Dissertations / Theses on the topic 'Southeastern Australia'

Chestnut rot of Castanea sativa Mill. (European chestnut) and Castanea crenata Siebold and Zucc. (Japanese chestnut) x Castanea sativa hybrids is a significant problem facing the Australian chestnut industry. It affects the chestnut kernel, manifesting as pale, medium and dark brown lesions occurring on the endosperm and embryo. Previous surveys of Melbourne Markets showed losses to chestnut rot up to 40% (Anderson 1993)*. This equates to losses of $5.2M in 2010; using projected production figures (HAL 2007). This research project was undertaken to create a better understanding of the scope and distribution of the chestnut rot problem in south-eastern Australia; clarify the confusion surrounding the taxonomy of the chestnut rot pathogen; elucidate the infection process and disease cycle; investigate the effectiveness of flotation disease grading as a post-harvest method of removing rotten chestnuts; and provide recommendations to growers on how to reduce the incidence of chestnut rot in their orchards. Twenty-two orchards were surveyed in 2008 and 21 in 2009, across New South Wales (NSW) and Victoria (VIC) (Chapter 2). The highest incidence of chestnut rot at individual orchards was 72%. Incidence varied widely between and within orchards between the two years sampled. Chestnut rot was present in all of the sampled 2 orchards. The important commercial varieties Decoppi Marone (DM), Purton’s Pride (PP), Red Spanish (RS) all displayed examples of both high incidence (>1%), and acceptable incidence (0-1%). This indicates these varieties are susceptible under the right conditions. There was a positive correlation between incidence and December rainfall of the previous year, indicating environmental factors as key to the infection process. In 2008 and 2009, surveys of Sydney Markets showed incidence >1% (2008: varieties DM, PP; 2009: varieties RS, PP), indicating that these varieties were capable of being affected by chestnut rot. Chestnut rot has recently been reported as caused by two fungal species, minorly in New Zealand by Diaporthe castaneti Nitschke. and majorly in Australia and New Zealand by Gnomonia pascoe prov. nom. (Smith and Ogilvy 2008). The current study only observed one causal agent of chestnut rot in Australia, the novel taxon, Gnomoniopsis smithogilvyi sp. nov. Isolates of G. smithogilvyi were obtained from tissues including rotten chestnuts collected in surveys of NSW and VIC, as ascospores from dead burrs from NSW, and as endophytes from asymptomatic female and male flowers, leaves, and stems from NSW. Morphology and phylogenetics were used to elucidate the taxonomy of the fungus. Morphological examination of G. smithogilvyi included the teleomorph from burrs (perithecia, asci, ascospore characters), and the anamorph in culture (colony, conidiomata and conidia characters). The RNA polymerase II (rpb2), internal transcribed spacer regions 1 and 3 2 encompassing the 5.8S rDNA (ITS), translation elongation factor 1-alpha (tef1-α), and beta-tubulin (β-tubulin) gene loci were sequenced and analysed in the context of the Diaporthales Nannf., Gnomoniaceae Winter. and Gnomoniopsis Berl. All of the chestnut rot isolates, ascospore isolates, and endophyte isolates on Castanea sativa, and Castanea crenata x C. sativa hybrids in Australia (NSW and VIC) were identified as G. smithogilvyi. An ITS phylogeny analysing the G. smithogilvyi isolates from the current Australian study with isolates of Gnomoniopsis on C. sativa from India, C. sativa from Italy, and C. crenata, C. sativa, and Castanea sp. from New Zealand (Chapter 3) grouped the Australian isolates, the Indian isolates, 17 of the 19 Italian isolates, and 3 of the 4 New Zealand isolates in the same lineage with 100% maximum parsimony (MP) bootstrap support, and 1.0 Bayesian posterior probability (BP). This suggests all these isolates belong to the genus Gnomoniopsis, and are highly likely to be G. smithogilvyi. A multi-gene phylogeny needs to be completed with all of these isolates to unequivocally determine if they are G. smithogilvyi. One of the 4 New Zealand isolates grouped with Gnomoniopsis paraclavulata in this analysis indicating that there is likely to be more than one species of Gnomoniopsis on Castanea spp. in New Zealand. Subsequent to the publication of G. smithogilvyi (Shuttleworth et al. 2012a), Gnomonia pascoe prov. nom. and a recently published taxon reported as the casual agent of nut rot of Castanea sativa in Italy, Gnomoniopsis castanea were all found to be synonyms of G. smithogilvyi based on 4 morphology and a two gene phylogeny (ITS, tef1-α) (Chapter 3). Chapters 3, 4 and 5 isolated the G. smithogilvyi in its anamorph form from rotten chestnuts, in its teleomorph form as a saprobe on dead burrs, and as an endophyte isolated from asymptomatic floral and vegetative chestnut tissues. Historically, there has been significant movement of chestnuts and budwood from Europe to Australia. It is therefore possible that the G. smithogilvyi was imported to Australia from Europe. The fungus could also potentially have been introduced from Japan, China, or the USA as Castanea from these countries have all been transported to Australia. There is also a possibility that the fungus has an endemic Australian origin. Further work with native plant species needs to be completed to determine if this is the case. The fungus could also have been transported between orchards in Australia and New Zealand by exchange of chestnuts and budwood between the two countries. G. smithogilvyi was isolated as an endophyte from various vegetative and floral tissues of Castanea in December 2008, and February, April, August, and December 2009 from an orchard in Mullion Creek, NSW (Chapter 4). The ranking of highest to lowest isolation frequency in chestnut tissues was female flowers (December 2008), mature burr equators, mature pedicels, living male flowers, dead male flowers, terminal leaf margins (April 2009), dead styles, dormant terminal buds, immature burr equators, pedicels (February 2009), leaf mid-veins, current-year stems (August 2009, 5 February 2009), and mature shell equators (April 2009). All other tissue types had ≤20% isolation frequency including current-year stems (December 2008, April 2009), 2 year-old stems, petioles, mature kernels, female flowers (December 2009), immature shell equators, living male flowers (December 2009) and 3 and 4 year-old bark. The endophyte was not isolated from 3 and 4 year-old xylem. There was a decreasing trend of isolation with increasing age of chestnut tissues in four of the five months. There was also a 72% reduction in isolation frequency from female flowers between 2008 (82%) and 2009 (10%), indicating a dynamic distribution of the fungus in chestnut flowers that changes over time. It also suggests a seasonal infection of female chestnut flowers. All tested varieties (DM, PP, RS) had the chestnut rot endophyte isolated from their tissues, indicating that they have the potential to be affected by chestnut rot. The observation of chestnut rot perithecia on burrs is central to the hypothesis of a floral infection by ascospores. This study observed G. smithogilvyi on dead burrs and branches in Mullion Creek, NSW (Chapters 3, 4). This observation of perithecia and ascospores on burrs supports the hypothesis of a floral infection. Ascospore infection of chestnut flowers has previously been found to be the primary stage of infection leading to chestnut rot. In this study ascospores were captured on PDA plates in a closed chamber laboratory experiment with chestnut burrs containing overwintered perithecia and ascospores of the G. smithogilvyi (Chapter 5). Three 6 colonies of the G. smithogilvyi anamorph grew in the second week of incubation. The incubation temperature was stable for the duration of the experiment at 23oC, suggesting fluctuations in temperature are not required for ascospore release, with moisture and humidity likely to be more important. A isolate that was grown from an ascospore was identified using morphological and molecular techniques. A segment of the ITS region of rDNA was sequenced and analysed. The captured ascospore isolate was morphologically identical to G. smithogilvyi, and it grouped next to G. smithogilvyi in the maximum parsimony (MP) ITS phylogenetic tree indicating the isolate is G. smithogilvyi. This experiment indicates that ascospores are released from the dead burrs into the air where they can potentially infect chestnut flowers, again supporting the floral infection hypothesis. Ascospores were found to be the primary source of inoculum in the infection of chestnut flowers, leaves and stems in December, leading to chestnut rot symptoms the following year. Chestnut rot ascospores were captured using a Burkard Volumetric Spore-Trap in an orchard in Mullion Creek, NSW (Chapter 5). The instrument was also used to determine daily patterns in ascospore capture from the orchard atmosphere. The highest mean hourly frequency of ascospore capture was 165 ascospores per m3 of air at 10pm. The time period of peak ascospore capture was between 8-11 pm and between 7-9 am. These times of ascospore capture correspond to sunset and the hours following sunset, and the hours following sunrise. No rain fell during the sampling 7 period, indicating ascospores are released even in the absence of rain. Flotation disease grading is a post-harvest method used to separate rotten chestnuts from healthy ones. Chestnuts that float are considered rotten, those that sink considered healthy. An experiment was carried out to investigate the effectiveness of flotation disease grading as a post-harvest method of removing chestnuts affected by chestnut rot (Chapter 6). Hot water treatment of chestnuts has also been found to be effective against fungal growth on chestnut shells and therefore a desirable treatment method used in combination with flotation disease grading. The temperatures tested were 4oC, 30oC, 50oC, 60oC, and 70oC. Both floating and sinking chestnuts were affected by chestnut rot. The method was most discriminating with water at 70oC, although 22 out of 80 of the chestnuts that sank were rotten in this treatment. The method was observed to work well on chestnuts that are highly desiccated, but less effectively on chestnuts with minor chestnut rot symptoms. However, there are many more rotten non-desiccated chestnuts than desiccated ones. This is a problem because non-desiccated rotten chestnuts increase in chestnut rot with increasing time in storage, especially after 60 days (Anderson 1993). Flotation disease grading needs to be used with caution as the method can potentially reduce grower profits by identifying healthy chestnuts as rotten and mis-identifying rotten chestnuts as healthy. Potential losses from mis-identified chestnuts in this experiment was calculated as 160-260 kg of chestnuts per metric tonne (t), valued at $800-$1300 per t.

