Review of the reporting of ecological effects of rodent eradications on Australian and New Zealand islands

Abstract

Island species are susceptible to invasive mammals because of their small populations, specialised habitats and reduced likelihood of recolonisation. For more than 50 years, invasive mammals have been eradicated from islands around the world. Despite the success of eradications, there are few publications in the primary literature detailing the ecological benefits and consequences of these eradications. Here we conduct a review of the published literature focussing on rodent eradications conducted on Australian and New Zealand islands and we evaluate the extent of reporting of non-target mortality and ecological monitoring following an eradication. A search of the Database of Island Invasive Species Eradications website identified that successful, whole-island rodent eradications were conducted on 66 Australian and 124 New Zealand islands in the period from 1964 to 2016. We found that non-target mortality was rarely ever reported (3% and 12% for eradications on Australian islands and New Zealand islands, respectively). Results of any quantitative ecological monitoring following eradications were published for only 10% of all successful rodent eradications on Australian islands and 19% of all eradications on New Zealand islands. There also has been no change in reporting of potential benefits and consequences of rodent eradications in Australia and New Zealand over the last few decades despite an increased awareness of the problem of under-reporting. We discuss the detailed benefits and consequences of these eradications in Australia and New Zealand and highlight the need to incorporate ecological monitoring into new projects to document benefits and consequences of eradications to inform future eradications.