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.
Kaka (Nestor meridionalis meridionalis) studied in Big Bush State Forest spent 35% of their feeding time digging out Ochrocydus huttoni larvae from live mountain beech trunks (Nothofagus solandri: var. cliffortioides).
Larvae of O. huttoni had a high energy value compared to that of other insects. The assimilation efficiency for energy of two captive kaka was 91 j: 3% when fed a diet of O. huttoni.
We quantify the notion of predictable species loss from progressively smaller islands, and apply the quantification to the indigenous forest-dwelling birds of a series of New Zealand islands and to the passerines of the Cyclades Archipelago in the Aegean Sea. The analysis focuses on the reasons why the species-area relationship deviates from a perfect rank-correlation. For both avifaunas, most species are found remarkably predictably: they approximate a pattern in which each species occupies all those and only those islands larger than some species-specific minimum area.
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.
Endemic biota of native grasslands commonly co-exist with introduced grazing mammals, and often this is seen as a conservation threat. The endangered pygmy bluetongue lizard (Tiliqua adelaidensis) is restricted to remnants of native grassland in the mid-north of South Australia, with a long history of sheep grazing. Pygmy bluetongue lizards use ambush predation from their burrow entrances, and prey capture may be more efficient in a habitat with low vegetation density. We experimentally investigated changes in predatory behaviour in this lizard, with different grass density.
The negative effects of introduced nest predators on the breeding success of endemic New Zealand parrots are well documented, as is their role in the general decline of these species. In contrast, little is known about the intrinsic intra-brood dynamics responsible for modulating fledging success in parrots breeding at sites free of introduced nest predators. We studied red-crowned parakeets over two breeding seasons on Tiritiri Matangi, an offshore island free of introduced mammalian predators.
In 1995 and 1996, release of 51 hihi (stitchbird, Notiomystis cincta) onto Tiritiri Matangi Island (wild caught on Hauturu, Little Barrier Island) marked the start of a research and ecological restoration success story. Although establishment of populations of hihi elsewhere in New Zealand has proven to be difficult, the population on Tiritiri Matangi Island has grown to c. 150 individuals and has become one of New Zealand’s few detailed case-study species.
Ongoing investigations into bird mortality caused by aerial 1080 poison operations to suppress pest populations will be required because the operational specifications continually change and improve. We summarise recent studies of bird deaths following 1080 operations and present six principles for use in prioritising future research into poison risk for bird populations. A decision tree (and supporting flow diagram) shows how the need for new surveys can be evaluated using these principles.
The use of non-destructive and non-invasive monitoring methods is often necessary for species of high conservation status. Developing monitoring methods to maximise numbers of individuals found is important, given that rare species can be difficult to locate. Artificial refuges called ‘weta motels’ have been used for monitoring tree weta (Orthoptera: Anostostomatidae) since 1992, but poor occupancy for Hemideina ricta and H. femorata necessitated an improved design and assessment of placement to encourage tree weta use.