conservation

A case for multi-species management of sympatric herbivore pest impacts in the central Southern Alps, New Zealand

Five herbivorous introduced mammals are sympatric in the central Southern Alps. All of these species have the potential to affect conservation values, yet the Department of Conservation at present monitors and mitigates the impacts of only one. We outline ecological arguments for multi-species management of sympatric herbivore pest impacts and use the two- species system of sympatric thar and chamois to highlight the need for multi-species management of the central Southern Alps alpine pest community.

Phormium tenax, an unusual nurse plant

In this paper we document the role of Phormium tenax as a nurse plant in unimproved pasture. We show that for our study area the regeneration of woody species was limited solely to P. tenax clumps with 22 native and one introduced regenerating woody species present. The number of woody species and of individual woody plants regenerating within P. tenax is not correlated with distance from the edge of the remnant forest but is significantly correlated with P. tenax clump area. P.

Lagomorph abundance around yellow-eyed penguin (Megadyptes antipodes) colonies, South Island, New Zealand

Predation of yellow-eyed penguin (Megadyptes antipodes) chicks may be reduced by removing stock around penguin breeding sites because long grass may reduce lagomorph abundance and hence small mammal predators. This study tests this hypothesis in the South Island, New Zealand. The abundance of lagomorph faeces (mainly rabbit Oryctolagus cuniculus, but some European hare Lepus europaeus) was used as an index of relative abundance of lagomorphs at 16 penguin breeding sites in winter 1991 and 37 sites in 1992/93.

Estimating the home range and carrying capacity for takahe (Porphyrio mantelli) on predator-free offshore islands: Implications for future management

Predator-free offshore islands play an important role in the conservation of many of New Zealand's endemic species. Takahe (Porphyrio mantelli) have small populations established on four offshore islands and although hatching success is lower than that of the wild mainland population in Fiordland, juvenile and adult survival is high and populations are growing exponentially. Accurate estimates of home range size and potential carrying capacities are therefore essential for the future management of the population as a whole.

Sign left by brushtail possums after feeding on bird eggs and chicks

Brushtail possums (Trichosurus vulpecula) were offered Japanese quail (Coturnix japonica) eggs and day-old domestic chickens (Gallus gallus) during a captive feeding trial. Differences in feeding sign left by possums of differing sex, age class, and hunger were slight or absent. Possum feeding trial remains were also compared with remains of North Island robin (Petroica australis longipes) and North Island tomtit (Petroica macrocephala toitoi) eggs and chicks preyed on by ship rats (Rattus rattus) at videoed nests.

A cross-fostering experiment between the endangered takahe (Porphyrio mantelli) and its closest relative, the pukeko (P. porphyrio)

New Zealand's avifauna is characterised by a variety of endemic, often flightless, birds most of which are critically endangered. One of these, the takahe, is a large flightless rail which has been reduced to one population of 115 birds in its natural alpine habitat plus 52 others introduced on four small offshore islands. By contrast the takahe's closest extant relative, the pukeko, has been highly successful since its invasion of New Zealand within the past 800 years.

Effects of habitat structure on distribution and abundance of lizards at Pukerua bay, Wellington, New Zealand

The distribution and abundance of lizards relative to habitat structure were studied at Pukerua Bay, Wellington between December 1982 and March 1988 in order to identify options for management of the habitat of the five species of lizards present. One species, Whitaker's skink (Cyclodina whitakeri), is a threatened species with only one known mainland population. Pitfall traps were set for 23 667 trap-days and yielded 2897 lizard captures. Highest capture rate was for common skinks (Oligosoma nigriplantare polychroma) and lowest rate was for C. whitakeri.

The ecology of Dactylanthus taylorii and threats to its survival

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.

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.

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