Office for Environmental Programs - Theses
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ItemA population viability analysis (PVA) for Eastern Sarus Crane, Grus antigone sharpii( 2005)The Sarus Crane Grus antigone (Linnaeus, 1758), a wetland bird species in South East Asia and Northern Australia, is currently listed as a globally vulnerable species. A subspecies of this bird, the Eastern Sarus Crane G. a. sharpii is distributed in the lower Mekong basin, South East Asia and is considered endangered due to its small population size, about 500-1000 individuals, inappropriate reserve management, and the intense development pressures in the region. A population viability analysis (PVA) of the birds may help managers to comprehend the processes governing the population dynamics and then highlight needs for future conservation, management, and research activities. Part 1 of this paper provides requisite data for the Eastern Sarus Cranes' PVA, including estimates of population abundance, survival and fecundity rates, and the carrying capacity of the area supporting the population. These data were obtained from fieldwork between the years 2001 and 2004 by the author and from a review of the literature. Part 2 is the description and simulations of the PVA models. Three stage-based demographic models of the population were run in RAMAS/Metapop 4.0 (Akcakaya 2002) to understand structural sensitivities of the models. Different scenarios were then run on the complete model to investigate the effects that each of them has on the model outcomes. The compiled data were also parameterised and simulated in VORTEX 9.5 (Lacy et al. 2005) to compare the risk estimates made by the two modelling packages. Part 3 involves discussions and conclusions of the results from the PVA models and proposals of management and conservation actions for the population. Although habitat loss has been considered the most threatening process to the population, the models were particularly sensitive to changes of poaching activities on the population. It is therefore suggested that improved population management is the most cost-effective option for the conservation of the endangered subspecies in the near future.
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ItemDistribution and abundance of five threatened marsupials at Mount Rothwell( 2005)The conservation and management of Australia's threatened marsupials must be based on a sound knowledge of their biology and ecology. Two aspects of ecology, distribution and abundance, are of particular importance. This study examined the distribution and abundance of five species reintroduced at Mt Rothwell. A brief examination was also made of each species' sex ratio and general condition. Data was collected via a markrecapture survey, and analysed using the MARK computer program and Arcview mapping software. An estimated 164 +-28 Rufous Bettong (Aepyprymnus rufescens) inhabit Mt Rothwell and were trapped predominantly in grassland habitat. Although the population size of Eastern Quoll (Dasyurus viverrinus) could not be reliably estimated, it is assumed to consist of 20 individuals, almost all found in the grasslands. Southern Brown Bandicoot (Isoodon obesulus) were the most populous species, with 289 +- 82 individuals inhabiting both woodland and grassland habitats. There was insufficient data to estimate the population size of the Eastern Barred Bandicoot (Perameles gunnii), but fourteen individuals were released one year ago, and all trapped individuals were in the grasslands. Conversely, Long-nosed Potoroo (Potorous tridactylus), estimated at 30 +- 12 individuals, were found exclusively in woodland habitat. The results of this study will provide baseline information necessary for future management decisions, and will be of great benefit to the conservation of these species at Mt Rothwell.
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ItemThe TDS content of treated wastewaters and how this impacts on the reuse of these wastewaters for irrigating crops: with particular reference to China and neighbouring countries( 2005)With the rapid growth of population, water shortage is becoming one of the major barriers for sustainable development of human society. Among various options to solve the problem, wastewater reuse is considered as an attractive way with great environmental and economical benefits. Worldwide, irrigation is a very common practice with regard to wastewater reuse. However, a major concern with the long-term application of treated wastewater in irrigation is the potential for salts to build up in the soil. With review of related literatures, this paper analysed the total dissolved salts in raw and treated wastewater and explained the potential salinity and sodicity hazards that they would cause. The formation of salinity and sodicity is a complex process that not only depends on the level of total dissolved salts but also relates to other factors such as weather conditions, crop selection, soil property, irrigation methods, legislation and field practice. Therefore, to maximise crop production and soil protection, it is necessary to adopt an integrated approach to manage crop irrigation using treated wastewater. And the implementation of the integrated approach will determine whether the reuse of treated wastewater is successful especially for countries that wastewater is directly used for crops irrigation without any protective procedures.
