Trading off action against learning when searching for invasive pests

Strategically searching for invasive pests presents a formidable challenge. Limited funding means choosing between cursorily surveying many sites, or focussing intensively on fewer sites. Existing knowledge may help to target more likely sites, but this knowledge is not flawless and improving it also requires investment.

This study examines how to best combine search coverage and accuracy (and its future improvement) within a single optimisation framework. It’s a rare example of trading-off action against knowledge gain.

More specifically it examines under which circumstances managers should adopt one of two search-and-control strategies (cursory or focussed), and when they should divert funding to improving knowledge, making better predictive maps that benefit future searches.

The study demonstrates the framework by linking quality-of-search-effort maps to a logistic model of invasive spread such as that for the red imported fire ant Solenopsis invicta in south-east Queensland, Australia.

Cursory widespread searching is only optimal if the pest is already widespread or knowledge is poor, otherwise focussed searching exploiting the map is preferable. For longer management timeframes, eradication is more likely if funds are initially devoted to improving knowledge, even if this results in a short-term explosion of the pest population.

This framework can improve the efficiency of any ecological management that relies on predicting occurrence.

More info: Peter Baxter

Baxter PWJ & HP Possingham (2011). Optimizing search strategies for invasive pests: learn before you leap. Journal of Applied Ecology 48: 86–95.


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