Animals or the environment? Public preference for trade-offs in invasive animal management

Lethal control methods for invasive animals are controversial. While ideally they would be humane, environmentally safe, and cost-effective, different tools involve financial and ethical trade-offs. Through a nation-wide choice modelling survey we investigated how the New Zealand public reconciles trade-offs in lethal control methods for invasive mammalian predators, for both suppression (ongoing efforts to reduce populations) and eradication (one-off killing or removal of a population). Results suggest that New Zealanders are more concerned about environmental than animal welfare harms or cost, with moderate by-kill and environmental contamination out-ranking animal welfare concerns of moderate pain and suffering. However, for suppression programmes severe pain and suffering were of higher concern than moderate environmental harms, suggesting that animal welfare becomes a major concern when harms are perceived as significant and ongoing. For eradication programmes, the baseline level of concern about lethal control and concern about severe pain and suffering were lower than for suppression. While there were also corresponding drops in concern about environmental harms, these were smaller and with weaker evidence in the case of moderate environmental contamination and moderate by-kill. These results suggest that the promise of eradication being time limited alleviates some concerns about lethal control of invasive animals, but potentially does not alleviate concerns about broader environmental impacts. We observed different preferences based on participants’ gender, residence, engagement in hunting, and support for the aerial use of toxins. Our study demonstrates the utility of choice modelling for informing conservation decision-making and developing novel lethal animal management tools.