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ItemSustainability, weeds, grasslands and Melbourne Water( 2005)Melbourne Water is responsible for large tracts of land throughout metropolitan Melbourne. Management of such large areas requires thorough knowledge of vegetation communities, threats they face and the relevant legislative requirements. Sustainability of many vegetation communities is directly threatened by the possible invasion by weed species. Weeds are a plant that has or has the potential to have detrimental effect on economic, social or conservation values. There are several different pieces of legislation that specifically relate to weeds. It is the Victorian Pest Management Framework 2002 that provides the strategic direction for the development of further weed management action plans. The principle means by which biodiversity may be protected is through the removal of weeds. The historical approach taken by Melbourne Water to weed control has been practical. Attention has always been focused on high value sites where native vegetation has the potential to recolonise the area naturally. Whilst the actual cost of the impact of weeds on ecosystems cannot be quantified, it is proven that weeds have the ability to reduce farm productivity, displace native species and contribute significantly to land and water degradation. Native grasslands are a threatened ecosystem. Their main threat is weed invasion. Unfortunately Melbourne Water is not currently doing anything to prevent weed infestation of these communities. There is no policy/strategy for dealing with weed management and this has adverse implications for operational efforts. At officer level there are pockets of strong awareness and expertise in relation to weeds and their impact, unfortunately there is no continuity of management standards or communication. These all combine to have little effect on the war against weeds and on the protection of threatened ecosystems.
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ItemAre we fiddling while Rome burns?: The what, why and how of a sustainable consumption strategy for Australia( 2005)No abstract available
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ItemThe effects of coupe level timber harvesting on the home range dynamics of the swamp wallaby (Wallabia bicolor) in the Pyrenees State Forest, Victoria( 2005)The effects of coupe-level timber harvesting on the swamp wallaby was investigated using home range dynamics and habitat selection as an indicator of the extent of the impact. An MBACI design incorporating five control sites and one impact site was used as control for background variation. The results indicate that there were significant changes in the home range size, home range overlap and the geographic centre of location. However, there was no significant change in the centre of activity. Harvesting only appeared to affect animals that had their home range directly on the coupe. The affected animals showed two responses to harvesting. They either increased their home range size or moved away from the coupe altogether. Those animals that did not use the coupe showed little change in home range dynamics. In selecting habitats, the wallabies showed a preference for old burnt forest and forest habitat rather than the harvested area and new burnt forest created by the timber harvesting.
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ItemChallenging values to effect change for sustainable future( 2005)The current paradigm in which we live is both environmentally destructive and socially unjust (Furman and Gruenewald 2004). The fundamental values of the paradigm can be traced back to changes in thinking around the time of the scientific revolution; with these values maintained through participation in the constructed dualisms and hierarchies of the capitalist and global market economies (Gruenewald 2003). Environmental education as a school subject does seem to have made much impact on dealing with the environmental crisis as a result of becoming a disciplinary subject. Place based education could challenge the current paradigm through giving place its full cultural identity.
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ItemBehaviour and management of common wombats (Vombatus ursinus) at Tidal River Campground, Wilsons Promontory National Park( 2005)The common wombat (Vombatus ursinus) is widespread and common throughout Wilsons Promontory National Park, particularly in Tidal River Campground. These wombats have been damaging tents searching for human food and acting aggressively towards campers since the 1990s. Tents were erected throughout the campground during October 2005 to find whether food was the wombats' motivation for entering tents. Bread was placed in one of three tents erected adjacent to each other and the tents were observed. An incident was recorded if a wombat entered this tent and ate the bread. Incidents occurred on eight out of 15 nights and the other two tents were never entered. This provides evidence that wombats will only enter tents containing food, which subsequently gives guidance to future management strategies.