Wildfire has been important in shaping Australian ecosystems through its direct and indirect effects on vegetation communities and faunal assemblages. Predictions that wildfire incidence and intensity will increase with forecast changes in climate, make it essential to understand wildfire impacts on native fauna and factors important for their recovery. The intention of this thesis is to contribute to this knowledge base. In December 2003 a high intensity Wildfire swept through large parts of Booderee National Park in southeastern Australia. Using a replicated design I studied the impacts of this fire on small mammal populations in open sclerophyll forest for 18 months after the fire. The small mammals present were Rattus fuscipes and Antechz'nus stuartz'z'. Additionally, I experimentally investigated factors that may have limited small mammals post-fire, specifically food and blood parasites. I monitored the response of R. fuscipes and A. stuartii to a food supplementation experiment at both the population level and at the scale of individual behaviour for one year. Immediately following the wildfire, populations of both R. fuscz'pes and A. stuartii declined to below 50% of populations unaffected by the fire. Rates of individual survival were low during the fire and for the first 3 months after the fire, probably due to high fire mortality, emigration and poor survival post-fire due to changes in resource availability and predator impact with the depletion of vegetation in the fire. However, within 18 months of the fire, populations of both species were present on all sites at approximately 50% the size of those on unbumt sites; survival rates matched those on unburnt sites and juveniles also were present in populations, indicating reproductive recruitment. This rapid post-fire recovery was attributed to the seasonal timing and patchiness of the wildfire, the presence of moist gullies in close proximity to study sites, and seemingly low numbers of feral predators due to fox control. The food supplementation experiment revealed that R. fuscipes was food limited post—fire, with populations increasing 2-fold on burnt supplemented sites, probably due largely to immigration and increased survival or residency of females. Behavioural studies showed that the added food (rat breeder pellets) was generally used only as a supplement because individuals did not aggregate around food stations or change their patterns of habitat use. Instead they preferred the denser vegetation associated with watercourses, which experienced rapid re—growth post-fire, just as did the individuals that received no additional food. This preference for dense cover, despite the provision of a constant and plentifiJl food source, suggests that predation risks are equally as important as food for small mammals. A. stuartii showed no response to the food supplementation despite accessing the food stations. This may be because the dried pellets were not an appropriate food source for this insectivore. Prevalence of blood parasite infection in R. fuscipes populations was not affected significantly by the wildfire or food supplementation, suggesting that parasite infection did not contribute to the variance in populations. However, any differences in host susceptibility between populations was not measured. The findings of this thesis have important implications for fire management in Australian eucalypt forests, within the context of conserving populations of small mammals and potentially other fauna. Future fire management regimes should aim to achieve mosaic landscapes characterised by vegetation of varying seral stages. A regime providing an intensity and frequency of burns that promotes plant diversity and preferred habitat structure of mammals should be adopted. Moist habitats such as gullies, swamps and rainforests should be protected from fire in any burning regime, or burnt very infrequently and in small patches. Additionally, when planning fire regimes, the breeding biology of fire-sensitive and threatened species should be considered, as should additional management applications such as feral predator control and food supplementation. The need for better planned and more comprehensive fire regimes will become increasingly important in the future given the projections for increases in fire severity and frequency with predicted changes in climate.

This study documented effects of fragmentation and disturbance on a coastal eucalypt dry open-forest plant community at Port Stephens-Myall Lakes, south-eastern Australia. The study evaluated the relative influence of fragment size (range <1-75ha), fragment or edge age (< 1-25y), time since fire (5-25y) and anthropogenic disturbance (minor, major) on microclimate, native plant species richness and weed invasion. Plots were sampled for native and exotic species richness per 25 m2 and edge transects for light, soil moisture, soil temperature, vegetation structure, native species richness and exotic species richness and cover. Depths of edge influence (DEI) were all < 20m inside the forest edge. Younger edge zones were lighter, had hotter and drier soils and more native species than forest interiors. Older edge zones were shadier, had warmer and moister soils and fewer native species than forest interiors, due to vegetation thickening in the edge zone. Light and soil moisture followed linear or monotonic edge-to-interior gradients in younger edges, but more complex patterns in older edges. Soil-temperature DEI decreased with increasing edge age. Fragment size had little influence on edge effects, but those for light developed more rapidly in smaller fragments, and recent fire was associated with reduced richness in edge zones of smaller fragments. Both anthropogenic disturbance and fire enlarged DEI for native species richness. Major anthropogenic disturbance coupled with fragmentation produced a stronger and more immediate loss of native species than fragmentation alone. Small fragments with minor disturbance had fewer native species per 25 m2 than larger fragments, but only after >10y since fragmentation. Analysis of forest interior portions of transects revealed that edge effects, and possibly disturbance, were largely responsible for this loss of native species with time, rather than effects of area. Despite a viable soil seed bank in fragments and the surrounding matrix, weed invasion in fragments was minimal. Exotic species were concentrated in edge zones, and were promoted by major anthropogenic disturbance within fragments. Results were highly dependent on fragment or edge age, and external influences of fragmentation (edge effects and disturbance), were more important than biogeographic (area-driven) factors. Impacts of fragmentation were compounded when combined with disturbance.

