Relative effectiveness of trapping and hand-capture for controlling invasive cane toads (Rhinella marina)

Abstract

ABSTRACTManagement of invasive vertebrates is a crucial component of conservation. Management strategies should increase the chance of removal of every individual, by exploiting behavioural characteristics, and by increasing the period over which removal occurs. For example, traps can operate automatically over long periods, and often include attractants to increase captures. Management strategies for the invasive cane toad (Rhinella marina) in Australia include hand capture and trapping adult individuals (toads are attracted to an acoustic lure, and to insects attracted to a light, also on the lure). We used capture-mark-recapture analysis to compare the efficacy of trapping and hand capturing cane toads over 10 weeks, in Townsville, Australia. We trapped 7.1%–22.4% of the estimated population per week, and hand captured 1.7%–6% of the estimated population per week. Trapping was more efficient than hand capture in our regime; overall, more toads were caught per trapping man-hour than per hand-capture hour. Traps attract toads and maximise the period over which removal occurs; thus, the probability of removal for each toad was higher than by hand capture. Because hand capture and trapping seemed to remove different toads, a combination of these methods may work well.