New Zealand has a unique opportunity to reshape the future of 1.2 million hectares, or 5% of the country. Since 1990, land clearance and development in the South Island high country have removed large areas of native vegetation, destroying already tenuous endemic species populations, and rare and threatened ecosystems. Important ecosystems and ecological values have been subtly or dramatically degraded through tenure review, discretionary consents, and invasions of plant and animal pests.
Dispersal is a fundamentally important aspect of animal behaviour, but empirical data describing it are lacking for many species. Here, we report on a field study aimed at measuring post-weaning movement distances of juvenile ship rats (Rattus rattus) and their mother away from a known natal nest site in an area with low conspecific population density. The movement behaviour of invasive species at low density is of particular interest, as it can inform design of surveillance arrays to detect incursion into predator-free areas.
Globally, biodiversity is declining due to increasing populations and land use pressures associated with development-induced land conversion, resource use, and food production. In New Zealand, a considerable proportion of remaining indigenous biodiversity occurs on farmland in private ownership outside of the public conservation land.
Reports of wetland loss in New Zealand are typically related to the historical, pre-European coverage of wetland ecosystems. It is widely accepted that large areas of wetlands were converted to other land uses prior to the 1990s before comprehensive national and regional environmental legislation was established. We sought to investigate recent (post 1990) changes in wetland extent to determine if current rates of wetland loss remain a concern for natural resources management.
Biodiversity assets often require conservation management, which, in turn, necessitates decisions about which ecosystem, community or species should be prioritised to receive resources. Population viability analysis (PVA) uses a suite of quantitative methods to estimate the likelihood of population decline and extinction for a given species, and can be used to assess a population's status, providing useful information to decision-makers. In New Zealand, a range of taxa have been analysed using the PVA approach, but the scope of its implementation has not previously been reviewed.
Taxonomy plays a central role in conservation programs of threatened New Zealand taxa. The role of taxonomy is especially relevant for highly vulnerable taxa, where the identification of distinct lineages is essential to define units of conservation and to appropriately allocate conservation resources. Taxonomy traditionally relied on phenotype, but in the past 30 years, the use of genetic data has become prominent in the field. While both phenotypic and genetic approaches to taxonomy have their own merit, they do not always agree.
Lethal control of wildlife is commonly used by conservation practitioners for population control. In some areas of New Zealand, changes in land-use and management have led to large increases in pukeko (Porphyrio melanotus melanotus) range and numbers. This native rail is sometimes considered a pest species, as they are known to uproot vegetation including tree seedlings, grass and crops. Here, we provide the first data on mortality during a lethal control operation that aimed to reduce pukeko population size at Tawharanui Regional Park in the North Island of New Zealand.
While invasive rats are demonstrably inimical to indigenous vertebrate species, there has not been unequivocal evidence of benefit to invertebrate communities from management of these invasive mammals in New Zealand forest systems. The present study examined the response of land snail communities to intensive management of ship and Norway rats by sampling paired rainforest blocks, one block of which had been subject to intensive management of rats, while the other block had been without management of invasive rats and thus subject to ambient rodent infestations.
Ecological research into rodents in New Zealand commenced in the late 1940s with the creation of the Animal Ecology Section, Department of Scientific and Industrial Research (DSIR). Field surveys of rodents were backed by study skins and skeletal material. Supplemented by specimens from the Wildlife Service and the public, these accrued over the next 45 years laying the foundation for our present knowledge of rodent distribution. In 1951, J. S. Watson joined the DSIR from the Bureau of Animal Population, Oxford, and brought much needed experience in rodent biology and control.
New Zealand has just passed half a century of rodent eradications on islands. Confirmation of the first rat eradication in New Zealand on Maria Island/Ruapuke coincided with the devastating rat invasion on Big South Cape Island/Taukihepa. We review the early history of rodent management in New Zealand leading up to and including the Big South Cape Island/Taukihepa ship rat invasion, and document the development and implementation of rodent eradication technologies on New Zealand islands up to the present day.