School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemNo Preview AvailableA decision support system for sustainable forest management(University of Melbourne, 2000)The main objective of this study is to develop a decision support system for sustainable forest management that employs criteria and indicators; preferably one that enables the process to be adaptive over successive cycles of monitoring indicators, thereby capitalizing to the fullest on the criteria and indicators approach. To meet this objective, this thesis develops (1) a methodology for monitoring indicators over time, and (2) a procedure appropriate for achieving a sustainable forest resource allocation, based on a review of literature. The resulting decision support system blends the decision maker's knowledge with the information processing capabilities of the computing tools employed and is applicable on the regional scale. The application of potentially useful criteria and indicators framework faces considerable difficulties due to: the issues of integration of spatial and non-spatial data coming from a variety of sources; the choice of methodologies to analyse the large quantities of data; the incorporation of joint production characteristics of forest values; the lack of reliable and cost-effective data, and; the uncertainty associated with data, sustainability thresholds, and decision-rules. The proposed monitoring methodology addresses these issues. It comprises uncertainty-based multi-criteria evaluation of the indicators at a forest management unit level using a geographic information system. It also focuses on determining two alternative indices of sustainability. These indices are calculated by using Zadeh's fuzzy set theory and Dempster-Shafer theory of evidence to model the uncertainty in sustainability thresholds and decision-rule respectively. They proved to be similar in nature. This monitoring methodology was applied to Landsat 5 TM data for the East Gippsland Region, Australia, with the objective of examining the design of the land-use indicators over successive monitoring cycles. While confirming the usefulness of the satellite imagery as a source of data on large spatial scales, this study highlighted the importance of classification errors in reliably monitoring indicators over short periods. A case study on Aravalli Project, India, was developed to demonstrate utility of the monitoring methodology by applying a range of indicators, including some specially framed area-specific indicators, to participatory forest management. The results of both studies emphasised the need of reliable `ground-truth' data for implementing criteria and indicator framework. The approach developed for sustainable forest resource allocation and land-use planning potentially provides a basis for ensuring a `non-declining total utility' accruing from the diverse forest values to the current and future generations. It satisfactorily addresses, in a utilitarian framework, several important issues, such as incorporating social preferences while satisfying intra- and intergenerational equity concerns; efficiency; complexity; uncertainty, and ecological irreversibility. Stochastic and fuzzy/ possibilistic approaches were used to deal with uncertainty on the short and long planning horizons respectively in a linear programming model that employed the concept of aspiration levels. A heuristic procedure was developed to distribute land units spatially to various forest values. Implementation of this approach required the integration of a geographic information system, mathematical modelling software, simulation models, graphic user interfaces, specially written computer programmes, and database management system. This decision support system, based on an ethically-oriented approach, could facilitate a more informed, and probably more socially and politically acceptable, public decision-making for achieving sustainability of forest resources.
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ItemNo Preview AvailableA decision support system for sustainable forest management(University of Melbourne, 2000)The main objective of this study is to develop a decision support system for sustainable forest management that employs criteria and indicators; preferably one that enables the process to be adaptive over successive cycles of monitoring indicators, thereby capitalizing to the fullest on the criteria and indicators approach. To meet this objective, this thesis develops (1) a methodology for monitoring indicators over time, and (2) a procedure appropriate for achieving a sustainable forest resource allocation, based on a review of literature. The resulting decision support system blends the decision maker's knowledge with the information processing capabilities of the computing tools employed and is applicable on the regional scale. The application of potentially useful criteria and indicators framework faces considerable difficulties due to: the issues of integration of spatial and non-spatial data coming from a variety of sources; the choice of methodologies to analyse the large quantities of data; the incorporation of joint production characteristics of forest values; the lack of reliable and cost-effective data, and; the uncertainty associated with data, sustainability thresholds, and decision-rules. The proposed monitoring methodology addresses these issues. It comprises uncertainty-based multi-criteria evaluation of the indicators at a forest management unit level using a geographic information system. It also focuses on determining two alternative indices of sustainability. These indices are calculated by using Zadeh's fuzzy set theory and Dempster-Shafer theory of evidence to model the uncertainty in sustainability thresholds and decision-rule respectively. They proved to be similar in nature. This monitoring methodology was applied to Landsat 5 TM data for the East Gippsland Region, Australia, with the objective of examining the design of the land-use indicators over successive monitoring cycles. While confirming the usefulness of the satellite imagery as a source of data on large spatial scales, this study highlighted the importance of classification errors in reliably monitoring indicators over short periods. A case study on Aravalli Project, India, was developed to demonstrate utility of the monitoring methodology by applying a range of indicators, including some specially framed area-specific indicators, to participatory forest management. The results of both studies emphasised the need of reliable `ground-truth' data for implementing criteria and indicator framework. The approach developed for sustainable forest resource allocation and land-use planning potentially provides a basis for ensuring a `non-declining total utility' accruing from the diverse forest values to the current and future generations. It satisfactorily addresses, in a utilitarian framework, several important issues, such as incorporating social preferences while satisfying intra- and intergenerational equity concerns; efficiency; complexity; uncertainty, and ecological irreversibility. Stochastic and fuzzy/ possibilistic approaches were used to deal with uncertainty on the short and long planning horizons respectively in a linear programming model that employed the concept of aspiration levels. A heuristic procedure was developed to distribute land units spatially to various forest values. Implementation of this approach required the integration of a geographic information system, mathematical modelling software, simulation models, graphic user interfaces, specially written computer programmes, and database management system. This decision support system, based on an ethically-oriented approach, could facilitate a more informed, and probably more socially and politically acceptable, public decision-making for achieving sustainability of forest resources.
