42 resultados para Fires.

em Deakin Research Online - Australia


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The Australian Unity Wellbeing Index monitors the subjective wellbeing of the Australian population. Our first survey was conducted in April 2001 and this report concerns a special Survey 25.1, undertaken in October 2011. The survey was commissioned to detect whether the disastrous floods in North Queensland in the period December 2010 through February 2011, and fires in Victoria in the period January through February 2009, continued to affect the subjective wellbeing of people continuing to live in the disaster areas.

This survey involved 1,215 respondents, with 600 drawn from Victoria and 615 from Queensland. The questionnaire comprised only the Personal Wellbeing Index and a small set of demographic questions. In all other respects the methodology of the survey followed our normal procedures.1

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This article explores insurability relating to loss occasioned by catastrophic events in Australia in the context of the current legal regulatory regime. The analysis includes two case studies, in which we juxtapose the Victorian Black Saturday fires in February 2--9 with the Queensland flooding and Cyclone Yasi (December 2010 - February 2011). We argue that the different responses to, and economic losses stemming from, these events illustrate the urgent need for a national regulatory and insurance regime for the prevention and alleviation of disasters and the management of their consequences.

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 During bushfires, firefighters often work long shifts with little sleep. Grace’s research showed that although firefighters’ sleep is restricted, it does not adversely affect their ability to perform physical tasks. This contrasts the cognitive impairments associated with sleep loss and could prompt revision of fatigue management guidelines in physically-demanding occupations.

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In southeastern Australia ecological burning is frequently used to maintain a number of plant and animal populations. However, many of these prescribed fires are small, and may focus intense grazing activity on new regrowth. At Reef Hills Regional Park, Victoria shrub species have senesced, presumably due to the absence of fire. Ecological burning may be necessary to promote regeneration, however, the population density of the Eastern Grey Kangaroo (Macropus giganteus) is high (approx 38 per km2), and grazing pressure presents a significant risk to postfire vegetation recovery. An assessment of grazing patterns and their effects on postfire recovery was carried out at Reef Hills Regional Park through grazing exclusion plots. Preferential grazing by Eastern Grey Kangaroos occurred on small burnt plots compared to adjacent unburnt areas as determined by faecal pellet counts. On burnt areas, there was a significant reduction in shrub diversity on grazed plots compared to ungrazed plots. Most observations of kangaroos were of animals grazing on farmland surrounding the Park, and it is likely that any burning might shift grazing from farmland to burnt areas when new growth occurs. This needs to be considered before any ecological burn plan is applied to manage vegetation communities, particularly if the plan requires small areas to be burnt. We recommended that a large area up to 200 ha area be burnt and monitored to determine whether burning larger areas disperses grazing pressure from macropods to a level where impacts on vegetation are reduced and localized plant extinctions do not occur.

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Since fighting fires can pose a great risk to the lives of firefighters, it is important to understand how they perceive risks in dynamic wildfire situations. The aim of the current study was to determine whether career and volunteer firefighters differ in their perception of the risk of a going vs. contained fire and whether descriptions of a fire as either going or contained affected perceptions of risk. It was expected that career firefighters would rate a contained fire as significantly riskier than would volunteer firefighters. The sample consisted of 55 career and 84 volunteer CFA Victorian firefighters (134 males and 5 females). An ambiguous wildfire scenario was presented and described as either going or contained and risk ratings were recorded. Two-way ANOVA results showed that career firefighters rated a going fire as equally risky as a contained fire. On the other hand, volunteer firefighters perceived a fire described as contained to be significantly less risky than a fire described as going, despite the fact that the same fireground conditions were described in both cases. It was concluded that a framing effect had occurred and that career firefighters demonstrated a higher level of situation awareness than volunteer firefighters due to their heightened levels of risk perception when exposed to contained wildfire scenarios. A practical implication of the current research is that those conducting firefighting briefings need to be aware of possible framing effects in the way information is presented to firefighters and need to ensure that all briefings make risks cognitively salient to firefighters.

