Al Glen | Landcare Research (original) (raw)

Papers by Al Glen

New Zealand Journal of Ecology, 2023

Cats (Felis catus) are among the most damaging invasive predators in the world, and their impacts... more Cats (Felis catus) are among the most damaging invasive predators in the world, and their impacts in Aotearoa New Zealand (NZ) are particularly severe. However, unlike the invasive predators that are targeted for eradication under the Predator Free NZ initiative, cats are also highly valued by people and therefore will likely remain widespread in NZ for the foreseeable future. This raises the question of how to manage the impacts of cats, which include predation, competition, and disease affecting native species, livestock, and humans. Appropriate management actions will depend on land use (e.g. urban areas vs wilderness), the values to be protected (e.g. wildlife, human health), as well as safety, humaneness, social acceptability, and cost-effectiveness. We review current knowledge on the impacts and management of cats in NZ and overseas, identify knowledge gaps preventing effective management, and suggest approaches for research to address these gaps. Our suggested research priorities include: (1) improved methods for monitoring cats and their impacts on natural, social and economic values, (2) development of humane, effective, and socially acceptable methods to manage the impacts of cats, (3) engagement with cat owners to improve outcomes for cats, people, and the environment, and (4) investigating potential indirect ecological effects of cat control, such as ecological release of prey or competitors.

Wildlife Research, 2023

Small mammalian predators can have low population densities, as well as cryptic and highly mobile... more Small mammalian predators can have low population densities, as well as cryptic and highly mobile behaviours, making these species challenging to manage. Monitoring tools such as camera traps, hair traps and footprint tracking devices can help detect cryptic species, but they require an animal to approach and, in most cases, interact with a device. They also have limited capacity to help capture animals. Wildlife-detection dogs can detect a wide range of species with a similar or higher efficiency than do other methods, partly because they are much less dependent on volitional decisions of target animals to interact with devices. By following scent trails, dogs can track down animals that actively avoid capture or detection. Dog-handler teams also have another advantage, namely, the handler can mount a rapid management response to capture or remove animals as soon as they are detected. We review ways in which dog-handler teams can contribute to active management of small mammalian predators by combining the dogs' ability to detect animals with their handlers' ability to mount a rapid response.

Conservation Science and Practice, 2023

The fungal genus Phytophthora includes an array of destructive plant pathogens that have had seve... more The fungal genus Phytophthora includes an array of destructive plant pathogens that have had severe impacts on native, agricultural, and horticultural systems worldwide. Preventing the spread of Phytophthora species is critical for protecting vulnerable plants and ecosystems; yet detection remains a challenge due to their microscopic size, broad host range, and latent and cryptic expression in host plants. We tested the effectiveness of trained detec

New Zealand Journal of Ecology, 2022

As a major threat to New Zealand's biodiversity, feral cats (Felis catus) are the subject of plan... more As a major threat to New Zealand's biodiversity, feral cats (Felis catus) are the subject of planned eradications on a number of offshore islands, including Rakiura Stewart Island. We used camera traps to estimate population density of feral cats on the northeast coast of Rakiura, and to investigate their movement behaviour and detection probability. We also used camera footage to compare the consumption of two types of non-toxic sausage baits (chicken and rabbit) with a view to future use of toxic baits. Population density of feral cats was likely between 1 and 2 cats per km 2. Non-target species (rats and possums) removed more than half the baits, greatly reducing bait availability for feral cats. Deer and birds (including kiwi) encountered baits but did not eat them. Cats had an apparent preference for chicken over rabbit baits, although small sample sizes prevent firm conclusions. Both bait types appeared to decline rapidly in palatability, and no baits were consumed by cats more than 5 days after deployment. Future trials and baiting regimes should consider ways to improve bait availability. Increased bait density, exclusion of rats and possums and/or more frequent replacement of baits will likely increase encounter rates by feral cats.

New Zealand Journal of Ecology, 2022

In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is pl... more In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is planned on Auckland Island in the New Zealand subantarctic region. This eradication will require detailed knowledge of the abundance, distribution, movement behaviour and detection probability of cats on the island. We investigated these parameters on a peninsula at the northern end of the island using live trapping, camera trapping, and scat searches with and without detection dogs. Here, we compare the results of these methods, and discuss their utility for the planned eradication. Four cats were captured and fitted with GPS collars. Camera traps with 500 m spacing detected all these individuals on multiple occasions, and at multiple locations. At least 12 other individuals were also captured on camera. Excluding every second camera (to simulate 1000 m spacing) resulted in failure to detect 32% of known individuals. Population density estimates from camera trapping varied from 0.7-1.0 cats km-2. Humans found 29 cat scats, and dogs found 33. Genetic analysis estimated that these came from a minimum of ten individuals. Camera trapping should be repeated during the operational and confirmation phases of the eradication to monitor spatial and temporal variation in cat density, detect survivors, and help confirm eradication success. Scat collection, with and without dogs, can supplement data from camera trapping. With larger sample sizes of scats, DNA profiling may also allow cat abundance to be estimated.

New Zealand Journal of Ecology, 2023

Feral cats (Felis catus) have a negative impact on native biodiversity in New Zealand. As such, t... more Feral cats (Felis catus) have a negative impact on native biodiversity in New Zealand. As such, their populations require careful management and monitoring of the effectiveness of these management operations. We used camera traps to assess (1) effectiveness of an intensive cat control operation, and (2) the level of reinvasion six months later. Cat abundance was estimated on a pastoral property in Hawke's Bay, North Island, New Zealand, subject to cat control using trapping and shooting. Forty cameras were placed on a grid with 500 m spacing and deployed for a total of nine weeks: (1) pre-control, (2) immediately post-control, and (3) six-months post control. Cat abundance was estimated using an index-manipulation-index (IMI) method. The IMI method estimated an c. 84% decrease in cat abundance immediately post-control, suggesting the operation worked well at removing most resident cats at this site. The detections observed six months later suggest reinvasion was very low.

