Estimates of abundance, age structure and sex ratio are essential for monitoring the status of populations. We report the first attempt to reliably estimate these parameters in a population of the recently discovered Raukumara tusked weta (Motuweta riparia), which is found almost entirely near streams. On two occasions we searched a 211-m section of creek for 4–5 successive nights and individually marked all weta. We estimated abundance of adults and juveniles using closed-population mark-recapture analysis.
The effects of an aerial 1080 possum poison operation using carrot baits on invertebrates in Whirinaki Forest Park are described from an un-replicated study of artificial refuges attached to tree trunks. Auckland tree weta (Hemideina thoracica), cave weta (Pharmacus sp.
This study examined whether the diversity and relative abundance of ground-dwelling invertebrates changed in relation to type of vegetation cover. Invertebrate taxon diversity and relative abundance were assessed with pitfall traps placed under the native shrubs Olearia bullata and Coprosma propinqua, and in surrounding patches of exotic pasture. A total of 1935 invertebrates and at least 152 invertebrate taxa were recorded from 49 pitfall traps. The number of native taxa was c.63% of all taxa recorded, whereas exotic invertebrates represented only c.9%.
We examined the threat status of the low tree Pittosporum patulum throughout its range in eastern South Island, based on plot-based sampling of habitat, defoliation by mammalian herbivores, demographic and dieback characteristics. Using environmental modelling (Land Environments of New Zealand), we found no explanation for the ‘gap’ in its disjunct distribution from Nelson–Marlborough–north Canterbury to south Canterbury as a component of upper montane Nothofagus forest and non-Nothofagus subalpine scrub.
We examine the height growth, diameter growth and below-ground allocation responses of mountain beech (Nothofagus solandri var. cliffortioides) seedlings to the experimental removal of root competition through root trenching and the addition of fertiliser within relatively intact-canopied mountain beech forest in the Craigieburn Range, Canterbury. Trenching and trenching combined with fertiliser increased relative height and diameter growth of mountain beech seedlings above that of controls.
Expenditure on endangered species management is increasing greatly, on a global basis. Managers need tools to evaluate the performance of endangered species programmes because there will always be more demand for resources than there are available. Cost Effectiveness Analysis (CEA) is used here to evaluate the performance of the kokako (Callaeas cinerea) recovery programme. This species is being managed at a number of sites in New Zealand and analysis shows a large variation in costs and effectiveness between these sites.
Artificial refuges and mark-recapture techniques were used to monitor the non-target impacts of handbroadcast application (simulating aerial application) of Wanganui No.7 cereal-based baits containing 0.15% (1500 µg g-1) 1080 on populations of weta and other invertebrates in Tararua Forest Park, North Island, New Zealand. Wellington tree weta (Hemideina crassidens) and a cave weta (Isoplectron sp.) were the only species of weta that occupied the refuges.
The most distinguishing feature of the tree weta genus Hemideina (Orthoptera: Anostostomatidae) is their cephalic weaponry, which is thought to be the result of sexual selection on males to aggressively defend groups of reproductive females. Mountain stone weta H. maori is a tree weta that shelters in cavities under flat rocks on rocky outcrops in the alpine region of the South Island.
There is a lack of comprehensive and consistent information to inform policy makers about the status of New Zealands forest biodiversity. Three reasons for collecting such information are: assessing the effectiveness of management, reporting on the status of biodiversity under national and international requirements, and improving our knowledge of ecosystem dynamics for designing effective management systems. The challenge is to design monitoring systems that address these multiple needs simultaneously, and at a range of spatial and temporal scales.
Although reproductive and behavioural studies have been conducted on captive tree weta, there have been very few ecological field studies of any of the weta species involving free-ranging, marked individuals. The mountain stone weta (Hemideina maori) is a tree weta that lives on rock tors in the alpine region of the South Island of New Zealand. Over three seasons each of 480 adults and 789 juveniles was individually marked on four large and 14 small tors to gather baseline information on aspects of H. maori’s life cycle and life history.