Showing papers in "Wildlife Research in 2021"

An overview of the history, current contributions and future outlook of iNaturalist in Australia

Abstract: Citizen science initiatives and the data they produce are increasingly common in ecology, conservation and biodiversity monitoring. Although the quality of citizen science data has historically been questioned, biases can be detected and corrected for, allowing these data to become comparable in quality to professionally collected data. Consequently, citizen science is increasingly being integrated with professional science, allowing the collection of data at unprecedented spatial and temporal scales. iNaturalist is one of the most popular biodiversity citizen science platforms globally, with more than 1.4 million users having contributed over 54 million observations. Australia is the top contributing nation in the southern hemisphere, and in the top four contributing nations globally, with over 1.6 million observations of over 36 000 identified species contributed by almost 27 000 users. Despite the platform’s success, there are few holistic syntheses of contributions to iNaturalist, especially for Australia. Here, we outline the history of iNaturalist from an Australian perspective, and summarise, taxonomically, temporally and spatially, Australian biodiversity data contributed to the platform. We conclude by discussing important future directions to maximise the usefulness of these data for ecological research, conservation and policy.

Flooding-induced mortality of loggerhead sea turtle eggs

Abstract: Context Marine turtle eggs incubate in dynamic beaches, where they are vulnerable to both saltwater and freshwater flooding. Understanding the capacity for marine turtle eggs to tolerate flooding will aid management efforts to predict and mitigate the impacts of climate change, including sea-level rise and increases in coastal flooding. Aims Evaluate the interactive effects of flooding duration and incubation stage on the hatching success of loggerhead turtle (Caretta caretta) eggs. Methods Groups of 20 eggs from multiple clutches were incubated in plastic containers in a beach hatchery. Eggs at six stages of incubation (0, 1, 2, 4, 6 and 7 weeks post-oviposition) were excavated from the hatchery and exposed to saltwater or freshwater flooding for seven durations of time (0, 1, 2, 3, 6, 24 or 48 h). Containers of eggs were either submerged in a bucket of water or left outside of the bucket (control; no flooding) for their designated duration, allowed to drain, then reburied in the hatchery. Following hatchling emergence, the hatching success of each group of eggs was evaluated. Key results Freshly laid eggs and eggs on the verge of hatching exposed to any flooding and all eggs exposed to extended periods of flooding (24 and 48 h) suffered complete mortality. Eggs at 20–80% development exposed to short periods of flooding (1–6 h) maintained high hatching success that was statistically equivalent to control eggs, while eggs at 80% development exhibited significant decreases in hatching success. Conclusions Marine turtle eggs in the middle of incubation can tolerate saltwater and freshwater flooding for up to 6 h. Outside of this period or when flooding is longer, disruption of gas concentrations and osmotic gradients in the egg chamber can lead to embryonic mortality. These findings have reinforced concerns regarding the capacity for marine turtle populations to continue to function as rising sea levels and increases in coastal flooding alter the hydrology of nesting beaches. Implications As current and predicted climate change threatens the suitability of the incubation environment used by marine turtles, corrective actions to maximise hatching success need to be taken before the eggs are flooded.

Reptiles as food: predation of Australian reptiles by introduced red foxes compounds and complements predation by cats

Abstract: Context. Invasive species are a major cause of biodiversity loss across much of the world, and a key threat to Australia’s diverse reptile fauna. There has been no previous comprehensive analysis of the potential impact of the introduced European red fox, Vulpes vulpes, on Australian reptiles. Aims. We seek to provide an inventory of all Australian reptile species known to be consumed by the fox, and identify characteristics of squamate species associated with such predation. We also compare these tallies and characteristics with reptile species known to be consumed by the domestic cat, Felis catus, to examine whether predation by these two introduced species is compounded (i.e. affecting much the same set of species) or complementary (affecting different groups of species). Methods. We collated records of Australian reptiles consumed by foxes in Australia, with most records deriving from fox dietary studies (tallying >35 000 samples). We modelled presence or absence of fox predation records against a set of biological and other traits, and population trends, for squamate species. Key results. In total, 108 reptile species (∼11% of Australia’s terrestrial reptile fauna) have been recorded as consumed by foxes, fewer than that reported for cats (263 species). Eighty-six species have been reported to be eaten by both predators. More Australian turtle species have been reported as consumed by foxes than by cats, including many that suffer high levels of predation on egg clutches. Twenty threatened reptile species have been reported as consumed by foxes, and 15 by cats. Squamate species consumed by foxes are more likely to be undergoing population decline than those not known to be consumed by foxes. The likelihood of predation by foxes increased with squamate species’ adult body mass, in contrast to the relationship for predation by cats, which peaked at ∼217 g. Foxes, but not cats, were also less likely to consume venomous snakes. Conclusions. The two introduced, and now widespread, predators have both compounding and complementary impacts on the Australian reptile fauna. Implications. Enhanced and integrated management of the two introduced predators is likely to provide substantial conservation benefits to much of the Australian reptile fauna.

