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A 2014 carcass search survey confirmed that Tiakina Ngā Manu aerial 1080 operations, undertaken to protect resident mohua (Mohoua ochrocephala) from increases to predator populations following subs...

Intensive ground-based searches for white-tailed deer carcasses were conducted in the Dart Valley/Routeburn catchments following the aerial application of 1080 (sodium fluoroacetate) cereal pellets...

Large-scale monitoring of wild populations in remote areas using traditional live-capturing methods is logistically and financially challenging. Devices that can be used to obtain biological material remotely and store it for an extended period have considerable potential to monitor population densities and health status, but their applicability remains largely unexplored. The present study describes a device that collects trace amounts of DNA from the saliva of small mammals that is deposited on the surface of a collection medium (WaxTags®). The device’s performance was evaluated on Australian brushtail possums (Trichosurus vulpecula), an invasive pest species and the most significant vector of bovine tuberculosis infective agent (Mycobacterium bovis), under field conditions in Canterbury, New Zealand. The retrieved DNA was used to amplify eight possum-specific microsatellite markers and bacterial 16S rRNA. The design is mechanically robust, and the quality of the recovered DNA was adequate for microsatellite-based identification of individual possums, estimation of population density, and partial reconstruction of their oral microbiomes as a potential indicator of health. Several medically important bacteria, including strains of environmental Mycobacterium sp., were detected. The design can be refined to monitor other animals’ populations proactively and provide different levels of information necessary to manage wild populations.

The marbled cat Pardofelismarmorata is a Near Threatened small felid. The cat’s presence in Nepal is based on an anecdote. A camera trap-based study to access diversity and abundance of terrestrial mammals in eastern Nepal accumulated 3,014 camera trap days and resulted in 5,176 photographs of 17 medium-large sized mammal species. Amongst them, a marbled cat was captured at a single camera trap station in January 2018. The camera trap-capturing the marbled cat was located in the secondary forest at an altitude of 2,750 m a.s.l., dominated by free-ranging cattle close to a permanent human settlement (1.4 km) and a temporary cattle herding camp (0.4 km). This is the first photographic evidence of a marbled cat in Nepal. In this survey, we also recorded three other felid species: common leopard Pantherapardus, Asiatic golden-cat Catopumatemminckii and leopard cat Prionailurusbengalensis. We recommend detailed year-round camera trap surveys in the mid-hills of eastern Nepal along with research on adaptation of the small felids to human-dominated areas and assessment of immediate threats for preparing sound conservation management plans of the marbled cat and its sympatric species. Initiation of conservation programmes engaging local dokpa (herders) is necessary.

The common brushtail possum (Trichosurus vulpecula), introduced from Australia in the mid-nineteenth century, is an invasive species in New Zealand where it is widespread and forms the largest self-sustained reservoir of bovine tuberculosis (Mycobacterium bovis) among wild populations. Conservation and agricultural authorities regularly apply a series of population control measures to suppress brushtail possum populations. The evolutionary consequence of more than half a century of intensive population control operations on the species’ genomic diversity and population structure is hindered by a paucity of available genomic resources. This study is the first to characterise the functional content and diversity of brushtail possum liver and brain cerebral cortex transcriptomes. Raw sequences from hepatic cells and cerebral cortex were assembled into 58,001 and 64,735 transcripts respectively. Functional annotation and polymorphism assignment of the assembled transcripts demonstrated a considerable level of variation in the core metabolic pathways that represent potential targets for selection pressure exerted by chemical toxicants. This study suggests that the brushtail possum population in New Zealand harbours considerable variation in metabolic pathways that could potentially promote the development of tolerance against chemical toxicants.

Carabidae (Coleoptera) are commonly used as indicators of ecosystem health due to their high diversity, conservation value and relative ease of identification. Carabids were monitored at Ah...

Control or eradication of feral cats (Felis cattus) is necessary for a number of reasons, including controlling zoonotic diseases and protecting native species in New Zealand. Estimating feral cat ...

Ōtamahua/Quail Island is an 85 ha Recreation Reserve in Lyttelton Harbour, New Zealand. It is being ecologically restored and cats, hedgehogs, rabbits, mustelids and rats have been eradicated. However, the house mouse (Mus musculus) survived two eradication attempts, a bait station operation in 2002 and an aerial operation in 2009. Data on aerial bait deposition, bait degradation, mouse resurgence and non-target mortalities were collected. Brodifacoum bait deposition in many areas was considerably lower than the prescribed rate of 8 kg/ha. Mouse sign was simultaneously detected at seven sites around the island 6 months after the aerial operation. Tails were collected from trapped mice on Quail Island, the adjacent mainland and on the stepping-stone island (King Billy) to undertake DNA analysis. Little genetic discrimination was observed between samples obtained after the 2009 aerial bait operation, and samples from before or outside of the bait drop. By contrast, samples taken from a location 15 k...