New Zealand Journal of Ecology, 2022

Managing invasive species requires knowledge of their ecology, including distribution, habitat us... more Managing invasive species requires knowledge of their ecology, including distribution, habitat use, and home range. In particular, understanding how biotic and abiotic factors influence home range can help with pest management decision-making, as well as informing native species management. Feral cats, self-sustaining cat populations that live independently of people, have caused numerous extinctions and continue to adversely affect native species globally. Managing feral cat populations requires spatially explicit knowledge to enable strategic deployment of management or monitoring devices, understand where native species are most likely to be at risk, and to mitigate the spread of cat-vectored diseases such as toxoplasmosis. Here, we present a meta-analysis of factors that influence feral cat home range size including land use types, differing levels of land use heterogeneity, and numbers of competitors. Male feral cats had larger home ranges than females, but effects of season, competitors, habitat heterogeneity, or land use on feral cat home range were not statistically significant, possibly due to high variability (male cat home range: 22.1 to 3232 ha; female cat home range: 9.6 to 2078 ha). This may reflect the fact that cats are generalists and are able to exploit any opportunity. Thus, we recommend that these factors and others, such as prey availability and composition, should be included in future research, so that the variability in home range size can be better understood. Improved understanding is vital for improving feral cat management in ecosystems where cats have been introduced.

New Zealand Journal of Ecology, 2021

The impact of feral cats on native wildlife is becoming increasingly recognised worldwide, making... more The impact of feral cats on native wildlife is becoming increasingly recognised worldwide, making their management a necessity. As New Zealand's Predator Free 2050 goal leads to larger and more ambitious landscape scale programmes, there is an important need for cost-and time-effective tools. Para-aminopropiophenone (PAPP) was first registered in New Zealand for feral cats and stoats in 2011 under the name PredaSTOP® and has higher target specificity for feral cats than currently used toxins. Following a successful trial of PAPP on Toronui Station, Hawke's Bay in 2017, a larger operation was undertaken in 2018 across 9123 ha of the Poutiri Ao ō Tāne project area in Hawke's Bay. Camera traps were used to monitor the relative abundance of feral cats on Opouahi Station (treatment site) and at Waitere Station(non-treatment site). A network of 287 bait stations was established in 500 m grid spacings across the treatment site. Two applications of non-toxic pre-feed minced meat baits were followed by two applications of toxic PAPP baits. PAPP baits were dyed green and contained 80 mg of PredaSTOP® in the centre of the bait. Each application of PredaSTOP® consisted of two baits placed at either end of each bait station. Toxic baits were removed from at least 130 bait stations. We assume that ≥ 130 feral cats are likely to have been killed, resulting in a 39% reduction in the relative abundance of feral cats after the operation. Our results suggest that PAPP has the potential to be a useful management tool across large areas alongside other methods.

New Zealand Journal of Zoology, 2020

Trends in Ecology & Evolution, 2020

Managing vertebrate pests is a global conservation challenge given their undesirable socio-ecolog... more Managing vertebrate pests is a global conservation challenge given their undesirable socio-ecological impacts. Pest management often focuses on the 'average' individual, neglecting individual-level behavioural variation ('personalities') and differences in life histories. These differences affect pest impacts and modify attraction to, or avoidance of, sensory cues. Strategies targeting the average individual may fail to mitigate damage by 'rogues' (individuals causing disproportionate impact) or to target 'recalcitrants' (individuals avoiding standard control measures). Effective management leverages animal behaviours that relate primarily to four core motivations: feeding, fleeing, fighting, and fornication. Management success could be greatly increased by identifying and exploiting individual variation in motivations. We provide explicit suggestions for cue-based tools to manipulate these four motivators, thereby improving pest management outcomes. Looking Beyond the 'Average' Individual in Vertebrate Pest Management Vertebrate pests, including invasive or overabundant predators and herbivores, frequently come into conflict with economic, social, and biodiversity values. Mammalian predators are responsible for some of the most devastating losses to native biodiversity [1] and frequently harm humans, their livestock, and pets, while herbivores can cause agricultural damage, vehicle collisions , and ecosystem-level impacts including overbrowsing [2,3]. Mitigating the impacts of vertebrate pests thus presents one of the major challenges currently facing wildlife managers. Managers require effective strategies to: (i) reduce pest populations (e.g., by attracting individuals to traps or toxic baits), and (ii) deter individuals from sensitive areas or valuable species (e.g., threatened prey or plant species, livestock, agricultural, and forestry sites). Yet, pest control measures are often only partially effective [4,5], with some individuals avoiding lethal control or ignoring deterrents. Attractants and deterrents typically target the 'average' individual in a population, with the goal of maximising the number of animals responding to stimuli. However, the most intractable challenges of vertebrate pest management may occur precisely because some individuals do not behave like the average, and therefore, are not effectively targeted. Within a pest population, individuals exhibit a range of responses to management actions. Deviations from the average response may be transient (e.g., dependent on internal state, body condition, current perceived risk, or density of conspecifics) [6], or may represent persistent , individual-level behavioural differences ('personalities') [7,8]. By understanding the drivers of individual-level differences in behaviour, management can be optimized to target not just the average individual, but the full range of behavioural types within a population. Such insights may be particularly valuable in managing rogue and recalcitrant individuals (see Glossary), two non-exclusive behavioural types that occur in many pest populations and often have Highlights The explicit consideration of individual traits is central to enhancing effective vertebrate pest management. We provide a heuristic framework for understanding animal motivations and cues across spatial scales. Focussing on individual motivations can improve population-level control measures and reduce the impacts of problematic individuals that cause the most damage. Incorporating principles of behavioural ecology will increase the effectiveness of any intervention while providing an opportunity to test behavioural theory in a natural context.

Pacific Conservation Biology, 2020

Managing the impacts of invasive predators on islands is a priority for conserving global biodive... more Managing the impacts of invasive predators on islands is a priority for conserving global biodiversity. However, large islands and islands with substantial human settlement present particular challenges that can be broadly categorised as social and logistical. Around the world, managers concerned with island biodiversity are tackling increasingly ambitious projects, and some examples from Japan and New Zealand have been at the forefront. We used dialogues with managers, researchers, and community members, as well as our respective experience as wildlife researchers in Japan and New Zealand, to compare the challenges faced by wildlife managers in each country. We note similarities and differences between the two countries, and identify lessons from each that will help advance invasive species management on islands globally. Our observations from Japan and New Zealand show that considerable progress has been made in managing invasive predators on large, inhabited islands. Further progress will require more effective engagement with island residents to promote the goals of invasive species management, to find common ground, and to ensure that management is socially and culturally acceptable.