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ItemCreating cultural landscapes : an ethnographic case study of nature conservation in the sheep/wheat belt of New South Wales( 2000)This thesis examines the nature conservation ethos and practices of farmers in the Genaren Hill Landcare Group near Peak Hill, New South Wales. It is argued that nature conservation projects developed by these farmers represent the creation of a new cultural landscape, one which should be valued by the wider community and supported as such by well-resourced institutions capable of supporting the role of farmers as practitioners of nature conservation. The farmers of this study grow crops and produce wool in an area which forms part of Australia's sheep/wheat belt. This cultural landscape of colonial settlement and frontier agriculture was created out of diverse temperate woodlands which once stretched from southern Queensland to south-west Western Australia. These woodlands were fragmented into a series of strips and patches increasingly degraded by isolation, grazing from introduced stock and from worsening environmental problems such as salinity. The task of preserving and possibly restoring the remnants of these woodlands is connected to the wider global crisis of loss of biodiversity. This crisis has been exacerbated by on-going habitat destruction and ecosystem fragmentation. As a consequence nature conservation must involve more than simply creating reserves out of `pristine' wilderness. Biodiversity protection must also occur `off-reserve' in modified ecosystems, amongst farmers and private landholders. This situation becomes more apparent when it is accepted that most ecosystems are `cultural landscapes', imbued with human meaning and shaped by hundreds or thousands of years of modification and management by people. In Australia various measures have been developed to ameliorate the effects of fragmentation on fauna and flora in the sheep/wheat belt. These measures include the National Landcare Program. This program, which encourages communities to form local groups to solve environmental problems, has been criticised for being an ad hoc and piecemeal strategy for landscape restoration. Despite this criticism, an advocacy-based case study approach was used to seek ethnographic understanding of `ad hoc' Landcare projects in the hope that lessons for off-reserve conservation may still be learnt from the work of Landcare participants. The study is based on participant observation and action research with farmers in the Ge?aren Hill Landcare Group, as well as with other farmers in the district. It focuses on the relationship between farms, the physical environment and the process of involvement with government agencies and nature conservation schemes. Analysis and interpretation of the results of extensive field work proceeds from a multidisciplinary perspective. `Landscape' is explored as a pragmatic and metaphorical concept for understanding both the `background' of ecosystem fragmentation in the case study area and the `foreground' of farmers' personal interest, conceptions of, and involvement in nature conservation. This research found that local landscape foreground is diverse. This diversity encompasses the manner in which both agriculture and nature conservation are conceived and practiced over many properties. It was discovered, however, that amongst Genaren Hill Landcare Group farmers concepts such as `connectivity' between patches of remnant vegetation had emerged as major unifying principles for nature conservation as implemented across diverse farms. Instances of agency facilitation were examined and in many cases it was found that farmer diversity and local interest in conservation issues were not accounted for within `expert' perspectives as a potentially positive feature for encouraging nature conservation in a `fragmented ecosystem'. This study argues that frank recognition of the complexity of human/environment relationships allows us to celebrate and promote the achievements of farmers who have developed constructive ideas for nature conservation as facilitated by government financial support. Nature conservation may then be regarded as a creative process from which we recognise new cultural landscapes emerging, not just an act of `preservation' that seeks to minimise or halt human `impact'.
