Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 19 (2019)
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Palms are ubiquitous as landscaping plants in many urban areas. Dispersed by frugivorous birds and often tolerated as self-seeded plants by the property owners, Phoenix canariensis (Canary Islands date palms) and two species of fan palms (Washingtonia robusta and Washingtonia filifera) in particular, have become established in many urban spaces. This paper examines the establishment of such self-seeded palms as epiphytic growth in crooks and branch scars of suburban street trees. Given the limited nutrient availability and the restricted space for rootmass development, these palms undergo a natural bonsai process. Some palms have persisted for over a decade without reaching sexual maturity. While the epiphytic growth demonstrates the palms' further dispersal capability, it does not appear to increase their potential invasiveness into new areas of land.
The occurrence of the coastal ferns Asplenium decurrens and Asplenium difforme (family Aspleniaceae) on the south coast of New South Wales are assessed and discussed. The Illawarra coast was the zone of overlap for these two coastal fern species and they reached their geographical limits in the Kiama area, with Asplenium decurrens reaching its northern limit of distribution and Asplenium difforme reaching its southern limit. All substantiated records of these ferns are documented and assessed. Both species require conservation consideration on the NSW south coast. For Asplenium decurrens the evidence suggests that New South Wales should follow Victoria and list this species as threatened under the Biodiversity Conservation Act 2016 (NSW). For Asplenium difforme local conservation action is needed at its most southern limit at Kiama.
In 2010, the plant fungal pathogen Austropuccinia psidii was detected in Australia. It has since spread rapidly through the eastern states of Australia causing significant population declines in a number of susceptible species. However, there are still a number of potentially vulnerable species that lack the necessary field observations that are needed to accurately gauge the risk Austropuccinia psidii poses to them. Because of this, rapid field assessments of these species have been given the utmost priority. In the spring of 2018 (October) we carried out rapid field assessments for five high priority species. We did not observe active Austropuccinia psidii infection on any of the species at the time of assessment despite the majority of individuals having susceptible new flush. However, we did find evidence of significant previous infection (branch dieback) in the largest Archirhodomyrtus beckleri population we assessed. Therefore, to confirm our observations, it is necessary to re-assess this population when environmental conditions are more favourable for infection to occur in order.
High grazing pressure from over-abundant macropods (kangaroos) is perceived to have a detrimental impact on biodiversity. Studies have shown potential changes in state and retardation of degraded vegetation recovery while other investigations have shown correlations with increased floristic diversity. The responses of grasslands to high impact macropod grazing may not be universal. Endangered Themeda triandra-dominated grasslands, on coastal headlands of New South Wales (NSW) and the associated threatened flora are thought to be negatively affected by high macropod grazing. We assess these assumptions via a comparative investigation across 46 headlands (467 plots) on the North Coast of NSW, and a BACI (Before and After Control Incident) design grazing exclusion experiment at a particularly significant site. We compare floristic richness, species density, evenness, Shannon H, Whittaker Beta Diversity, occurrence of listed threatened flora, average sward height and macropod density. Look At Me Now Headland (LAMN), between Coffs Harbour and Woolgoolga has one of the highest recorded population densities of macropods. Here 16 permanent plots were placed with grazing exclusion cages erected around half. Sampling occurred annually (October-November) for four consecutive years (2015-2018). Under high macropod grazing pressure LAMN Headland was found to have the highest scores for total richness, species density, species diversity and moderate to high values for species evenness and beta diversity. Within grazing exclusion plots the sward height increased significantly and was associated with a significant decrease in species density, beta and alpha diversity. Our results indicate that macropod grazing, even at the highest intensities, may be beneficial to floristic species diversity within the endangered Themeda-grasslands of coastal headlands and seacliffs within the North Coast Bioregion of NSW; our broader comparative study would suggest that this may also be the case on other headlands.
Thomas Reedy (1842-1929) was head gardener for Sir William Macarthur. In 1875, as an expeditionary member on the Chevert Expedition, he collected plants from islands in the Great Barrier Reef, the Torres Strait and New Guinea for Macarthur. Three surviving letters to his employer, Sir William Macarthur, are introduced, transcribed and minimally annotated.
An album of 50 watercolour illustrations depicting Norfolk Island plants attributed to convict artist John Doody, in the early 1790s, and associated notes apparently written by William Paterson (1755-1810), one-time commander of the military detachment on Norfolk Island, Lieutenant Governor of New South Wales, and amateur botanist, are described and assessed. Illustrated are 48 plant species growing on Norfolk Island at the time, all but three of which are indigenous. The notes and the watercolours represent the only treatment of the island's flora in the 18th century and include descriptive and ecological material for the species at the time of first European occupation. Two of the species are now extinct. Paterson's notes also include an introductory description of the flora and fauna of the Island. The importance of this material to the modern study of the Norfolk Island flora is highlighted.