New Zealand

The Sensitivity of the Brushtail Possum (Trichosurus vulpecula) to 1080 Poison

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.

Does genetic variation among invasive house mice in New Zealand affect eradication success?

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.

Are introduced takahe populations on offshore islands at carrying capacity? Implications for genetic management

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.

Identification of predators at black-fronted tern Chlidonias albostriatus nests, using mtDNA analysis and digital video recorders

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).

Stoat density, diet and survival compared between alpine grassland and beech forest habitats

In New Zealand, alpine grasslands occur above the treeline of beech forest. Historically stoat control paradigms in New Zealand’s montane natural areas have assumed alpine grassland is a marginal habitat that limits dispersal between beech forest stoat populations. We compared the summer-to-autumn (January–April) density, weight, diet and winter survival of stoats between these two habitatsduring years of low beech seedfall.

New Zealand’s historically rare terrestrial ecosystems set in a physical and physiognomic framework

Terrestrial ecosystems that were rare before human colonisation of New Zealand often have highly specialised and diverse flora and fauna characterised by endemic and nationally rare species. Although many of these ecosystems are under threat from anthropogenic modification and their biodiversity values are declining, they still are not adequately identified by current land classifications. We compiled a list of 72 rare ecosystems from the literature and by canvassing New Zealand ecologists and land managers. Rare ecosystems are defined as those having a total extent less than 0.5% (i.e.

Site conditions affect seedling distribution below and outside the crown of kauri trees (Agathis australis)

It has been suggested that plants can change soil characteristics via their litter to favour their own species. The New Zealand kauri tree (Agathis australis) presents an interesting case for studying such a positive feedback between plant and soil because it has a huge impact upon the soil. We hypothesised that, under mature kauri trees, compared with sites outside the projection of the crown, seedlings of angiosperm trees are relatively rare, while kauri seedlings are relatively common, due to the poor soil conditions and the higher light intensity.

Kauri trees (Agathis australis) affect nutrient, water and light availability for their seedlings

Plants can change the soil that they grow on, for example by producing litter. If litter characteristics are such that their effect on the soil increases a plant's fitness, a positive feedback can develop between the plant and the soil. Several studies indicate that New Zealand kauri trees (Agathis australis) lower the availability of nutrients in the soil beneath their crown. Low nutrient availability would be positive for the survival of kauri seedlings as they are known to use nutrients more efficiently than angiosperm species.