As we arrived at the Antipodes Islands on the HMNZS Wellington on the morning of the 20th February, three Subantarctic pipit landed on the deck of the vessel. This was exciting to see, and the team looked forward to getting ashore and starting the result monitoring for the mouse eradication and the outcome monitoring to determine any changes in avian and invertebrate diversity and numbers.
Previous studies comparing invertebrates on Antipodes Island and the pest-free islands of Bollons and Archway, 1.5 km to north, found significant impacts from mice on Antipodes (Russell, 2012; Marris, 2000). These impacts include two large beetle species, Loxomerus n. sp and Tormissus guanicola, being wiped out from Antipodes Island but they are still present on Bollons Island. A mysterious weta has also been seen on Bollons previously but has never been caught or described and has never been seen on Antipodes main island. Without mice and with time these species should recover and disperse and hopefully the mysterious weta will one day return. Anecdotally the monitoring team have noticed the large number of caterpillars on the vegetation and flies which land on you whenever you stop for lunch and provide a tasty snack for pipits.
The outcome monitoring is an important way of assessing changes in diversity and density of native and endemic fauna on the island prior to and after the eradication attempt of mice on the Antipodes Islands. Who knows maybe a new invertebrate species might be discovered!
Marris, J.W.M. 2000: The beetle (Coleoptera) fauna of the Antipodes Islands, with comments on the impacts of mice; and an annotated checklist of the insect and arachnid fauna. Journal of the Royal Society of New Zealand 30 (2): 169-195
Russell, J.C. 2012: Spatio-termporal patterns of introduced mice and invertebrates on Antipodes Island. Polar Biology 35: 1187-1195