The next frontier: assessing the feasibility of eradicating mammalian pests from Auckland Island. (Special Issue: Restoration of New Zealand subantarctic islands.)

ABSTRACT

Auckland Island, the fifth largest island in New Zealand, is the only island in New Zealand's subantarctic region where introduced mammalian pests remain (pigs, Sus scrofa;mice, Mus musculus;cats, Felis catus). The island has unique biodiversity and is a key site for progressing New Zealand's goal to be free of several introduced predators by 2050. Recent island eradication successes have rekindled interest in eradicating pests from Auckland Island, and for the first time considering all three pests in one project. Over a 3-year period, we tested the feasibility of eradicating pigs, mice and cats by looking at what it would take to succeed, rather than what we could practically deliver with the tools we currently have. We proposed adaptations to current methods and used an evidence-based approach by undertaking large-scale field trials to test uncertainties and emerging technologies in-situ. We gathered data and evaluated proposed methods against five established principles of eradication while considering the logistics and infrastructure requirements of the project. Eradicating pigs, mice and cats from Auckland Island is worthwhile and feasible but dependent on further development of emerging technologies and capabilities for efficient delivery with an acceptable level of risk. Three eradication operations are required with specific sequencing and timing, supported by initial establishment of infrastructure. The project needs a large investment spread over 8 to 10 years to yield permanent and internationally important benefits with low ongoing cost to sustain. The feasibility study exposed the project's scale and was used to inform decision makers, who postponed the work in 2020 in response to the economic impacts of COVID-19. The study focusses future preparations on identified planning issues and dependencies to progress project readiness in anticipation of it being launched when economic conditions allow.