Office for Environmental Programs - Theses
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ItemCommunity reactions towards wind farms in Victoria, Australia: a comparative study between an inland and coastal site( 2004)Wind energy is a promising alternative to energy forms that contribute to global and regional environmental problems such as climate change and air pollution. The industry is now the fastest growing energy technology in the world (SEDA, 2002). However wind farm proposals often struggle to gain public acceptance. Commonly held perceptions regarding wind farms were explored in order to provide the background for understanding community reactions. Two operational Victorian wind farms were presented as case studies to identify the key circumstances that influence the local reactions. The Toora wind farm in South Gippsland received mixed local support whilst the Challicum Hills wind farms, in central western Victoria received overwhelming support from the local community. The location of the two wind farms appeared to play a key role in influencing community attitudes, the coastal location attracting greater negative reactions than the inland location. The idea that the communities' reactions were correlated with the values attributed to the landscape was explored, drawing on the link with visual impact as a key negative perception. Understanding and managing negative perceptions regarding visual amenity and considering the values attributed to landscapes by local communities are important in ensuring the success of future wind farm proposals in Victoria.
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ItemDesign for persistence: graph-based connectivity, habitat reserves and species persistence( 2007)Connectivity is widely thought to play a key role in the persistence of metapopulations. However, there is no generally accepted approach to measuring connectivity in landscapes. Current reserve selection algorithms tend to focus on clustering habitat sites as an approach to maximising connectivity. An alternative approach to understanding connectivity is, however, to focus on the spatial configuration of habitat patches in a landscape. In this study, graph methods are used to represent habitat networks and investigate the relationship between spatial configuration and the flow of species moving across the network. Betweenness Centrality, a graph metric designed to measure the proportion of traffic passing through any node in a network, is applied in modified form as a reserve selection algorithm. The performance of reserves selected using Betweenness Centrality is assessed against species persistence measures from the metapopulation model RAMAS and compared to equivalent reserve selections for other well known reserve selection algorithms. Within the limited set of cases considered, this study found that Betweenness Centrality has a high degree of success in designing reserves for species with high dispersal characteristics, but is unable to predict appropriate reserve sites for low or non-dispersing species. Further directions for research in the field are suggested, with an emphasis on rigorously validating this type of approach to understanding connectivity.
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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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ItemGroundwater environments around the proposed nuclear waste repositories: compare and contrast the use of porous mediums versus fractured bedrock as barriers in radioactive waste disposal( 2004)Investigations are being carried out by many scientific bodies to study the long-term effectiveness of nuclear waste repositories in a number of different geological settings. Knowledge of how water and rock interact is an important factor when assessing how effective the radioactive waste repository will be. Water-rock reactions in the original material provide boundary conditions for monitoring the behaviour of backfill and buffer materials. They also control the geochemical speciation of leaking waste solutes and therefore the mobility and sorption retardation of the solute. The aim of this assignment is to compare and contrast the effectiveness of low hydraulic conductivity porus media, and fractured bedrock as hydrologic barriers for radioactive waste disposal. The Opalinus Clay and the Yucca Mountains will be used as examples.
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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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