New Zealand fur seals are one of many pinniped species that survived the commercial sealing of the eighteenth and nineteenth centuries in dangerously low numbers. After the enforcement of a series of protection measures in the early twentieth century, New Zealand fur seals began to recover from the brink of extinction. We examined the New Zealand fur seal populations of Banks Peninsula, South Island, New Zealand using the mitochondrial DNA control region. We identified a panmictic population structure around Banks Peninsula. The most abundant haplotype in the area showed a slight significant aggregated structure. The Horseshoe Bay colony showed the least number of shared haplotypes with other colonies, suggesting a different origin of re-colonisation of this specific colony. The effective population size of the New Zealand fur seal population at Banks Peninsula was estimated at approximately 2500 individuals. The exponential population growth rate parameter for the area was 35, which corresponds t...

The New Zealand fur seal (Arctocephalus forsteri) is one of many pinniped species that has shown a remarkable recovery from the brink of extinction after cessation of commercial sealing during the eighteenth and nineteenth centuries. It is commonly believed that this species competes with recreational and commercial fisheries. We identified prey items using massive parallel sequencing from New Zealand fur seal faecal samples that were collected throughout the species distribution. The data support generalist feeding behaviour for this species. The diet composition showed significant geographical and inter-seasonal variation. As many as 46 species of fish and 18 species of cephalopod were identified from a single colony. The data suggest cartilaginous species (sharks, rays, and skates) constitute an important part of the New Zealand fur seal diet. Approximately 10 % of the species identified in the seal diet were of significant commercial value, which indicates some qualitative food competition between New Zealand fur seals and commercial fisheries in exploiting marine species.

All multicellular organisms host a wide diversity of microorganisms in and on their bodies, which are collectively known as their microbiome. Characterising microbial communities that inhabit different body niches in wild animals is critical to better understand the dynamics of microbiome diversityand its functional significance. The current study is the first to apply massively parallel sequencing of 16S rRNA to characterise the microbial diversity and functional content of oral microbiota in two of New Zealand’s most important invasive mammals, the omnivorous common brushtail possum (Trichosurus vulpecula) and the carnivorous stoat (Mustela erminea). In total, strains of bacteria belonging to 19 different phyla, 27 classes, 52 orders, 103 families, 163 genera and 51 known species were identified from the oral cavities of the study species. Strains of the phyla Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Actinobacteria dominated the core oral microbial diversity in both species, while other taxa were comparatively less abundant. Despite invasive populations typically demonstrating limited genetic variation, intraspecific variation of the core bacterial taxa in the oral microbiota was considerable. This suggests that a complex interaction between genetic, physiological, and environmental factors determines the diversity of the study species’oral microbiome.

The New Zealand fur seal (Arctocephalus forsteri) passed through a population bottleneck due to commercial sealing during the eighteenth to nineteenth centuries. To facilitate future management options, we reconstructed the demographic history of New Zealand fur seals in a Bayesian framework using maternally inherited, mitochondrial DNA sequences. Mitogenomic data suggested two separate clades (most recent common ancestor 5000 years ago) of New Zealand fur seals that survived large-scale human harvest. Mitochondrial haplotype diversity was high, with 45 singletons identified from 46 individuals although mean nucleotide diversity was low (0.012 ± 0.0061). Variation was not constrained geographically. Analyses of mitogenomes support the hypothesis for a population bottleneck approximately 35 generations ago, which coincides with the peak of commercial sealing. Mitogenomic data are consistent with a pre-human effective population size of approximately 30,000 that first declined to around 10,000 (due to the impact of Polynesian colonization, particularly in the first 100 years of their arrival into New Zealand), and then to 100-200 breeding individuals during peak of commercial sealing.

The complete mitochondrial genome of three mustelid species, stoats (Mustela erminea), weasels (Mustela nivalis) and ferrets (Mustela furo), and the New Zealand fur seal (Arctocephalus forsteri) were sequenced using direct mitochondrial DNA extraction and overlapping long PCRs. The usual 37 mammalian mitochondrial genes (13 protein coding genes, 22 t-RNA and 2 r-RNA) were identified in all four mitogenomes. The divergence of stoats from other members of the sub-family Mustelinae was dated 4.5 million years ago. The mitogenomic data were consistent with a bear-like origin of seals.

