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Darryl I MacKenzie

Darryl I MacKenzie
Proteus Wildlife Research Consultants

BSc, DApStat, PhD

About

120
Publications
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Publications

Publications (120)
Article
In order to prioritize the conservation and management efforts to protect jaguars ( Panthera onca) , it is of utmost importance to determine their tolerance in face of human disturbances, habitat modifications and varying degrees of prey availability. We assessed the occupancy probability of jaguars and five of their most common prey species throug...
Article
Full-text available
Context. Vehicle-based shooting has been widely used to kill deer, but the animal-welfare outcomes of this technique have not been evaluated in Australasia. Aim. To assess the animal-welfare outcomes of peri-urban deer culling by quantifying the fates of deer seen and shot at, the duration of procedures, and the number and location of bullet wounds...
Preprint
Full-text available
Benefits of invasive species management for terrestrial biodiversity are widely expected and promoted in New Zealand. Evidence for this is presented in policy and scientific reviews of the literature, but the robustness and repeatability of the underpinning evidence-base remains poorly understood. We evaluated the design of field-based studies asse...
Article
Full-text available
Monitoring the response of wildlife populations to conservation management, such as translocations, is crucially important for assessing its effectiveness. Passive acoustic monitoring (PAM) is an emerging tool for monitoring cryptic and elusive species and is increasingly used in the management of kiwi. Inferences from data collected by PAM can be...
Article
Full-text available
Aim Snow leopards are distributed across the mountains of 12 countries spread across 1.8 million km² in Central and South Asia. Previous efforts to map snow leopard distributions have relied on expert opinions and modelling of presence-only data. Expert opinion is subjective and its reliability is difficult to assess, while analyses of presence-onl...
Article
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• Patterns in, and the underlying dynamics of, species co-occurrence is of interest in many ecological applications. Unaccounted for, imperfect detection of the species can lead to misleading inferences about the nature and magnitude of any interaction. A range of different parameterizations have been published that could be used with the same fund...
Article
Full-text available
Robust assessment and monitoring programs are critical for effective conservation, yet for many taxa we fail to understand how trade-offs in sampling design affect power to detect population trends and describe spatial patterns. We tested an occupancy-based sampling approach to evaluate design considerations for detecting watershed-scale population...
Method
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PAWS aims to produce a robust estimate of the snow leopard’s population status
Article
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Interspecific competition among carnivores has been linked to differences in behavior, morphology, and resource use. Insights into these interactions can enhance understanding of local ecological processes that can have impacts on the recovery of endangered species, such as the ocelot (Leopardus pardalis). Ocelots, bobcats (Lynx rufus), and coyotes...
Article
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Coordinated counts of waders across New Zealand have been undertaken in November and June since 1983; the consistent timing of counts aimed to reduce variation from the effect of seasonal changes in bird numbers. The Australian Shorebird census and the wider Asian Waterbird Census, however, are conducted in January, making direct comparison with th...
Article
1.The infrequent and unpredictable nature of earthquakes means that their landslide‐generated impacts on forests are rarely investigated. In montane forests, landslides are the main cause of tree death and injury during earthquakes. Landslides range from soil movements that uproot and bury trees over extensive areas to rock falls that strike indivi...
Article
Full-text available
There is increasing scrutiny of the animal welfare impacts of all animal use activities, including agriculture, the keeping of companion animals, racing and entertainment, research and laboratory use, and wildlife management programs. A common objective of animal welfare monitoring is to quantify the frequency of adverse animal events (e.g., injuri...
Article
Context: Designing effective long-term monitoring strategies is essential for managing wildlife populations. Implementing a cost-effective, practical monitoring program is especially challenging for widespread but locally rare species. Early successional habitat preferred by the New England cottontail (NEC) has become increasingly rare and fragment...
Presentation
Full-text available
A graphical diagnostic for assessing the fit of occupancy models, particularly covariate relationships
Presentation
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From SEEM 2017 conference, Queenstown, NZ
Presentation
Full-text available
A overview of occupancy modeling including important sampling issues.
Book
Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence, Second Edition, provides a synthesis of model-based approaches for analyzing presence-absence data, allowing for imperfect detection. Beginning from the relatively simple case of estimating the proportion of area or sampling units occupied at the time of surve...
Article
Full-text available
In a recent paper, Hutto (2016a) challenges the need to account for detectability when interpreting data from point counts. A number of issues with model-based approaches to deal with detectability are presented, and an alternative suggested: surveying an area around each point over which detectability is assumed certain. The article contains a num...
Article
