Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 9, Issue 4 (2006)
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The sand spit that separates Shallow Inlet from Waratah Bay (38º52ʹ S, 146º13ʹ E), near Wilsons Promontory in southern Victoria, has developed since the previous spit was washed out in 1901. Initially without vegetation, the spit was colonised in the 1960s by the exotic grasses *Thinopyrum junceiforme and to a lesser extent *Ammophila arenaria. These species are native to the coast of western Europe, where they fulfil a key role in dune establishment. Being able to grow through sand accumulating among the culms, these grasses formed mounds where seeds or rhizome fragments were washed up during king tides. Where somewhat sheltered from the strongest impact of the westerlies, mounds gradually coalesced and formed short ridges at the landward side of the spit, and ‘dune fields’ towards its distal end. Circumstances favourable for dune field formation were enhanced by episodic processes in spit growth due to channel shifting in the tidal delta and the gradual lengthening of the main outlet channel.
Austrofestuca littoralis and Spinifex sericeus joined the two foreign grasses in their pioneering role. The herbaceous Actites megalocarpa and the shrub Ozothamnus turbinatus established in the lee of the grasses, but conditions on mounds, dune crests and windward slopes are too severe for other species. Only at more sheltered sites is further development of vegetation possible. In the lee of the dune fields it has progressed into an open shrubland, initially of Ozothamnus turbinatus, Olearia axillaris and Olearia glutinosa, later enriched by Acacia longifolia var. sophorae, Leptospermum laevigatum and Leucopogon parviflorus. Wind-dispersed taxa form the dominant component of the vegetation, but several animal-dispersed species became established as well. The complement of woody species begins to resemble that of the dune scrub found elsewhere along this part of the Victorian coast, but several wind-dispersed species, notably Banksia integrifolia, are still lacking and it would appear that dispersal is still a limiting factor in vegetation development. It is pointed out that dune development on the sand spit was initiated by exotic grasses and that without their presence, it is doubtful whether any vegetation would have established there.
Many photos support the text- the narrative will say what words can say but words can never say it all (Love 1999).
Diversity and distribution of exotic plant taxa in Kosciuszko National Park in south-eastern Australia were reviewed based on 1103 records of exotics from 18 vegetation surveys conducted between 1986 and 2004. 154 taxa from 23 families were recorded in the alpine to montane zones, with eleven taxa in the alpine, 128 taxa in the subalpine and 69 taxa in the montane zone. Nearly all taxa were associated with anthropogenic disturbance with only four taxa exclusively recorded in natural areas. 62 taxa were recorded from subalpine ski resort gardens, and although not recorded as naturalised in the vegetation surveys, their presence in the Park is a concern.
Road verges provided habitat for numerous exotics (65 taxa). 44 taxa were recorded in both disturbed and natural locations but most were uncommon (33 taxa < 2% frequency). Nine common taxa Acetosella vulgaris, Achillea millefolium, Agrostis capillaris, Anthoxanthum odoratum, Cerastium spp., Dactylis glomerata, Hypochaeris radicata, Taraxacum officinale and Trifolium repens comprised 68% of records. These species are common to disturbed areas in other areas of Kosciuszko National Park, NSW and worldwide. The forb Acetosella vulgaris was the most ubiquitous species particularly in natural areas where it was recorded at 36% frequency. Based on the data presented here and a recent review of other data sets, there are at least 231 exotic taxa in the Park (including exotics in gardens). The increasing diversity and abundance of exotics is a threat to the natural values of this Park.
African Olive, Olea europaea subsp. cuspidata (Wall. ex G.Don) Cif. (family Oleaceae) is a dense-crowned tree introduced into Australia for horticulture in the mid 19th century. In recent decades, African Olive has become an aggressive woody weed, capable of forming a dense and permanent canopy in a wide range of vegetation types in south-west Sydney and beyond. Characteristics of African Olive invasion in south-west Sydney, and its seed dispersal by frugivorous birds are consistent with experience from Norfolk Island and Hawaii. We use records and aerial photographs from Mount Annan Botanic Garden and other bushland areas in south-west Sydney to describe the invasion stages and impacts of African Olive. The capacity for African Olive to establish in both temperate and subtropical zones, underlie the potential for spread well beyond current distribution in New South Wales. Research is now required to further develop control techniques and ecological restoration strategies for areas of heavy African Olive infestation. Mapping of current locations and a coordinated control strategy for African Olive is required to prevent future permanent loss of native plant diversity.
A survey covering almost all known sites and most areas of potential habitat of the rare plant Blandfordia cunninghamii (family Blandfordiaceae) in 2004 recorded over 4000 plants from 27 locations, with 80% of the plants in the upper Blue Mountains west of Sydney (lat 33° 40' S, long 150° 20' E), and the remainder as a disjunct occurrence on Mount Kembla in the Illawarra. Habitat requirements of Blandfordia cunninghamii were found to be southern aspect (SE to SW), a slope of > 30°, high rainfall (>1200 mm a year), good drainage, partial canopy cover (30-50%), and acid clayey sands with a pH of 4.5-5, at an altitude between 500 and 950 m. Using International Union for Conservation of Nature (IUCN) parameters, we consider that the number of plants (less than 10 000), their Extent of Occurrence (940 square km), Area of Occupancy (80 km2) are below the threshold for Vulnerable. There is observed decline in habitat and numbers and we conclude that there may be less than 10 locations (under IUCN definitions). This would mean that the species could be considered Vulnerable under IUCN Criteria.