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Large scale bushfire (or wildfire) suppression activities are conducted under the control of an Incident Management Team (IMT) comprising four major functions: Command, Operations, Planning, and Logistics. Four methodologies were used to investigate processes determining the effectiveness of IMT decision making activities: (a) laboratory experiments using the Networked Fire Chief computer simulation program; (b) analyses of reports of significant fires; (c) structured interviews with experienced IMT staff; and, (d) cognitive ethnographic studies of IMTs. Three classes of team processes were found to be important determinants of IMT effectiveness: information sharing and management; matching of the four component function goals to overall IMT goals; and monitoring of the overall IMT situation to detect and correct task disruptive processes. Several non-rational processes with the potential for hindering IMT effectiveness were noted. Team metacognition emerged as a key process for understanding effective IMT decision making.

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Victoria is facing its driest summer for nearly one hundred years, with conditions worse than in 1983 when the state was swept by the devastating Ash Wednesday bushfires. The fires were particularly fierce in Mount Macedon in central Victoria, and the Woodend Fire Brigade is in the front line of the struggle to avoid a repeat of Ash Wednesday. Trial by Fire follows this brigade as they do all that they can to keep their community safe from the devastation of the fires.

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This thesis is involved with changes that have occurred to small mammal populations following a major disturbance in the Anglesea region as a result of the 1983 Ash Wednesday fires. Fire, with its effects on spatial and temporal heterogeneity, was found to be an important factor in the maintenance of vegetation and small mammal community structure and diversity in the region. Successional changes in vegetation and small mammal communities were described by multivariate analyses, using data collected annually from 22 study sites. The use of factor analysis techniques, in reducing the annual capture data content, enabled long-term changes in the structure of mammal communities to be interpreted. The small mammal communities in the coastal heath and forest vegetation in the Anglesea region show evidence of a general resilience, (the degree and speed of recovery), to disturbance. Two phases of successional response to fire by mammal species have been proposed; a ‘re-establishment’ phase which occurs in the initial 5-6 years post-fire and is accompanied by rapid increase in species’ abundance, and a subsequent ‘maintenance’ phase accompanied by relatively minor changes in abundance. Habitat Suitability Indices were produced relating to these phases. Vertical density measures of understorey shrubs and herb layers showed significant relationships with small mammal species abundance at the study sites. Long term studies following major disturbances are needed to distinguish between short term recovery of plant and animal species and long term changes in these species. Studies extending over a number of years enable a better directional view of changes in small mammal communities than can be determined from . observations made over a short period. As a part of the investigation into temporal change, it was proposed to undertake trial reintroductions of the Swamp antechinus, Ant echinus minimus, a marsupial dasyurid species which was trapped in the area prior to the 1983 fire, but rarely subsequently. Other more commonly observed native small mammal species (e.g. Rattus fuscipes,R. lutreolus, Antechinus stuartii, Sminthopsis leucopus) had re-invaded the proposed reintroduction site after this fire. Failure of A. minimus to re-establish may have been due to spatial separation of the pre-fire populations coupled with the extensive area burnt in 1983, A source population of the species was located about 100km to the west and habitat utilization and interspecific and niche relationships between the species making the small mammal community explored. Discriminant analysis revealed some spatial separation of species within a habitat based on structural vegetation factors rather than floristic factors. Temporal separation of species was observed, asA. minimus were more active than Rattus species during daylight periods. There was evidence of micro-habitat selection by species, and structural vegetation factors were most commonly identified in statistical analyses as contributing towards selection by small mammal species. Following a theoretical modelling study three reintroduction trials were carried out near Anglesea during 1992-94. Individuals were subsequently radio tracked, and habitat relationships between the species in the small mammal community investigated. Although successful breeding of A, minimus occurred during the latter two trials, the subsequent fate of offspring was not determined. Invasive techniques required to adequately monitor young animals were considered potentially too damaging. Telemetry studies indicated a preference of A. minimus for short, wet heath vegetation. Structural vegetation factors were identified as being significant in discriminating between capture locations of species. Small scale and inexpensive trial reintroductions have yielded valuable additional data on this species and may be viewed as a useful tool in the conservation of other small native mammals.

