Dissertations / Theses on the topic 'Red fox – Australia'

I studied aspects of the ecology of the Murray River turtle, Emydura macquarii, to determine the impact of the introduced red fox, Vulpes vulpes. The fox is one of Australia's worst vertebrate pests through its predation on livestock and native mammals, but their impact on reptilian communities is not known. I conducted a large-scale mark-recapture study to evaluate population growth of E. macquarii in the Albury region of the upper Murray River by determining growth, reproduction and survival. The study was conducted downstream of the first, and largest, impoundment on the Murray River, Lake Hume. Emydura macquarii predominantly inhabit the lagoons in the upper Murray River, as the mainstream and Lake are possibly too cool to maintain metabolic processes. They are easily captured in hoop traps and the use of live decoys maximises trap success. Over 2000 hatchling turtles were marked and released into two lagoons between January 1997 and January 1998. Growth of these individuals is rapid over the first few years but declines towards maturity, and is indeterminate after maturity. Although growth annuli are not well defined, even on young individuals, the von Bertalanffy model describes the growth of both male and female E. macquarii. Male turtles mature at 5-6 years and females mature at 10-12 years. Female turtles may maximise reproductive potential by delaying maturity and producing one relatively large clutch (mean = 21 eggs) per year, which is positively correlated with body size (PL). Although primarily related to body size, clutch size varies annually because of environmental conditions. If winter and summer rainfalls are below average and temperatures are above average, E. macquarii may reduce clutch size to increase the chance of the eggs surviving. Nesting predominantly occurs during the first major rain-bearing depression in November. Habitat variables, including distance from water, nearest nest, and tree, and soil type were measured for each nest to determine characteristics that attract predators. Nests close to the shoreline and trees are heavily preyed on, and nests constructed in sand are less likely to be destroyed by predators. Foxes detect nests through a combination of chemical cues from eggs and slight soil disturbances, whereas birds only destroy nests observed being constructed during the day. Female turtles alter nesting behaviour and construct nests much further away from water when foxes were removed and as a result, nests are less dense and away from trees. Thus in high predation risk areas, turtles minimise emergence and search times to reduce the risk of direct predation by foxes. Predation is reduced when nests are in lower densities and away from trees, because predators increase search efforts when nests are in higher densities and birds are more likely to destroy nests close to trees. Reproductive success is further reduced in high predation risk areas because more nests are constructed in sandy substrates where clutch success is reduced compared to incubation in more dense substrates. Where predators are a significant source of mortality, prey may use indirect methods, such as chemical recognition, to avoid encounters. Nesting turtles did not avoid areas where fox odour was present, suggesting that they assess predation pressure from foxes by other mechanisms, such as visual recognition. However, an innate response occurs to the odour of a once common predator on the Murray River, the eastern quoll (Dasyurus viverrinus), whereby turtles recognise and avoid nesting in areas where quoll odour is present. Therefore nesting turtles show a similar avoidance response to two different predators, using different mechanisms of detection. Similarly, predation risk may influence hatching times and nest emergence. The rate of embryonic development of E. macquarii may increase or eggs may hatch early so that the clutch hatches synchronously, thereby reducing the risk of predation through group emergence from the nest. Emydura macquarii reach densities of over 100 turtles.ha-1, with the majority of the population consisting of sexually mature individuals. Emydura macquarii has a Type III survival curve where mortality is extremely high in the egg stage (93% nest predation), remaining high over the hatchling stage (minimum survival rate- 10%), but decreasing rapidly throughout the juvenile stage (~70% juvenile survival). Adult survival is extremely high, with greater than 95% of adults surviving each year. Foxes through nest predation cause most mortality but a small proportion (~3%) of nesting adult females are killed by foxes each year. A removal program evaluated the impact of foxes. In 1996, fox numbers were monitored around four lagoons by spotlighting and non-toxic bait uptake. Foxes were removed from around two of the lagoons throughout 1997 and 1998, using spotlight shooting and 1080 bait poisoning. Fox numbers were continually monitored around all four lagoons during the study. Nest predation rates remained around 90% in all sites where foxes were present, but fell to less than 50% when foxes were removed. At the same time, predation on nesting female turtles was eliminated where foxes were removed. Demographic models using staged based survival schedules, together with growth and fecundity values for E. macquarii show a decline of 4% per year in these populations. Elasticity analyses shows that survival of adult female E. macquarii has the major influence on population stability and a reduction of nest predation alone is unlikely to address the population decline. Management options, such as reducing foxes prior to nesting around key lagoons, will stabilise the population decline, and eliminating foxes completely from certain areas with high dispersal potential, will promote recruitment of juvenile E. macquarii.