Global Ecology and Conservation , 2019

Damage function models can determine the nature of relationships between the pest population and ... more Damage function models can determine the nature of relationships between the pest population and impact, and can provide guidance about when pest control is required. However, damage functions usually assess risk to species currently occupying conservation areas. Damage functions are not currently used to predict risk to species yet to be reintroduced to conservation areas. While the impacts of several mammalian pest species, such as rats (Rattus spp.), are relatively well-known in urban forest fragments, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Conservation areas within cities provide important habitat for native species and are a focus of current conservation efforts. We developed a damage function describing the relationship between the relative abundance of hedgehogs (determined using a chew card index) and their potential impact (estimated by egg mortality in artificial nests) in a New Zealand urban environment. Egg mortality was positively related to hedgehog abundance, although some egg mortality occurred even at the lowest hedgehog abundances measured. Conservation managers should prioritise hedgehog control at sites of highest hedgehog relative abundances and/or sites containing high value species likely to be at risk. Our results demonstrate the need for conservation managers to proactively assess potential threats to protected areas. Further, we show that damage functions provide an objective means of assessing threats prior to reintroduction of species.

New Zealand Journal of Ecology, 2019

Invasive predator control to protect native fauna usually takes place in native habitat. We inves... more Invasive predator control to protect native fauna usually takes place in native habitat. We investigated the effects of predator control across 6000 ha of multi-tenure, pastoral landscape in Hawke's Bay, North Island, New Zealand. Since 2011, low-cost predator control has been conducted using a network of kill traps for mustelids (Mustela spp.), and live trapping for feral cats (Felis catus). Although not deliberately targeted, other invasive mammals (particularly hedgehogs Erinaceus europaeus) were also trapped. We monitored predators and native prey in the predator-removal area and an adjacent non-treatment area. Predator populations were monitored using large tracking tunnels, which also detected native lizards. Invertebrates were monitored using artificial shelters (weta houses). Occupancy modelling showed that site use by cats and hedgehogs was significantly lower in the predator-removal area than in the non-treatment area. Site use by mustelids also appeared to be lower in the treatment area, although sample sizes were too small to allow firm conclusions. Site use by invasive rats (Rattus spp.) was higher in the treatment area, while that of house mice (Mus musculus) showed no difference between treatments. There was evidence of positive responses of some native biodiversity, with site use by native lizards increasing significantly in the treatment area, but not in the non-treatment area. Counts of native cockroaches were higher in the treatment area, but other invertebrates were detected in similar numbers in both areas. Our results show that low-cost predator control in a pastoral landscape can reduce invasive predator populations, with apparent benefits for some, but not all, native fauna.

New Zealand Journal of Ecology, 2019

Urbanisation causes fragmentation of natural habitats, which results in loss of biodiversity, whi... more Urbanisation causes fragmentation of natural habitats, which results in loss of biodiversity, while promoting an environment that can facilitate invasive species. However, forest fragments are an important refuge for native species and therefore understanding and mitigating threats in fragments is critical. While the impacts of some mammalian pest species, such as rats (Rattus spp.), are relatively well-known in New Zealand, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Hedgehogs are abundant and widespread in New Zealand, with a relatively broad diet that can include invertebrates, lizards and bird eggs. We examined the stomach contents of 44 hedgehogs collected from 10 forest fragments in urban Auckland, New Zealand. Hedgehogs were feeding predominantly on invertebrates (Coleoptera, found in 53% of stomachs; earthworms, 43%; slugs, 23%), but also weta (13%), giant centipedes (5%), birds (7%) and lizards (2%) at lower frequencies. Hedgehogs are likely to be affecting community composition primarily through predation of invertebrates, with unknown effects on their populations.

Animals, 2019

Simple Summary: Feral cats are detrimental to native biodiversity worldwide. In New Zealand, fera... more Simple Summary: Feral cats are detrimental to native biodiversity worldwide. In New Zealand, feral cats are well established across much of the pastoral landscape, including forested areas. Feral cats, like many carnivore species, are elusive in their nature, and often occur at low densities, making them difficult to detect. Camera traps are a useful, non-invasive monitoring device, capable of 'capturing' feral cats as they pass by. Although cameras provide a wealth of information about animals within their field of view; there remains much to be learned about optimal camera trap placement within a landscape, if maximizing detection probability is the objective. Here, we report the results of two methods of camera trap deployment within similar sites: (1) systematic deployment on a grid and (2) strategic deployment, predominantly favoring habitats with assumed higher cat activity. Using the Royle-Nichols abundance-induced heterogeneity model (RN), which assumes detection probability and animal abundance are linked, we found that more cats were detected by cameras at forest margins than in mixed scrub or open farmland (but only slightly more than in forest locations). If maximizing cat detections is the aim, we recommend that cameras should be placed at the edges of forests (including forest fragments) whenever feasible. Abstract: We deploy camera traps to monitor feral cat (Felis catus) populations at two pastoral sites in Hawke's Bay, North Island, New Zealand. At Site 1, cameras are deployed at predetermined GPS points on a 500-m grid, and at Site 2, cameras are strategically deployed with a bias towards forest and forest margin habitat where possible. A portion of cameras are also deployed in open farmland habitat and mixed scrub. We then use the abundance-induced heterogeneity Royle-Nichols model to estimate mean animal abundance and detection probabilities for cameras in each habitat type. Model selection suggests that only cat abundance varies by habitat type. Mean cat abundance is highest at forest margin cameras for both deployment methods (3 cats [95% CI 1.9-4.5] Site 1, and 1.7 cats [95% CI 1.2-2.4] Site 2) but not substantially higher than in forest habitats (1.7 cats [95% CI 0.8-3.6] Site 1, and 1.5 cats [95% CI 1.1-2.0] Site 2). Model selection shows detection probabilities do not vary substantially by habitat (although they are also higher for cameras in forest margins and forest habitats) and are similar between sites (8.6% [95% CI 5.4-13.4] Site 1, and 8.3% [5.8-11.9] Site 2). Cat detections by camera traps are higher when placed in forests and forest margins; thus, strategic placement may be preferable when monitoring feral cats in a pastoral landscape.

