Office for Environmental Programs - Theses
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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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ItemAllometric equations of Dicksonia antarctica for estimating aboveground biomass and its associated contribution to forest carbon stocks in Victoria( 2013)The use of forests as carbon sinks is increasingly recognised as a way to mitigate greenhouse gas emissions. Driven by the need to estimate carbon stocks for national greenhouse gas balance Inventories, regional and species-specific biomass data sets and allometric equations need to be developed to enable accurate prediction of aboveground carbon. Within Australian temperate moist forests, tree ferns are known to form a large component of the under storey; Dicksonia Antarctica in particular has been known to form large single-species stands excluding all other vegetation. Beets et aL (2012) recently conducted a study to develop mixed-species allometric equations for estimating carbon stocks of 4 New Zealand tree fern species in natural forests. However, there are currently no allometric models for Australian tree fern species and uncertainty remains regarding their quantitative contribution to the total carbon pool within these forests, and the application of allometrics developed for New Zealand tree fern species. The new allometric equations developed from this study are specific to D. Antarctica and have made it possible to predict total biomass for both the caudex and frond component to calculate the total stored carbon from 2 parameters; height and base diameter. Diameter at base was consistently found to be the best predictor of other parameters including: height, number of fronds, frond radius, caudex biomass, frond biomass and total tree fern biomass. The addition of height to allometrics also resulted in further improvements of biomass estimations. Aboveground carbon predictions were on average 50% higher than New Zealand allometric estimates with approximately 1937 tonnes of carbon per hectare stored in D. Antarctica demonstrating the importance of allometric equations developed through direct methods (destructive harvesting) that are species-specific. This significant contribution of D. Antarctica in the wet and temperate rain forests of the Central Highlands of Victoria have a number of implications for management in relation to the major drivers of carbon stock change predicted to occur in these forests including; frequent planned and unplanned bush fires, harvesting operations within publicly managed land, as well as future climate Change predictions for South-eastern Australia which could adversely impact on tree ferns and their associated contribution to forest carbon pools. The establishment of allometric relationships between parameters of Ii Antarctica can be coupled with light detection and ranging (LiDAR) prediction models so that it can be applied at a larger scale and allow for rapid estimation of available biomass and thus aid in planning for sustainable management of D. Antarctica.
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ItemA comparative study of Melbourne's freeway planting designs: implications for biodiversity conservation( 2006)Extensive planting projects have been undertaken along freeways in Melbourne, Australia. This report is a comparative study of seven of these planting designs completed over a period of forty years. The aim of this project is to assess these designs in terms of their implications for biodiversity and make recommendations for future ecological designs. The analysis explores how variability between the planting designs relates to factors including plant species richness, diversity, plant abundance, use of indigenous and/or weed species and the inclusion of aquatic and under storey planting. Drawing from the scientific literature, these areas of variability between the planting schemes are assessed in terms of the positive and negative ecological effects, particularly relating to biodiversity conservation. The florist analysis shows that there is distinct variation between the planting designs and that some designs are far more beneficial for biodiversity conservation than others. The results of this study suggest that in the future, landscape architects and ecologists should work together on the design of freeway planting with a shared aim of providing a new sustainable ecosystem that is based on the structure, composition and ecological processes of the original plant communities.
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ItemOptions for the management of biomass in the western Victorian basalt plains native grassland communities( 2004)No abstract available
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ItemIntegrating species distribution modelling and cost-efficiency analysis to prioritise Platypus habitat management activities in the greater Melbourne region( 2012)Conservation activities are restricted by budget. This fact calls for an efficient use of resources for management activities that are expected to improve the condition of conservation targets. Prioritisation of management activities based on cost-efficiency has been advocated as a means to increase efficiency and achieve larger conservation benefits at a lower cost. Cost-efficiency assessments require estimation of costs and expected benefits of management activities. If the conservation target is a particular species or a group of species, benefits can be predicted from species distribution models (SDM) which relate species' records to environmental variables. Platypus (Ornithorhynchus anatinus) distribution models were developed and embedded in a conservation investment prioritisation protocol to demonstrate how financial costs and benefits to platypus of riparian vegetation restoration could be efficiently balanced. The platypus is a unique, charismatic focal species for conservation efforts in the case study region of greater Melbourne (south-east Australia). Platypus habitat is increasingly threatened in the case study area, mostly due to urbanisation and its impacts on habitat and water quality. Development of platypus SDMs was guided by selection of predictor variables that balance ecological relevance and possibility of change via management actions (i.e. riparian vegetation cover, catchment imperviousness), with the aim of using these models to predict platypus habitat benefits from management activities, in addition to current habitat suitability. Potential locations for vegetation management activities were prioritised based on expected platypus habitat benefits which were traded against the financial costs of achieving those benefits using a benefit-cost ratio analysis. Cost-efficiency analysis was undertaken between and within catchments to identify locations in which greatest habitat benefits can be achieved at the lowest cost. Predictions from SDMs show low platypus habitat suitability for most of the study area, with the exception of the middle and upper reaches of the Yarra catchment and upper reaches of the Bunyip River. High platypus habitat suitability is restricted to non-urban areas in streams with high riparian tree cover, relatively high precipitation during dry periods and low topographic wetness index. Results of the cost-efficiency analysis show greatest habitat benefits can be achieved at the lowest cost in locations with a medium current vegetation condition (riparian tree cover between 40 and 60%) and low to medium expected vegetation change from management activities (10-20% addition to riparian tree cover). These features are found in the middle sections of the main Yarra River and in the lower sections of the Tarago River. Budget allocation based on cost-efficiency prioritisation achieves up to 26 times more habitat benefits than prioritisation based only on benefits. This effect is more pronounced for a small budget ($1 million) but makes little difference for larger budgets (>$20 million). Highest cost-efficiency of vegetation management actions is concentrated in locations within the Yarra and Westernport systems, which are between 6 and 100 times more cost-efficient than locations in the Werribee and Dandenong catchments. These results show the importance of integrating cost and benefit information when prioritising management actions, especially when costs and benefits are variable and heterogeneous across the landscape.
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