Occupancy-detection models that account for imperfect detection have become widely used in many areas of ecology. As with any modelling exercise, it is important to assess whether the fitted model encapsulates the main sources of variation in the data, yet there have been few methods developed for occupancy-detection models that would allow practit...
Presentation
Full-text available
A brief overview of occupancy modeling to set the scene for presentations that followed in the session at TWS 2016
Research
Full-text available
USFWS report on spatial-temporal trends of greater sage grouse. • A Bayesian spatial-temporal model (STM) was used to analyze data from sage grouse management zones (MZ) I-V and VII, of the maximum number of males counted per lek per year. • A STM accounts for both spatial and temporal correlations among lek counts. This may be important when the...
Article
Context Feral pigs (Sus scrofa) have a wide global distribution that includes large parts of Australia and New Zealand. There is concern about the impacts of feral pigs on above- and below-ground flora and fauna, but little is known about their habitat use and feeding activity in temperate rainforests. Aims We evaluated the importance of abiotic an...
Article
Line-transect mark-recapture distance sampling methods can be used to estimate abundance when at least two observers sight and record distances to detected groups of individuals within the survey area. However, a lack of independence between the observer’s detections will cause biased abundance estimates. Studies are also typically designed such th...
Article
Full-text available
Shooting is widely used to reduce the abundances of terrestrial wildlife populations, but there is concern about the animal welfare outcomes ('humaneness') of these programmes. Management agencies require methods for assessing the animal welfare outcomes of terrestrial wildlife shooting programmes. We identified four key issues in previous studies...
Article
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Assemblages of introduced taxa provide an opportunity to understand how abiotic and biotic factors shape habitat use by coexisting species. We tested hypotheses about habitat selection by two deer species recently introduced to New Zealand's temperate rainforests. We hypothesised that, due to different thermoregulatory abilities, rusa deer (Cervus...
Article
Research that yields conflicting results rightly causes controversy. Where methodological weaknesses are apparent, there is ready opportunity for discord within the scientific community, which may undermine the entire study.We use the debate about the role of dingoes Canis dingo in conservation in Australia as a case study for a phenomenon that is...
Article
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Reliable estimates of invasive pest mammal abundance and distribution in New Zealand are vital for effective conservation management of endangered native species. In this study, passive detection devices were used to monitor site occupancy by ship rats (Rattus rattus) in temperate rainforest in the Eglinton Valley, Fiordland, New Zealand. Ship rat...
Article
Faecal pellet counts have been widely used to monitor the abundances of introduced ungulates in New Zealand, but ground-based sampling cannot be conducted safely in the steep non-forest habitats that are common in New Zealand's Southern Alps. Helicopter counts may be an effective technique for monitoring ungulates in steep non-forest habitat. We ev...
Article
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In a recent paper, Welsh, Lindenmayer and Donnelly (WLD) question the usefulness of models that estimate species occupancy while accounting for detectability. WLD claim that these models are difficult to fit and argue that disregarding detectability can be better than trying to adjust for it. We think that this conclusion and subsequent recommendat...
Article
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The large land snail Placostylus ambagiosus (Pulmonata: Bulimulidae) was studied in northernmost New Zealand from 1988 to 2004. At Cape Maria van Diemen (CMvD), more juveniles than adults were found, although estimates showed adults as the most abundant. A cohort, hatched after rodent control commenced in 1990, began maturing in 1995, but 89% died...
Article
Conservation programs often manage populations indirectly through the landscapes in which they live. Empirically, linking reproductive success with landscape structure and anthropogenic change is a first step in understanding and managing the spatial mechanisms that affect reproduction, but this link is not sufficiently informed by data. Hierarchic...
Article
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The past decade has seen an explosion in the development and application of models aimed at estimating species occurrence and occupancy dynamics while accounting for possible non-detection or species misidentification.We discuss some recent occupancy estimation methods and the biological systems that motivated their development. Collectively, these...
Data
Data used in our analyses of common carp population dynamics in six New South Wales rivers, 1984/85–2001/02 (Microsoft® Office Excel spreadsheet; OnlineResource2.xls)
Data
Data used in our analyses of common carp population dynamics in the Murray-Darling Basin rivers, 1962/63–2001/02 (Microsoft® Office Excel spreadsheet; OnlineResource1.xls)
Article
Full-text available
Population modelling is an invaluable tool for identifying effective management strategies for threatened species whose populations are too small for experimental manipulation. Recently developed Bayesian approaches allow us to combine deterministic models with probability distributions to create stochastic models that account for uncertainty. We i...
Chapter
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Many of the impediments to successful conservation management faced in countries such as Sri Lanka stem from a fundamental lack of data and analysis skills for interpreting biodiversity trends in relation to land use, management practices, and ecological or environmental factors such as invasive species and changing climates. Alternative metrics th...