Animals, 2020

Simple Summary: Camera trap wildlife surveys can generate vast amounts of imagery. A key problem ... more Simple Summary: Camera trap wildlife surveys can generate vast amounts of imagery. A key problem in the wildlife ecology field is that vast amounts of time is spent reviewing this imagery to identify the species detected. Valuable resources are wasted, and the scale of studies is limited by this review process. The use of computer software capable of extracting false positives, automatically identifying animals detected and sorting imagery could greatly increase efficiency. Artificial intelligence has been demonstrated as an effective option for automatically identifying species from camera trap imagery. Currently available code bases are inaccessible to the majority of users; requiring high-performance computers, advanced software engineering skills and, often, high-bandwidth internet connections to access cloud services. The ClassifyMe software tool is designed to address this gap and provides users the opportunity to utilise state-of-the-art image recognition algorithms without the need for specialised computer programming skills. ClassifyMe is especially designed for field researchers, allowing users to sweep through camera trap imagery using field computers instead of office-based workstations. Abstract: We present ClassifyMe a software tool for the automated identification of animal species from camera trap images. ClassifyMe is intended to be used by ecologists both in the field and in the office. Users can download a pre-trained model specific to their location of interest and then upload the images from a camera trap to a laptop or workstation. ClassifyMe will identify animals and other objects (e.g., vehicles) in images, provide a report file with the most likely species detections, and automatically sort the images into sub-folders corresponding to these species categories. False Triggers (no visible object present) will also be filtered and sorted. Importantly, the ClassifyMe software operates on the user's local machine (own laptop or workstation)-not via internet connection. This allows users access to state-of-the-art camera trap computer vision software in situ, rather than only in the office. The software also incurs minimal cost on the end-user as there is no need for expensive data uploads to cloud services. Furthermore, processing the images locally on Animals 2020, 10, 58 2 of 16 the users' end-device allows them data control and resolves privacy issues surrounding transfer and third-party access to users' datasets.

Pacific Conservation Biology, 2020

Managing the impacts of invasive predators on islands is a priority for conserving global biodive... more Managing the impacts of invasive predators on islands is a priority for conserving global biodiversity. However, large islands and islands with substantial human settlement present particular challenges that can be broadly categorised as social and logistical. Around the world, managers concerned with island biodiversity are tackling increasingly ambitious projects, and some examples from Japan and New Zealand have been at the forefront. We used dialogues with managers, researchers, and community members, as well as our respective experience as wildlife researchers in Japan and New Zealand, to compare the challenges faced by wildlife managers in each country. We note similarities and differences between the two countries, and identify lessons from each that will help advance invasive species management on islands globally. Our observations from Japan and New Zealand show that considerable progress has been made in managing invasive predators on large, inhabited islands. Further progress will require more effective engagement with island residents to promote the goals of invasive species management, to find common ground, and to ensure that management is socially and culturally acceptable.

Damage function models can determine the nature of relationships between the pest population and ... more Damage function models can determine the nature of relationships between the pest population and impact, and can provide guidance about when pest control is required. However, damage functions usually assess risk to species currently occupying conservation areas. Damage functions are not currently used to predict risk to species yet to be reintroduced to conservation areas. While the impacts of several mammalian pest species, such as rats (Rattus spp.), are relatively well-known in urban forest fragments, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Conservation areas within cities provide important habitat for native species and are a focus of current conservation efforts. We developed a damage function describing the relationship between the relative abundance of hedgehogs (determined using a chew card index) and their potential impact (estimated by egg mortality in artificial nests) in a New Zealand urban environment. Egg mortality was positively related to hedgehog abundance, although some egg mortality occurred even at the lowest hedgehog abundances measured. Conservation managers should prioritise hedgehog control at sites of highest hedgehog relative abundances and/or sites containing high value species likely to be at risk. Our results demonstrate the need for conservation managers to proactively assess potential threats to protected areas. Further, we show that damage functions provide an objective means of assessing threats prior to reintroduction of species.

Context. Dogs are often used to find rare or cryptic species, but search methods are not standard... more Context. Dogs are often used to find rare or cryptic species, but search methods are not standardised, making it difficult to interpret and compare results. Standardised approaches are needed to optimise search effectiveness and/or efficiency. Designing an optimal search strategy requires knowledge of the effective sweep width, which is related to the probability of detection (POD) at various distances between the searcher and the search object. Aims. Our primary aim was to estimate effective sweep width for wildlife-detector dogs searching for rodents. We also tested whether dogs differed in their reaction on encountering a laboratory rat (Rattus norvegicus) or a wild-caught Norway rat (wild-type R. norvegicus). Methods. We conducted field trials using trained rodent-detector dogs to locate dead laboratory rats. We used the numbers of detections and non-detections at distances of 0–100 m to estimate detection probability and effective sweep width. Key results. Dog teams located 100% of rats (regardless of strain) placed directly in their search path. POD declined rapidly with an increasing distance, yielding an observed detection rate of 33% at 10 m, and close to zero at !20 m. The data were best described by an exponential decay function. Effective sweep width was estimated to be 16.8 m (95% confidence interval 12.3–21.4 m), corresponding to a strip extending 8.4 m on either side of a walked track. Handlers could not consistently judge whether a dog had encountered a laboratory rat or a wild rat. Conclusions. Our results suggest that when dogs are >10 m from a source of rat odour, POD declines sharply. We estimate that the effective distance explored when searching for a stationary rodent is 8.4 m either side of the search path. Implications. This information will allow users to optimise the search pattern that dog teams should follow for a given search scenario.

Monitoring rare or cryptic species can be challenging, especially with limited time and resources... more Monitoring rare or cryptic species can be challenging, especially with limited time and resources. Dogs are often used for this purpose, but methods are highly variable. There is a need to optimise search methods for dog teams so that time and resources are used as efficiently as possible. Some degree of standardisation is also desirable so that search results are comparable between different times and places. The discipline of search theory has developed effective methods to maximise the probability of detecting a search object and/or maximise the efficiency of a search. However, these advances have not been explicitly applied to the use of dogs to search for plants and animals in the wild. Here, we provide a brief introduction to search theory, then discuss how ideas from search theory might be used to standardise and optimise the use of conservation detection dogs. We describe approaches that have been used, discuss their strengths and weaknesses, and suggest priorities for further research. Standardised methods based on search theory could increase the effectiveness of conservation detection dogs, and make search results more comparable across different locations and times.