1. Physical structure and species composition of vegetation determine spider diversity through habitat availability. Here, we assess, for the first time, the role of plant structure on spider communities in New Zealand native alpine tussock grasslands. We investigate the specific associations between spider assemblages and plant communities and test the hypothesis that spider diversity increases with plant diversity and tussock cover. 2. Spiders were sampled using density- and abundance-activity-dependent methods. Data on physical characteristics and species composition of plants revealed gradients in vegetation, driven by distinct intra-ecosystem plant communities. Effects of vegetation on spider diversity and composition were assessed through linear mixed-effects models. Redundancy analysis was used to determine and visualise the spider species–level response to gradients in plant compositions. 3. There was a positive relationship between plant diversity and spider diversity, while the effects of tussock cover varied with spider taxa. Overall, physical structure and species composition of vegetation had effects on the abundance of a similar number of spider species and families. 4. Gradients in vegetation were matched to gradients in spider communities, whose diversity and composition varied according to their habitat preference. The family Orsolobidae was associated with wetland vegetation, and Linyphiidae with shrubs. The abundance of certain spider families and species, such as Lycosidae and Anoteropsis hilaris, was consistently affected by vegetation. 5. Environmental factors, such as soil moisture, may affect plant species composition and physical structure in tussock grasslands, which in turn determine spider assemblages. Lycosidae were identified as potential indicators of structural changes in tussock grassland plants and could be valuable for ecological monitoring in conservation management.

Bennett's wallaby (Macropus rufogriseus rufogriseus) are an introduced pest requiring control in New Zealand. Historically, sodium fluoroacetate (1080) has been used, but there is political resistance to this method of control from specific interest groups. Previous trials with captive animals have shown that Feratox® cyanide pellets are efficacious for Bennett's wallaby and the aim of this study was to field test Feratox®. A 300-ha treatment block was pre-fed non-toxic bait for 2 weeks followed by the presentation of 200-mg Feratox® pellets. Rates of faecal pellet accumulation were markedly higher in the non-treatment block following control and the Guildford score of wallaby abundance reduced from 5 to 2 in the treatment block. In total, 110 dead wallabies were found less than 50 m from the baiting sites. These results suggest that Feratox® is an effective ground-based alternative to 1080 for Bennett's wallaby control.

Secondary metabolites in fruit are compounds that are not directly associated with plant growth; some are directly related to plant reproductive processes, specifically seed protection and dispersion. There is a complex and species-specific interaction between these plant compounds and their avian seed dispersers. To determine whether two important secondary metabolites in wine grapes – tannins and colour pigments – might be important cues to two of the avian species that forage on wine grapes, and how species-specific this interaction might be, comparative field experiments were run with Australasian silvereyes (Zosterops lateralis) and European blackbirds (Turdus merula). Both species were offered a glucose/fructose artificial nectar with increasing concentrations of grape tannins. In a second experiment, they were offered both green and purple artificial grapes where only the colour differed. Both species showed aversion to tannins; silvereyes appeared to have greater tolerance than blackbirds of tannin concentrations above 5%. In summer no preference was shown between green and purple coloured artificial grapes, but in late autumn blackbirds took only purple grapes whereas silvereyes pecked mostly at green. Links between tannin for seed protection and colour signals to birds are discussed. Colour may cue the two species to different species-specific aspects of fruit nutritive value.

In New Zealand, the vertebrate pesticide sodium fluoroacetate (Compound 1080) is aerially applied in baits for control of the brush-tailed possum Trichosurus vulpecula (Kerr, 1792). Maori, the indigenous people of New Zealand, have raised concerns about 1080 impacts on culturally-important species. Here, we outline two steps taken to help Maori assess 1080 risk. First, field research was undertaken to determine if naturally-occurring plants utilized by a Maori community for food and medicine would take up 1080 from baits. Single baits were placed at the base of individual plants of two species, pikopiko (Asplenium bulbiferum) and karamuramu (Coprosma robusta). Plants were sampled at various times up to 56 days, and samples were analyzed for 1080 content. No 1080 was detected in any of the pikopiko samples, whereas 1080 was detected in karamuramu, at a maximum concentration of 5 ppb after seven days, and 2.5 ppb after 14 days. This concentration decreased to 0 at 28 days, indicating that 1080 was not persistent. The results of the present study suggest there is negligible risk of humans being poisoned by consuming plants that have taken up 1080 from baits. To allay community concerns that minute concentrations of 1080 might influence the medicinal properties of plants, it is suggested that a withholding period of 30 days after 1080 control operations could be adopted. Second, after further consultation we undertook a review of the scientific literature relating to 1080 impacts on additional non-target species of cultural importance to Maori. The information was presented on an interactive foodweb database that allowed the collection and presentation of a large volume of complex information about 1080 in a holistic and pictorial fashion. This database was presented to many Maori communities throughout New Zealand, and feedback was overwhelmingly positive. The database is likely to play a key role in informing these communities about 1080, and is seen as an important new tool to help these communities make their own risk assessments.

