Open Access

Seed production varies from year-to-year in most species. Factors influencing this variation can include pollination and dispersal mechanisms, seed predation and resource availability. Here we examine a long-term (12– year) photographic record of seed cone production for the Australian endemic conifer Wollemia nobilis (Araucariaceae). Coefficient of variation (a commonly used measure of variation in seed production) was low for the two trees analysed, compared with published values for other polycarpic plants. Nevertheless, cone production decreased with increasing spring minimum temperatures (during pollination) and increased with summer total rainfall (during cone initiation). Hence, Wollemia nobilis cone production was correlated with weather, in line with the resource-matching hypothesis. Impacts of variation in cone production on the Wollemia nobilis population are likely to be buffered by the shade-tolerant, slow-growing juvenile life stage of Wollemia nobilis.

The results of a field survey of Prostanthera tallowa (family Lamiaceae), a rare and only recently described shrub from the lower Shoalhaven River valley, on the NSW South Coast, are described. The extent and size of populations in the vicinity of the type locality at Tallowa Dam are greatly expanded and several new and distant populations are described. Information is provided on all known populations and their habitat. The species is regarded as adequately reserved, as almost all known populations occur in protected areas though the actual area of occupancy is small. The species recruits after fire with most sites having been burnt about 10 years ago; the total known population size is currently over 3,300 plants.

Eastern Suburbs Banksia Scrub (ESBS) is a listed Endangered Ecological Community that becomes senescent and loses species diversity in its plant cover in the long-term absence of fire. However, the reintroduction of fire into remnant vegetation within urban areas presents management challenges and selective thinning is sometimes presented as an alternative management option. This project sought to evaluate fire and selective thinning of dominant species as tools for reinvigorating senescent ESBS. Two peri-urban ESBS sites at North Head, Sydney, New South Wales, scheduled for hazard reduction burns to protect assets, were surveyed for their floristic attributes. Surveys were carried out in 7 x 7 metre quadrats, one third of which were fenced after fire to assess predation by herbivores. Similar quadrats were established on adjoining unburnt sites from which dominant species were removed through selective thinning. Twelve months after treatment (and to a lesser extent at 6 months) burned ESBS displayed greater vigour and diversity than did thinned sites. Burned ESBS had more native plants, greater plant cover, more native species, greater species diversity and fewer weeds than did thinned ESBS. Burned and thinned ESBS sites had significantly low overlap in native species mix. Areas that had been fenced after fire had “superior” attributes to those that had not been fenced. There was nearly complete overlap of species between fenced and unfenced ESBS subjected to fire. The results suggest that fire can be used advantageously to rejuvenate this type of heath and that this method produces superior results to thinning, but with a different species mix. These advantages accrue with time. The results of either method would be greatly inferior were attempts not made to control predation by exotic herbivores such as rabbits.

A botanical survey of the vegetation of Strzelecki National Park, on south-western Flinders Island, Tasmania (lat. 40° 13' S; long. 148° 06' E) resulted in 313 vascular plant taxa, being recorded. Of these, 16 are introduced. Of the native flora, 9 are currently considered threatened according to the Tasmanian Threatened Species Protection Act 1995. Some of these occur on the calcareous rocks and soils on the western coastal fringe of the Park. There is low species diversity in large areas, for reasons that include extensive ground disturbance by pigs, very high fire frequency in some areas and the depauperate nature of island floras. There were also 137 species of liverworts and mosses recorded for the Park. Most plant habitats on Flinders Island are represented in the Park. The flora retains an interesting rainforest and wet forest element which shares floristic similarities with rainforest gullies in mainland south-eastern Australia, with the Tasmanian north-eastern highlands, and even with western Tasmania. There are also some affinities with the dry Bass Strait and southern Australian floras. The pattern and composition of the vegetation is strongly shaped by several factors. Extensive fires have been promoted by fuel accumulation and deliberate burning on the Park perimeter. Topography strongly influences the vegetation (Mt Strzelecki is 756 m high) due to the degree of exposure to strong winds and protection from fire. Cloud capping of the mountain increases the potential moisture available. Wind is a large local factor in vegetation structure. Controls on vegetation at any given site are also responsive to aspect, bedrock depth and other factors. Eleven vegetation mapping communities are defined, the Park being important for the reservation of several of these. The Park is characterised by the presence of rainfall and evapotranspiration extremes and the vegetation varies accordingly, with rainforest patches in fire protected niches of the mountains and dry heathland on the coastal areas. Strong westerly winds combined with the abruptly rugged mountainous topography have caused some violent localised destruction of forest and scrub canopies by wind.

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.