Seventeen exclosures were built by the New Zealand Forest Service within Urewera forests over the period 1961-68 to exclude ungulates. Forest structure and species composition inside and outside these exclosures were compared in 1980-81. Some relatively shade tolerant species such as the fern Asplenium bulbiferum, the liane Ripogonum scandens, the sub-canopy shrubs Geniostoma ligus,Trifolium and Coprosma australis and the canopy species Beilschmiedia tawa were less abundant in certain tiers outside the exclosures than inside.
The takahe (Notornis mantelli), an endangered rail once widely distributed through New Zealand, had become restricted to Fiordland, and possibly Nelson and the Ruahine Ranges, by European times. Two contentious viewpoints have been advanced to explain the decline: climate and vegetational changes in the late Pleistocene and Holocene; and ecological changes induced by early Polynesians. These theories are examined in relation to the habitat requirements of takahe in its present restricted range, the historical and sub-fossil record, and the possible age of the sub-fossils.
This paper considers how habitat geometry affects New Zealand bird distributions on land-bridge islands, oceanic islands, and forest patches. The data base consists of distributions of 60 native land and freshwater bird species on 31 islands. A theoretical section examines how species incidences should vary with factors such as population density, island area, and dispersal ability, in two cases: immigration possible or impossible. New Zealand bird species are divided into water-crossers and non-crossers on the basis of six types of evidence.
It will be necessary to establish reserves for the conservation of New Zealand's forest avifauna largely in the absence of detailed autecological studies. Hence the empirical findings of island biogeography may provide the best available guide to the reserve size necessary for the preservation of both species communities and individual species.
The lesser short-tailed bat (Mystacina t. tuberculata) has been found in 18 locations in indigenous forest in North Island since 1961, mainly in Northland kauri forest (including Little Barrier Island), on the volcanic plateau (including Tongariro National Park), Urewera National Park and in Tararua Range. In South Island this bat has only been reported once since 1961, in North West Nelson Forest Park, and must be regarded as endangered. It is present also on Codfish Island, but is thought to have become extinct on Big South Cape and Solomon Islands about 1967.
A knowledge of the sensitivity of the brushtail possum (Trichosurus vulpecula) to 1080 poison is important as a basis for planning effective control campaigns. This study assesses the effects that experimental procedure may have on determining the LD50 of 1080 for brushtail possums and reports on the variation in sensitivity within and between different populations of the species in Australia, where it is indigenous. LD50s obtained ranged from 0.39–0.92 mg kg-1, with 95 % confidence limits of from 0.29–1.20 mg kg-1.
Provenance variation was studied in the growth and morphology of seedlings of silver beech (Nothofagus menziesii), red beech (N. fusca), hard beech (N. truncata), black beech (N. solandri: var. solandri:), and mountain beech (N. solandri: var. cliffortioides). Seedlings were grown for 2_ years in replicated provenance experiments at Rangiora and Rotorua.
House mice (Mus musculus) were introduced to New Zealand accidentally in 1824 following the stranding of an Australian ship. Phylogeographic analyses have revealed many subsequent introductions from diverse sources. Mice have significant negative impacts on native ecosystems in New Zealand and elsewhere. This makes their eradication a desirable conservation outcome, yet a large proportion of mouse eradication attempts worldwide have failed for unknown reasons.
Translocation to island reserves is a common strategy in New Zealand and elsewhere for safeguarding species against introduced predators. When successful, however, the closed nature and relatively small size of many island sanctuaries can result in populations quickly reaching their carrying capacity, which in itself can present further challenges such as reduced productivity and population growth rates associated with density-dependent effects as well as increased rates of inbreeding.
Predators at black-fronted tern (Chlidonias albostriatus) nests on the Wairau braided riverbed in Marlborough, New Zealand, were identified using (1) mtDNA analysis of 438 swabs from shell remains, nest contents, and carcass remains, and (2) digital video surveillance of 85 nests. DNA analysis suggested harriers (Circus approximans) were the main predator of tern eggs (171 of 192 shell samples containing predator DNA).