Unexpected outcomes of invasive predator control: the importance of evaluating conservation management actions

Decisions regarding the implementation of conservation management actions should be based on the effectiveness of past investments. However, because of limited evaluation of existing data, actions may be prescribed without evidence of producing a beneficial conservation outcome. We analysed empirical data, collected over 23 years across southern Australia, on the impact of fox baiting on malleefowl to determine its effectiveness. We employed data from extensive monitoring surveys to evaluate the observed relationships between investment in fox control, fox baiting intensity, fox presence and two alternative measures of the malleefowl's response: the number of breeding pairs and population growth. This study is the first to quantify the return on investment from fox control in a conservation context. We discovered there is limited quantitative evidence for a benefit of fox baiting on malleefowl, despite it being the main management action implemented for this nationally threatened, well-studied and iconic species. We found that fox baiting did not significantly decrease the presence of foxes and fox presence was positively correlated with malleefowl conservation. Malleefowl breeding population size increased with investment in baiting, although this relationship depended on the number of years the site had been baited. Nonetheless, most sites had a negative relationship between investment and breeding population. In contrast, malleefowl population growth did not benefit from baiting, suggesting that fox baiting is generally not a cost-effective management action for the conservation of this species. This study provides a powerful example of why management decisions should be based on evidence, rather than ecological intuition. Even though the malleefowl is one of the best-monitored species of conservation concern in Australia, we are still uncertain how to cost-effectively manage this species. We emphasize the urgent need to assess what data we have and determine which species and what actions are most in need of evaluation.