Predation by exotic predators (cats Felis catus and foxes Vulpes vulpes) is believed to be one of the factors that has contributed to the decline of medium-sized mammals in arid Australia. Other factors include habitat degradation by introduced herbivores (rabbits Oryctolagus cuniculus and grazing stock) and altered fire regimes after Aboriginal people moved into permanent settlements. In general, the impact of exotic predators on arid zone mammals is believed to be significant only when predator numbers have been elevated by increased food availability from exotic prey species (rabbits, house-mice Mus domesticus, cattle carcasses) or when native prey populations have already been dramatically reduced by competition from introduced herbivores. In much of the spinifex grasslands of the central Australian deserts, pastoralism never occurred, rabbit colonisation was extremely patchy and in some areas, traditional burning was still being practised when the extinctions commenced. None of the current models of mammalian extinctions adequately explain the declines in this environment. In this study I examined predator-prey interactions in two areas of the Tanami Desert to investigate whether predation by exotic predators may be a primary agent of extinction in its own right, capable of causing mass declines even in the absence of other human-induced perturbations. If this were the case then the following would be expected: (i) cats and foxes would eat medium-sized mammals when they are available, but be able to survive on alternative prey when mammals are scarce; (ii) populations of cats and foxes would be buffered against the declines of mammals during droughts, or would be able to recover more quickly than medium-sized mammals after droughts; (iii) medium-sized mammals would be more vulnerable to predation by cats and foxes than by dingoes Canis lupus dingo and other native predators, and (iv) there would be a correlation between the timings of the extinctions and the colonisation (or sudden increase) of cats and foxes. These predictions were investigated by monitoring the diets and relative abundance of cats, foxes and dingoes in relation to fluctuating prey availability in two areas of the Tanami Desert at latitudes separated by approximately 400 km. Mean annual rainfall is higher and more reliable in the northern study area which was situated in the centre of bilby Macrotis lagotis distribution within the Northern Territory, whereas the southern study area was located on the southern edge of the bilby�s range. Within each study area, monitoring occurred at three sites, approximately 20 km apart. Each site contained a sub-plot in each of two habitat types. Field work was conducted between September 1995 and December 1997. When the study began, the southern study area was experiencing drought conditions, however both study areas received significant rainfall in early 1997. The population dynamics of a variety of potential prey groups were monitored to examine their resilience during droughts, patterns of recolonisation after rainfall, and use of two habitat types: the ubiquitous sandplain, and the moister, nutrient enriched palaeodrainage habitat which is believed to have provided a refuge for medium-sized mammals during droughts. Native mammals were uncommon throughout the study period. Bilbies and macropods were significantly more abundant in the northern study area, and tended to occur more frequently in palaeodrainage habitat than sandplain. However, the palaeodrainage habitat did not appear to provide adequate refuge for the medium and large mammals during drought conditions in the southern study area, as they disappeared from the study sites altogether. Small mammals were significantly more abundant in the southern study area but densities remained low (less than 2% trap success) throughout the study, and showed little response to improved seasonal conditions. In contrast, the abundance and species richness of birds showed a marked increase following rainfall in the southern study area. Flocks of nomadic birds arrived within several months of drought-breaking rains, increasing the relative abundance of birds from 9.3 per km of transect in December 1996 to 49/km in July 1997. Reptiles were the most resilient prey group during the drought conditions. Both varanids and smaller reptiles were equally abundant in the wet and dry years and showed no difference in abundance between study areas. However, reptiles showed marked temperature-related patterns in activity, with many species becoming inactive in the winter months. A total of 142 cat scats, 126 fox scats and 75 dingo scats were analysed to investigate predator diets in the two study areas. Unlike cat, fox and dingo diets elsewhere in Australia (and the world), mammalian prey did not dominate. Reptile was the prey category that was most frequently consumed by cats and foxes in �summer� (October-April) and by dingoes throughout the year, and was identified as a �seasonal staple� prey type for all three predators in the Tanami Desert. When biomass of prey was taken into account, the varanids (predominantly the sand goanna Varanus gouldii) were the most important prey sustaining predators in the two study areas. Birds were an important part of the diets of cats and foxes in winter when reptiles were less active. Small mammals were consumed by cats and foxes throughout the study, in proportion to their field abundances. Invertebrates were a major component of the diets of foxes, representing 31% of prey items consumed. There was considerable overlap in the diets of the three predator species, but dingoes ate more medium (100-999 g) and large (greater than 1000 g) prey than cats and foxes did. The scarcity of medium-sized mammals in the study areas provided little opportunity to find evidence of predation events on such prey. However, bilby remains were found in two cat scats and one dingo scat in the northern study area, mulgara Dasycercus cristicauda remains occurred in several cat and fox scats from the southern study area, and there were fourteen occurrences of marsupial mole Notoryctes typhlops in predator scats during the study, primarily in fox scats. Elsewhere in Australia, there is ample evidence that cats and foxes regularly consume medium-sized mammalian prey (e.g. rabbits and ringtail possums Pseudocheirus peregrinus) when it is available. Overall cats were the most abundant eutherian predators in the two study areas, and they were significantly more abundant in the northern study area than the southern study area. Surveys revealed that cats can persist into droughts by feeding on reptilian prey. When the study commenced, cats occurred on five of the six sub-plots in the southern study area, despite six consecutive years of below-average rainfall. However, by the end of the first year, they could only be detected on one sub-plot. Recolonisation of the sites rapidly occurred after significant rainfall (260 mm in 2 months), when nomadic birds colonised the sites and provided a plentiful food source. Foxes also declined to very low densities during drought in the southern study area, but they had recolonised all sites by the winter of 1997. This coincided with the increase in abundance of birds, which became their most frequently consumed prey item. Overall, foxes were equally