Ageing mallee eucalypt vegetation after fire : insights for successional trajectories in semi-arid mallee ecosystems

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.

A framework for mapping vegetation over broad spatial extents : a technique to aid land management across jurisdictional boundaries

Mismatches in boundaries between natural ecosystems and land governance units often complicate an ecosystem approach to management and conservation. For example, information used to guide management, such as vegetation maps, may not be available or consistent across entire ecosystems. This study was undertaken within a single biogeographic region (the Murray Mallee) spanning three Australian states. Existing vegetation maps could not be used as vegetation classifications differed between states. Our aim was to describe and map ‘tree mallee’ vegetation consistently across a 104 000km2 area of this region. Hierarchical cluster analyses, incorporating floristic data from 713 sites, were employed to identify distinct vegetation types. Neural network classification models were used to map these vegetation types across the region, with additional data from 634 validation sites providing a measure of map accuracy. Four distinct vegetation types were recognised: Triodia Mallee, Heathy Mallee, Chenopod Mallee and Shrubby Mallee. Neural network models predicted the occurrence of three of them with 79% accuracy. Validation results identified that map accuracy was 67% (kappa = 0.42) when using independent data. The framework employed provides a simple approach to describing and mapping vegetation consistently across broad spatial extents. Specific outcomes include: (1) a system of vegetation classification suitable for use across this biogeographic region; (2) a consistent vegetationmapto inform land-use planning and biodiversity management at local and regional scales; and (3) a quantification of map accuracy using independent data. This approach is applicable to other regions facing similar challenges associated with integrating vegetation data across jurisdictional boundaries.

New governance, green planning and sustainability : Tasmania together and growing Victoria together

Bridgman and Davis(2000:91) have argued that ‘ideally government will have a well developed and widely distributed policy framework, setting out economic, social and environmental objectives’. This article compares and evaluates two such frameworks or plans, Tasmania Together and Growing Victoria Together, in terms of their potential to promote sustainability. It argues that they are very different exercises in new governance, aimed at reconnecting with community priorities and at redirecting macro-policy setting away from a preoccupation with economic priorities, respectively. Nevertheless, both plans have the capacity to ‘green’ state planning, in Tasmania in terms of more purposeful benchmarks, and in Victoria in terms of enhanced sustainability emphasis in the macro-policy setting. The article encounters tensions in its review of the plans between deliberation and planning, policy empowerment and policy progress, and policy institutionalisation and politicisation as means of achieving policy change. It finds that whilst Tasmania and Victoria are re-engaged states that are reinventing state policy, as yet they are failing to meet the governance challenges of sustainability.

Tasmania together and growing Victoria together : can state plans deliver environmental sustainability?

Sustainability has always been a contested term, environmental sustainability in particular. It presents challenges and opportunities for policy making at all levels. This paper suggests that state plans have a key role to play in the pursuit of sustainability. It argues that, in theory, sustainability requires well integrated, interactive, informed and informing, as well as institutionalised policy processes. It reviews state plans in Tasmania and Victoria to analyse their capacity for delivering sustainability. Tasmania Together and Crowing Victoria Together are very different plans, so very different conclusions are drawn here, however we find that both of them lack the explicit political and policy commitment to sustainability that is required to turn rhetoric into state planning practice.

Collapse

Collapse was a visual performance installation presented at the Old Port of Melbourne in 2008. The audience travelled by boat across Port Phillip Bay to witness the performance begins at Sciencework’s Spotswood Jetty, where the audience travelled by ferry across the Port Phillip Bay to a remote location, where society has “collapsed”. The performance then becomes a walking tour around this new location, encountering and experiencing the world that Red Cabbage has created.

“At that point…the collapse of their morale, their will power and their patience was so abrupt that they felt they would never be able to climb back out of their hole…Hence, floundering halfway between the abyss and the peak, they drifted rather than lived, given up to aimless days and sterile memories, wandering shadows who could have only found strength by resigning themselves to taking root in the soil of their distress.”- Albert Camus The Plague

Floundering halfway between the abyss and the peak…exist those that have not yet fallen…in a state of recurring collapse. The girl in the yellow dress, the man in the grey suit, the old man in the brown pants, the woman in the blue shirt and the man in the red hat are suspected carriers of the white sickness. They have been removed from their homes to the edge of the city for standard assessment. Here they meet the others, processed…waiting…isolated. By boat…they travel across the bay to their final destination. Not another Hollywood style apocalyptic melodrama in which our heroes find grace, hope and redemption in the utter destruction of modern civilization…in the collapse of lived time the ruins of humanity are exposed as already existent…the limits of our ability to be graceful were discovered long ago…the trauma of the end of time a given…the plague is now.

More than Ballyhoo? : The importance of understanding film consumption in Australia

We have all become used to reading stories filled with alarm and recrimination, or (more rarely) tentative optimism concerning the local production industry's percentage of the domestic box office. This blunt but exploitable indicator greatly simplifies the interaction between film product and its consumer.

Meta-learning for data summarization based on instance selection method

The purpose of instance selection is to identify which instances (examples, patterns) in a large dataset should be selected as representatives of the entire dataset, without significant loss of information. When a machine learning method is applied to the reduced dataset, the accuracy of the model should not be significantly worse than if the same method were applied to the entire dataset. The reducibility of any dataset, and hence the success of instance selection methods, surely depends on the characteristics of the dataset, as well as the machine learning method. This paper adopts a meta-learning approach, via an empirical study of 112 classification datasets from the UCI Repository [1], to explore the relationship between data characteristics, machine learning methods, and the success of instance selection method.