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This dissertation explores the relationship between the urban rural interface, with particular reference to air pressure, wind patterns, and the build up of hot ash deposits adjacent to combustible surfaces, in order to devise strategies relating to the design of building forms.

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A critical requirement in the ecological management of fire is knowledge of the age-class distribution of the vegetation. Such knowledge is important because it underpins the distribution of ecological features important to plants and animals including retreat sites, food sources and foraging microhabitats. However, in many regions, knowledge of the age-class distribution of vegetation is severely constrained by the limited data available on fire history. Much fire-history mapping is restricted to post-1972 fires, following satellite imagery becoming widely available. To investigate fire history in the semi-arid Murray Mallee region in southern Australia, we developed regression models for six species of mallee eucalypt (Eucalyptus oleosa F.Muell. ex. Miq. subsp. oleosa, E. leptophylla F.Muell. ex. Miq., E. dumosa J. Oxley, E. costata subsp. murrayana L. A. S. Johnson & K. D. Hill, E. gracilis F.Muell. and E. socialis F.Muell. ex. Miq.) to quantify the relationship between mean stem diameter and stem age (indicated by fire-year) at sites of known time since fire. We then used these models to predict mean stem age, and thus infer fire-year, for sites where the time since fire was not known. Validation of the models with independent data revealed a highly significant correlation between the actual and predicted time since fire (r = 0.71, P < 0.001, n = 88), confirming the utility of this method for ageing stands of mallee eucalypt vegetation. Validation data suggest the models provide a conservative estimate of the age of a site (i.e. they may under-estimate the minimum age of sites >35 years since fire). Nevertheless, this approach enables examination of post-fire chronosequences in semi-arid mallee ecosystems to be extended from 35 years post-fire to over 100 years. The predicted ages identified for mallee stands imply a need for redefining what is meant by ‘old-growth’ mallee, and challenges current perceptions of an over-abundance of ‘long-unburnt’ mallee vegetation. Given the strong influence of fire on semi-arid mallee vegetation, this approach offers the potential for a better understanding of long-term successional dynamics and the status of biota in an ecosystem that encompasses more than 250 000 km2 of southern Australia.

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Knowing how species respond to fire regimes is essential for ecologically sustainable management. This axiom raises two important questions: (1) what knowledge is the most important to develop and (2) to what extent can current research methods deliver that knowledge? We identify three areas of required knowledge: (i) a mechanistic understanding of species’ responses to fire regimes; (ii) knowledge of how the spatial and temporal arrangement of fires influences the biota; and (iii) an understanding of interactions of fire regimes with other processes. We review the capacity of empirical research to address these knowledge gaps, and reveal many limitations. Manipulative experiments are limited by the number and scope of treatments that can be applied, natural experiments are limited by treatment availability and confounding factors, and longitudinal studies are difficult to maintain, particularly due to unplanned disturbance events. Simulation modelling is limited by the quality of the underlying empirical data and by uncertainty in how well model structure represents reality. Due to the constraints on large-scale, long-term research, the potential for management experiments to inform adaptive management is limited. Rather than simply recommending adaptive management, we define a research agenda to maximise the rate of learning in this difficult field. This includes measuring responses at a species level, building capacity to implement natural experiments, undertaking simulation modelling, and judicious application of experimental approaches. Developing ecologically sustainable fire management practices will require sustained research effort and a sophisticated research agenda based on carefully targeting appropriate methods to address critical management questions.

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This research introduces a method of using Lindenmayer Systems to model the spreading and behavior of fire inside a factory building. The research investigates the use of L-System propagated fires for determining factors such as where the fire is most likely to spread first and how fast. It also looks at an alternative way of storing the Lindenmayer System, not in the form of a string but rather as a graph. A variation on the building and traversal process is also investigated, in which the L-System is traversed depth first instead of breadth first. Results of fire propagation are presented and we conclude that L-Systems are a suitable tool for fire propagation.