Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 19 (2019)
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A review has been undertaken of herbarium records, point location and full floristic data to assess the distribution, habitat and conservation status of Macrozamia flexuosa (Zamiaceae), a rare cycad endemic to the Hunter Region of New South Wales. Spatial analysis of all records (n=588) showed that the species is most prevalent on Permian-aged sediments but also occurs on older Carboniferous sediments and younger Triassic Narrabeen and Quaternary substrates. Point records intersect with a wide range of annual average rainfall bands (<700 to 1400 mm/yr), suggesting either that the species is tolerant of a variety of soil moisture gradients, or that current distribution may be representative of a differing climatic environment. Interpolation of database records (n=397) across 175,000 hectares of high-resolution vegetation mapping showed Macrozamia flexuosa to most frequently occur within the Lower Hunter Spotted Gum-Ironbark Forest (41%), followed by Kurri Sands Swamp Woodland (16%), Coastal Foothills Spotted Gum-Ironbark Forest (15%) and Coastal Plains Smooth-barked Apple Woodland (13%). Numerical analysis of full floristic plot data (n=86) largely supported these results, with the addition of Hunter Valley Moist Forest to these four regional communities. A revised assessment of the conservation significance of Macrozamia flexuosa suggests that the existing conservation risk code of 2K be amended to 3RCa (distributional range >100km; rare but not immediately threatened; adequately conserved in at least 14 conservation reserves). An extent of occurrence of 6,319 km2 and an area of occupancy of 696 km2 have been determined for the species, and an estimated population size of between 1,740,000 and 43,500,000 individuals has been calculated. Under IUCN threat criteria, a code of NT (Near Threatened) is here considered appropriate for Macrozamia flexuosa, recognising uncertainties applicable to the assessment of Criteria A and B. It is noted, however, that Macrozamia flexuosa may currently be in slow decline due to as yet unknown limitations in flowering, pollination and/or dispersal mechanisms over a long period of time (many decades), with the longevity of individual specimens confounding any observable trends. A lack of demographic data relevant to these life traits limits comprehensive assessment, and further research to address these data gaps is recommended.
A review and update to the list of significant vascular plant taxa has been made for the c. 500 000 ha Wollemi National Park, approximately 100 km north-west of Sydney, New South Wales. A previous assessment in 2008 revealed the presence of 94 significant taxa, including 15 listed as Endangered and 22 listed as Vulnerable in NSW Threatened Species legislation. New field surveys, coupled with analysis of observation (NSW OEH Bionet Atlas) and specimen collection (Australasian Virtual Herbarium) databases, has added a further 16 significant taxa to the reserve total, elevating it to 110. A revised assessment of the total threatened flora, as listed on the NSW Biodiversity Conservation Act 2016, shows there to be 1 Critically Endangered, 19 Endangered, 26 Vulnerable taxa and 2 Endangered Populations. For Commonwealth listed taxa under the Environment Protection and Biodiversity Conservation Act 1999, there are 1 Critically Endangered, 9 Endangered and 23 Vulnerable taxa. Sixty-one taxa are currently unrepresented within either legislation and may be considered rare, 8 taxa remain scientifically undescribed (one addition in this revision, Pultenaea 'monticola' Mt Irvine), while updated names are provided for two taxa now formally described (Eucalyptus expressa and Prostanthera stenophylla). Following assessment of all newly added taxa against IUCN criteria, one currently unlisted species (Hibbertia coloensis) qualifies as Critically Endangered, while a second (Bertya linearifolia) qualifies as Endangered. Discussion is also provided on six taxa where database records show them to be present within Wollemi, but are here excluded following closer examination.
Hand-pollination increases seed set in the critically endangered orchid Thelymitra kangaloonica
(2019)
Thelymitra kangaloonica is a listed Critically Endangered sun-orchid (family Orchidaceae) with a highly restricted distribution. In recent years both individual abundance and capsule set rates have been low in this species. The flowers of Thelymitra kangaloonica possess some traits associated with autogamy (self-fertilisation) and others associated with entomophily (insect-pollination), however the pollination mechanisms have not been explicitly tested. This study compared the capsule set rate of flowers cross-pollinated by hand among individuals, against flowers which received no treatment. We found that capsule set rate in hand cross-pollinated flowers was significantly higher than in flowers receiving no treatment (23.1% versus 4.4%). This suggests that Thelymitra kangaloonica relies primarily on entomogamy to achieve seed set. Hand cross-pollination may assist management of the species by increasing the number of seeds in the soil seed bank and potentially assist in increasing the population size. In addition, it facilitates seed collection for seed banking and development of an ex-situ population for future population augmentation or translocation.
Insects visiting flowering trees of Syzygium floribundum, Syzygium smithii and Tristaniopsis laurina (Myrtaceae) were recorded in lowland subtropical rainforest communities in the Manning Valley, mid-north coast of New South Wales. These species are visited by a taxonomically broad assemblage of insects, many of which are known to frequent other rainforest- and open forest-flowering plant species. Consequently there is likely to be a regional pool of potential pollinators found throughout the range of each plant.
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.
