Bio-dynamic control involves burning pest tissue or organs and spreading the ash on areas to be protected. In New Zealand, bio-dynamic methods have been suggested for repelling possums where they damage forests or spread disease. We assessed the repellent effects of five bio-dynamic tinctures. First we tested these materials on possums in pens and noted their effects on foraging behaviour, food consumption, and body weight. Then we monitored bait consumption from treated and untreated feeder stations in the field.
Historical and recent records indicate that kiwi are less numerous and widespread in Hawke's Bay than they used to be. The birds are still scattered throughout the ranges to the west and north of the region, usually at densities of about one bird per 100 ha. Kiwi have now almost completely disappeared from their former lowland habitats. The decline of kiwi in Hawke's Bay may have started before European settlement, but has been particularly rapid in the last 70 years. RePeat surveys of three populations between 1984 and 1990-91 indicate that the decline is continuing.
Collections of gannet regurgitations at most of New Zealand's gannetries allowed the identification of major components in the gannet diet and an estimate of the total annual consumption of the most important prey species. Major species were pilchard (Sardinops neopilchardus), anchovy (Engraulis australis), saury (Scomberesox saurus), and jack mackerel (Trachurus novaezelandiae).
Low acceptance of protein baits by common (Vespula vulgaris) and German (V. germanica) wasps (Hymenoptera: Vespidae) occurred after rain in honeydew beech forest. This corresponded with a sharp decrease in the proportion of natural protein in the diet of V. vulgaris and V. germanica, and a reduction in the concentration of carbohydrate-rich honeydew in the crops of foraging wasps carrying liquid.
A plant sociological survey of tall-tussock grasslands in the Mackenzie country was repeated after an interval of 26-28 years. Changes in physiognomy of the grasslands which have been inferred from earlier studies have been found to be continuing on many sites. A noteworthy feature of most sites has been a reduction in number of indigenous species found. An increase in abundance of Hieracium pilosella or H. praealtum has occurred at most sites.
The vegetation of 10 quadrats from each of 26 sites, in and around the Tongariro National Park, which contained the introduced dwarf shrub, Calluna vulgaris (L.) Hull, was analysed using Reciprocal Averaging and Indicator Species Analysis.
Replacement patterns under buddleia (Buddleja davidii) groves aged between 2 and 17 years were studied in streambeds in the western Ikawhenua Range and in the upper Waioeka catchment, Te Urewera National Park. Height and basal diameter growth followed an exponential pattern, with rapid early growth (0.5 m/year and 1 cm/year respectively), levelling off after 15 years or more. Intense self-thinning occurred in younger stands. Typical forest floor vegetation was developing within 15 years of colonisation by buddleia.
In the past 1000 years New Zealand has experienced a major 'extinction event', losing 40-50% of the avifauna, at least 50% of the frog fauna, and unknown proportions of the lizard and invertebrate faunas. During this period, bird species became extinct at different times and rates depending on the particular aspects of their ecology and life history which made them vulnerable to habitat loss, hunting, predation, and competition for food resources. Three groups of species with different levels of vulnerability are recognised within this event:
The history of the New Zealand biota over the last 7000 years may be divided into three phases. BC 5000 to AD 1000 was a period of comparative ecological stasis. That equilibrium was disrupted between AD 1000 and AD 1800 by the destruction of most of the New Zealand plant-herbivore systems, the co-evolutionary relationship between the plants and the vertebrate herbivores being decoupled by about AD 1400. After AD 1800 new plant-herbivore systems were progressively developed and new ecological relationships forged.
The heathland vegetation of northern New Zealand is usually regarded as a "derived" vegetation type resulting from forest destruction during the Maori and European periods of settlement. Plant species cover-abundance data from sample quadrats in the Far North are analysed using Detrended Correspondence Analysis (DCA) and Two-way Indicator Species Analysis (TWINSPAN) and are then correlated with soil nutrient data. Variations in species composition of heaths appear to be related primarily to soil type. Age since last fire is also important but was not examined in detail in this study.