New Zealand Journal of Ecology (2011) 35(2): 193- 193

Reliable mop-up of surviving pests: a more cost-effective and fail-safe approach to local extirpation

Conference Abstract
Peter Sweetapple  
Graham Nugent  
  1. Landcare Research, PO Box 40, Lincoln 7640, New Zealand

Achieving very low densities of small mammal pests is routinely attained by expensive, large-scale, broadcast poisoning. There are two strategic responses to maintaining these low pest densities (or attempting to eradicate the survivors) – repeat the poisoning at regular intervals, or attempt to detect and mop- up the survivors. Here we report preliminary trials working toward the latter approach for possums (Trichosurus vulpecula) in a large mainland forest in New Zealand, and show that detection-and-mop-up is not only feasible but also possibly the most economically sensible and reliable way of achieving 100% kills. We use a simple bioeconomic model to predict the optimal surveillance (detection) strategy for possum mop-up, based on the characteristics of the detection device, and the few data available on the aggregation patterns of possums at extreme low density.