A tool to support the decision to switch between eradication and containment of an invasion

Abstract

The primary objective of this project is to develop a tool that will improve decisions about appropriate pest management activities over time (eradicate, contain or do nothing) and use case studies to determine rulesof-thumb for management in a range of invasion scenarios. The tool was implemented as an Excel spreadsheet and is based on a model that considers the simplest possible representation of a managed invasion, accounting for the spread rate of the invasion, damages caused by the invader and control costs. We present and solve this generic model to obtain an understanding of the eradication / containment decision. We then apply the model to two case studies and present results from both case studies in addition to some generic modelling to help gain insight into the decision problem.<br/>Two case studies were selected through a workshop attended by a range of Commonwealth, State and academic participants. The two case studies chosen were Siam weed in Queensland and European House Borer (EHB) in Western Australia:<br/><ul><li>Siam Weed is one of the world’s worst weeds. It is a fast growing perennial shrub that thrives in disturbed habitats and can completely dominate the landscape it invades. It was first detected in Australia in 1994, and became the target of a national cost-shared eradication programme in 1995. Siam weed has the potential to infest large areas of coastal land in northern Australia, invading productive agricultural land and ecosystems known for their high environmental values.</li><li>EHB is a serious insect pest of untreated dry softwood. In areas near Perth it has been found in pine plantations, where it infests dead pinewood, and in untreated manufactured articles derived from pine timber, including structural timber in several homes. Most of the damage is experienced by households and businesses that use pine wood, and control involves “packages” of actions that include building restrictions, and early harvest of infested plantations.</li></ul>Finally, we provide recommendations for future development and use of the tool and associated model, including practical suggestions for data recording and extraction in future pest/disease management programmes.