Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Individual heterogeneity affects the outcome of small mammal pest eradication.

Abstract

The eradication of invasive small mammal pests is a challenging undertaking, but is needed in many areas of the world to preserve biodiversity. Trapping and poisonous baits are some of the most widespread tools for pest control. Most of the models used to make predictions and to design effective trapping protocols assume that pest populations are behaviourally homogeneous and, in particular, that all individuals react the same way when confronted with a trap or bait. In this study, we analyse the effect of consistent variations in trappability across a pest population on the success of eradication and the time taken to be confident that eradication has occurred. 2. We present results obtained using both a simple, stochastic, individual-based model, and an analytical approach. Simulations were run using two different modelling techniques, one where individuals display consistent daily behaviour towards traps and one with variable daily behaviour. We then show how to use our model to detect and measure heterogeneity in a population using capture data. 3. Results show that neglecting individual heterogeneity in trappability leads to overly optimistic predictions for the efficacy of eradications operations. The presence of even a small proportion of relatively trap-shy individuals is shown to make eradication much more difficult 4. In this study we reveal how individual heterogeneity can affect capture probabilities and the outcome of pest eradications. Such information contributes towards improved pest management designs, needed by ecological operations making use of trapping systems.