monitoring

Comparison of footprint tracking and pitfall trapping for detecting skinks

Inventory and monitoring of biodiversity requires effective sampling tools. Footprint tracking tunnels, developed in New Zealand to monitor small mammals, may also be useful for sampling lizards and other reptiles but more research is needed to verify this. We compared the detectability of terrestrial skinks using two methods: pitfall trapping and footprint tracking. In New Zealand, the former is the traditional method for sampling skinks, while the latter is routinely used to monitor populations of introduced rodents and mustelids.

Sounding out the nest: Unobtrusive localisation of North Island brown kiwi (Apteryx mantelli) incubation burrows

Monitoring breeding outcomes of cryptic nocturnal species such as the North Island brown kiwi (Apteryx mantelli) is an important aim for conservation management in New Zealand. While fitting male kiwi with radio transmitters enables incubation burrows to be found and monitored, it is invasive and expensive. Remote monitoring methods (without handling of birds) are preferable.

Penned release reduces area use by translocated barking geckos (Naultinus punctatus)

Globally, translocations of herpetofauna have been notoriously unsuccessful. Most previous translocations of green geckos (Naultinus spp.) have failed to result in population establishment. However, recent penned releases of jewelled geckos (moko kākāriki; Naultinus gemmeus) have led to increased site fidelity, reduced dispersal, reduced home range sizes, and reduced minimum daily movements, facilitating population establishment.

Biodiversity monitoring, ecological integrity, and the design of the New Zealand Biodiversity Assessment Framework

The New Zealand Department of Conservation is responsible for biodiversity management over approximately one-third of New Zealand’s land area and a network of marine protected areas; it also has a more general role in managing protected species and biodiversity advocacy. In 2004 the Department of Conservation began the development of a national natural heritage monitoring framework known as the New Zealand Biodiversity Assessment Framework, which has been operational since 2011.

Calibrating brushtail possum (Trichosurus vulpecula) occupancy and abundance index estimates from leg-hold traps, wax tags and chew cards in the Department of Conservation’s Biodiversity and Monitoring Reporting System

Abstract: The Department of Conservation has implemented a Biodiversity and Monitoring Reporting System (BMRS) that estimates occupancy rates and relative abundances of introduced brushtail possums (Trichosurus vulpecula) at a representative sample of sites on public conservation land. Leg-hold traps have been used to monitor possums in the BMRS, but wax tags and chew cards have logistical and financial advantages over traps.

Compliance with biodiversity compensation on New Zealand’s public conservation lands

This article assesses compliance with biodiversity compensation on New Zealand’s conservation land. Of the 261 Department of Conservation (DOC) concessions for commercial activity searched, only about 15% included compensation provisions. A sample of 20 concessions of that 15% suggests 68% achieve full compliance. Our results suggest compliance is influenced by factors such as habitat and activity type, protected area category, and whether a concession holder has pending concessions and/or renewals. Inconsistencies in compliance monitoring, enforcement, and reporting merit attention.

Assessing and comparing population densities and indices of skinks under three predator management regimes

Introduced mammalian predators threaten populations of endemic New Zealand skinks. Their effects on skink populations have been not often quantified on the mainland and are known primarily from skink population increases on islands from which mammals have been eradicated. Estimating skink population density with capture–recapture trapping is time-consuming and costly. Counting skinks in artificial retreats in specific weather conditions may be a useful and relatively quick way to index population density, but needs calibration for different habitats and species.

Using home-range data to optimise the control of invasive animals

Invasive species have been identified by the Convention on Biological Diversity as a significant threat to biodiversity. Conservation managers often lack tools for addressing uncertainty about the control intensity required to achieve cost-effective management of invasive species. We describe a modelling approach for informing the spacing of control-device lines given the availability of home-range data. To demonstrate its utility, we used data on stoats (Mustela erminea), an introduced mammalian predator responsible for the decline of endemic birds in New Zealand.

Placement period of artificial retreats affects the number and demographic composition but not the body condition of skinks

Monitoring is important in conservation management, essential for assessing population trends, making decisions and allocating resources. Artificial retreats can offer a reliable, low impact and efficient method for monitoring cryptic herpetofauna. Methods for monitoring artificial retreats vary between different conservation management programmes in New Zealand, however, and a deeper understanding of the causes of these variations would encourage greater standardisation and enable more reliable comparisons to be made across temporal and spatial scales.

Efficacy of chew-track-card indices of rat and possum abundance across widely varying pest densities

Chew-track-cards (CTCs) are potentially a cost-effective way to estimate the relative abundance of invasive rats and possums in New Zealand, but previous research suggested that their high sensitivity may limit use to low-density populations. Using a short two-night deployment period, we compared CTC indices of rat and possum abundance with a footprint tracking rate (RTR) index of rat abundance and a wax tag bite rate index (WTI) of possum abundance in 11 forest remnants that varied widely in rat and possum abundance (RTR and WTI of 0–100% over two nights).