- Office for Environmental Programs - Theses
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ItemFinding the last Hawkweed plant: how detection rate scales with cluster sizeKozel, Ben ( 2018)When surveying or monitoring a species, the assumption that all the individuals living in the sampling area will be detected rarely holds. Even for plants, detection probabilities are typically less than 1 (where 1 represents perfect detection). Detectability estimates can be affected by ecological processes, observational processes, and by the interactions between the two. For invasive species control programs understanding the factors affecting detectability is critical to determining the effort needed to reduce population density to a desired level, or prevent their establishment in new areas. The influence of cluster size on detection rate was investigated in the context of Orange Hawkweed and King-Devil Hawkweed, herbaceous species with the potential to cause significant environmental harm in Australian alpine habitats. Detection rate was modelled using a well-recognised time-to-detection modelling approach. In this model, detection rate is proportional to a power function of Hawkweed cluster size, with a scaling exponent that depends on the nature of this relationship. All other factors being equal, rate of detection is expected to increase less-than-proportionally with increasing cluster size; specifically, it should rise with the square root of cluster size, owing to rudimentary mathematics governing apparent size. The scaling exponent, and other model parameters, were estimated using data from search experiments involving six different Hawkweed cluster sizes and 15 searchers. The data support the validity of the model. High inter-observer variability in detection rates generated substantial credible intervals for the scaling exponent estimates. Nevertheless, these estimates suggest a deviation from the expectation that detection rate varies with the square root of cluster size. Reasons for this discrepancy are proposed, centring on the influence of perception psychology in the formation of Hawkweed ‘images’ by searchers. The findings may couple well with distance sampling methodology to refine the systematic monitoring, or eradication, of Hawkweed within a defined area. Quantifying the Detection rate – Cluster-size relationship yields better estimates of the minimum effort required to find solitary plants, which, in turn, improves resource allocation.
ItemCivil society advocacy towards sustainable food systems policy in VictoriaSheridan, Jennifer ( 2016)The current food system is widely regarded as unsustainable, in terms of its impact on the environment and population health, and in the inequality of current access to food. A policy shift is needed to drive a transformation towards sustainable food systems. Civil society groups are key actors in driving policy change, but little is known about the strategies that these groups are using in Australia to drive change. This research investigated how civil society stakeholders in Victoria advocate for sustainable food systems, including the role of alliances in their work and how the policy context shapes their work. The research used semi-structured interviews with civil society stakeholders, supplemented with documentary analysis, to explore the strategies used to advocate for sustainable food systems in Victoria. The research found that policy advocacy was not a current priority for many stakeholders, due to past disappointments with attempts to influence policy, and due to a lack of resources. Those stakeholders undertaking policy advocacy generally reacted to policy threats, rather than undertaking proactive and strategic policy actions. Many stakeholders focused on building an alternative food system rather than policy advocacy. The research concluded that while these actions contribute to a more sustainable food system, there is currently a lack of focus on proactive and strategic advocacy for policy change.
ItemThe effect organisational purpose has on staff engagementStark, Anthony ( 2018)As the environmental and social impacts of large corporates continues to place a strain on an already stretched planet, the shift to a more ethical and sustainable business model has become increasingly important. Organisations that are ‘Purpose’ driven generally exhibit strong pro-social and environmental values and operate by the ‘do well by doing good’ philosophy. Understanding the effect organisational purpose has on staff engagement is important in furthering academic knowledge as well as practical applications for industry.