Epiphytes are generally considered rare in complex forests on the western edge of the Atherton Tablelands, north Queensland. This assertion is based on comparisons with wetter forests in the Wet Tropics bioregion, but is of limited use in restoration projects where targets need to be quantified. We quantified ‘rarity’ for a subset of the epiphyte community in one of the largest remaining patches of Type 5b rainforest at Wongabel State Forest(17°18' S, 145°28' E). The bundance of large individuals of the epiphytic fern species Asplenium australasicum, Drynaria rigidula, Platycerium bifurcatum, and Platycerium superbum were recorded from 100 identified midstorey or canopy trees. Epiphytes were less rare than the canopy trees sampled, averaging 1.7 individuals per tree. A clumped distribution was suggested with large epiphytes only occurring on 57 of the 100 trees. As tree size increased so did the number of individuals and species of large epiphytes recorded; only trees taller than 20 m yielded more than one epiphyte. Trees from the Meliaceae and Rutaceae hosted the most epiphytes, but host tree specificity patterns were not conclusive. Techniques for including epiphytes in restoration planning and projects are considered, and a quantified restoration target for epiphyte communities in Type 5b plantings is outlined.
The extent of eucalypt decline in moist coastal forests of south-eastern Australia is increasing with resultant losses in biodiversity and productivity. This survey aimed to identify factors associated with the decline of Eucalyptus saligna (Sydney Blue Gum) in Cumberland State Forest, a moist sclerophyll forest within urban Sydney. Eucalyptus saligna was the dominant overstorey species in six 20 m radius plots, which differed in floristic composition, structure and crown condition. One plot was colonised by bell miners (Manorina melanophrys). A range of leaf, tree and plot scale parameters were assessed including insect damage and free amino acid content, visual crown condition, floristics and soil chemistry. The plot permanently colonised by bell miners also had Eucalyptus saligna trees in the poorest condition. Both the weed Lantana camara and the soil pathogen Phytophthora cinnamomi were present in some of the plots but neither was strongly consistent with the severity of crown decline. There were, however, significant correlations among the foliar traits of insect damage, free amino acid content and relative chlorophyll content. Free amino acid content differed significantly between leaf age cohorts. Plots differed notably in topsoil organic matter and soil nitrogen, but the plot with the poorest visual crown condition score had intermediate mean values for both soil properties within the ranges presented by the six plots. Overall, crown condition score was weakly negatively correlated with topsoil organic carbon and total nitrogen content. The unhealthiest plot also had the highest density of shrubby understorey. Site factors that could influence both the quantity and quality of foliage (e.g. free amino acid content) in eucalypt crowns, and hence the population dynamics of herbivorous insects and bell miners, are discussed in relation to Eucalyptus saligna crown decline.
Distribution of plant size and reproductive success is investigated in the temperate epiphytic orchid Sarcochilus australis (Lindl.) Rchb. f. at Kinglake National Park, Victoria, in south-eastern Australia, and applied to estimating the effective population size. Plant size distribution (leaf number, length of longest leaf and number of flowers) was not normally distributed. Most individuals were vegetative and it is estimated that more than half of all individuals are too small to flower, however exceptionally large individuals even though rare are able to have more than one active inflorescence. Flowering probability is plant size dependent and follows a sigmoid curve. The minimum observed leaf size of a flowering individual was 26 mm, however these small individuals have a low probability of flowering (<30%), while large plants (> 80 mm) have a much higher probability of flowering (90%). The effective population size (Ne) of the Kinglake population of Sarcochilus australis was estimated from the distribution of flower production, and shown to be small (Ne = 10–19%) and comparatively similar to some of the other published estimates of effective populations size in orchids. From this basic survey of size distribution in Sarcochilus australis it is predicted that genetic diversity is low.
Ludwig Leichhardt had to abandon a large and important collection of botanical specimens during his Expedition from Moreton Bay to Port Essington. Here we attempt to assess the significance of the lost collection by identifying the botanical references in his detailed published journal from the journey. From Leichhardt’s description of the plants and their habitats, and with our accurate knowledge of current distribution, it has been possible, in most cases, to identity his botanical references to a single species. In other cases there is lower degree of certainty. Well over one hundred of the species recorded in Leichhardt’s journal would have been new to science at the time if specimens had survived. The record does identify some potential locations for species that would represent range extensions and suggests an indigenous status for a number of plant species that where previously considered exotic. Certainly Leichhardt was a talented botanist and his significant contribution to Australian natural science should be recognised.