New Zealand Journal of Ecology, 2023

Cats (Felis catus) are among the most damaging invasive predators in the world, and their impacts... more Cats (Felis catus) are among the most damaging invasive predators in the world, and their impacts in Aotearoa New Zealand (NZ) are particularly severe. However, unlike the invasive predators that are targeted for eradication under the Predator Free NZ initiative, cats are also highly valued by people and therefore will likely remain widespread in NZ for the foreseeable future. This raises the question of how to manage the impacts of cats, which include predation, competition, and disease affecting native species, livestock, and humans. Appropriate management actions will depend on land use (e.g. urban areas vs wilderness), the values to be protected (e.g. wildlife, human health), as well as safety, humaneness, social acceptability, and cost-effectiveness. We review current knowledge on the impacts and management of cats in NZ and overseas, identify knowledge gaps preventing effective management, and suggest approaches for research to address these gaps. Our suggested research priorities include: (1) improved methods for monitoring cats and their impacts on natural, social and economic values, (2) development of humane, effective, and socially acceptable methods to manage the impacts of cats, (3) engagement with cat owners to improve outcomes for cats, people, and the environment, and (4) investigating potential indirect ecological effects of cat control, such as ecological release of prey or competitors.

Wildlife Research, 2023

Small mammalian predators can have low population densities, as well as cryptic and highly mobile... more Small mammalian predators can have low population densities, as well as cryptic and highly mobile behaviours, making these species challenging to manage. Monitoring tools such as camera traps, hair traps and footprint tracking devices can help detect cryptic species, but they require an animal to approach and, in most cases, interact with a device. They also have limited capacity to help capture animals. Wildlife-detection dogs can detect a wide range of species with a similar or higher efficiency than do other methods, partly because they are much less dependent on volitional decisions of target animals to interact with devices. By following scent trails, dogs can track down animals that actively avoid capture or detection. Dog-handler teams also have another advantage, namely, the handler can mount a rapid management response to capture or remove animals as soon as they are detected. We review ways in which dog-handler teams can contribute to active management of small mammalian predators by combining the dogs' ability to detect animals with their handlers' ability to mount a rapid response.

Conservation Science and Practice, 2023

The fungal genus Phytophthora includes an array of destructive plant pathogens that have had seve... more The fungal genus Phytophthora includes an array of destructive plant pathogens that have had severe impacts on native, agricultural, and horticultural systems worldwide. Preventing the spread of Phytophthora species is critical for protecting vulnerable plants and ecosystems; yet detection remains a challenge due to their microscopic size, broad host range, and latent and cryptic expression in host plants. We tested the effectiveness of trained detec

New Zealand Journal of Ecology, 2022

As a major threat to New Zealand's biodiversity, feral cats (Felis catus) are the subject of plan... more As a major threat to New Zealand's biodiversity, feral cats (Felis catus) are the subject of planned eradications on a number of offshore islands, including Rakiura Stewart Island. We used camera traps to estimate population density of feral cats on the northeast coast of Rakiura, and to investigate their movement behaviour and detection probability. We also used camera footage to compare the consumption of two types of non-toxic sausage baits (chicken and rabbit) with a view to future use of toxic baits. Population density of feral cats was likely between 1 and 2 cats per km 2. Non-target species (rats and possums) removed more than half the baits, greatly reducing bait availability for feral cats. Deer and birds (including kiwi) encountered baits but did not eat them. Cats had an apparent preference for chicken over rabbit baits, although small sample sizes prevent firm conclusions. Both bait types appeared to decline rapidly in palatability, and no baits were consumed by cats more than 5 days after deployment. Future trials and baiting regimes should consider ways to improve bait availability. Increased bait density, exclusion of rats and possums and/or more frequent replacement of baits will likely increase encounter rates by feral cats.

New Zealand Journal of Ecology, 2022

In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is pl... more In order to conserve important biodiversity values, eradication of feral cats (Felis catus) is planned on Auckland Island in the New Zealand subantarctic region. This eradication will require detailed knowledge of the abundance, distribution, movement behaviour and detection probability of cats on the island. We investigated these parameters on a peninsula at the northern end of the island using live trapping, camera trapping, and scat searches with and without detection dogs. Here, we compare the results of these methods, and discuss their utility for the planned eradication. Four cats were captured and fitted with GPS collars. Camera traps with 500 m spacing detected all these individuals on multiple occasions, and at multiple locations. At least 12 other individuals were also captured on camera. Excluding every second camera (to simulate 1000 m spacing) resulted in failure to detect 32% of known individuals. Population density estimates from camera trapping varied from 0.7-1.0 cats km-2. Humans found 29 cat scats, and dogs found 33. Genetic analysis estimated that these came from a minimum of ten individuals. Camera trapping should be repeated during the operational and confirmation phases of the eradication to monitor spatial and temporal variation in cat density, detect survivors, and help confirm eradication success. Scat collection, with and without dogs, can supplement data from camera trapping. With larger sample sizes of scats, DNA profiling may also allow cat abundance to be estimated.

New Zealand Journal of Ecology, 2023

Feral cats (Felis catus) have a negative impact on native biodiversity in New Zealand. As such, t... more Feral cats (Felis catus) have a negative impact on native biodiversity in New Zealand. As such, their populations require careful management and monitoring of the effectiveness of these management operations. We used camera traps to assess (1) effectiveness of an intensive cat control operation, and (2) the level of reinvasion six months later. Cat abundance was estimated on a pastoral property in Hawke's Bay, North Island, New Zealand, subject to cat control using trapping and shooting. Forty cameras were placed on a grid with 500 m spacing and deployed for a total of nine weeks: (1) pre-control, (2) immediately post-control, and (3) six-months post control. Cat abundance was estimated using an index-manipulation-index (IMI) method. The IMI method estimated an c. 84% decrease in cat abundance immediately post-control, suggesting the operation worked well at removing most resident cats at this site. The detections observed six months later suggest reinvasion was very low.

New Zealand Journal of Ecology, 2022

Managing invasive species requires knowledge of their ecology, including distribution, habitat us... more Managing invasive species requires knowledge of their ecology, including distribution, habitat use, and home range. In particular, understanding how biotic and abiotic factors influence home range can help with pest management decision-making, as well as informing native species management. Feral cats, self-sustaining cat populations that live independently of people, have caused numerous extinctions and continue to adversely affect native species globally. Managing feral cat populations requires spatially explicit knowledge to enable strategic deployment of management or monitoring devices, understand where native species are most likely to be at risk, and to mitigate the spread of cat-vectored diseases such as toxoplasmosis. Here, we present a meta-analysis of factors that influence feral cat home range size including land use types, differing levels of land use heterogeneity, and numbers of competitors. Male feral cats had larger home ranges than females, but effects of season, competitors, habitat heterogeneity, or land use on feral cat home range were not statistically significant, possibly due to high variability (male cat home range: 22.1 to 3232 ha; female cat home range: 9.6 to 2078 ha). This may reflect the fact that cats are generalists and are able to exploit any opportunity. Thus, we recommend that these factors and others, such as prey availability and composition, should be included in future research, so that the variability in home range size can be better understood. Improved understanding is vital for improving feral cat management in ecosystems where cats have been introduced.