abundant in the two study areas, but statistical analyses revealed a significant interaction between latitude and habitat because in the southern study area foxes tended to utilise the palaeodrainage habitat more than the sandplain, whereas in the northern study area the majority of fox sign was detected in the sandplain habitat. This may have been due to the abundance of dingoes in the palaeodrainage habitat in the northern study area. Dingoes were significantly more abundant in the northern study area than the southern, where they were usually only present at one of the three sites. The northern study area had higher densities of macropods (supplementary prey for dingoes) and more reliable access to drinking water, which persisted in the palaeodrainage channels for up to 6 months after significant rain events. Dingo numbers were relatively stable throughout the study and did not increase in response to improved seasonal conditions in the southern study area in 1997. This study revealed that the distribution of foxes extends further north into the Tanami Desert than has previously been reported, and is not necessarily tied to the distribution of rabbits in the Northern Territory. Furthermore, discussion with Aboriginal people who lived a traditional lifestyle in the area until the 1940s, revealed that foxes were already present in the northern Tanami desert at that time, before the disappearance of many medium-sized mammal species. The patterns of medium-sized mammalian extinctions in the northern and western deserts between 1940 and 1960 is thus consistent with the colonisation of the fox. Although cats had been present in central Australia for at least 50 years before the mammalian declines occurred, this does not discount them from contributing to the extinction process. It is postulated that during the early decades of their colonisation of the arid interior, cat populations may have been maintained at low levels by predation from dingoes and also Aboriginal people (for whom cats were a favoured food). But between 1920 and 1960 the western deserts were depopulated of Aboriginal people, and human hunting of cats diminished. This coincided with the introduction of the dingo bounty scheme, which encouraged many Aboriginal people to continue making regular excursions into the deserts to collect dingo scalps. In this study, cat remains occurred in 9% of dingo scats, suggesting that dingoes may be an important predator of cats. Thus, there may have been an increase in the cat population between 1930 and 1960, producing a more significant impact on native mammal populations than had previously occurred. Information collected during this study was used to construct a new model of mammalian extinctions in the spinifex grasslands of central Australia that promotes predation by cats and foxes as the primary agent of extinction. The model proposes that cats and foxes will eat medium-sized mammals when they are available, but are capable of subsisting on naturally occurring alternative prey when mammals are scarce. Thus, cats and foxes can persist into drought periods by feeding on reptilian prey, which remains an abundant resource regardless of rainfall (at least during the warmer months). Predator populations eventually decline after a series of dry winters. When the drought breaks, the rapid response of nomadic birds provides a readily available food source for cats and foxes as they recolonise areas and commence breeding. Predation by cats and foxes thereby has the potential to exacerbate the declines of native prey populations during droughts and delay their recovery when seasonal conditions improve. In this way, introduced predators are capable of causing local extinctions of medium-sized mammals when populations contract during drought periods, even in the absence of introduced herbivores and altered fire regimes. Although dingoes also prey upon medium-sized mammals, dingoes did not cause extinctions of medium-sized mammals in the spinifex grasslands because (i) they are more reliant on drinking water than foxes and cats, thus waterless areas would have provided some degree of predation refugia, and (ii) their social structure and territoriality prevent high densities accumulating, even when resources are abundant. If further extinctions of medium-sized mammals (such as the bilby) are to be prevented, it may be necessary for wildlife managers to establish a series of predation refugia where fox and cat populations can be controlled without extinguishing local dingo populations. This could be achieved with a combination of predator-proof enclosures, zones in which foxes are killed through poison baiting and areas where Aboriginal people are employed to utilise traditional hunting methods to control introduced predators.

There is a paucity of data on the diet of red foxes (Vulpes vulpes) and feral cats (Felis catus) in the south west region of Western Australia. Information is needed to determine the impact of these introduced predators on native wildlife, and to establish whether competitive and predatory interactions are likely to exist between foxes and cats. Therefore the diets of both species were quantified and compared by examining the stomach contents of 542 foxes and 56 cats collected from across the south west region in association with the Red Card for the Red Fox community feral control program. This study provides the first insight into the summer dietary preferences of the red fox and feral cat in south west Western Australia. This study provided a ‘snapshot’ of dietary intake, revealing that there was little overlap in the diets of red foxes and feral cats (26%), with the proportions of different prey categories consumed differing significantly between the predators (ANOSIM- R=0.1352, p<0.0001). Overall, foxes consumed mostly domestic sheep as carrion or lamb (64%, using Index of Relative Importance values for this food category), as well as a large amount of fruit, grains and invertebrates. With numerous bird species as their staple prey (32%, by IRI), feral cats are actively hunting a greater proportion of native vertebrate species (43%, by IRI), than foxes (6%, by IRI). Surprisingly, cats deliberately consumed a large amount of plant material (18%, by IRI), which may suggest that this atypical food source plays a role in sustaining feral cats during summer. From analysis of fox and cat diets it can be surmised that in the south west, interspecific competition between the predators may not be strong because of their reliance on different food categories. However, removal experiments and investigation of spatial interactions between the two species are required to confirm that resource partitioning and not antagonistic interactions are causing dietary differences (e.g. interference competition). Findings from the current study into the diets of red foxes and feral cats have implications for both farmers and conservationists in the south west. If carrion is responsible for sustaining large fox populations (hyperpredation) during a period of reduced resources, removal of carrion may reduce fox population sizes substantially. If, however, active control of foxes then leads to mesopredator release, feral cats may have a greater impact on the south west’s remaining native species, especially if cats have increased access to carrion.