Natural interactions between riparian vegetation, large woody debris (LWD) and the fluvial geomorphology of forest streams in North America and Europe have been well researched. In southeastern Australia, where rainfall and runoff are highly variable, where riparian vegetation species are unique and where many streams have been altered since European settlement, there is a paucity of research on such biogeomorphic interactions. This thesis aimed to partly address this knowledge gap by undertaking detailed case studies of four undisturbed streams that varied in their degree of lateral confinement by materials of limited erodibility, i.e. differences in the size and nature of the valley floor trough. These included a laterally and vertically bedrock-confined channel flanked by a series of discontinuous inchannel benches but with no floodplain (Mogo Creek); a laterally bedrock-confined channel flanked by a discontinuous high vertically accreted floodplain and a series of discontinuous in-channel benches (Wheeny Creek); a partially bedrock- and terrace-confined channel discontinuously flanked by pockets of floodplain (Bruces Creek); and a slightly terraceconfined channel continuously flanked by floodplain (Tonghi Creek). Extensive radiocarbon dating of floodplain charcoal at each site highlighted the fact that episodic, rainfall-generated cataclysmic floods have occurred during the late Holocene. These floods totally removed alluvial landforms, including the floodplain forest, from within the valley floor trough. Riparian vegetation communities that have colonised the landforms that redeveloped in the erosional void exhibit a distinct lateral and vertical zonation of species that is determined by the degree of resistance of different species to natural flood disturbance. More flood-resistant tree species, such as Tristaniopsis laurina, are able to grow and survive within the channel and on the channel banks and in—channel benches; possess the ability to reshoot from epicormic buds following high-energy flood disturbance; and can rapidly colonise recently formed alluvial landforms. Less flood—resistant species, such as the Eucalyptus species, grow on higher parts of the floodplain or on remnant Pleistocene river terraces where flood flows are of lower energy and occur less frequently. Measured LWD loadings ranged from 47 m3ha‘I at Mogo Creek to 751 m3ha‘l at Bruces Creek and varied in relation to specific stream power, the relaxation period between cataclysmic floods and the age-structure of the riparian vegetation community from which the LWD was recruited. Large woody debris recruitment processes varied in relation to the geomorphic setting and zonation of riparian vegetation. Episodic bank erosion, undercutting and senescence were identified as the dominant LWD recruitment processes from T. laurina trees growing along the banks of Tonghi and Bruces Creeks, while episodic windthrow was identified as the LWD recruitment process from Eucalyptus trees growing on the floodplains and terraces at these sites. At Mogo and Wheeny Creeks, destruction of in—channel benches by catastrophic floods was identified as the dominant LWD recruitment process from T. laurina and Leptospermum polygalifolium shrubs, while episodic windthrow was the dominant LWD recruitment process from the Eucalyptus trees growing on the high floodplains, where present, and adjacent hillslopes. The longitudinal distribution, orientation and hydraulic impacts of LWD pieces, and the development of log-steps were strongly influenced by the energy of flows experienced and the ratio of tree and LWD size to channel size. Due to high timber densities LWD tends to sink and become partially or completely buried by bedload. It is only in streams with high LWD loadings, low to medium energy bankfull flows and high LWD size to channel size ratios, such as Bruces Creek, that interlocking, wedged pieces of LWD form closely spaced debris dams. The maximum residence time for LWD identified by radiocarbon dating was 980 years on Eucalyptus timber in Wheeny Creek and was interpreted as representing the relaxation period following the most recent cataclysmic flood. Biogeomorphic evidence indicates that riparian vegetation and large woody debris can exert a significant influence on the fluvial geomorphology of sand-bed, forest streams in southeastern Australia by contributing to processes such as pool formation, stream energy dissipation, bank strength, sediment storage patterns, bed stability, oblique bank accretion, in—channel bench and mid-channel bar formation. However, rainfall—generated cataclysmic floods, capable of totally obliterating all landforms within the valley floor trough, including the floodplain forest, have occurred during the late Holocene. Cataclysmic floods exceed vegetationcontrolled thresholds of channel and floodplain stability and resultant specific stream powers of at least 2500 Wm‘2 enable the flood to erode the channel and floodplain to bedrock. Such floods occur more frequently in flood variable regions on high energy streams in narrow valley floor troughs. The width and nature of the valley floor trough, specific stream power and the relaxation period between floods are identified as important factors determining the subsequent influence of riparian vegetation and LWD on the stability of the landforms that redevelop in the erosional void.

Gastropods, like many other marine invertebrates undergo a two-stage life cycle. As the adult body plan results in narrow environmental tolerances and restricted mobility, the optimum opportunity for dispersal occurs during the initial larval phase. Dispersal is considered to be a major influence on the evolutionary trends of different larval strategies. Three larval strategies are recognised in this research: planktotrophy, lecithotrophy and direct development. Planktotrophic larvae are able to feed and swim in the plankton resulting in the greatest dispersal potential. Lecithotrophic larvae have a reduced planktic period and are considered to have more restricted dispersal. The planktic period is absent in direct developing larvae and therefore dispersal potential in these taxa is extremely limited. Each of these larval strategies can be confidently inferred from the shells of fossil gastropods and the evolutionary trends associated with modes of development can be examined using both phylogenetic and non-phylogenetic techniques. This research uses Cenozoic gastropods from southeastern Australia to examine evolutionary trends associated with larval mode. To ensure the species used in analyses are distinct and correctly assigned, a taxonomic review of the six families included in this study was undertaken. The families included in this study were the Volutidae, Nassariidae, Raphitomidae, Borsoniidae, Mangeliidae and Turridae. Phylogenetic analyses were used to examine the relationships between taxa and to determine the order and timing of changes in larval mode throughout the Cenozoic. Traditionally, planktotrophy has been considered the ancestral mode of development. However, using maximum parsimony and maximum-likelihood analysis, this research suggests that the ancestral developmental mode cannot be confidently determined in gastropods from southeastern Australia. Similarly, evidence that transitions between larval strategies might be reversible contradicts the general view that regaining the specialised structures associated with planktotrophy is so difficult that it is considered extremely unlikely to occur. When the timing of switches in larval mode was examined they were found to be scattered at different points in time rather than clustered to specific periods and therefore no inference can be made as to the likely factors driving transitions between larval modes. The correlation between mode of development and macroevolutionary trends was examined using non-phylogenetic techniques. The results do not concur with the hypothesis that species with planktotrophic larvae will exhibit wider geographic ranges, longer species durations and lower speciation rates then lecithotrophic or direct developing taxa. The analyses are thought to be hindered by a strong preservation bias and gaps within the fossil record. The quality of the fossil record and the congruence between phylogenies and stratigraphy is examined using the Stratigraphic Consistency Index, the Relative Completeness Index and the Gap Excess Ratio.

Bibliography: leaves 182-217. This study was conducted to determine the etiology of a blight disease of chickpea in south-eastern Australia and the factors affecting disease development. The disease had previously been identified as phoma blight. Pathogenicity testing revealed two isolates subsequently identified as Asochyta rabiei, the first conclusive identification in the southern hemisphere. Greenhouse screening of chickpea varieties identified types resistant to ascochyta blight. The effects of plant age and environmental conditions on disease development were investigated under controlled conditions in growth rooms. Seedlings were more susceptible than older plants. The optimum conditions for ascochyta blight were 20° C and a 48-96 h period of leaf wetness. Through field trials it was found that disease intensity increased over time, especially in cv. Desavic. The means of penetration of the chickpea host was established in histological studies. This study provided advance warning of this disease for the expanding chickpea industry, and has allowed the implementation of appropriate disease management strategies. It is recommended that cv. Desavic should not be grown where ascochyta blight is likely to be a problem.

This thesis examines the hypothesis that, in southern New South Wales and northeast Victoria, Australia, palatable taxa of E. curvula offer advantages that complement those of the species that are traditionally sown in temperate pastures in a landscape context.This hypothesis was based on a review of literature showing that, prior to European settlement, the vegetation, the landscape and the climate were broadly in balance, and the wateruse pattern of the vegetation of southeastern Australia resulted in water being used more-or-less completely by the end of summer. This maximised the capacity of the soil to take up and store water during autumn and winter.Three grazing experiments and one spaced-plant species evaluation study were used to assess the role of summer-growing, C4 Eragrostis curvula in pastures in the temperate zone of southeastern Australia.Issues relating to pasture production and the productivity of wool-growing sheep were investigated. Factors affecting the sustainability of the pastures and their potential on and off site impacts were emphasised.Modelling was used to explore issues of water use, arising from the grazing experiments. It is concluded that the persistence, production, water use patterns, and the adaptability of palatable varieties of E. curvula make it a useful and complementary addition to the range of species that are currently available for use as sown pastures in southern Australia.
Doctor of Philosophy (PhD)

The Torquay Group outcrops between Bells Headland and Bird Rock, southwest of Torquay on the coast of Victoria. It formed part of the basis of the Haq et al. (1988) sealevel Curve, and has been portrayed as a classical example of sequence stratigraphic development generated by global eustatic oscillations. This study tests that assertion, based on a detailed investigation of the sedimentology and stratigraphy within the Torquay section, using mainly three cores from the larger Torquay Drilling Program, supplemented by cliff face stratigraphic sections from the present and previous studies.