New Zealand Journal of Ecology, 2021

The impact of feral cats on native wildlife is becoming increasingly recognised worldwide, making... more The impact of feral cats on native wildlife is becoming increasingly recognised worldwide, making their management a necessity. As New Zealand's Predator Free 2050 goal leads to larger and more ambitious landscape scale programmes, there is an important need for cost-and time-effective tools. Para-aminopropiophenone (PAPP) was first registered in New Zealand for feral cats and stoats in 2011 under the name PredaSTOP® and has higher target specificity for feral cats than currently used toxins. Following a successful trial of PAPP on Toronui Station, Hawke's Bay in 2017, a larger operation was undertaken in 2018 across 9123 ha of the Poutiri Ao ō Tāne project area in Hawke's Bay. Camera traps were used to monitor the relative abundance of feral cats on Opouahi Station (treatment site) and at Waitere Station(non-treatment site). A network of 287 bait stations was established in 500 m grid spacings across the treatment site. Two applications of non-toxic pre-feed minced meat baits were followed by two applications of toxic PAPP baits. PAPP baits were dyed green and contained 80 mg of PredaSTOP® in the centre of the bait. Each application of PredaSTOP® consisted of two baits placed at either end of each bait station. Toxic baits were removed from at least 130 bait stations. We assume that ≥ 130 feral cats are likely to have been killed, resulting in a 39% reduction in the relative abundance of feral cats after the operation. Our results suggest that PAPP has the potential to be a useful management tool across large areas alongside other methods.

New Zealand Journal of Zoology, 2020

Trends in Ecology & Evolution, 2020

Managing vertebrate pests is a global conservation challenge given their undesirable socio-ecolog... more Managing vertebrate pests is a global conservation challenge given their undesirable socio-ecological impacts. Pest management often focuses on the 'average' individual, neglecting individual-level behavioural variation ('personalities') and differences in life histories. These differences affect pest impacts and modify attraction to, or avoidance of, sensory cues. Strategies targeting the average individual may fail to mitigate damage by 'rogues' (individuals causing disproportionate impact) or to target 'recalcitrants' (individuals avoiding standard control measures). Effective management leverages animal behaviours that relate primarily to four core motivations: feeding, fleeing, fighting, and fornication. Management success could be greatly increased by identifying and exploiting individual variation in motivations. We provide explicit suggestions for cue-based tools to manipulate these four motivators, thereby improving pest management outcomes. Looking Beyond the 'Average' Individual in Vertebrate Pest Management Vertebrate pests, including invasive or overabundant predators and herbivores, frequently come into conflict with economic, social, and biodiversity values. Mammalian predators are responsible for some of the most devastating losses to native biodiversity [1] and frequently harm humans, their livestock, and pets, while herbivores can cause agricultural damage, vehicle collisions , and ecosystem-level impacts including overbrowsing [2,3]. Mitigating the impacts of vertebrate pests thus presents one of the major challenges currently facing wildlife managers. Managers require effective strategies to: (i) reduce pest populations (e.g., by attracting individuals to traps or toxic baits), and (ii) deter individuals from sensitive areas or valuable species (e.g., threatened prey or plant species, livestock, agricultural, and forestry sites). Yet, pest control measures are often only partially effective [4,5], with some individuals avoiding lethal control or ignoring deterrents. Attractants and deterrents typically target the 'average' individual in a population, with the goal of maximising the number of animals responding to stimuli. However, the most intractable challenges of vertebrate pest management may occur precisely because some individuals do not behave like the average, and therefore, are not effectively targeted. Within a pest population, individuals exhibit a range of responses to management actions. Deviations from the average response may be transient (e.g., dependent on internal state, body condition, current perceived risk, or density of conspecifics) [6], or may represent persistent , individual-level behavioural differences ('personalities') [7,8]. By understanding the drivers of individual-level differences in behaviour, management can be optimized to target not just the average individual, but the full range of behavioural types within a population. Such insights may be particularly valuable in managing rogue and recalcitrant individuals (see Glossary), two non-exclusive behavioural types that occur in many pest populations and often have Highlights The explicit consideration of individual traits is central to enhancing effective vertebrate pest management. We provide a heuristic framework for understanding animal motivations and cues across spatial scales. Focussing on individual motivations can improve population-level control measures and reduce the impacts of problematic individuals that cause the most damage. Incorporating principles of behavioural ecology will increase the effectiveness of any intervention while providing an opportunity to test behavioural theory in a natural context.

Pacific Conservation Biology, 2020

Managing the impacts of invasive predators on islands is a priority for conserving global biodive... more Managing the impacts of invasive predators on islands is a priority for conserving global biodiversity. However, large islands and islands with substantial human settlement present particular challenges that can be broadly categorised as social and logistical. Around the world, managers concerned with island biodiversity are tackling increasingly ambitious projects, and some examples from Japan and New Zealand have been at the forefront. We used dialogues with managers, researchers, and community members, as well as our respective experience as wildlife researchers in Japan and New Zealand, to compare the challenges faced by wildlife managers in each country. We note similarities and differences between the two countries, and identify lessons from each that will help advance invasive species management on islands globally. Our observations from Japan and New Zealand show that considerable progress has been made in managing invasive predators on large, inhabited islands. Further progress will require more effective engagement with island residents to promote the goals of invasive species management, to find common ground, and to ensure that management is socially and culturally acceptable.

Global Ecology and Conservation , 2019

Damage function models can determine the nature of relationships between the pest population and ... more Damage function models can determine the nature of relationships between the pest population and impact, and can provide guidance about when pest control is required. However, damage functions usually assess risk to species currently occupying conservation areas. Damage functions are not currently used to predict risk to species yet to be reintroduced to conservation areas. While the impacts of several mammalian pest species, such as rats (Rattus spp.), are relatively well-known in urban forest fragments, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Conservation areas within cities provide important habitat for native species and are a focus of current conservation efforts. We developed a damage function describing the relationship between the relative abundance of hedgehogs (determined using a chew card index) and their potential impact (estimated by egg mortality in artificial nests) in a New Zealand urban environment. Egg mortality was positively related to hedgehog abundance, although some egg mortality occurred even at the lowest hedgehog abundances measured. Conservation managers should prioritise hedgehog control at sites of highest hedgehog relative abundances and/or sites containing high value species likely to be at risk. Our results demonstrate the need for conservation managers to proactively assess potential threats to protected areas. Further, we show that damage functions provide an objective means of assessing threats prior to reintroduction of species.

