Integrating Ecoclimatic Niche Modelling Methods Into Classical Biological Control Programmes

Much of the success of a classical biological control programme hinges on identifying effective candidate agents, and once approved for release deploying them in the range invaded by the target organism at site-specific times of the year when they have the best chance of establishing. While suitable ecoclimatic modelling methods are available to guide decision-making, they have not been well integrated into biological control praxis. We present a framework that shows how ecoclimatic modelling techniques can be usefully and cost-effectively integrated into biological control programmes. The framework consists of a range of modelling methods within the CLIMEX software toolbox, differing in their information demands and outputs. To demonstrate the framework, we use different types of invasive plants in Australia: the annual forbs Conyza bonariensis (syn. Erigeron bonariensis) and Sonchus oleraceus, the woody perennial shrub Lycium ferocissimum, and the submerged aquatic Cabomba caro-liniana. Simple climate-matching techniques, which only require data on the distribution of the target invasive species, are shown to be useful to identify the regions to search for candidate agents in the native range that are climatically adapted to those in the invaded range where biological control is most wanted. More sophisticated niche models can inform both where and when to search for candidate agents in the native range and when and where to release approved agents in the invaded range so that their hosts are actively growing and at the appropriate life stage at the selected sites. We demonstrate how simple manipulative experiments on the tem-perature response of the target invasive species can be used to parameterise these more complicated niche models. While the modelling framework has been demonstrated using invasive plants as targets, it is equally applicable to arthropod pests. The modelling has been a valuable component of the current biological control programmes, guiding agent prospecting and future deployment efforts in time and space.