This study investigated the causes of high level of intra-and inter-population variation known to occur in the morphology of fish in the genus Hypseleotris Eleotride in southern Australia, particularly within the Murray-Darling river system. The three major objectives of the study were, identify the number and distribution of species,determine the genetic structure of the populations and analyse relationships between species and consider the process of speciation in this species complex. The investigation of morphological variation in Hypseleotris confirmed the presence of two well known species i.e. H. compressa and H. galli, in the coastal rivers and also of the inland species H. klunzingeri. Populations of Hypseleotris klunzigeri sensu lato in inland river were found to be very highly variable and analysis using discriminant functions and principle component analysis showed the widespread presence of three forms (A, B1 and B2). The analysis was confused by the presence of north/south clines and upstream/downstream variation in characteristic in each form. After these factors were removed, there was still a great deal of variation in each population. The presence of hybrids between each pair of inland species, identified by both morphological and genetic data, further confused the analysis and makes identification of all specimens to species in the field difficult. Examination of type material of H. Klunzingeri showed that this belonged to form B2. The other forms can be related to the undescribed species, Midgley's carp gudgeon and Lake's carp gudgeon. Keys to the species in the complex in southeastern Australia are given. The morphological and genetic data show that H. compressa and H. klunzingeri are sister species, primarily separated by the eastern uplands. Similarly, the coastal species, H. galli is related to form B1 and more distantly, to form A. Possible scenarios for the complex are given.
Doctor of Philosophy (PhD)

Thesis (Ph.D.)--University of Western Sydney, Hawkesbury, 1999.
"A Thesis submitted to the Faculty of Science and Technology in fulfilment of the requirements for the Degree of Doctor of Philosophy". "November 1999". Bibliography : leaves 147-155.

This study presents an investigation into the geomorphological, sedimentological and geotechnical properties of submarine landslides present on the continental slope offshore Fraser Island. An extensive range of previously undiscovered features including marginal plateaus, linear rills, ridges and gullies, canyon systems, as well as slides and slumps were identified. Gravity cores (5.65 m and 3.64 m long) taken in the ‘Upper Slope Slide’ (25 km2 in area, 200-300 m thick), and the ‘Middle Slope Slide’ (11 km2 in area, 100-150 m thick) indicate the slide scars contain drapes of Pleistocene to Recent hemipelagic mud. Shorter gravity cores (1.33 m and 0.43 m long) taken adjacent to both slides terminated in stiff muds of upper Pliocene to lower Pleistocene age (Upper Slope Slide), and upper Miocene to lower Pliocene age (Middle Slope Slide). This unique pattern shows that the sediment is being accumulated and protected inside the slide hollows, while being actively removed from the exposed adjacent slopes, most likely by abrasion. Biostratigraphic ages determined for the basal material demonstrate that the seafloor surfaces at both sites are effectively erosional unconformities. The basal, stiff sediments on the upper slope was deposited between 2 and 2.5 Ma BP; this material was scoured and then buried beneath a 1 m thick sediment drape at 0.45 Ma BP. Sediments exposed on the seafloor adjacent to the Middle Slope Slide were dated at around 6-8.5 Ma BP. This indicates that the smooth upper continental slope developed its morphology by the late-mid Pleistocene, while the middle slope is a Post-Pliocene feature. It is thought that Pliocene-Pleistocene geological events including fluctuations in the intensity of surface and abyssal ocean currents are responsible for re-sculpting the continental slope’s morphology and have a) increased abrasion and erosion of the middle and upper slope; while b) suppressed sediment delivery.

Doctor of Philosophy(PhD)
It is generally accepted that tree roots can reinforce soil and improve the stability of vegetated slopes. Tree root reinforcement is also recognised in riverbanks although the contribution that the roots make to bank stability has rarely been assessed due to the reluctance of geomorphologists to examine riverbank stability by geomechanical methods that allow for the inclusion of quantified biotechnical parameters. This study investigates the interaction between alluvial soil and the roots of four southeastern Australian riparian trees. It quantifies the amount and distribution of root reinforcement present beneath typically vegetated riverbanks of the upper Nepean River, New South Wales, and examines the effect of the reinforcement on the stability of these banks. The ability of a tree to reinforce the soil is limited by the spatial distribution of its root system and the strength that the roots impart to the soil during shear. These two parameters were determined for the following four species of native riparian tree: Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata, and Acacia floribunda. The four species all exhibit a progressive reduction in the quantity of root material both with increasing depth and with increasing lateral distance from the tree stem. In the vertical direction there are two distinct zones that can be described. The first occurs from between 0 and approximately 15 % of the maximum vertical depth and consists of approximately 80 % of the total root material quantity. In this zone the root system consists of both vertical and lateral roots, the size and density of which varies between species. The second zone occurs below approximately 15 % of the maximum vertical depth and consists primarily of vertical roots. The quantity of root material in this zone decreases exponentially with depth due to the taper of individual roots. The earth reinforcement potential in terms of both geometric extent and the quantity of root material expressed as the Root Area Ratio (RAR) varies significantly from species to species. E. elata exhibited the highest values of RAR in soil zones beneath it while E. amplifolia reinforced a greater volume of soil than any of the other species examined. The increased shear resistance (Sr) of alluvial soil containing roots was measured by direct in-situ shear tests on soil blocks beneath a plantation. For three of the species (C. glauca, E. amplifolia, E. elata) Sr increased with increasing RAR measured at the shear plane, in a similar linear relationship. The shear resistance provided by A. floribunda roots also increased with increasing RAR at the shear plane but at a much greater rate than for the other three species. This is attributable to A. floribunda’s greater root tensile strength and therefore pull-out resistance, as well as its smaller root diameters at comparative RARs which resulted in a greater proportion of roots reaching full tensile strength within the confines of the test. Tree roots fail progressively in this system. Therefore determining the increased shear strength from the sum of the pull-out or tensile strengths of all individual roots and Waldron’s (1977) and Wu et al’s (1979) simple root model, would result in substantial over estimates of the overall strength of the soil-root system. The average difference between Sr calculated in this manner and that measured from direct in-situ shear tests is 10.9 kPa for C. glauca, 19.0 kPa for E. amplifolia, 19.3 kPa for E. elata, and 8.8 kPa for A. floribunda. A riverbank stability analysis incorporating the root reinforcement effect was conducted using a predictive model of the spatial distribution of root reinforcement beneath riparian trees within the study area. The model is based on measurements of juveniles and observations of the rooting habits of mature trees. It indicates that while the presence of vegetation on riverbank profiles has the potential to increase stability by up to 105 %, the relative increase depends heavily on the actual vegetation type, density, and location on the bank profile. Of the species examined in this study the greatest potential for improved riverbank stability is provided by E. amplifolia, followed by E. elata, A. floribunda, and C. glauca. The presence of trees on banks of the Nepean River has the potential to raise the critical factor of safety (FoS) from a value that is very unstable (0.85) to significantly above 1.00 even when the banks are completely saturated and subject to rapid draw-down. It is likely then that the period of intense bank instability observed within this environment between 1947 and 1992 would not have taken place had the riparian vegetation not been cleared prior to the onset of wetter climatic conditions. Typical ‘present-day’ profiles are critically to marginally stable. The introduction of vegetation could improve stability by raising the FoS up to 1.68 however the selection of revegetation species is crucial. With the placement of a large growing Eucalypt at a suitable spacing (around 3-5 m) the choice of smaller understorey trees and shrubs is less important. The effect of riparian vegetation on bank stability has important implications for channel morphological change. This study quantifies the mechanical earth reinforcing effect of some native riparian trees, thus allowing for improved deterministic assessment of historical channel change and an improved basis for future riverine management.

