John Marris AO poster.FH11 Fri Aug 06 13:00:23 2004 Page 1
John W.M. Marris Antipodes antipasto: Bio-Protection and Ecology Division, PO Box 84, Lincoln University, Canterbury, mice make a meal of Subantarctic insects NEW ZEALAND Email:[email protected]
Introduction
Invertebrate surveys on Antipodes Island and adjacent Bollons Island provided a unique opportunity to examine the impact of mouse predation on the invertebrate fauna. The diversity and abundance of larger beetle species (length > 4 mm) on mouse-infested Antipodes Island were Wandering albatross and John Marris compared with those of mouse-free Bollons Island.
Antipodes Islands Lord Howe I North I New Zealand
The Antipodes Islands lie 730 km 400S South I Chatham Is southeast of the South Island of New 0 2km Bounty Is Stewart I
Zealand and are part of New Zealands 500 Antipodes Is Antipodes Island Auckland Is
Campbell I Macquarie I Subantarctic World Heritage Site. The Bollons I 1600 1700E 1800 islands support about 150 insect species, Antipodes Island parakeet Antipodes Island many of which are endemic, and are 49°40S Anchorage Bay Reef Point Hut Stella Bay Windward Is important breeding grounds for several Bollons Island
MtMt Galloway Galloway
Leeward I land and seabird species including large Central Plateau Mt Waterhouse Stack Bay
Ringd penguin and albatross colonies. ove S tm Relia Table 1 Comparison of numbers of larger (>4 mm) beetle species collected n ce Ringdove Bay R id g e House mice (Mus musculus) were first Albatross Pt from Antipodes Island (over 26 days) and Bollons Island (over 7 hours). recorded from Antipodes Island in 1909 Species (max. length in mm) Antipodes Island Bollons Island 178°45E 50 (Map courtesy of the Department of Conservation) and are the only resident introduced Carabidae mammal. They occur from the coast to the highest peak at high densities Kenodactylus audouini (4.8) 18 1 Loxomerus n. sp. (11.8) 0 19 (up to 117 catches/100 trap nights). No other island of the Antipodes Oopterus clivinoides (5.6) 7 33 group has mice. Hydrophilidae Tormissus guanicola (5.5) 0 8 Staphylinidae Methods Quediocafius insolitus (10.9) 3 15 Tenebrionidae Invertebrates were collected over 26 days on Antipodes Island and Pseudhelops antipodensis (7.2) 3 0 during a 7-hour visit to Bollons Island. Antipodes Island collecting Pseudhelops clandestinus (8.2) 5 50 included pitfall, pan, Malaise and light trapping, sweeping, beating, Curculionidae Rockhopper penguin Gromilus insularis antipodarum (5.4) 19 3 insecticide fogging, litter extraction and hand collecting. Habitats sampled included the littoral zone, around penguin colonies, tussock grassland, herb fields and rocky outcrops. Collecting on Bollons Island was by hand and litter sampling among tussock grassland, herb fields Summary and around penguin colonies. Antipodes and Bollons Islands share similar geological, climatic and vegetational characteristics.
Light-mantled sooty albatross Results and Discussion The main biological difference between the islands is the presence Beetle species composition of mice on Antipodes Island. Two species, Loxomerus n. sp. and Tormissus Differences in beetle diversity and abundance between the islands guanicola, were found on Bollons Island but are probably mainly due to mouse predation, resulting in the not on Antipodes Island, despite the greater extinction or severe depression of beetle populations on collecting effort there. Antipodes Island. No live Loxomerus n. sp. have ever been found Mouse predation may restrict some species distributions, with relict New Zealand fur seals on Antipodes Island, although beetle remains populations limited to high altitude areas of low mouse density. collected in 1969 indicate its past existence. Looking forward Loxomerus n. sp. Beetle abundance Future studies s