Auckland Island

Primary poisoning is an important method to ensure the successful eradication of cats (Felis catus) from large islands. Poison bait options for feral cat eradications and landscape-scale control in New Zealand are limited at present. As part of the development of a toxic bait for cats that can be aerially distributed, a nontoxic palatability trial was undertaken on Auckland Island to compare three types of prototype meat-based bait and one currently registered fishmeal polymer pellet for their palatability to feral cats and non-target species.

Restoration initiatives of ecosystems transformed by human actions require optimisation of eradication measures of introduced species, particularly in fragile insular ecosystems. We studied aspects of the spatial ecology of introduced feral cats (Felis catus) on subantarctic Auckland Island of New Zealand to assist eradication efforts of pests from this remote, biologically rich island. Firstly, we estimated home range sizes and identified core areas of activity based on movement-rooted dynamic Brownian bridge models.

A feasibility study for removing feral pigs (Sus scrofa) from Auckland Island trialled feeders monitored by trail cameras to determine their effectiveness for detecting and attracting feral pigs. Ten automatic feeders were installed during January–February 2019 (summer) and again in August–September 2019 (winter) on Auckland Island. They delivered kibbled maize daily for a period ranging from 25 to 37 days. Sites selected for feeder installation needed to be of appropriate relief and area to allow feeder and trap installation, as would occur during an eradication operation.

Feral goats (Capra aegagrus hircus) were eradicated from Auckland Island, a National Nature Reserve and World Heritage site, between 1989 and 1991. Goats had established on the main Auckland Island following several releases in the 19th century. The population, amongst the most southerly ever recorded, was restricted to the northernmost areas of the island, with environmental conditions appearing unfavourable for southward spread, and the population stable at c. 100 individuals during scientific studies in the 1970s and 1980s.

New Zealand manages five island groups in the Southern Ocean New Zealand subantarctic region: The Snares (Tini Heke), Bounty Islands, Antipodes Islands, Auckland Islands (Motu Maha or Maungahuka) and Campbell Island / Motu Ihupuku. Charted by Europeans in the late 18th and early 19th centuries, their preservation commenced in the early 20th century and restoration in the late 20th century.

Mineral element concentrations are presented in leaf and bark material from six woody species growing at a single site on the subantarctic Auckland Islands. Foliar total mineral element concentrations range from 5.81% (Olearia lyallii) to 2.71 % (Dracophyllum longifolium), the lowest concentrations occurring in slow growing species tolerant of nutrient-poor soils.

Marked sites established around Port Ross in 1973 were re-examined in 1983 to measure changes in the vegetation and assess the impact of goats and pigs. Goats had not increased in numbers, nor extended beyond their earlier range, but they were seen higher on the Hooker Hills. Pigs were scarce, but their sign was seen throughout. Photopoints and numerical methods both showed that Chionochloa antarctica tussock was eliminated or greatly reduced where goats and pigs occurred together, and where only pigs were present it was reduced slightly.