It is generally accepted that tree roots can reinforce soil and improve the stability of vegetated slopes. Tree root reinforcement is also recognised in riverbanks although the contribution that the roots make to bank stability has rarely been assessed due to the reluctance of geomorphologists to examine riverbank stability by geomechanical methods that allow for the inclusion of quantified biotechnical parameters. This study investigates the interaction between alluvial soil and the roots of four southeastern Australian riparian trees. It quantifies the amount and distribution of root reinforcement present beneath typically vegetated riverbanks of the upper Nepean River, New South Wales, and examines the effect of the reinforcement on the stability of these banks. The ability of a tree to reinforce the soil is limited by the spatial distribution of its root system and the strength that the roots impart to the soil during shear. These two parameters were determined for the following four species of native riparian tree: Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata, and Acacia floribunda. The four species all exhibit a progressive reduction in the quantity of root material both with increasing depth and with increasing lateral distance from the tree stem. In the vertical direction there are two distinct zones that can be described. The first occurs from between 0 and approximately 15 % of the maximum vertical depth and consists of approximately 80 % of the total root material quantity. In this zone the root system consists of both vertical and lateral roots, the size and density of which varies between species. The second zone occurs below approximately 15 % of the maximum vertical depth and consists primarily of vertical roots. The quantity of root material in this zone decreases exponentially with depth due to the taper of individual roots. The earth reinforcement potential in terms of both geometric extent and the quantity of root material expressed as the Root Area Ratio (RAR) varies significantly from species to species. E. elata exhibited the highest values of RAR in soil zones beneath it while E. amplifolia reinforced a greater volume of soil than any of the other species examined. The increased shear resistance (Sr) of alluvial soil containing roots was measured by direct in-situ shear tests on soil blocks beneath a plantation. For three of the species (C. glauca, E. amplifolia, E. elata) Sr increased with increasing RAR measured at the shear plane, in a similar linear relationship. The shear resistance provided by A. floribunda roots also increased with increasing RAR at the shear plane but at a much greater rate than for the other three species. This is attributable to A. floribunda’s greater root tensile strength and therefore pull-out resistance, as well as its smaller root diameters at comparative RARs which resulted in a greater proportion of roots reaching full tensile strength within the confines of the test. Tree roots fail progressively in this system. Therefore determining the increased shear strength from the sum of the pull-out or tensile strengths of all individual roots and Waldron’s (1977) and Wu et al’s (1979) simple root model, would result in substantial over estimates of the overall strength of the soil-root system. The average difference between Sr calculated in this manner and that measured from direct in-situ shear tests is 10.9 kPa for C. glauca, 19.0 kPa for E. amplifolia, 19.3 kPa for E. elata, and 8.8 kPa for A. floribunda. A riverbank stability analysis incorporating the root reinforcement effect was conducted using a predictive model of the spatial distribution of root reinforcement beneath riparian trees within the study area. The model is based on measurements of juveniles and observations of the rooting habits of mature trees. It indicates that while the presence of vegetation on riverbank profiles has the potential to increase stability by up to 105 %, the relative increase depends heavily on the actual vegetation type, density, and location on the bank profile. Of the species examined in this study the greatest potential for improved riverbank stability is provided by E. amplifolia, followed by E. elata, A. floribunda, and C. glauca. The presence of trees on banks of the Nepean River has the potential to raise the critical factor of safety (FoS) from a value that is very unstable (0.85) to significantly above 1.00 even when the banks are completely saturated and subject to rapid draw-down. It is likely then that the period of intense bank instability observed within this environment between 1947 and 1992 would not have taken place had the riparian vegetation not been cleared prior to the onset of wetter climatic conditions. Typical ‘present-day’ profiles are critically to marginally stable. The introduction of vegetation could improve stability by raising the FoS up to 1.68 however the selection of revegetation species is crucial. With the placement of a large growing Eucalypt at a suitable spacing (around 3-5 m) the choice of smaller understorey trees and shrubs is less important. The effect of riparian vegetation on bank stability has important implications for channel morphological change. This study quantifies the mechanical earth reinforcing effect of some native riparian trees, thus allowing for improved deterministic assessment of historical channel change and an improved basis for future riverine management.

Thesis (Ph. D.)--School of Geosciences, Faculty of Science, University of Sydney, 2004.
Degree awarded 2004; thesis submitted 2003. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Geosciences, Faculty of Science. Title from title screen (viewed 13 January 2009). Includes bibliographical references. Also available in print form.

This thesis reports the results obtained, and conclusions made regarding research into the hydrochemistry of a small impounded karst area in southeastern Australia. Water samples were collected from a variety of sites over a period of approximately six years and include samples that are representative of baseflow (drought conditions) and flood (high flow conditions) the two extremes of the flow regime. Four distinct water types were found to be associated with the karst spring and cave water sites sampled. In terms of physical, chemical and computed parameter values these have been classed as TYPE 1 water (median parameter values similar to those noted for the surface stream sites sampled with catchments of non-carbonate material); TYPE 2 water (catchment predominantly of limestone); TYPE 3 water (catchment predominantly of dolomite); TYPE 4 water (high median chemical concentrations). Spatial variation within the study area is considerable and intrinsic factors such as catchment lithology, the residence time of recharge, aspect and vegetation cover are the major natural controls in determining physical and chemical characteristics.

Stable continental margins experience submarine landslides relatively frequently and some of the largest slides on record have been shed from these relatively passive terrains. Despite this, and the obvious accompanying tsunami hazard, slides from passive margins such as Australia are poorly understood when compared to other settings, such as the flanks of volcanic islands, active subduction-zone margins and submarine fans. This work presents an investigation into the submarine landslides occurring along east Australia’s (EA) continental margin, with a focus on investigating the causes, timing, and mechanisms responsible for these features. It has focused on analysing gravity core samples and interpreting of high-resolution multibeam and subbottom profiles. The age, morphology, composition, and origin of particular submarine landslides on the EA continental margin offshore New South Wales/Queensland has been described and the mechanical characteristics of sediments from the EA continental slope has been presented. The hazard posed by these submarine landslides has also been evaluated by investigating their potential to generate tsunamis along this margin. The widespread occurrence of slides across the EA margin indicates that submarine sliding should be considered to be a common characteristic of this margin. Engineering properties imply that the sediment forming the margin is reasonably strong and inherently stable and classical limit-equilibrium modeling indicates that submarine landslides should not be a common occurrence. This indicates that a pre-conditioning trigger, or some other mechanism, is required to destabilise the slope and enable failure. The most likely suspected processes include: 1) dramatic reduction of the shear strength of the sediments to extremely low values; 2) long-term modification of the slope-geometry; and/or 3) seismic events large enough to trigger sediment liquefaction or a sudden increase of pore-fluid pressure.

Intertidal wetland habitats in southeastern Australia have changed significantly during the past sixty years. Mangrove habitats have expanded both seawards and landwards, the latter being at the expense of saltmarsh habitats. This relatively common phenomenon is generally suggested to be an outcome of sea-level rise. Several factors potentially responsible for this change are examined, including changes in mean sealevel during the past 50 to 100 years, changes in climate, population growth, catchment landuse, and estuary type. A protocol for mapping estuarine habitats was developed and implemented, incorporating the application of geographic information systems. Spatial and temporal coastal wetland habitat changes at nine sites along the New South Wales coast are illustrated. These habitat dynamics were shown to not correlate between sites. The results demonstrate that sea-level rise in this region cannot solely account for the extent of change during the past sixty years. With the exception of one site (Careel Bay), there have been no correlations between contemporary mean sea-level rise and mangrove incursion of the saltmarsh habitats at the study sites, or with rainfall patterns, at the scale of observation in this study, which was largely decadal. The only correlations determined during this study have been between population growth and coastal wetland habitat dynamics in some sites. In spite of saltmarsh habitat loss being a regional phenomenon, local factors appear to have a profound bearing on the rates of change. Neither contemporary mean sea-level rise, rainfall patterns, estuary type, catchment landuse, catchment natural cover nor population pressure can account solely for the patterns in the spatial and temporal dynamics of the coastal wetlands of New South Wales. It seems apparent that regional factors create preconditions favourable for mangrove incursion, but that localised conditions have been responsible for the extent of these incursions from site to site. That is, despite higher sea-level and greater rainfall, the extent of change has been determined by the unique characteristics of each site. The results have important implications for current estuary management practices in the state of New South Wales. The lack of spatial and temporal trends in coastal wetland habitat dynamics point to the need for management to be conducted on a localised, rather than regional scale. Additionally, anthropogenic influences must be carefully managed, since the extent of mangrove habitat expansion into saltmarsh areas is unlikely to be a natural occurrence.

