Managing feral pigs to mitigate kauri dieback disease in the face of ecological and epidemiological uncertainty

Abstract

ABSTRACT Kauri (Agathis australis), a tree species endemic to northern New Zealand, is threatened by kauri dieback disease, caused by the plant pathogen Phytophthora agathidicida. Some human and animal activities capable of disturbing and transferring infected soil may facilitate the spread of this pathogen. Feral pigs (Sus scrofa) are thought to be especially important due to their foraging behaviour. Consequently, management of feral pigs has been proposed as a key mitigation strategy for reducing the impacts of kauri dieback disease. We reviewed the evidence for feral pigs facilitating the spread of P. agathidicida. Although feral pigs can spread other plant pathogens, there is scant direct evidence that they act as vectors or transport hosts of P. agathidicida. Whether this is due to the lack of in-depth investigations, limitations in current detection methods, or simply that feral pigs are not playing a substantial role in the spread of kauri dieback disease is currently unknown. If management agencies proceed with a management strategy for feral pigs such as sustained control or eradication, under the assumption that this will mitigate unwanted impacts on kauri, an adaptive management approach should be taken to increase our understanding of the importance of feral pigs in this system.