I attempted to track a population of urban foxes in Kings Park, but due to collar failure, only one collar was retrieved. The GPS telemetry data from this fox produced home range estimates for minimum convex polygon (MCP) and kernel density (KD) of 0.302 km² and 0.331 km², respectively. The fox was predominantly active at night, with a ten-fold increase in movement during nocturnal periods when compared to daytime movements. Roads and man-made tracks were important for facilitating movement of the fox through its home range, with almost 97% of location fixes recorded within 100m of these features. The fox showed a preference for parrot bush Banksia sessilis shrubland and disturbed areas containing exotic weeds and revegetation, while avoiding woodlands and open spaces. Monitoring programs aimed at assessing the abundance of invasive species, as well as the severity of their impacts to the environment, are crucial for designing and implementing effective control strategies. I investigated the relative occupancy and diet of foxes at the local scale. Thirty one fox scats taken from two urban reserves revealed that medium-sized mammals, particularly brush-tailed possums (Trichosurus vulpecula) and quenda (Isoodon fusciventer), and black rats (Rattus rattus) comprised a large proportion of fox diet. Fruits and seeds, predominantly those produced by the Moreton Bay Fig (Ficus macrophylla), also contributed to a large portion of the diet of foxes. I used 21 motion cameras deployed across 10 monitoring sites to estimate fox occupancy within Kings Park. Seasonality had a significant influence on probability of occupancy and detection for foxes inhabiting Kings Park, with the highest rates of detection seen during the summer months (December-February). This spike in detections is consistent with the timing of dispersing juveniles, which are likely to be immigrating into the area in search of a suitable home range. Improving the effectiveness of conservation strategies through collaborative research is a key outcome of the Kings Park and Botanic Gardens Management Plan 2014-2019 strategic framework and implementing control measures for pest animals is a priority target for both this plan and the Bold Park Management Plan 2011-2016. Numerous methods have been used to control and/or mitigate their impacts within Australia, however, the success rates of these strategies vary. With the information gained from this investigation, it is my hope that future fox monitoring and control programs can be improved within the reserves and surrounding land uses.

Odour plays an important role in many predator/prey interactions. In the northern hemisphere, many mammalian prey species have been shown to respond to predator odours. It is also widely assumed that mammalian predators utilise odours to locate their prey. This thesis explores the importance of odour in Australian mammalian predator/prey interactions. Responses of native Australian species to the faecal odour of two predators; the native tiger quoll Dasyurus maculatus and the introduced red fox Vulpes vulpes, were evaluated through live-trapping and focussed behavioural studies of captive animals. Tiger quoll responses to prey olfactory cues were investigated in a captive experiment. Native rodents (bush rats Rattus fuscipes, swamp rats R. lutreolus and eastern chestnut mice Pseudomys gracilicaudatus) equally avoided traps scented with either quoll or fox faeces, and in captive experiments, bush rats and swamp rats reduced their average speed in response to both predator odours. Of the marsupial species, northern brown bandicoots Isoodon macrourus and common brushtail possums Trichosurus vulpecula were captured more frequently in quoll-scented traps than unscented traps or foxscented traps, while captures of brown antechinus Antechinus stuarttii, long-nosed bandicoots Perameles nasuta and southern brown bandicoot I. obesulus were unaffected by the either predator odour. In captive experiments, brown antechinus, long-nosed and northern brown bandicoots decreased their foraging in response to both predator odours, and spent less time in areas scented with quoll faeces. Tiger quolls didn't appear to detect odour sources from a distance of >65 cm, but they did follow scent trails and spent more time in areas scented with the urine and faeces of potential prey. Chemical analysis revealed no common components in fox and quoll odour which prey species could be responding to. Therefore, these native species have evolved to respond to fox odour since foxes were introduced to Australia 130 years ago. The stronger response of native rodents to fox odour may be a legacy of their co-evolution with canid predators prior to entering Australia. A better understanding of how odour is utilised in Australian predator/prey interactions may lead to a greater ability to protect Australia's unique mammalian fauna from introduced predators.