Fauna conservation outside protected areas can make an important complementary contribution to conservation within reserves. This thesis aimed to contribute new information and analytical frameworks to the science of fauna conservation in human-modified landscapes. Two approaches were used: (1) empirical data collection and analysis, and (2) the discussion and development of conceptual landscape models. ¶ Empirical work focused on lizard distribution patterns in two production landscapes in southeastern Australia. Lizards were targeted because ectotherms are frequently neglected by conservation biologists. The “Nanangroe grazing landscape” was used for sheep and cattle grazing. In this landscape, approximately 85% of pre-European woodland cover had been cleared, and understorey vegetation was sparse. Lizards were surveyed at 16 landscape units, which were stratified by aspect, topographic position and amount of tree cover. Each landscape unit contained three sites, and each site contained three plots. Regression modelling showed that different species responded differently to their environment. For example, the four-fingered skink (Carlia tetradactyla) and Boulenger’s skink (Morethia boulengeri) were more likely to occur at woodland sites with northerly aspects, whereas the striped skink (Ctenotus robustus) and olive legless lizard (Delma inornata) were more likely to inhabit sites with a simple microhabitat structure. Statistical analysis further showed that the habitat attributes that lizards were related to varied continuously through space, and over different spatial scales. For example, invertebrate abundance (a proxy for food availability) varied most strongly over tens of metres, whereas the amount of grass cover varied most strongly over hundreds to thousands of metres. Thus, work at Nanangroe revealed spatially complex patterns of lizard occurrence and habitat variables. ¶ The “Tumut plantation landscape” was a spatial mosaic of native eucalypt (Eucalyptus) forest patches embedded within a plantation of the introduced radiata pine (Pinus radiata). In this landscape, thirty sites were surveyed for lizards. Sites were stratified by forest type and patch size, and included eucalypt patches, pine sites, and extensive areas of eucalypt forest adjacent to the plantation. Regression modelling showed that lizard species responded to various habitat attributes, including elevation, the amount of eucalypt forest within 1 km of a site, invertebrate abundance and ground cover. Variables related to habitat fragmentation often were significant predictors of lizard occurrence. However, work at Tumut suggested that important additional insights into lizard distribution patterns could be obtained by considering variables related to food and shelter resources, and climatic conditions. ¶ The Nanangroe and Tumut landscapes were in close proximity, but together spanned an altitudinal gradient of 900 m. An investigation of changes in lizard community composition with altitude showed that (1) only one species was common to Nanangroe and Tumut, (2) different species had different altitudinal preferences, and (3) ecologically similar species replaced one another with increasing altitude. These results highlighted that even in highly modified landscapes, natural gradients (such as climate) can play an important role in shaping animal assemblage composition and species distribution patterns. ¶ Empirical work suggested that, in some landscapes, the frequently used “fragmentation model” is a relatively weak conceptual basis for the study of animal distribution patterns. The fragmentation model implicitly assumes that “habitat patches” can be defined unequivocally across many species, and that patches are located within a relatively inhospitable matrix. Where these assumptions are breached, conservation guidelines arising from the fragmentation model may be too simplified. In spatially complex production landscapes, it may be more appropriate to maintain habitat heterogeneity at multiple spatial scales than to focus solely on the management of large, pre-defined patches. ¶ Given the potential limitations of the fragmentation model, a new, more holistic landscape model was developed. The “continuum model” was derived from continuum theory as developed for plant ecology. The continuum model recognises (1) spatial continua of environmental variables, and (2) species’ individualistic responses to these variables. For animals, key environmental variables may be related to the availability of food, shelter, sufficient space, and suitable climatic conditions. Unlike the fragmentation model, the continuum model is inherently process-based and thus may help to link the perceived gap between patterns and processes in landscape ecology. ¶ Three general conclusions arise from this thesis: 1. Some heterogeneous production landscapes support many native species, and therefore represent important conservation opportunities. 2. In some modified landscapes, the fragmentation model does not capture the complexity of animal distribution patterns. In those landscapes, conservation recommendations derived from the fragmentation model may be overly simplistic. 3. The continuum model may be a useful extension of the fragmentation model. It provides a process-based conceptual basis for empirical work on animal distribution patterns.

Tree-ring based climate reconstructions have been critical for understanding past variability and recent trends in climate worldwide, but they are scarce in Australia. This is particularly the case for temperature: only one tree-ring width based temperature reconstruction – based on Huon Pine trees from Mt Read, Tasmania – exists for Australia. Here, we investigate whether additional tree- ring parameters derived from Athrotaxis cupressoides trees growing in the same region have potential to provide robust proxy records of past temperature variability. We measured wood properties, including tree-ring width (TRW), mean density, mean cell wall thickness (CWT), and tracheid radial diameter (TRD) of annual growth rings in Athrotaxis cupressoides, a long-lived, high-elevation conifer in central Tasmania, Australia. Mean density and CWT were strongly and negatively correlated with summer temperatures. In contrast, the summer temperature signal in TRW was weakly positive. The strongest climate signal in any of the tree-ring parameters was maximum temperature in January (mid-summer; JanTmax) and we chose this as the target climate variable for reconstruction. The model that explained most of the variance in JanTmax was based on TRW and mean density as predictors. TRW and mean density provided complementary proxies with mean density showing greater high-frequency (inter-annual to multi-year) variability and TRW showing more low-frequency (decadal to centennial-scale) variability. The final reconstruction model is robust, explaining 55% of the variance in JanTmax, and was used to reconstruct JanTmax for the last five centuries (1530–2010 C.E.). The reconstruction suggests that the most recent 60 years have been warmer than average in the context of the last ca. 500 years. This unusually warm period is likely linked to a coincident increase in the intensity of the subtropical ridge and dominance of the positive phase of the Southern Annular Mode in summer, which weaken the influence of the band of prevailing westerly winds and storms on Tasmanian climate. Our findings indicate that wood properties, such as mean density, are likely to provide significant contributions toward the development of robust climate reconstructions in the Southern Hemisphere and thus toward an improved understanding of past climate in Australasia.

Microxeromagna armillata ( Lowe, 1852 ) is a snail introduced snail to Australia which has established populations in the Riverland and Sunraysia citrus growing regions. Citrus exported from these regions to the USA has been rejected due to contamination with M. armillata, causing significant economic losses. The life history, phenology and activity of Microxeromagna armillata has not been studied in Australia : this forms the basis of this thesis. Microxeromagna armillata employs an iteroparous egg laying strategy in semi - field conditions and lays approximately 500 eggs per year. Field populations can reach high densities ( ∼ 4000 snails / m ² ), particularly during the winter months when juvenile recruitment occurs. Snails reach sexual maturity at ∼ 6mm in shell diameter and can grow to this size from a juvenile stage ( 2mm ) within six weeks. Microxeromagna armillata can reproduce successfully by self-fertilisation, and juveniles are able to aestivate with little reduction in subsequent fecundity. These traits make control of this pest a significant challenge. Leaf litter is the preferred habitat of M. armillata, but snails do move in the tree canopy. Cues for snail activity in the leaf litter and canopy appear to differ, as does the size of active snails in these areas. Microxeromagna armillata activity was low in the tree canopy during harvest compared to post harvest, intimating that fruit contamination is either occurring infrequently or post - harvest. Copper trunk bands were shown to minimise snail movement into the canopy and may be an important preventative measure. These findings have changed the recommendations for M. armillata management in citrus groves of south eastern Australia.
Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2007.

