New Zealand

Spider density and diversity in relation to disturbance in agroecosystems in New Zealand, with a comparison to England

Spider assemblages were sampled by quantitative sampling in pasture and arable habitats under different management regimes in the lower North Island of New Zealand. Density and species diversity increased with decreasing frequency and/or intensity of disturbance from two species and 1.8 individuals per m in wheat to 16 species and 130 indiv. per m in an abandoned, ungrazed pasture. The spider fauna was dominated by introduced species of money spiders (Linyphiidae). The most abundant species, Lepthyphantes tenuis, is also the most abundant one in British cultivated habitats.

Population biology of small mammals in Pureora Forest Park .2. The feral house mouse (Mus musculus)

Over five years from November 1982 to November 1987, we examined 395 mice collected from unlogged and logged native forest and from exotic forest at Pureora Forest Park, in the central North Island of New Zealand. Sex ratio, litter size, and breeding effort (pregnancy rate in females, proportion of males with visible tubules) were similar in all samples.

Distribution and abundance of small mammals in relation to habitat in Pureora Forest Park

Populations of ship rats (Rattus rattus), Norway rats (R. norvegicus), feral house mice (Mus musculus), stoats (Mustela erminea), weasels (M. nivalis), and ferrets (M. furo) were sampled with killtraps every three months from November 1982 to November 1987 in logged and unlogged native forest and in exotic plantations of various ages at Pureora Forest Park, central North Island. Mice (n=522 collected) were fewest in unlogged native forest, more abundant in road edge cutover forest, and most abundant in a young (5-10 year old) plantation.

The ecology of Bonamia and decline of bivalve molluscs

Bonamia is a protozoan parasite of the haemocytes of oysters (Tiostrea chilensis), in which it has an annual developmental cycle between November and August each year. The parasite transmits directly, oyster to oyster, and therefore disease spread is related to host stock density. The Foveaux Strait oyster population experiences large mortalities every 20-30 years, and these may be attributable to Bonamia. The parasite appears to become less pathogenic at the end of, and probably between, mass mortalities, and some oysters appear more tolerant of infection than others.

Sudden decline of cabbage tree (Cordyline australis): Search for the cause

Many cabbage trees (Cordyline australis) are dying throughout much of the North Island and the northern South Island of New Zealand. The symptomatology of those dying in urban environments is described, and is concluded to be consistent with the hypothesis that death is caused by a biotic agent entering through a leafy tuft of the branch system. This disease, which has been named Sudden Decline, usually leads to almost total defoliation of affected trees within 2-12 months. Disease incidence has increased linearly at about 11% per annum since 1987/88. Cultivated trees of C.

Predicting the impacts of biological and physical disturbances: Does theoretical ecology hold any answers?

Biological and physical disturbance has had a severe impact on New Zealand's endemic flora and fauna. Along with the lessons of the past, predicting the sensitivity of communities to disturbance in the future may help direct more attention to those communities with a greater need for preservation (i.e., a lower ability to recover from any such disturbances). In theory it is possible to measure the resilience (or local stability) of a community by constructing a matrix to describe that community and then examining its eigenvalues.

The vegetation of Flat Top Hill: An area of semi-arid grassland/shrubland in Central Otago, New Zealand

An account is given of the vegetation of Flat Top Hill, in the driest part of semi-arid lowland Central Otago, New Zealand. Although highly modified, the area was acquired for conservation in 1992, following almost 150 years of pastoral use. The vegetation was sampled in a composite scheme using permanent monitoring sites placed to include the majority of habitats and communities present. A number of environmental factors were measured in each sample. Native species comprise 53% of the vascular flora of the area (211 species).

Foods and Foraging of Forest Birds in Temperate Rainforest, South Westland, New Zealand

Habitat use of a forest bird community was studied in temperate rainforests in South Westland, New Zealand between 1983 and 1985. This paper examines foraging methods, feeding stations and seasonal variations in the availability and use of food types and provides a brief review of the subject. The forest bird community was comprised of a large number of apparently generalist feeders and few dietary specialists. However, the degree of foraging specialisation should not be viewed only in relation to the food types consumed.

Dune Slack Vegetation in Southern New Zealand

A range of slack vegetation in southern New Zealand was described by detailed sampling of four dune slacks, contrasting in topographic situation and in vegetation. Comparison is made with a slack previously sampled on Stewart Island. The five slacks differed markedly in the plant communities present. One slack, where there was considerable peat accumulation, was dominated by the megaherb Phormium tenax and the restiad Leptocarpus similis.