School of BioSciences - Research Publications

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    Integrated perspective on translating biophysical to economic impacts of climate change
    Piontek, F ; Drouet, L ; Emmerling, J ; Kompas, T ; Mejean, A ; Otto, C ; Rising, JS ; Soergel, B ; Taconet, N ; Tavoni, M (NATURE PORTFOLIO, 2021-06-17)
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    Early Decision Indicators for Foot-and-Mouth Disease Outbreaks in Non-Endemic Countries
    Garner, MG ; East, IJ ; Stevenson, M ; Sanson, RL ; Rawdon, TG ; Bradhurst, RA ; Roche, SE ; Van Ha, P ; Kompas, T (Frontiers Media, 2016)
    This Research Topic presents valuable studies presenting different aspects and implementations of mathematical modeling for disease spread and control in the veterinary field.
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    Optimal surveillance against foot-and-mouth disease: the case of bulk milk testing in Australia
    Kompas, T ; Pham, VH ; Hoa, TMN ; East, I ; Roche, S ; Garner, G (WILEY, 2017-10-01)
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    Optimal surveillance against bioinvasions: a sample average approximation method applied to an agent-based spread model
    Hoa-Thi-Minh, N ; Pham, VH ; Kompas, T (WILEY, 2021-10-24)
    Trade-offs exist between the point of early detection and the future cost of controlling any invasive species. Finding optimal levels of early detection, with post-border active surveillance, where time, space and randomness are explicitly considered, is computationally challenging. We use a stochastic programming model to find the optimal level of surveillance and predict damages, easing the computational challenge by combining a sample average approximation (SAA) approach and parallel processing techniques. The model is applied to the case of Asian Papaya Fruit Fly (PFF), a highly destructive pest, in Queensland, Australia. To capture the non-linearity in PFF spread, we use an agent-based model (ABM), which is calibrated to a highly detailed land-use raster map (50 m × 50 m) and weather-related data, validated against a historical outbreak. The combination of SAA and ABM sets our work apart from the existing literature. Indeed, despite its increasing popularity as a powerful analytical tool, given its granularity and capability to model the system of interest adequately, the complexity of ABM limits its application in optimizing frameworks due to considerable uncertainty about solution quality. In this light, the use of SAA ensures quality in the optimal solution (with a measured optimality gap) while still being able to handle large-scale decision-making problems. With this combination, our application suggests that the optimal (economic) trap grid size for PFF in Queensland is ˜0.7 km, much smaller than the currently implemented level of 5 km. Although the current policy implies a much lower surveillance cost per year, compared with the $2.08 million under our optimal policy, the expected total cost of an outbreak is $23.92 million, much higher than the optimal policy of roughly $7.74 million.
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    Equilibrium Modeling for Environmental Science: Exploring the Nexus of Economic Systems and Environmental Change
    Cantele, M ; Bal, P ; Kompas, T ; Hadjikakou, M ; Wintle, B (AMER GEOPHYSICAL UNION, 2021-09-01)
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    Post-outbreak surveillance strategies to support proof of freedom from foot-and-mouth disease
    Bradhurst, R ; Garner, G ; East, I ; Death, C ; Dodd, A ; Kompas, T ( 2021-04-28)
    Abstract Whilst emergency vaccination may help contain foot-and-mouth disease in a previously FMD-free country, its use complicates post-outbreak surveillance and the recovery of FMD-free status. A structured surveillance program is required that can distinguish between vaccinated and residually infected animals, and provide statistical confidence that the virus is no longer circulating in previously infected areas. Epidemiological models have been well-used to investigate the potential benefits of emergency vaccination during a control progam and when/where/whom to vaccinate in the face of finite supplies of vaccine and personnel. Less well studied are post-outbreak issues such as the management of vaccinated animals and the implications of having used vaccination during surveillance regimes to support proof-of-freedom. This paper presents enhancements to the Australian Animal Disease Model (AADIS) that allow comparisons of different post-outbreak surveillance sampling regimes for establishing proof-of-freedom from FMD. A case study is provided that compares a baseline surveillance sampling regime (derived from current OIE guidelines), with an alternative less intensive sampling regime. It was found that when vaccination was not part of the control program, a reduced sampling intensity significantly reduced the number of samples collected and the cost of the post-outbreak surveillance program, without increasing the risk of missing residual infected herds.
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    Approaches for estimating benefits and costs of interventions in plant biosecurity across invasion phases
    Welsh, MJ ; Turner, JA ; Epanchin-Niell, RS ; Monge, JJ ; Soliman, T ; Robinson, AP ; Kean, JM ; Phillips, C ; Stringer, LD ; Vereijssen, J ; Liebhold, AM ; Kompas, T ; Ormsby, M ; Brockerhoff, EG (WILEY, 2021-05-06)
    Nonnative plant pests cause billions of dollars in damages. It is critical to prevent or reduce these losses by intervening at various stages of the invasion process, including pathway risk management (to prevent pest arrival), surveillance and eradication (to counter establishment), and management of established pests (to limit damages). Quantifying benefits and costs of these interventions is important to justify and prioritize investments and to inform biosecurity policy. However, approaches for these estimations differ in (1) the assumed relationship between supply, demand, and prices, and (2) the ability to assess different types of direct and indirect costs at invasion stages, for a given arrival or establishment probability. Here we review economic approaches available to estimate benefits and costs of biosecurity interventions to inform the appropriate selection of approaches. In doing so, we complement previous studies and reviews on estimates of damages from invasive species by considering the influence of economic and methodological assumptions. Cost accounting is suitable for rapid decisions, specific impacts, and simple methodological assumptions but fails to account for feedbacks, such as market adjustments, and may overestimate long-term economic impacts. Partial equilibrium models consider changes in consumer and producer surplus due to pest impacts or interventions and can account for feedbacks in affected sectors but require specialized economic models, comprehensive data sets, and estimates of commodity supply and demand curves. More intensive computable general equilibrium models can account for feedbacks across entire economies, including capital and labor, and linkages among these. The two major considerations in choosing an approach are (1) the goals of the analysis (e.g., consideration of a single pest or intervention with a limited range of impacts vs. multiple interventions, pests or sectors), and (2) the resources available for analysis such as knowledge, budget and time.
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    Budgeting and portfolio allocation for biosecurity measures
    Kompas, T ; Chu, L ; Pham, VH ; Spring, D (WILEY, 2019-07-01)
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    Look before you treat: increasing the cost effectiveness of eradication programs with aerial surveillance
    Spring, D ; Croft, L ; Kompas, T (SPRINGER, 2017-02-01)
    Most successful invasive species eradication programs were applied to invasions confined to a small area. Invasions occupying large areas at a low density can potentially be eradicated if individual infestations can be found at affordable cost. The development of low cost aerial surveillance methods allows for larger areas to be monitored but such methods often have lower sensitivity than conventional surveillance methods, making their cost-effectiveness uncertain. Here, we consider the cost-effectiveness of including a new aerial monitoring method in Australiaâ s largest eradication program, the campaign to eradicate red imported fire ants (Solenopsis invicta). The program previously relied on higher sensitivity ground surveillance and broadcast treatment. The high cost of those methods restricted the total area that could be managed with available resources below the level required to prevent ongoing expansion of the invasion. By increasing the area that can be monitored and thereby improving the targeting of treatment and ground surveillance, we estimate that remote sensing could substantially reduce eradication costs despite the methodâ s low sensitivity. The development of low cost monitoring methods could potentially lead to substantially improved management of invasive species.