The brushtail possum is a major agricultural and ecological pest in New Zealand. A novel noninvasive DNA sampling tool for detecting its presence (WaxTags, or WT) was tested. DNA was recovered from saliva left on WT, and two lengths (407 bp and 648 bp) of the cytochrome c oxidase I (COI) barcoding region were amplified by polymerase chain reaction (PCR). PCR products were considered (+) when a DNA band was clearly visible by electrophoresis. Different factors that might affect PCR (+) were investigated with captive possums: (i) both extraction protocols of the QIAGEN DNeasy Blood and Tissue Kit, (ii) effect of an overnight or longer delay of up to 3 weeks before DNA extraction on both COI amplicons, and (iii) effect of the individual, order and magnitude of the bite. Extraction protocols were not significantly different. The effect of the overnight delay was not significant, and amplification of the short amplicon was significantly higher (100%) than for the long fragment (48%). After a two or 3-week delay, the short amplicon had 94% and 56% PCR (+), success rates, respectively. Individual, order and magnitude of a bite had no significant effect. The delay trial was repeated with WT from the wild, for which PCR (+) rate of the short amplicon was 63%, regardless of freshness. Four microsatellites were amplified from captive WT samples. We conclude that DNA from saliva traces can be recovered from WT, a potential new tool for noninvasive monitoring of possums and other wildlife.

Author(s): Ross, James G.; Sam, Shona | Abstract: Possum numbers have been significantly reduced in many regions of New Zealand. However, research has indicated some unexpected consequences of possum control. At some sites, rat numbers have more than doubled 2 years after possum control. What this suggests is that the removal of a direct competitor has enabled a rapid increase in rat numbers relative to slower possum recovery. This has serious implications, as high rat numbers could inhibit ongoing possum ground control. To investigate this, an experimental trial was run where we tested the following research hypotheses by manipulating the rat density: i) Null hypothesis (H0) ‒ rat density has no influence on possum foraging behaviour around bait stations, ii) Alternative hypothesis (H1) ‒ rat density indirectly influences possum behaviour by removing all bait before possums can access it, and/or iii) Alternative hypothesis (H2) ‒ rat density directly influences possum behaviour by physically excluding them from bait stations. The experimental site was divided into 2 parts, a treatment block and a control (non-treatment) block. Rat control was undertaken using Victor® kill traps and 96 rats were removed over 6 nights (density estimated at 4.6 rats/ha). To quantify the effect of rat density on possum foraging behaviour, non-toxic bait stations were stapled to a tree every 10 m along 18 monitoring lines (n = 50). Possum behaviour was then monitored using both modified tracking cards and IR camera traps. Prior to trapping, 92% of all the baits were removed by rats on the first night. Following trapping, this reduced down to 8% in the treatment block. Rats turned up earlier than possums at the majority of the monitored sites (~1 hour before sunset). Before trapping, baits were only available 33% of the time when a possum visited a bait site (n = 15), and no baits were removed. After trapping, baits were available 100% of the time and 2 baits were removed by possums. These results support H1 and suggest that the smaller-bodied competitor can dominate food resources in NZ forests. This has the potential to make possum ground control more difficult when using control techniques that do not target rodents.

Author(s): Kavermann, Matt; Ross, James; Paterson, Adrian; Eason, Charles | Abstract: Improving vertebrate pest control operations relies on increasing pest animal interactions with control devices (e.g., bait stations, bait bags, and/or traps). Interactions are encouraged using a variety of baits and lures that stimulate an animal’s visual, olfactory, or auditory sense, orientating the target species towards a control device. On a generalised spatial scale of conspicuousness, an auditory lure will function over a greater distance for mammals in forested ecosystems than both visual and olfactory lures, suggesting auditory lures could have the greatest luring potential. In New Zealand, there is an overabundance of the introduced Australian brushtail possum that is the subject of ongoing control. Ground-based control operations typically use visual (e.g., a flour blaze), and to a lesser extent olfactory (e.g., cinnamon) lures for attracting possums to control devices. However, the potential for an auditory stimulus remains largely unexamined and underutilised. Research presented here expands on previous studies with captive animals and examines the development and field testing of an audio lure for possum control. The results from three preliminary field trials show that possums found audio-lured devices sooner than un-lured devices, and that a greater proportion of lured devices were located over time. In addition, possums were recorded investigating lured sites at a higher rate compared to un-lured sites, suggesting that possums were more likely to interact with a control device if it has an audio-lure than if it does not.

