Ecological restoration of the invertebrate fauna on Quail Island (Ōtamahua)

Abstract

The Quail Island Ecological Restoration Trust in partnership with Department of Conservation and Te Hapu o Ngāti Wheke of Rāpaki was established in 1998. The main aim of the Trust was to facilitate the restoration of indigenous vegetation and fauna on Ōtamahua/Quail Island and provide refuge for locally extinct or rare and endangered species of the Banks Peninsula region. The terrestrial invertebrate fauna has been surveyed as part of an ecological restoration programme for the island. The survey results identified eleven Banks Peninsula endemic species and several rare species on Quail Island. Eradication of introduced mammalian predators including rats and hedgehogs has been successful. Ninety percent of mustelids (stoats, weasels & ferrets) are trapped en route to Quail Island. Mice are the only remaining mammalian pest on Quail Island. The relationship between these introduced pests and abundance of larger invertebrate species is discussed. The suitability of wooden discs as habitat for ground beetles and leaf-vein slugs was investigated. Wooden discs cut from logs were used as substitutes for naturally occurring logs, which are absent in areas of native vegetation on Quail Island. Treemounted shelters were also constructed and used to monitor weta (Orthoptera) and spider species. These two restoration and non-destructive sampling techniques have led to the translocation of three invertebrate species from populations on from Banks Peninsula: ground beetle Megadromus guerinii (Carabidae), Banks Peninsula tree weta Hemideina ricta (Anostostomatidae) and leaf-vein slug Pseudaneitea maculata (Anthoracophoridae) to Quail Island. The success of these restoration techniques is discussed.