New Zealand Journal of Ecology, 2019

Invasive predator control to protect native fauna usually takes place in native habitat. We inves... more Invasive predator control to protect native fauna usually takes place in native habitat. We investigated the effects of predator control across 6000 ha of multi-tenure, pastoral landscape in Hawke's Bay, North Island, New Zealand. Since 2011, low-cost predator control has been conducted using a network of kill traps for mustelids (Mustela spp.), and live trapping for feral cats (Felis catus). Although not deliberately targeted, other invasive mammals (particularly hedgehogs Erinaceus europaeus) were also trapped. We monitored predators and native prey in the predator-removal area and an adjacent non-treatment area. Predator populations were monitored using large tracking tunnels, which also detected native lizards. Invertebrates were monitored using artificial shelters (weta houses). Occupancy modelling showed that site use by cats and hedgehogs was significantly lower in the predator-removal area than in the non-treatment area. Site use by mustelids also appeared to be lower in the treatment area, although sample sizes were too small to allow firm conclusions. Site use by invasive rats (Rattus spp.) was higher in the treatment area, while that of house mice (Mus musculus) showed no difference between treatments. There was evidence of positive responses of some native biodiversity, with site use by native lizards increasing significantly in the treatment area, but not in the non-treatment area. Counts of native cockroaches were higher in the treatment area, but other invertebrates were detected in similar numbers in both areas. Our results show that low-cost predator control in a pastoral landscape can reduce invasive predator populations, with apparent benefits for some, but not all, native fauna.

New Zealand Journal of Ecology, 2019

Urbanisation causes fragmentation of natural habitats, which results in loss of biodiversity, whi... more Urbanisation causes fragmentation of natural habitats, which results in loss of biodiversity, while promoting an environment that can facilitate invasive species. However, forest fragments are an important refuge for native species and therefore understanding and mitigating threats in fragments is critical. While the impacts of some mammalian pest species, such as rats (Rattus spp.), are relatively well-known in New Zealand, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Hedgehogs are abundant and widespread in New Zealand, with a relatively broad diet that can include invertebrates, lizards and bird eggs. We examined the stomach contents of 44 hedgehogs collected from 10 forest fragments in urban Auckland, New Zealand. Hedgehogs were feeding predominantly on invertebrates (Coleoptera, found in 53% of stomachs; earthworms, 43%; slugs, 23%), but also weta (13%), giant centipedes (5%), birds (7%) and lizards (2%) at lower frequencies. Hedgehogs are likely to be affecting community composition primarily through predation of invertebrates, with unknown effects on their populations.

Animals, 2019

Simple Summary: Feral cats are detrimental to native biodiversity worldwide. In New Zealand, fera... more Simple Summary: Feral cats are detrimental to native biodiversity worldwide. In New Zealand, feral cats are well established across much of the pastoral landscape, including forested areas. Feral cats, like many carnivore species, are elusive in their nature, and often occur at low densities, making them difficult to detect. Camera traps are a useful, non-invasive monitoring device, capable of 'capturing' feral cats as they pass by. Although cameras provide a wealth of information about animals within their field of view; there remains much to be learned about optimal camera trap placement within a landscape, if maximizing detection probability is the objective. Here, we report the results of two methods of camera trap deployment within similar sites: (1) systematic deployment on a grid and (2) strategic deployment, predominantly favoring habitats with assumed higher cat activity. Using the Royle-Nichols abundance-induced heterogeneity model (RN), which assumes detection probability and animal abundance are linked, we found that more cats were detected by cameras at forest margins than in mixed scrub or open farmland (but only slightly more than in forest locations). If maximizing cat detections is the aim, we recommend that cameras should be placed at the edges of forests (including forest fragments) whenever feasible. Abstract: We deploy camera traps to monitor feral cat (Felis catus) populations at two pastoral sites in Hawke's Bay, North Island, New Zealand. At Site 1, cameras are deployed at predetermined GPS points on a 500-m grid, and at Site 2, cameras are strategically deployed with a bias towards forest and forest margin habitat where possible. A portion of cameras are also deployed in open farmland habitat and mixed scrub. We then use the abundance-induced heterogeneity Royle-Nichols model to estimate mean animal abundance and detection probabilities for cameras in each habitat type. Model selection suggests that only cat abundance varies by habitat type. Mean cat abundance is highest at forest margin cameras for both deployment methods (3 cats [95% CI 1.9-4.5] Site 1, and 1.7 cats [95% CI 1.2-2.4] Site 2) but not substantially higher than in forest habitats (1.7 cats [95% CI 0.8-3.6] Site 1, and 1.5 cats [95% CI 1.1-2.0] Site 2). Model selection shows detection probabilities do not vary substantially by habitat (although they are also higher for cameras in forest margins and forest habitats) and are similar between sites (8.6% [95% CI 5.4-13.4] Site 1, and 8.3% [5.8-11.9] Site 2). Cat detections by camera traps are higher when placed in forests and forest margins; thus, strategic placement may be preferable when monitoring feral cats in a pastoral landscape.

Animals, 2020

Simple Summary: Camera trap wildlife surveys can generate vast amounts of imagery. A key problem ... more Simple Summary: Camera trap wildlife surveys can generate vast amounts of imagery. A key problem in the wildlife ecology field is that vast amounts of time is spent reviewing this imagery to identify the species detected. Valuable resources are wasted, and the scale of studies is limited by this review process. The use of computer software capable of extracting false positives, automatically identifying animals detected and sorting imagery could greatly increase efficiency. Artificial intelligence has been demonstrated as an effective option for automatically identifying species from camera trap imagery. Currently available code bases are inaccessible to the majority of users; requiring high-performance computers, advanced software engineering skills and, often, high-bandwidth internet connections to access cloud services. The ClassifyMe software tool is designed to address this gap and provides users the opportunity to utilise state-of-the-art image recognition algorithms without the need for specialised computer programming skills. ClassifyMe is especially designed for field researchers, allowing users to sweep through camera trap imagery using field computers instead of office-based workstations. Abstract: We present ClassifyMe a software tool for the automated identification of animal species from camera trap images. ClassifyMe is intended to be used by ecologists both in the field and in the office. Users can download a pre-trained model specific to their location of interest and then upload the images from a camera trap to a laptop or workstation. ClassifyMe will identify animals and other objects (e.g., vehicles) in images, provide a report file with the most likely species detections, and automatically sort the images into sub-folders corresponding to these species categories. False Triggers (no visible object present) will also be filtered and sorted. Importantly, the ClassifyMe software operates on the user's local machine (own laptop or workstation)-not via internet connection. This allows users access to state-of-the-art camera trap computer vision software in situ, rather than only in the office. The software also incurs minimal cost on the end-user as there is no need for expensive data uploads to cloud services. Furthermore, processing the images locally on Animals 2020, 10, 58 2 of 16 the users' end-device allows them data control and resolves privacy issues surrounding transfer and third-party access to users' datasets.