Article
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Tigers are globally endangered and continue to decline due to poaching, prey depletion and habitat loss. In Nepal, tiger populations are fragmented and found mainly in four protected areas (PAs). To establish the use of standard methods, to assess the importance of prey availability and human disturbance on tiger pres-ence and to assess tiger occup...
Article
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Two conservation tools have been developed over the last 10–15 years for species on the New Zealand mainland that are vulnerable to introduced mammalian predators: landscape-scale predator trapping networks, and eradication of predators within mammal-proof exclosures. We tested whether these tools would allow population growth of critically endange...
Article
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There is much interest in managing invasive freshwater fish, but little is known about the dynamics of these populations following establishment. We used annual commercial catch-per-unit-effort data at multiple spatio-temporal scales to test hypotheses about the population dynamics of invading common carp (Cyprinus carpio) in the Murray-Darling Bas...
Article
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Robust monitoring systems are required to improve the ecological outcomes of management actions aimed at preventing biodiversity loss. We present a pilot study that measured assemblages of widespread and common bird species at the national scale in New Zealand. Bird surveys were undertaken at 18 sampling locations (six per land cover class: forest,...
Article
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The last remaining natural population of the critically endangered takahe (Porphyrio hochstetteri) is confined to the Murchison Mountains in Fiordland, New Zealand. This mainland population contains about half of the c. 300 remaining takahe and benefits from one of the costliest recovery programmes in the country. Management activities include deer...
Article
Seven introduced deer taxa are present in New Zealand and there is interest in the dynamics of these populations. Estimating the abundance of deer is problematic, but faecal pellet counts (an index of abundance) have been conducted on New Zealand's public conservation land since the 1950s. We compiled faecal pellet count data from published and unp...
Article
Appropriate monitoring tools are essential for assessing the effectiveness of management for all threatened insect taxa. In New Zealand the large-bodied flightless orthopterans in the genus Deinacrida have mostly been monitored by searching through habitat during the day or spotlighting at night but this is time consuming and the results depend on...
Article
1. Assessing spatial distributions of threatened large carnivores at landscape scales poses formidable challenges because of their rarity and elusiveness. As a consequence of logistical constraints, investigators typically rely on sign surveys. Most survey methods, however, do not explicitly address the central problem of imperfect detections of an...
Article
1. Relationships between animal populations and their habitats are well known and commonly acknowledged to be important by animal ecologists, conservation biologists and wildlife managers. Such relationships are most commonly viewed as static, such that habitat at time t is viewed as a determinant of animals present at that same time, t, or sometim...
Article
1. Binomial mixture models use repeated count data to estimate abundance. They are becoming increasingly popular because they provide a simple and cost-effective way to account for imperfect detection. However, these models assume that individuals are detected independently of each other. This assumption may often be violated in the field. For inst...
Article
Full-text available
The endangered grand skink (Oligosoma grande) is a New Zealand endemic lizard that persists as metapopulations occupying rock patches within matrices of mixed native vegetation and modified agricultural pasture. Parameterisation of metapopulation models applied in conservation biology assumes complete detectability of target species. Incomplete det...
Article
Full-text available
Understanding population dynamics is of great interest in many different contexts. Traditionally, population dynamics have often been considered in terms of individual-based demographic parameters (e.g., abundance, survival, and reproductive rates), estimation of which generally requires information from marked individuals. Alternatively, in some s...
Article
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ABSTRACT  A majority of North American breeding habitat for neotropical migrants exists on private lands, requiring monitoring strategies focused on habitat in these private holdings. We outline study designs and protocols using repeated Presence-Absence surveys across a gradient of patch sizes to develop a range-wide monitoring program for the end...
Article
Occupancy modeling focuses on inference about the distribution of organisms over space, using temporal or spatial replication to allow inference about the detection process. Inference based on spatial replication strictly requires that replicates be selected randomly and with replacement, but the importance of these design requirements is not well...
Article
Full-text available
The estimation of life-history parameters for a threatened species is important for understanding its biology and helping to determine management options. This research investigates age- and sex-related survival estimates incorporating tag loss for New Zealand (NZ) sea lions (Phocarctos hookeri) from Sandy Bay, Enderby Island, Auckland Islands, New...
Article
Full-text available
The trade-off between survival and reproduction by individuals is central to understanding life-history parameters of a species. Few mammal species have life-history information from long-term research. Instead, demographic models are commonly utilized to investigate an individual’s life-history strategy, species dynamics, and population trends. Th...