Seed dispersal by Neotropical bats in human-disturbed landscapes

Abstract: In human-modified landscapes, where large bird and mammal species are often functionally extinct, bats are the main seed dispersers. However, the role of seed dispersal by bats for the maintenance of habitat dynamics in fragmented landscapes is still not understood, with information lacking on landscape-level effects of plant–bat interactions. We present some key topics related to spatial ecology of bats and discuss the potential influence of habitat fragmentation on several aspects of seed dispersal by Neotropical bats. We suggest that future studies need to evaluate bat–plant networks along habitat-loss and fragmentation gradients at the landscape level, including changes in land-cover types and habitat structural complexity, going beyond patch-based analysis. By advancing on the comprehension of ecosystem functioning in fragmented landscapes, we will better understand the bat-modulated seed-dispersal process, supporting regeneration and restoration programs that benefit from bat-based functions.

Ontogenetic changes in energy expenditure and resting behaviour of humpback whale mother–calf pairs examined using unmanned aerial vehicles

Abstract: Context Baleen whale calves rapidly increase in size and improve locomotion abilities, while on their low-latitude breeding ground, allowing them to undertake a successful migration to high-latitude feeding grounds. Aims We investigated energy expenditure and resting behaviour of humpback whale (Megaptera novaeangliae) mother–calf pairs in regard to changes in calf length on an undisturbed breeding/resting ground off Exmouth Gulf, Western Australia. Methods Data were collected from August to October in 2018 and 2019 on lactating mothers that were predominantly resting on the surface with their calf. Focal follows on mother–calf pairs (n = 101) were conducted using an unmanned aerial vehicle to obtain detailed video of behaviours and respirations (23.7 h). Body length measurements of individual whales were calculated from aerial still frames. Key results Results on calves ranging in length from ~4–8 m demonstrated that calf respiration rate decreased with an increase in calf length and increased with presence of activity (P < 0.001). Calf inter-breath intervals became longer in duration with an increase in calf length (P < 0.01). Calf activity level and resting behaviour remained constant, with calves logging for 53% of the time their mothers were logging. Maternal respiration rate remained low and did not differ with respect to maternal or calf length. Conclusions Results highlighted the importance of resting grounds for energy preservation, which benefits the calves’ rapid growth before migration to polar waters. Implications Findings from the present largely undisturbed population serve as a baseline for understanding the impacts of anthropogenic disturbance on resting behaviour and energy expenditure in humpback whale mother–calf pairs globally.

Comparison of three methods of estimating the population size of an arboreal mammal in a fragmented rural landscape

Abstract: Context Precise and accurate estimates of animal numbers are often essential for population and epidemiological models, as well as for guidance for population management and conservation. This is particularly true for threatened species in landscapes facing multiple threats. Estimates can be derived by different methods, but the question remains as to whether these estimates are comparable. Aims We compared three methods to estimate population numbers, namely, distance sampling, mark–recapture analysis, and home-range overlap analysis, for a population of the iconic threatened species, the koala (Phascolarctos cinereus). This population occupies a heavily fragmented forest and woodland habitat on the Liverpool Plains, north-western New South Wales, Australia, on a mosaic of agricultural and mining lands. Key results All three methods produced similar estimates, with overlapping confidence intervals. Distance sampling required less expertise and time and had less impact on animals, but also had less precision; however, future estimates using the method could be improved by increasing both the number and expertise of the observers. Conclusions When less intrusive methods are preferred, or fewer specialised practitioners are available, we recommend distance sampling to obtain reliable estimates of koala numbers. Although its precision is lower with a low number of sightings, it does produce estimates of numbers similar to those from the other methods. However, combining multiple methods can be useful when other material (genetic, health and demographic) is also needed, or when decisions based on estimates are for high-profile threatened species requiring greater confidence. We recommend that all estimates of population numbers, and their precision or variation, be recorded and reported so that future studies can use them as prior information, increasing the precision of future surveys through Bayesian analyses.