Red-brown hardpan occurs extensively in Western Australia in the arid and semi-arid regions of the Murchison, Pilbara and Eastern Goldfields divisions, between longitudes 115ºE and 124ºE and latitudes 23ºs and 30ºs. It occupies an area of about 360,000 sq. km, two thirds of which occurs in the Yilgarn Craton. The purpose of this research is to map the distribution of red-brown hardpan in the Yilgarn Craton of Western Australia; study the relationship between landscape, soil texture and vegetation; investigate the physical characteristics, petrology, mineralogy, geochemistry and cementing agents; and thereby determine the processes invaded in forming red-brown hardpan. The relation of red-brown hardpan to gold is investigated and determined its implications in mineral exploration. The main case study areas were the Goldfields Gas Pipe Line, the Federal Open Pit Gold mines and the Menzies district in the Kalgoorlie-Menzies region of the Eastern Goldfields; areas in and around the Woolgorong Station in the Murchison Province and at the Wiluna Gold Mines in the Northeastern Goldfields. The findings and conclusions of this research are summarised below. Red-brown hardpan occurs at or near the land surface and may vary from less than one metre to more than 10 m thick. It is exclusively developed in colluvium and alluvium, showing varying stages of cementation ranging from weakly cemented through moderate to strongly cemented. In addition, calcrete and red-brown hardpan occurs together in many places, south of the Menzies line, and this distribution suggests that red-brown hardpan was once more extensive and has been subsequently replaced by carbonate to form calcareous red-brown hardpan and calcrete. Red- brown hardpan predominantly occurs in regions with Q50 mm annual rainfall.In present-day higher rainfall (400 to 500 mm) regions, red-brown hardpan is being weathered. There is no relationship between the distribution of mulga (Acacia aneura) and red-brown hardpan. Red-brown hardpan is exclusively developed in colluvium containing a minimum of 20% quartz, 15% clays and 2% iron oxides. It is bright reddish brown to reddish brown, earthy, with a sandy loam texture, blocky structure and porous. Red-brown hardpan is hard (up to 12 MPa), being characterised by sub-horizontal laminations predominantly of uncemented kaolinite. Ped surfaces may be coated by Mn oxide and carbonate which may be precipitated along the laminations. The mineralogy of the cement is complex. Data from XRD, SEM, TEM, EFTEM, FTIR and NIR investigations show poorly-ordered kaolinite and opal-A as the main components. Illuvial multilayered argillaceous cutans containing silica and alumina in a ratio of 2:l form the cement. Secondary silica (SiO2-95%) coatings are common, mainly as opal-A, on ped surfaces and on the inner walls of voids and vughs. Etch pits are developed in these coatings and some of them are filled by kaolinitic clays. Selective dissolution experiments using acid ammonium oxalate show that oxalate- soluble amorphous and poorly ordered silica and alumina in red-brown hardpan have molar ratios of about 1.6 to 2 A1203:SiO2.These results suggest that red-brown hardpans were formed where there was sufficient water during the wet season to dissolve alumina and silica, but insufficient to leach them. During the subsequent dry season, the dissolved alumina and silica was precipitated as poorly-ordered kaolinite and opal-A. Successive dissolution and precipitation led to fusion of poorly-ordered kaolinite and opal-A at a nanometre scale to progressively cement the colluvium. The age of the red-brown hardpans, estimated by paleomagnetic dating of hematite, is from Pleistocene to present. Based on the findings of this research, the red-brown hardpan is redefined and primarily classified on its degree of cementation as: (1) weakly cemented, (2) moderately cemented and (3) strongly cemented. It is further classified chemically into: (1) siliceous, (2) calcareous and (3) ferruginous. In the Yilgarn Craton, red-brown hardpan is believed to occur mainly north of the 'Menzies Line'. However, this study reveals the presence of red-brown hardpan 75- 150 km south of the Menzies Line and the new southern boundary is closer to latitude 29ºs. Geochemical investigation at the Federal Open Pit Gold mines, Broad Arrow, north of Kalgoorlie indicate that there are Au anomalies in red-brown hardpan. Gold concentration is up to 50 ppb against the background anomaly of 10 ppb. Sequential and partial extraction analyses show significant correlation of Au with Ag, Ca, Ce, Co, Mg, Mn and Ni. This suggests that the Au concentration in red-brown hardpan is due to: (a) mechanical dispersion due to reworking of Au-bearing clasts in the sediment and (b) hydromorphic dispersion from the underlying mineralisation. It can therefore be used as a useful sampling medium for gold exploration.

Red-brown hardpan occurs extensively in Western Australia in the arid and semi-arid regions of the Murchison, Pilbara and Eastern Goldfields divisions, between longitudes 115ºE and 124ºE and latitudes 23ºs and 30ºs. It occupies an area of about 360,000 sq. km, two thirds of which occurs in the Yilgarn Craton. The purpose of this research is to map the distribution of red-brown hardpan in the Yilgarn Craton of Western Australia; study the relationship between landscape, soil texture and vegetation; investigate the physical characteristics, petrology, mineralogy, geochemistry and cementing agents; and thereby determine the processes invaded in forming red-brown hardpan. The relation of red-brown hardpan to gold is investigated and determined its implications in mineral exploration. The main case study areas were the Goldfields Gas Pipe Line, the Federal Open Pit Gold mines and the Menzies district in the Kalgoorlie-Menzies region of the Eastern Goldfields; areas in and around the Woolgorong Station in the Murchison Province and at the Wiluna Gold Mines in the Northeastern Goldfields. The findings and conclusions of this research are summarised below. Red-brown hardpan occurs at or near the land surface and may vary from less than one metre to more than 10 m thick. It is exclusively developed in colluvium and alluvium, showing varying stages of cementation ranging from weakly cemented through moderate to strongly cemented. In addition, calcrete and red-brown hardpan occurs together in many places, south of the Menzies line, and this distribution suggests that red-brown hardpan was once more extensive and has been subsequently replaced by carbonate to form calcareous red-brown hardpan and calcrete. Red- brown hardpan predominantly occurs in regions with Q50 mm annual rainfall.