The application of substantial quantities of phosphorus (P) has been required to increase productivity on many Australian soils. Unfortunately, these applications have often resulted in increased concentrations of P in surface runoff that contributes to excessive algal growth in surface waters and consequently a decline in their quality. The concentrations of P in runoff from intensively managed pastures are often high (1-5 mg/L) and typically at least an order of magnitude higher than water quality targets. Although a substantial amount of research has been devoted to the problem of P accumulation and mobilisation in arable systems ( in which P is typically mobilised by the action of raindrop impact and subsequently transported in particulate form ), there has been substantially less research in intensively managed pasture systems. Consequently, there is a paucity of knowledge concerning the fundamental processes and factors responsible for P in runoff from these systems and a dearth of truly effective remedial strategies. In this thesis, the accumulation of P in soil under intensively managed pastures used for dairying and the processes responsible for its mobilisation in surface runoff were investigated. This research was undertaken at two research sites in South - east Australia, i.e. Camden in New South Wales and Flaxley in South Australia. A number of factors relating to scale and hydrology may influence the processes of P mobilisation and its concentration in runoff. A comparison was made of the forms and concentrations of P in runoff between a typical rainfall simulation methodology and large runoff plots. The effect of rainfall intensity on the forms and concentrations of P was also investigated. The concentrations of P in runoff from small - scale, high - intensity rainfall simulations were on average 33 % lower than those from large plots ( approximating hillslopes ) although the processes of mobilisation ( as evidenced by runoff P forms ) were similar. Increasing rainfall intensity resulted in decreasing P concentrations, but similar forms of P. It was hypothesised that changes in hydrological characteristics ( residence time and depth of runoff ) were responsible for the differences in the P concentrations. A model of P mobilisation ( incorporating hydrological and P - release characteristics ) was developed and shown to successfully predict runoff P concentrations under a range of rainfall intensities. These findings and the subsequent model were used in the successful modelling of landscape scale nutrient exports based on rainfall simulation data as part of a separate, but complementary project. There is anecdotal evidence to suggest that Australian soils are relatively ' leaky ' in terms of P in runoff compared to soils overseas. Consequently, comparisons of the labile soil P characteristics and soil P - runoff P relationships were made between Australian soils and soils of similar fertility from the USA, UK and New Zealand ( using both experimental data and data sourced from the literature ). It was concluded that Australian soils leak more P than soils of similar fertility in the USA, UK and New Zealand, although it was beyond the scope of the thesis to make more detailed comparisons between Australian and overseas soils. The accumulation and mobilisation of P in two soils used for intensive pasture production in Australia were investigated. In intensive pasture systems P accumulated in the shallowest zones of the soil and principally as inorganic P. The concentrations of labile P were 3 - 5 times higher in the top 0.01 m than in the top 0.1 m. Using a simple model, it was estimated that only the top several mm of soil influence runoff P concentrations. The dominant form of P in runoff was shown to be orthophosphate although in low to moderate fertility soils, dissolved organic P can constitute a substantial proportion of the P in runoff. These results confirm the need to reduce the pool of P available for mobilisation in the immediate topsoil in order to reduce runoff P concentrations. Because P is stratified, it was hypothesised that one method to reduce the pool of P available for mobilisation is to de - stratify the soil ( i.e. mix the topsoil ). The effect of this technique on runoff P concentrations was investigated in laboratory and rainfall simulation experiments. These experiments revealed that reductions in runoff P concentrations between 45 and 70 % can be achieved by de - stratification of soils under permanent pastures. It was hypothesised that the benefits of de - stratification could be maximised using a combination of information relating to catchment hydrology and the spatial distribution of soil P and that this would result in large reductions in P exports with a relatively small degree of inconvenience to land managers. Given the limited opportunities identified in previous research to reduce P exports in runoff, the strategic utilisation of de - stratification is a potentially important option in water quality management for the dairy industry and warrants further investigation.
Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.

The application of substantial quantities of phosphorus (P) has been required to increase productivity on many Australian soils. Unfortunately, these applications have often resulted in increased concentrations of P in surface runoff that contributes to excessive algal growth in surface waters and consequently a decline in their quality. The concentrations of P in runoff from intensively managed pastures are often high (1-5 mg/L) and typically at least an order of magnitude higher than water quality targets. Although a substantial amount of research has been devoted to the problem of P accumulation and mobilisation in arable systems ( in which P is typically mobilised by the action of raindrop impact and subsequently transported in particulate form ), there has been substantially less research in intensively managed pasture systems. Consequently, there is a paucity of knowledge concerning the fundamental processes and factors responsible for P in runoff from these systems and a dearth of truly effective remedial strategies. In this thesis, the accumulation of P in soil under intensively managed pastures used for dairying and the processes responsible for its mobilisation in surface runoff were investigated. This research was undertaken at two research sites in South - east Australia, i.e. Camden in New South Wales and Flaxley in South Australia. A number of factors relating to scale and hydrology may influence the processes of P mobilisation and its concentration in runoff. A comparison was made of the forms and concentrations of P in runoff between a typical rainfall simulation methodology and large runoff plots. The effect of rainfall intensity on the forms and concentrations of P was also investigated. The concentrations of P in runoff from small - scale, high - intensity rainfall simulations were on average 33 % lower than those from large plots ( approximating hillslopes ) although the processes of mobilisation ( as evidenced by runoff P forms ) were similar. Increasing rainfall intensity resulted in decreasing P concentrations, but similar forms of P. It was hypothesised that changes in hydrological characteristics ( residence time and depth of runoff ) were responsible for the differences in the P concentrations. A model of P mobilisation ( incorporating hydrological and P - release characteristics ) was developed and shown to successfully predict runoff P concentrations under a range of rainfall intensities. These findings and the subsequent model were used in the successful modelling of landscape scale nutrient exports based on rainfall simulation data as part of a separate, but complementary project. There is anecdotal evidence to suggest that Australian soils are relatively ' leaky ' in terms of P in runoff compared to soils overseas. Consequently, comparisons of the labile soil P characteristics and soil P - runoff P relationships were made between Australian soils and soils of similar fertility from the USA, UK and New Zealand ( using both experimental data and data sourced from the literature ). It was concluded that Australian soils leak more P than soils of similar fertility in the USA, UK and New Zealand, although it was beyond the scope of the thesis to make more detailed comparisons between Australian and overseas soils. The accumulation and mobilisation of P in two soils used for intensive pasture production in Australia were investigated. In intensive pasture systems P accumulated in the shallowest zones of the soil and principally as inorganic P. The concentrations of labile P were 3 - 5 times higher in the top 0.01 m than in the top 0.1 m. Using a simple model, it was estimated that only the top several mm of soil influence runoff P concentrations. The dominant form of P in runoff was shown to be orthophosphate although in low to moderate fertility soils, dissolved organic P can constitute a substantial proportion of the P in runoff. These results confirm the need to reduce the pool of P available for mobilisation in the immediate topsoil in order to reduce runoff P concentrations. Because P is stratified, it was hypothesised that one method to reduce the pool of P available for mobilisation is to de - stratify the soil ( i.e. mix the topsoil ). The effect of this technique on runoff P concentrations was investigated in laboratory and rainfall simulation experiments. These experiments revealed that reductions in runoff P concentrations between 45 and 70 % can be achieved by de - stratification of soils under permanent pastures. It was hypothesised that the benefits of de - stratification could be maximised using a combination of information relating to catchment hydrology and the spatial distribution of soil P and that this would result in large reductions in P exports with a relatively small degree of inconvenience to land managers. Given the limited opportunities identified in previous research to reduce P exports in runoff, the strategic utilisation of de - stratification is a potentially important option in water quality management for the dairy industry and warrants further investigation.
Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.

The archaeological record of southeastern Australia, from the Pleistocene to the mid-tolate Holocene, is seen to reflect a transition from dispersed Aboriginal land use patterns to those of increasing) y populous, sedentary and socioeconomically complex hunter gatherers. This unilinear development model is nevertheless based on broad trends in rates of site formation and intensity of use, limited dating and functional analysis of spatially patterned evidence, and scarce data for the comparative complexities of the Pleistocene cultural environment. The present study reviews assumptions and evidence underlying this model, and contributes the results of a new large scale sample survey, and excavation program, in the Central Murrumbidgee Riverine Plain. The regional study enables a reformulation of the Holocene land use model, especially for riverine plains environments, and identifies avenues for further investigation. A major weakness underlying the population-sedentism model is the inadequate understanding of the definition, formation processes, functions and dating of the 'mound' sites which are common in some southeastern Australian environments. These were therefore a special focus of the research. The vast majority of such sites in the study region were formed as a result of the operation of earth ovens. Multiple dates from individual oven mounds demonstrated the very long periods over which they were revisited and used. Such use highlights the caution required in interpreting their surficial groupings, and relationship to proximate artefact scatters and other sites, as contemporaneous settlement patterns. Their formation, even in large groupings, is argued to be well within the capability of a population of modest densities within a regime of seasonal or semi-sedentary usage. The unilinear development model is also found to inadequately appreciate the degree to which Aboriginal peoples reorganised their regional land use pattern at different times within the Holocene. The major Pleistocene-Holocene environmental transition has been a moment of expected cultural change, whilst intra-Holocene change has been more readily interpreted as a result of a socioeconomic transition. Nevertheless, Holocene environments underwent punctuated localised change. These are important parameters in explaining the archaeological record. Such change was managed through complex and flexible subsistence patterns, and elaborate technology and socioeconomic organisation, which characterised the hunter gatherer societies of Aboriginal Australia from the mid Holocene to the 19th century. It is argued, for the Central Murrumbidgee Riverine Plain, that this process did not necessarily involve dramatic population increases, demographic pressures, or a substantial adoption of the strictures of sedentism.

