Approaches to strategic risk analysis and management of invasive plants: lessons learned from managing gamba grass in northern Australia

Given the environmental damages caused by invasive species, it is critical to allocate limited management budgets carefully. To address this need, there are a variety of approaches for analysing invasive species risk and designing management strategies; these range from pre-border risk assessment through to local-scale prioritisation of management actions. Risk assessment can be broadly characterised into three components: risk analysis, risk characterisation and risk management. For each component we give a brief review of current approaches and then present innovative tools being developed and applied in northern Australia. We use gamba grass (Andropogon gayanus Kunth.) as a case study to contrast the benefits of the different approaches presented. With our case study, we demonstrate the practical application of novel risk management tools, with results from these tools that are being used locally to prioritise management actions. Lastly, we note that for even greater benefit to be achieved, the new spatial prioritisation approaches presented must be accompanied by further development of data and methods to accommodate planning for multiple weed species and incorporation of further human dimensions (e.g. social and cultural values).