In present-day higher rainfall (400 to 500 mm) regions, red-brown hardpan is being weathered. There is no relationship between the distribution of mulga (Acacia aneura) and red-brown hardpan. Red-brown hardpan is exclusively developed in colluvium containing a minimum of 20% quartz, 15% clays and 2% iron oxides. It is bright reddish brown to reddish brown, earthy, with a sandy loam texture, blocky structure and porous. Red-brown hardpan is hard (up to 12 MPa), being characterised by sub-horizontal laminations predominantly of uncemented kaolinite. Ped surfaces may be coated by Mn oxide and carbonate which may be precipitated along the laminations. The mineralogy of the cement is complex. Data from XRD, SEM, TEM, EFTEM, FTIR and NIR investigations show poorly-ordered kaolinite and opal-A as the main components. Illuvial multilayered argillaceous cutans containing silica and alumina in a ratio of 2:l form the cement. Secondary silica (SiO2-95%) coatings are common, mainly as opal-A, on ped surfaces and on the inner walls of voids and vughs. Etch pits are developed in these coatings and some of them are filled by kaolinitic clays. Selective dissolution experiments using acid ammonium oxalate show that oxalate- soluble amorphous and poorly ordered silica and alumina in red-brown hardpan have molar ratios of about 1.6 to 2 A1203:SiO2.
These results suggest that red-brown hardpans were formed where there was sufficient water during the wet season to dissolve alumina and silica, but insufficient to leach them. During the subsequent dry season, the dissolved alumina and silica was precipitated as poorly-ordered kaolinite and opal-A. Successive dissolution and precipitation led to fusion of poorly-ordered kaolinite and opal-A at a nanometre scale to progressively cement the colluvium. The age of the red-brown hardpans, estimated by paleomagnetic dating of hematite, is from Pleistocene to present. Based on the findings of this research, the red-brown hardpan is redefined and primarily classified on its degree of cementation as: (1) weakly cemented, (2) moderately cemented and (3) strongly cemented. It is further classified chemically into: (1) siliceous, (2) calcareous and (3) ferruginous. In the Yilgarn Craton, red-brown hardpan is believed to occur mainly north of the 'Menzies Line'. However, this study reveals the presence of red-brown hardpan 75- 150 km south of the Menzies Line and the new southern boundary is closer to latitude 29ºs. Geochemical investigation at the Federal Open Pit Gold mines, Broad Arrow, north of Kalgoorlie indicate that there are Au anomalies in red-brown hardpan. Gold concentration is up to 50 ppb against the background anomaly of 10 ppb. Sequential and partial extraction analyses show significant correlation of Au with Ag, Ca, Ce, Co, Mg, Mn and Ni. This suggests that the Au concentration in red-brown hardpan is due to: (a) mechanical dispersion due to reworking of Au-bearing clasts in the sediment and (b) hydromorphic dispersion from the underlying mineralisation. It can therefore be used as a useful sampling medium for gold exploration.

Long term storage of bauxite residue materials requires a capping stratum which will limit erosion while stabilizing slopes, limit deep infiltration of water into storage piles, and be aesthetically acceptable to the surrounding community. A diverse native vegetative community capable of surviving seasonal drought, low plant available water and nutrient constraints has the best potential of satisfying most, if not all of these requirements. Current and past rehabilitation of residue disposal areas (RDAs) using species native to southwest Western Australia has exhibited varying success. Current practices at Alcoa World Alumina Australia’s (Alcoa) Western Australia refineries have bauxite residue fines (< 150 ìm) stored within impoundments, in which the outer embankments are constructed with bauxite residue sands (> 150 ìm). The residue sands are also used as the growth media in the capping stratum for vegetation establishment on the disposal sites. Despite the inherently hostile properties of residue sand (pH > 10, EC(1:5) > 4 dS m-1, and ESP > 50), reductions in alkalinity (pH), salinity (EC) and sodicity (ESP) are corrected, through freshwater leaching, to a greater extent than is possible with residue fines. Although leaching can reduce the hostile character of residue sand, additions of phosphogypsum are typically added to expedite the removal of Na and alkalinity, and inorganic fertilizers are incorporated to improve the nutrient status of the growth media. However, due to the inconsistencies in vegetation establishment, which are attributed to poor water retention, inherent nutrient deficiencies and rapid loss of nutrients within residue sands (because of high hydraulic conductivity), further amendments are required. The aim of this study was to determine if amending the residue sand capping layer with residue fines would enhance its overall growth potential for vegetation establishment. Additions of fines to residue sands were predicted to increase water retention, add nutrients and increase the ability of the growth media to retain nutrients. Comparisons were made between the treated residue fines (seawater washed, carbonated, or unaltered) at a series of fines additions (1 - 20 % w/w) and a control(residue sand) amended with 2% (w/w) phosphogypsum and inorganic fertilizer. Comparisons were to determine the differences in 1) water retention, 2) nutrient concentrations and nutrient retention, and 3) plant growth responses and plant biomass nutrient concentrations between the growth media treatments. Four experiments were set up to measure differences in these variables which included: a glasshouse study involving the growth of Acacia saligna; a germination and emergence study (A.saligna); a two year field study in Western Australia; and a glasshouse column leaching study. Water retention increased with increasing percentage of residue fines addition. Plant available water (PAW) increased up to 110 %, with a 20 % increase in fines, representing an increase of 0.026 m3 PAW m-3 residue growth media, when compared to the residue sand only. This increase in PAW was attributed to changes in pore space distributions, due to the increasing fines contents altering the sandy texture to loamy sand texture class. However, initially much of this increase in PAW may not be realized, due to estimated temporary increases in osmotic potential associated with the high salt contents of residue sand and fines. Fines materials have much greater salt contents, and thus need to be leached to a greater extent than sands to remove the associated osmotic potential effects. Essential plant nutrients (P, K, S, Ca, Mg, and B) were increased with additions of residue fines in the glasshouse studies, although many nutrients (Mg, Zn, Mn and B) were still marginal