part of Kosciuszko National Park. Abrief survey of the flora of Nungar Plain (December 2001–January 2002) recorded 206 taxa, 18 of which were introduced. Seven taxa appear to be of especial significance. The great floral diversity of Nungar Plain suggests that the botanical significance of sub-alpine plains in Kosciuszko National Park has been under-estimated. The flora and vegetation of Nungar Plain are threatened by pigs, which have scoured large areas of grassland vegetation. In six pairs of quadrats across disturbance boundaries, damage by pigs was found to have greatly reduced the cover and diversity of vegetation. Control of pigs is urgently required.
The fires of January 2003 burnt much of the treeless high mountain country of Victoria, New South Wales and the Australian Capital Territory, and were the first extensive conflagration of this area since 1939. For this reason there are remarkably few studies of the response of alpine plants and vegetation to fire. A flora survey of treeless subalpine vegetation in the Kosciuszko area in late 2002 sampled 215 sites. Of the 119 sites that were burnt, 60 were relocated and re-sampled in late 2003 to assess the mode and extent of regeneration in a range of treeless plant communities. Twenty-four species (including 3 exotics) were recorded only in the pre-fire sampling. Fifty species (including 18 exotics) were recorded only in the post-fire sampling. One species, Chenopodium erosum, had not previously been recorded in Kosciuszko National Park, and is believed to be the first native chenopod recorded in alpine vegetation in Australia. There was no significant difference in mean number of species per quadrat between pre-fire and post-fire quadrats. The average number of weeds per quadrat was, however, significantly greater post-fire. Most of this difference was attributable to the significantly greater number of weeds per quadrat in bog vegetation after the fire. Of the 290 species recorded, 111 species regenerated from seed, 197 species regenerated from resprouting organs (roots, tubers and/or basal stems) and 49 species regenerated from both seed and resprouts. Based on the regeneration observed, most plant communities will return naturally to their pre-fire species composition and cover over a period between a few years and a few decades. Major exceptions will be those communities where the ‘keystone’ species appear to have been lost at least at a local scale. Principal amongst these are bog communities that incorporated significant biomass of Sphagnum cristatum pre-fire, Podocarpus lawrencei shrublands and Celmisia costiniana closed herbfields. Consideration might be given to augmenting their recovery. It will be important to exclude fire from these communities until their recovery is complete.
Based on 1222 floristic quadrat samples, 56 plant communities were identified in treeless vegetation in the Australian Alps of south-eastern Australia. (c. 35º 30´–38ºS, 146°–149°E). The study encompassed vegetation from above the upper limit of trees on mountain tops (i.e. the truly alpine environment) and below the inverted treeline in subalpine valleys. Generally, grasslands develop on deep humus soils, heathlands occur on shallower or rocky soils, and wetland communities are found in places of permanent or intermittent wetness. Duration of snow cover, lithology, altitude and exposure are also important determinants of the spatial arrangement of communities. Broadly, communities within a geographic region are more closely related to each other than to communities of similar structure or dominants from other geographic areas. Many communities are either very localised or are widespread with a small area of occupancy. Fourteen communities are probably eligible for listing as threatened, either alone or as aggregates with associated communities. A total of 710 native taxa from 82 families has been recorded. There is a high level of endemism – 30% of taxa are ± restricted to treeless vegetation in the Australia Alps and a further 14% are ± restricted to treeless vegetation but occur in mountain areas outside the Australian mainland (e.g. Tasmania and New Zealand). Thirteen taxa are listed in the Environment Protection and Biodiversity Conservation Act 1999 as threatened and a further 18 taxa are identified that may be eligible for listing as threatened nationally. 131 non-native taxa have been recorded in natural vegetation. Treeless vegetation has been intensively utilised since European settlement, initially as summer pastures for cattle and sheep but more recently as water catchments for electricity production and as tourist attractions both in winter and summer. Many communities are slowly recovering from past pressures and from the fires of 2003, which burnt most of the area for the first time since 1939. The treeless vegetation of the Australian Alps faces an uncertain future because of increased pressure from tourism and the unknown impacts of global warming.
Although Kosciuszko National Park is one of the largest and oldest in New South Wales, the vascular flora found within it has not been fully documented. An understandable focus on the alpine and subalpine flora has resulted in a lesser focus on the flora of the extensive tracts of forest and woodlands found in the montane, tableland and lower Snowy River zones of the Park. Here we summarise and provide an overview of the entire vascular flora across the full range of floristic zones within Kosciuszko, building upon earlier summaries focussed solely on the alpine and subalpine zones. Our compilation of records resulted in a total vascular flora for Kosciuszko National Park of 1435 taxa, of which 1105 taxa (77%) are native and 330 taxa (23%) are alien, excluding cultivated taxa. Based on 1990 data for the flora of New South Wales, Kosciuszko National Park hosts 24% of the State’s native vascular flora and 26% of the State’s alien vascular flora. There are 25 species of vascular plant that are endemic to the park and all but one (Haloragis milesiae) occur in the alpine and subalpine zones. A further 86 species have their NSW occurrences confined to the park. Many of the 24 endangered or vulnerable species found within the park also have their main occurrences in treeless subalpine and alpine vegetation. An additional 105 species are at the limits of their geographic distribution, have disjunct occurrences in the park or are uncommon in the Alps and these occur across a range of floristic zones. At least one species, Euphrasia scabra, is listed as presumed extinct in the park although it occurs elsewhere in New South Wales. Although well surveyed overall, areas including the Byadbo Wilderness, Pilot Wilderness and forests on the western flanks are by comparison under sampled and will require further survey effort in future to fully document the flora of the park. Historical legacies of past land use practices and impacts from current recreational uses, as well as impacts from feral herbivores and alien plant species all pose ongoing threats to the long term survival of many plant species found within the park. The interaction of these threats with increasing temperatures, shifting rainfall patterns including snow cover and changing fire regimes will require ongoing monitoring and increased resourcing if significant changes to ecosystems are to be effectively managed.
Phytophthora cinnamomi is an oomycete (water mould) with a large host range. It infects plants through their roots and in some cases will kill them. The pathogen is readily dispersed in soil and water, over short distances by its swimming spores and over large distances by humans. While Phytophthora cinnamomi has been well-studied in other parts of Australia, its distribution and impact are poorly known in New South Wales (NSW). In the current study we compiled existing data on Phytophthora cinnamomi occurrence and filled spatial gaps in sampling. We found about 1000 records of Phytophthora cinnamomi presence in over 5000 tests of soil and root material, and collected a further 457 samples from areas where no sampling had previously been done. The resulting data set enabled modelling of Phytophthora cinnamomi habitat suitability using the software program MaxEnt with climate and soil spatial layers. We found that coastal areas and adjacent tablelands were most suitable for the pathogen, although some areas within that may be unsuitable because of soil properties. We then modelled assets (threatened species) potentially affected by Phytophthora cinnamomi to produce a layer of risk. Using projected climate layers, we found that habitat suitability and risk will decline in parts of northern NSW by 2070 but be amplified in the south. New susceptible species in places such as the Australian Alps are likely to be exposed to the pathogen in the future. We offer advice for managing Phytophthora cinnamomi in NSW. Management is difficult where the effects of this pathogen are often inconspicuous and its distribution is widespread. However, basic hygiene to limit spread to susceptible assets will have great benefit regardless.