north island

Introduced ungulates are an important management issue on New Zealand’s public conservation land (PCL). Ungulates are harvested by recreational and commercial hunters, with some government-funded culling. A robust monitoring system is needed to reliably report trends in occupancy and abundance, and to evaluate management effectiveness. We first describe the design and implementation of a monitoring programme enabling ungulate occupancy and relative abundances to be estimated on New Zealand’s PCL.

We measured horse density, social structure, habitat use, home ranges and altitudinal micro-climates in the south-western Kaimanawa ranges east of Waiouru, New Zealand. Horse density in the Auahitotara ecological sector averaged 3.6 horses.per km² and ranged from 0.9 to 5.2 horses.per km² within different zones.

Poisonous baits used for pest control in New Zealand commonly contain green dye and cinnamon oil to make them less attractive to birds. Research aimed at reducing the impact of poison based pest control on birds has shown that some birds are initially deterred from feeding on blue or, to a lesser extent, green coloured food and are attracted to yellow or red food. We determined whether colours that deter or attract birds affected the acceptance of non-toxic and toxic cereal baits by captive brushtail possums (Trichosurus vulpecula).

Primary successions involving teatree (Kunzea ericoides var. ericoides with some Leptospermum scoparium) were studied on shallow landslide scars on soft sedimentary (mudstone) hill country under extensive pastoral use in the East Cape (Tairawhiti) region, using a 5-72 yr chronosequence established from sequential aerial photography and the age of the oldest teatrees on scars. Dynamics of primary even-aged teatree stands are similar to those in secondary successions on reverting pasture described previously from the region.

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.

Dactylanthus taylorii, a root parasite in the family Balanophoraceae, is New Zealand's only fully parasitic flowering plant. It grows attached to the roots of a wide range of hardwood trees and shrubs, often in fire-induced secondary forest on the margin of podocarp-hardwood forest. It is inconstantly dioecious with a skewed sex ratio of approximately 5:1 male to female inflorescences. The inflorescences, especially the males, contain a large quantity of nectar, up to 1.6 mi, and can produce 0.5 mi per day for 10 days.

Exclosure plots established in three separate areas of kanuka (Kunzea ericoides var. ericoides) forest on south Kaipara spit in 1983 to assess the impact of introduced fallow deer (Dama dama) were remeasured in 1993. Kanuka shared canopy dominance with mapou (Myrsine australis), houpara (Pseudopanax lessonii) and mahoe (Melicytus ramiflorus ssp. ramiflorus) in relatively old forest in Lookout Bush, Woodhill, and dominated exclusively in two younger stands at South Head; Coprosma rhamnoides dominated understories throughout.

Benthic invertebrates and samples of blue duck faeces were collected in September 1988 from sites along Manganuiateao River, central North Island, and in November 1988 from seven rivers and streams on the East Cape. The occurrence of invertebrate taxa in the faeces varied within and between rivers, and within pairs of birds and family groups on the East Cape. In both regions, most blue duck had been consuming large proportions of cased caddisfly larvae.

Feral horses (Equus caballus L.) occupy 64 000 ha of montane- subalpine tussock grassland in the south-western Kaimanawa Mountains, an area zoned for military training. Since 1979, the population has increased at 16.7% per annum, reaching 1102 in 1990. The most extensive habitat, red tussock (Chionochloa rubra) grassland, was variably affected by horses; tussocks in restricted mesic sites were heavily grazed and mostly eliminated, but those in extensive xeric grasslands showed little impact.