for sustainable plant growth and development. Seawater treated residue fines additions produced the greatest increases in growth media nutrients with substantial increases in soluble (> 7 mg L-1) and exchangeable (> 0.10 cmolc kg-1) Mg, being up to 400 % greater than all other treatments. Along with these necessary nutrients, concentrations of Na were also increased in all fines additions treatments. Added Na may offset the benefits of fines additions, at least in the short term, due to inhibitions of cation uptake from Na competition. However, in the column leaching study soluble and exchangeable Na was lost rapidly from the profile, due to Ca and K displacement of Na from exchange sites during leaching. Soluble Na was removed from the profile to < 5 % of initial concentrations, after only three pore volumes of leaching, and exchangeable Na was removed from charge sites to less than 25 % of the initial concentration. Fines additions did increase concentrations of Mg and K on exchange sites, thus reflecting increased nutrient retention capacity relative to that in residue sand only. Plant growth responses and plant biomass nutrient concentrations were altered with the additions of residue fines to residue sands. The germination and emergence study demonstrated that the emergence of native seedlings was affected by additions of fines, due to the increased salinity and sodicity of the materials. Acacia saligna seedling emergence was inhibited by EC(1:5) > 2 dS m-1, which was highly correlated with a Na/Ca ratio of > 40, for all treatments, except the seawater fines additions. Seeds sown in seawater treatments emerged from growth media with EC(1:5) as high as 3.33 dS m-1 and appeared to be better correlated with Ca/Mg ratios than any other variable. Native vegetation growth responses showed mixed results in fines treated residues in the field. In the greenhouse study, plant growth tended to decrease with fines additions. Poor plant growth with increasing fines additions occurred despite the increased water retention and increased nutrients. This was attributed to the addition of Na associated with the residue fines, as increases in Na, EC and ESP in fines treatments all appear to have limited growth of Acacia saligna in the glasshouse over three months. Seawater fines additions had elevated Mg and B concentrations in plant biomass, and performed better than the carbonated or unaltered fines treatments, but still had reduced growth compared to the residue sand, which contained lower Na concentrations. Additional plant growth limitations may have occurred, due to possible plant nutrient deficiencies including: Mg, Zn, Mn and B and Na toxicity. Incorporation of residue fines into residue sands did increase water retention, nutrient concentrations and the nutrient retention capacity, but did not enhance the overall growth potential for vegetation, at least in the short term. Reductions in germination and emergence of seedlings and reduced plant growth were attributed to increases in Na concentrations introduced from the fines. Seawater washed residue fines had lower ESP and greater concentrations of nutrients, thus reducing the negative impacts from the additional Na introduced, and showed the greatest promise as a fines amendment. As leaching occurs over the first few initial months of rehabilitation, it is expected that the majority of the Na will be removed, from a system with an addition of 5 to 10 % fines, and the positive benefits of the fines additions will than be realized. Findings also illustrate that delaying the planting of vegetation on RDAs, until adequate leaching has occurred to reduce the Na concentrations, will substantially increase vegetation emergence and establishment.

Australia produces approximately 40% of the world’s bauxite and over 30% of the world’s alumina. Each year, about 25 million tonnes of bauxite residue is produced in Australia, requiring storage and maintenance. The construction and operation of such large impoundment areas is costly. During the extraction of alumina from bauxite ore using the Bayer process, a fine residue is produced called Red Mud. In West Australia, Darling Range bauxite deposits contain high levels of quartz which result in a coarse residue fraction also being produced. This fraction has been termed Red Sand with a typical particle size in excess of 90 microns. Typically, red mud and red sand are produced in almost equal quantity. Processing of red sand can neutralise the residual caustic and lower the salt content as required. Magnetic separation is also possible to produce a high silica fraction having low iron oxide content. The sustainable use of coarse bauxite residues for road construction is an attractive option with a high potential for large volume reuse.This study focuses on whether red sand is a viable option for use as a road base, embankment fills and as seawall fills in Western Australia. Red sand comes from bauxite ore, a product of intense tropical weathering. Hence, there are various physical properties resulting from the weathering process. Thus it is necessary to fully understand the characterisation of red sand with respect to its engineering properties in the initial part of this research. To satisfy minimum requirements of road bases, a soil stabilisation technique (a Pozzolanic- Stabilised Mixture, PSM) was used. The intent of this stabilisation technique was to use Western Australia’s by-products as stabilising materials. A Pozzolanic - Stabilised Mixture consisting of Class F fly ash (a by-product from a coal power station) and activators (the byproduct from the quicklime manufacturing in terms of lime kiln dust) were employed to develop pozzolanic activity. Once the appropriate mixture of red sand, fly ash, and activators was established (based on a maximum dry density and a value of unconfined compressive strength), a set of laboratory tests were performed which included a triaxial compressive strength test, a resilient modulus test, and a permanent deformation test.Comparisons were made between the stabilised red sand and the conventional road base material in Western Australia (crushed rock added with 2% General Purpose (GP) Portland Cement named Hydrated Cemented Treated Crushed Rock Base, HCTCRB). As for the use of red sand for embankments, the representative stabilised red sand (from red sand for road bases) was used to be an alternative fill embankment material. A testing program to evaluate the important properties of stabilised red sand for embankments including permeability, compressibility and strength was undertaken. The permeability, compressibility, and strength of the representative type of red sand were examined to assess the suitability of red sand as seawall fill. The application of red sand and stabilised red sand on three structures (road bases, embankments and seawalls) is also discussed.