Microxeromagna armillata ( Lowe, 1852 ) is a snail introduced snail to Australia which has established populations in the Riverland and Sunraysia citrus growing regions. Citrus exported from these regions to the USA has been rejected due to contamination with M. armillata, causing significant economic losses. The life history, phenology and activity of Microxeromagna armillata has not been studied in Australia : this forms the basis of this thesis. Microxeromagna armillata employs an iteroparous egg laying strategy in semi - field conditions and lays approximately 500 eggs per year. Field populations can reach high densities ( ∼ 4000 snails / m ² ), particularly during the winter months when juvenile recruitment occurs. Snails reach sexual maturity at ∼ 6mm in shell diameter and can grow to this size from a juvenile stage ( 2mm ) within six weeks. Microxeromagna armillata can reproduce successfully by self-fertilisation, and juveniles are able to aestivate with little reduction in subsequent fecundity. These traits make control of this pest a significant challenge. Leaf litter is the preferred habitat of M. armillata, but snails do move in the tree canopy. Cues for snail activity in the leaf litter and canopy appear to differ, as does the size of active snails in these areas. Microxeromagna armillata activity was low in the tree canopy during harvest compared to post harvest, intimating that fruit contamination is either occurring infrequently or post - harvest. Copper trunk bands were shown to minimise snail movement into the canopy and may be an important preventative measure. These findings have changed the recommendations for M. armillata management in citrus groves of south eastern Australia.
Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2007.

In fire-prone ecosystems, plant species exhibit a range of traits which allow them to persist under certain fire regimes. Two critical traits are resprouting and regeneration from seed. Resprouters and seeders can coexist within plant communities, but their relative proportion varies. This research investigated variation in patterns of community composition, in terms of fire response traits, across a mountainous region of south-eastern Australia. The relative importance of fire regimes, habitat, vegetation cover and resource gradients in influencing these patterns was tested. Associations between leaf traits and fire response types were also explored to investigate whether traits related to fire persistence can be considered as part of a broader spectrum of plant ecological strategies, and assist in explaining landscape patterns. In January 2003 unplanned fires burned through the region, creating the opportunity to investigate the responses of locally occurring plants. An initial study of observed field data demonstrated that some species varied in their response between sites. Furthermore, observed responses often differed from those reported in a fire response trait database. As such, the decision was taken to use observed site-specific data on fire response traits where possible to analyse community composition across the region. Data were subsequently collated from five post-fire surveys conducted across 284 sites in the study area. Resprouting was a dominant response of species in the region. However, woody obligate seeders, although infrequent, were often structurally important. Within-species variation was identified, with variability in post-fire seed regeneration particularly evident in trees. The results unexpectedly identified 'dataset' as the factor most strongly associated with the observed patterns, raising important questions about the use of data collated from different sources. Obligate resprouters were favoured at sites burned with no short intervals between fires, whereas several woody obligate seeding types were in higher proportions at sites burned with one or two short intervals. This suggests that some degree of fire is required for obligate seeder persistence. However, the possibility that woody obligate seeders had already been eliminated from the region prior to this study, due to short inter-fire intervals, could not be discounted. Significant differences between habitats were identified, with woody obligate seeders found in high proportions on rock outcrops and in wet grasslands. However, trends in the proportions of fire response types across habitats could not be reconciled with trends in habitat characteristics such as canopy height and understorey cover. Understorey cover was negatively associated with seeders and facultative resprouters, suggesting an important influence of competition post-fire. Leaf trait comparisons showed that facultative resprouters differed from obligate seeders and obligate resprouters, indicating that this strategy requires an investment into rapid acquisition of resources and fast growth to compete. Differences in leaf traits in species with a canopy seed bank were also identified, raising some important considerations regarding approaches to classifying species by fire response traits. This research illustrates the value of considering the relative importance of fire in relation to other factors for developing a thorough understanding of the processes governing community composition in fire-prone ecosystems. Importantly, the approaches taken in this thesis also revealed a range of issues regarding the application of trait data, which are discussed in relation to trait-based ecological research and management.

The Late Neogene sedimentary sequence of the Murray Basin provides an excellent opportunity to examine paleoenvironmental change across southeastern Australia. A detailed stratigraphic analysis of sediments deposited within the basin in the last 10 Ma was undertaken to assess the influence of tectonic and eustatic processes on deposition.
Stratigraphic observations and radiogenic isotope analysis reveals the onset of deposition by 7.2 Ma with a transgressive episode that deposited the marine marls of the Bookpurnong Beds. Deposition was restricted to the central and eastern parts of the basin due to the Hamley Fault. In the west, subsurface elevation contours indicate the presence of incised paleodrainage channels above Miocene limestones, which facilitated the formation of a large estuary system at 5.3 Ma. The sediments of the Norwest Bend Formation were deposited within this western region, while further east, the Loxton-Parilla Sands strandplain deposited over 214 coastal ridges. The basal parts of this unit occur as lateral equivalents to the sediments of the Lower Norwest Bend Formation (in the west). Topographic and magnetic data reveal that tectonism was active during this period and resulted in the erosion and truncation of strandlines.
Tectonic evidence and an estimated minimum 28,037 year cyclicity between strandline sets, suggests that the Loxton-Parilla Sands strandlines do not represent an unbroken record of glacioeustatic change. The subaerial exposure of these sediments at approximately 3.0 Ma caused the formation of a calcareous karst above the Norwest Bend Formation and a ferruginous and/or silicious cap (the Karoonda Surface) above the Loxton-Parilla Sands. The stratigraphic position of these surfaces are indicative of a regional widespread unconformity.
The Douglas-Blackburn paleodrainage system in western Victoria was dammed during the Mid-Late Pliocene by uplift associated with the Padthaway High, which caused the formation of a 400,000 km2 lacustrine system, known as Lake Bungunnia. Topographic analysis indicates that Lake Bungunnia comprised at least four distinct sub-basins with water depths of up to 30 metres, with lake shorelines indicating that active tectonism occurred during this period. The resulting lack of sediment input to the coast caused the formation of the Kanawinka Escarpment, a large erosional scarp along the southern margin of the Padthaway High.
The geomorphology of the modern Murray Basin can be directly attributed to the demise of the Lake Bungunnia system. Movement along the Morgan Fault in the west at approximately 700 Ka, resulted in the draining and progressive drying of Lake Bungunnia as a breach was created along the Padthaway High. The Murray River gorge as observed today was incised following this episode. The modern Murray River (and playa lakes such as Lake Tyrell) occupy the lowest elevations along the former sub-basins of Lake Bungunnia.
The Late Neogene sedimentary sequence across the Murray Basin illustrates a complex interaction of eustatic and tectonic processes on deposition. Sedimentation within strandline, estuarine and lacustrine systems, particularly in the western Murray Basin, display evidence of significant tectonic control. This highlights the important role that neotectonic processes have played in shaping southeastern Australia.

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library.
Tasmanian fossil sites are rich in Cupressaceae genera and species and yet only three genera (Artrotaxis, Diselma, Callitris) survive there today. The aim of this study is the identification of some new and previously undescribed Cupressacea-related Tasmanian fossils. This is achieved by comprehensive morphological reviews of the foliage and cones (ovulate and pollen) of six extant Southern Hemisphere Cupressaceae genera.
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Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

The thesis investigates members of the crustose and largely calcified red algal family Peyssonneliaceae through molecular analyses and anatomical and ultrastructural observations. Mitochondrial CO1 DNA barcoding was implemented, in combination with fine-scale anatomy, to recognise species boundaries and identify complexes of cryptic species. Nuclear and organellar DNA markers were employed to construct a multigene phylogeny for Vanuatu and southern Australian members of the family facilitating the recognition of two undescribed genera Annea and Incendia.