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ItemEffects of resistance to prehension and structure of pastures on grazing behaviour and intake of dairy cows( 2000)Pasture intake by dairy cows is affected by plant and sward structural characteristics of the pasture. In the meantime, grazing animals are constrained to gather their food bite by bite removing only a portion of the herbage present at the location which they bite. The extent to which grazing animals overcome the constraints imposed by the plant and structural characteristics of the pasture is the major determinant of herbage intake. The experiments which form the basis of this thesis concentrated on determining the role of sward resistance to prehension, measured in situ, as an integrating sward characteristic that determines foraging decisions of cows and the extent to which they defoliate pasture swards. Under rotational grazing systems, a cow is offered an area of pasture that is often smaller than the area from which the cow harvests its bites (defoliated area, DA). The cow therefore faces changing sward conditions during the process of grazing down into the sward and removing bites at successive lower defoliation planes. The defoliation pattern in grazing down the sward profile and the consequent herbage intake and diet composition, are examined in this thesis. A novel apparatus was designed to measure the BFF in situ at different sward profile heights. In the initial experiment, changes in BFF down the sward profile of six pasture species were examined in order to evaluate the mechanical efficiency of defoliating bites at different depths, in terms of bite weight:BFF ratio. The hypothesis tested was that cows remove 30 - 40% of the sward height at each bite due to a mechanical advantage in terms of BW:BFF. The BFF varied more between defoliation strata than between pasture species. The bite weight and BFF increased with the depth of defoliation. The mechanical efficiency of defoliating bites estimated as the BW:BFF ratio declined slightly with bite depth until a depth of about 30 - 40% of the sward height is reached, when the ratio declined more rapidly. Based on these results and those of Wade (1991), four theoretical defoliation planes (DPI, DP2, DP3 & DP4) were set each at 35% of the pre-grazing sward heights to estimate the total area defoliated by grazing cows under different sward conditions. DP2 is the plane of removal of a second bite after a first bite has removed DPI. Three spring grazing experiments were conducted to explore relationships between pasture allowance and/or sward structure and intake dynamics. In the first experiment, cows were offered a herbage allowance (HA) of 50 kg DM/cow/day either as one block with continuous access for 24 hours, or as six equal break rations opened at intervals during a 24 hour period. In the two subsequent experiments, different sward types were created in order to alter the BFF. In the second experiment swards were created with two different surface heights (USH) and in a 2 x 2 factorial, cows were offered two HA (35 and 70 kgDM/cow/day). In the third experiment, swards with three different tiller densities were created and cows were offered a similar HA of 8 kg DM/cow/3 hours. The defoliation pattern, BFF at 30, 50 and 70% of USH, DM intake, grazing behaviour and the energetics of grazing were measured. The major conclusions derived from these experiments are as follows. The average depth of defoliation (DD) increased with sward height and fell between DP2 and DP4. However, the proportion of area defoliated at each defoliation plane declined down the profile, at rates that varied with HA and tiller density but was unaffected by sward height. At a HA of 70 kg, cows barely reached DP4. The area defoliated at DP4 increased with decreasing herbage allowance and decreasing tiller density. The initial bulk density and post-grazed bulk density declined with USH, but the grazed-stratum bulk density was not significantly affected by USH. Therefore, it was concluded that the volume of canopy defoliated was the major determinant of intake. With increasing HA, the average bite weight (BW) increased, prehension bite rate declined but the overall intake rate increased. The time cost of a bite increased with BW. However, the energy expenditure on prehending a bite did not show a consistent relationship with BW. The BFF increased with sward height and tiller density. However, BFF in the leafy layer of 70% of the sward height was not affected by initial sward height or tiller density. The increase in BFF with initial sward height and tiller density was greater in the lower stemmy layer of 30% sward height. The average bite area (BA) and BW increased with HA. Intake was positively correlated with HA (R = 0.49), HM (R = 0.65) and tiller density (R = 0.51). Multiple regression analysis with herbage intake as the dependent variable indicated that, in addition to HM and HA (R2 = 0.887) , inclusion of the difference in BFF between that at 30% USH and that at 70% USH (BFFdif) as a sward characteristic provided an equation with a substantially better fit (R2 = 0.956). DMI = -3.47 + 1.80 HM + 0.225 HA R2 = 0.887 DMI = -2.73 I + 2.76 HM + 0.732 HA - 0.0416 BFFdif R2 = 0.956 It is concluded that the BFFdif has a significant value in integrating the changes in sward characteristics down the profile and is useful in improving the intake model.