Mestrado Vinifera EuroMaster - Instituto Superior de Agronomia
The aim of this study was to understand the effects of different maceration winemaking techniques on the phenolic composition of red grapevine variety ‘Tempranillo’ (Vitis vinifera L.). Experimental winemaking included 4 different treatments with 3 replicates. (5days pre-fermentation maceration at 11°C, fermentation without any pre-fermentation or post-fermentation extended maceration (control wines), and 3- and 6-days post- fermentation extended maceration on skins). Spectroscopic and RP-HPLC analysis were used to determine changes in phenolic components and between treatments during the alcoholic fermentation, and as they aged in the bottle. It was determined if the wines made with pre-fermentation maceration had increased color intensity compared to the control wines, as well as if the wines that underwent extended maceration had increased concentration of (+)-catechin and (-)-epicatechin, increased color hue, decreased color intensity compared to the control wines. Prolonging the maceration from 7 to 10 and 13 days, lead to significantly higher concentrations of total phenolics, and the monomeric flavan-3-ols, (+)-catechin and (-)-epicatechin, and lead to a significant decrease of the total anthocyanins. Further investigation is needed in order to analyse the effect of the phenolic, tannin’s and anthocyannin’s composition on the quality of the wine in terms of color stabilization and mouth-feel. Post-fermentation EM reduced wine colour intensity and imparted a browner hue to the wine compared to the Control wine. This EM treatment is therefore unlikely to benefit winemakers who are seeking to produce highly coloured wines. However, post-fermentation extended maceration increased the concentration of wine flavan-3-ols ((+)-catechin and (-)-epicatechin). Therefore, the winemakers by varying the duration of post-fermentation EM may influence the desired balance between the extraction of these wine phenolics and the mouth-feel properties, taking into consideration the economic factor

This study comprises an essay entitled ‘Ten Pounds for Adults, Kids Travel Free’ and a creative component entitled ‘The Red Pipe: a Novella Set in Port Hedland’. The essay focuses upon the children of the ‘golden era’ of British migration to Australia, between 1961 and 1971, when over 300,000 arrived as part of an unprecedented post-war population drive. Most travelled under an assisted passage scheme in which adults paid £10 towards their fare and their children travelled free of charge. Consequently, these assisted British immigrants were known by Australians as the ‘Ten Pound Poms’. Two decades on from the introduction of the scheme, immigration motives had shifted from the desperation born of immediate post-war austerity to the heightened expectations of the increasingly affluent Sixties and Seventies. The vast majority of these later British migrants came in family units, for the future of their children was a major consideration for most of the parents. Many of them faced significant struggle settling in to what was promised to be a ‘British way of life’, whilst, in reality, Australia was becoming an increasingly multicultural and unfamiliar society. This study is distinctive in that it examines the long-term consequences of migration upon the lives of the British children. It seeks to acknowledge, but ultimately to shift the focus from, the decisions and achievements of the parents to their children, the ‘second generation’, who travelled for free. It also considers the ongoing ramifications of the migration decision, as the parents age and pass on and their children, themselves, become parents and grandparents. It does so by utilising the recollections of a focus group of 31 British migrants, who travelled to Australia during this period. Eleven of these participants were parents at the time of migration, whilst the remaining interviewees were aged under eighteen. This thesis has a predominant focus upon Western Australia, for most of the participants originally disembarked in Fremantle. Today, all except two live in this state. The key child protagonists of the creative component are both British child migrants who immigrated to Western Australia with their families during the late 1960s. The novella, entitled The Red Pipe, is loosely based upon the author’s childhood experience of Cyclone Joan’s visit to Port Hedland in 1975. Joan was the most destructive cyclone to affect the Pilbara district in over thirty years. Over eighty-five per cent of the buildings were damaged and the town was left without power and communications for days. The author spent a harrowing night waiting out the storm with her family, narrowly escaping injury when the cyclone breached the family home. Utilizing the perspectives of two pivotal child protagonists, the novella traces the circumstances, severity and aftermath of Cyclone Joan upon the town and its culturally eclectic inhabitants. This little-known, yet significant incident in the history of Western Australia is set in a geographically significant port town, at a time before the mining boom. The ferocity of nature upon an ancient and isolated landscape provides the catalyst for the resultant exploration of the tenacity of childhood, set against the inherent fragility of the nuclear family unit and interwoven with the transient nature of the migrant condition.