Pacific Conservation Biology, 2020

Managing the impacts of invasive predators on islands is a priority for conserving global biodive... more Managing the impacts of invasive predators on islands is a priority for conserving global biodiversity. However, large islands and islands with substantial human settlement present particular challenges that can be broadly categorised as social and logistical. Around the world, managers concerned with island biodiversity are tackling increasingly ambitious projects, and some examples from Japan and New Zealand have been at the forefront. We used dialogues with managers, researchers, and community members, as well as our respective experience as wildlife researchers in Japan and New Zealand, to compare the challenges faced by wildlife managers in each country. We note similarities and differences between the two countries, and identify lessons from each that will help advance invasive species management on islands globally. Our observations from Japan and New Zealand show that considerable progress has been made in managing invasive predators on large, inhabited islands. Further progress will require more effective engagement with island residents to promote the goals of invasive species management, to find common ground, and to ensure that management is socially and culturally acceptable.

Damage function models can determine the nature of relationships between the pest population and ... more Damage function models can determine the nature of relationships between the pest population and impact, and can provide guidance about when pest control is required. However, damage functions usually assess risk to species currently occupying conservation areas. Damage functions are not currently used to predict risk to species yet to be reintroduced to conservation areas. While the impacts of several mammalian pest species, such as rats (Rattus spp.), are relatively well-known in urban forest fragments, hedgehogs (Erinaceus europaeus) are relatively understudied invasive mammals, and their impacts in urban fragments are unknown. Conservation areas within cities provide important habitat for native species and are a focus of current conservation efforts. We developed a damage function describing the relationship between the relative abundance of hedgehogs (determined using a chew card index) and their potential impact (estimated by egg mortality in artificial nests) in a New Zealand urban environment. Egg mortality was positively related to hedgehog abundance, although some egg mortality occurred even at the lowest hedgehog abundances measured. Conservation managers should prioritise hedgehog control at sites of highest hedgehog relative abundances and/or sites containing high value species likely to be at risk. Our results demonstrate the need for conservation managers to proactively assess potential threats to protected areas. Further, we show that damage functions provide an objective means of assessing threats prior to reintroduction of species.

Context. Dogs are often used to find rare or cryptic species, but search methods are not standard... more Context. Dogs are often used to find rare or cryptic species, but search methods are not standardised, making it difficult to interpret and compare results. Standardised approaches are needed to optimise search effectiveness and/or efficiency. Designing an optimal search strategy requires knowledge of the effective sweep width, which is related to the probability of detection (POD) at various distances between the searcher and the search object. Aims. Our primary aim was to estimate effective sweep width for wildlife-detector dogs searching for rodents. We also tested whether dogs differed in their reaction on encountering a laboratory rat (Rattus norvegicus) or a wild-caught Norway rat (wild-type R. norvegicus). Methods. We conducted field trials using trained rodent-detector dogs to locate dead laboratory rats. We used the numbers of detections and non-detections at distances of 0–100 m to estimate detection probability and effective sweep width. Key results. Dog teams located 100% of rats (regardless of strain) placed directly in their search path. POD declined rapidly with an increasing distance, yielding an observed detection rate of 33% at 10 m, and close to zero at !20 m. The data were best described by an exponential decay function. Effective sweep width was estimated to be 16.8 m (95% confidence interval 12.3–21.4 m), corresponding to a strip extending 8.4 m on either side of a walked track. Handlers could not consistently judge whether a dog had encountered a laboratory rat or a wild rat. Conclusions. Our results suggest that when dogs are >10 m from a source of rat odour, POD declines sharply. We estimate that the effective distance explored when searching for a stationary rodent is 8.4 m either side of the search path. Implications. This information will allow users to optimise the search pattern that dog teams should follow for a given search scenario.

Monitoring rare or cryptic species can be challenging, especially with limited time and resources... more Monitoring rare or cryptic species can be challenging, especially with limited time and resources. Dogs are often used for this purpose, but methods are highly variable. There is a need to optimise search methods for dog teams so that time and resources are used as efficiently as possible. Some degree of standardisation is also desirable so that search results are comparable between different times and places. The discipline of search theory has developed effective methods to maximise the probability of detecting a search object and/or maximise the efficiency of a search. However, these advances have not been explicitly applied to the use of dogs to search for plants and animals in the wild. Here, we provide a brief introduction to search theory, then discuss how ideas from search theory might be used to standardise and optimise the use of conservation detection dogs. We describe approaches that have been used, discuss their strengths and weaknesses, and suggest priorities for further research. Standardised methods based on search theory could increase the effectiveness of conservation detection dogs, and make search results more comparable across different locations and times.

Proceedings of the 35th Australasian Wildlife Management Society Conference, 2022

Camera traps are useful for monitoring wildlife, but can produce thousands of images, which are t... more Camera traps are useful for monitoring wildlife, but can produce thousands of images, which are time-consuming and costly to process. We have developed a free online tool, CamTrapNZ, that allows camera trap users to manage their images quickly and easily. Using artificial intelligence, our tool can identify images of 13 taxa commonly detected by camera traps in New Zealand: kiwi, other bird, cat, ferret, stoat/weasel, possum, rat, mouse, hedgehog, lagomorph, wallaby, pig, and livestock. The model could be trained to recognise more taxa in future. Results are presented in a spreadsheet, which shows the species/taxon identified in each image, as well as a confidence score. In addition, the online tool allows users to produce maps, graphs, and other reports of their results. The software is hosted on TrapNZ (www.trap.nz), a free online platform widely used for recording pest control, monitoring, and biodiversity outcome data in New Zealand.