Behavioural and physiological responses of captive Antillean manatees to small aerial drones

Abstract: Context Unmanned aerial vehicles or drones are powerful tools for wildlife research. Identifying the impacts of these systems on target species during operations is essential to reduce risks of disturbance to wildlife, to minimise bias in behavioural data, and to establish better practices for their use. Aims We evaluated the responses of captive Antillean manatees to the overhead flight of a small aerial drone. Methods We used aerial and ground videos to compare manatee activity budgets and respiration rates in three 15-min sampling periods: ‘before’, ‘during’ and ‘after’ flights with a DJI Phantom 3 Advanced. The drone was hovered stationary for 3 min at five altitudes (100 m, 40 m, 20 m, 10 m, 5 m) to determine whether manatees display behavioural responses compared with the control period, and whether they respond more at lower altitudes. Only one flight was performed per manatee group to avoid bias owing to habituation to the drone. Key results Manatees responded to drone flights by (1) increasing their activity levels during and after flights, therefore signalling after effects; (2) decreasing their respiration rate during flights; and (3) displaying behavioural reactions including grouping, tail-kicking, fleeing from their original position and moving under submerged structures. From the 11 individuals displaying behavioral reactions, 9 reacted in the first ~2 min of flight, preventing assessments of altitude effects and suggesting manatees responded to the drone sound at take-off. Conclusions Behavioural changes of responding manatees were similar to previous reports of disturbance responses to boats and drones in this species. Our use of a control period showed shifts in respiration rates and activity budgets that persisted after flights. Several manatees reacted to the drone from the time of take-off and first minutes of flight, indicating that the sound of the electric rotors could be a strong negative stimulus to manatee and highlighting the importance of establishing safe distances for take-off. Implications Future studies should consider that drones could elicit conspicuous and inconspicuous responses in manatees. Our results emphasise the need for control data on animal behaviour to better assess the impact of drones on wildlife and to design non-invasive protocols.

Harvesting predators: simulation of population recovery and controlled harvest of saltwater crocodiles Crocodylus porosus

Abstract: Context The population of saltwater crocodiles, Crocodylus porosus, in the Northern Territory, Australia, has been recovering from a period of intensive, unregulated harvest (1945–1971) since protection in 1971. Consequently, the management goal is shifting from restoring a seriously depleted population to managing an abundant population through controlled harvests for both commercial purposes and public safety. Aims We conducted this study to (1) examine whether the controlled harvest of eggs and adults since protection has had an adverse effect on population size and structure, and (2) explore the effect of future harvest scenarios on population size and structure by adjusting harvest levels of both eggs and adults. Methods On the basis of 40 years of population monitoring data and knowledge of population attributes from previous research, we developed density-dependent, structured matrix population models to explore our aims. Key results The models supported that the depleted population recovered rapidly under protection and that the harvest rates since protection were benign. The model estimated the 2017 harvested population, 46 years after protection, to be ~102 000 non-hatchlings (>0.6 m crocodiles), of which 42.2% are large (>2.1 m total length) individuals. This is similar to the estimated population before the period of intensive, unregulated harvest. Like other crocodilians, the harvest simulations showed that the viability of the population is highly sensitive to adult survival rates. The estimated population should be able to sustain an annual harvest of up to 135 500 eggs if the harvest of large crocodiles remains small (<500 per year). Conclusions Although egg harvest has little impact on population size and structure, population size is sensitive to adult harvest. Implications Crocodile populations are highly sensitive to adult survival, which needs to be taken into account when considering future harvest scenarios.

Red deer allocate vigilance differently in response to spatio-temporal patterns of risk from human hunters and wolves

Abstract: Context Ungulate prey can use increased vigilance to reduce their risk of predation, but little is known of the combined and interactive risk effects from humans and wolves in determining ungulate behaviour across time and space. Understanding the interplay between these risk effects is increasingly important, considering the recolonisation of several large carnivores to more human-dominated landscapes in Europe. Aim The aim of the present study was to assess the vigilance behaviour expressed by red deer (Cervus elaphus) in response to both humans and wolves in the Polish Bialowieza Forest. Methods Using a camera-trap transect, the effect of distance to human settlements, hunting season, patterns of space use by wolves (Canis lupus), canopy openness, canopy height, time of day, as well as sex/age of individuals, on the vigilance behaviour observed in red deer was studied using a model-selection approach. Key results We did not find a clear effect of patterns of space use by wolves or distance to human settlements on red deer vigilance behaviour at the landscape scale. However, red deer showed increased vigilance during the hunting season and during the day outside of protected areas and reserves, because disturbance from human hunters is highest. Conversely, we also found that red deer were more vigilant at night within more protected areas, which is likely to be explained by the increased activity of wolves because human activity is strictly limited. Conclusions Our study showed that vigilance behaviour of red deer in Bialowieza Primeval Forest is more driven by human hunting than by the frequency of wolf presence at a landscape scale. This could be explained by the higher temporal and spatial predictability of human hunting activities than wolf risk. We found that patterns of wolf space use, as opposed to the omnipresent fear effects from humans, had only localised effects by increasing vigilance levels during night hours in non-hunting areas of the forest. The reverse was observed outside of protected reserves. Understanding how prey species respond to this new combination of risk from natural predators and humans, is increasingly important in a landscape where human risk is becoming ever more potent and carnivores recolonise.