Author(s): Ross, James G.; Eason, Charles T.; Ogilvie, Shaun C. | Abstract: The brushtail possum, introduced to New Zealand in 1858, is a significant conservation pest and a major vector of bovine tuberculosis. Previous control-simulation studies have suggested that aerial delivery of bait containing sodium fluoroacetate (1080) is the most cost effective (large scale) possum control strategy. Over the past decade, considerable improvements in groundcontrol techniques have been developed by private contractors and bait manufacturers. These techniques are not reliant on 1080, and there have been major cost reductions as the new baits and delivery mechanisms have been optimized. In addition to this, our research team (in collaboration with Connovation Research Ltd.) have recently developed a new bait station design that has the potential to be left out in the field for up to 5 years without the need for servicing. These devices are self setting and have the ability to deliver gel or liquid spray, and ‘target-specific’ toxicants. Preliminary cost analysis suggests that this new bait station design has the potential to save NZ$21 million per annum from the amount currently spent on possum ground control.

Author(s): Ross, James G.; Bicknell, Katie B. | Abstract: The brushtail possum is a significant conservation pest and major vector of bovine tuberculosis in New Zealand. Previous control simulation studies have suggested that aerial control with bait containing sodium monofluoroacetate (1080) is the most cost-effective large-scale possum control strategy. However, there is a growing awareness that the survivors of 1080 control can develop ‘bait shyness’, and this can markedly alter the efficacy of ongoing 1080 control operations. Several alternative toxicants are registered for possum control but all are ground based, differ in their mode of action, and are more expensive than aerial 1080 control. A new possum control simulation model was developed to assist in identifying the most cost-effective control strategy that would achieve a sustained 80% population reduction, given bait-shy behaviour and immigration from adjacent non-controlled areas. The simulation results indicated that it is possible to achieve a sustained 80% population reduction (over a 10-year period) using a 1080-based control strategy, provided at least 90% of all ‘susceptible’ possums are killed in each control operation. In the event of an unsuccessful 1080 control operation (i.e., only a 60% kill), cyanide bait plus trapping, or brodifacoum bait provided the most cost-effective strategy of ‘mopping up’ 1080 bait-shy survivors. However, sufficient numbers of traps must accompany the cyanide bait to ensure that the majority of 1080 bait-shy possums are targeted. Sensitivity analysis indicated that the most important variable influencing the overall success of any control strategies was the rate of re-colonization following control. With the high rates of immigration that are sometimes observed in small forest reserves (i.e., l100 ha), it was not possible to sustain an 80% population reduction using any combination of toxicants. However, higher rates of immigration are probably exceptional and the rate used in these simulations is considered more typical, particularly for moderate-to-large forest stands where most possum control is conducted.

Context In New Zealand, the Australian brushtail possum is a pest, because this species preys on native birds and transmits bovine tuberculosis (bTB) to livestock. Previous studies on possums have shown that home-range characteristics differ depending on habitat and/or population density. However, direct comparisons between studies are limited because of the use of differing monitoring techniques, some of which are now out-dated and imprecise. Understanding how possum ranging behaviour varies in response to habitat and density may allow the development of more effective and site-specific control operations. For example, variations in home-range characteristics (e.g. home-range overlap with conspecifics) among populations may mean that bTB transmission risk is not uniform among populations, resulting in the need for some sites to be prioritised for control over others. Aims To investigate whether home-range characteristics varied among three sites of differing habitat and population density, and investigate whether possum home-range characteristics varied between males and females. Methods Global Positioning System (GPS)- and VHF-tracking were used to compare possum home-range characteristics among three sites. Two sites were within pine (Pinus radiata) habitat and had low-density possum populations, and one site was within oak (Quercus robur) and sycamore (Acer pseudoplatanus) habitat, and had a higher-density possum population. Key results Possum home-range characteristics did not vary between the two low-density sites. However, these populations exhibited considerably larger home-range sizes and home-range overlap between pairs of collared possums than did the high-density population. In addition, the low-density populations used more dens and changed these more often. Across all sites, there were generally no intersexual differences in home-range characteristics. Key conclusions The present research highlights that the home-range characteristics of possums can vary among populations, depending on habitat and/or population density. Implications Further research into the drivers of possum home-range characteristics would be beneficial to allow identification of how spatial behaviour is likely to vary depending on habitat and density. This would allow the design of more targeted and therefore effective control strategies that account for these variations in behaviour, such as using a larger spatial scale of control devices where possums are known to range further.