Fine-scale vertical habitat use of white sharks at an emerging aggregation site and implications for public safety

Abstract: Context Over the past decade, the coastal waters off Cape Cod, Massachusetts, have emerged as the only known aggregation site for the white shark (Carcharodon carcharias) in the western North Atlantic. During periods of seasonal residency, white sharks patrol the shoreline in search of pinniped prey, bringing them in close proximity to popular beaches where people recreate. Aim To examine whether white sharks off Cape Cod are more likely to occupy shallow depths (and consequently more likely to overlap with recreational water users) under certain conditions. Methods We deployed short-term, pop-up satellite archival transmitting (PSAT) tags and acoustic transmitters on 14 subadult and adult white sharks off the coast of Cape Cod during the summer and fall of 2017. PSAT tags provided fine-scale depth and temperature data, which were combined with high-resolution location data obtained from an acoustic telemetry array, to identify the depth and temperature preferences of white sharks when resident in the area. Key results Sharks spent the majority (95%) of tracked time at depths of 0–31 m and at temperatures from 8.9°C to 20.7°C. During resident periods along Cape Cod, individuals spent almost half (47%) of their time at depths of less than 4.5 m, but made frequent excursions to mid-shelf depths, alternating between the surf zone and deeper offshore waters. Sharks were slightly more likely to occupy shallow depths at night during the new moon. The relationship between shark depth and lunar phase varied over the course of the day, suggesting the mechanism underlying lunar effects differs among diel periods. Conclusions Although the overall risk posed to humans by white sharks is low, there is a high potential for overlap between white sharks and recreational water users off Cape Cod. The risk of interaction may be slightly higher during periods when local environmental conditions favour the species’ predatory stealth by influencing prey behaviour or detectability. Implications This study provides the first glimpse into the fine-scale vertical habitat use of white sharks off Cape Cod, which can be used to better understand the risk to recreational water users and to inform public safety practices.

Damage to silo bags by mammals in agroecosystems: a contribution for mitigating human–wildlife conflicts

Abstract: Context Damage to harvest storage systems by mammals and associated postharvest losses generate human–wildlife conflicts. Silo bags have been widely adopted worldwide as a type of temporary harvest storage for agricultural crops. The basis of silo-bag technology is the hermetic condition of the plastic lining. Breaks in this silo-bag lining by mammals generate damage of stored content and are a serious concern for farmers, who generally take actions against wildlife with consequent impacts on the environment. Aims We described the incidence and intensity of breaks in silo-bag linings by different mammal groups (armadillos, canids and rodents) in agroecosystems of central Argentina, and we analysed the influence of extrinsic and intrinsic factors on patterns of breakage of silo bags, and propose management options based on cultural methods tending to prevent damage and reduce human–wildlife conflicts. Methods Sampling was conducted during the austral summer and winter of 2018, at three sites in the Pampas of Argentina. At each site, we chose farms that were using at least one silo bag, described silo-bag characteristics, and recorded the number of breaks in silo bags generated by mammals. Key results We sampled a total of 306 silo bags from 38 farms. Damage incidence by mammals comprised 49% of silo bags sampled. Statistical analyses (GLMMs) revealed that damage intensity generally increased with storage time. Seasonality played a key role, with breakage being higher during summer for armadillos, when they are most active, and in winter for rodents, when they are most abundant. Damage by armadillos exhibited geographic variation and also decreased significantly with increasing distance to the nearest plot edge in which the silo bag was placed. Damage by rodents was higher for bags containing grains rather than forage. Conclusions Damage to silo bags by mammals was affected by both extrinsic (seasonal and geographical) and intrinsic (stored content, storage time and distance to nearest edge) factors; however, these effects varied according to the mammal group considered. Implications Relocation of silo bags away from plot edges could significantly reduce damage by armadillos, the most harmful mammals to silo bags.

Minimising mortalities in capturing wildlife: refinement of helicopter darting of chital deer (Axis axis) in Australia

Abstract: Context Helicopter darting has been used to capture wild deer, but this method has never been used for chital deer (Axis axis). Aim The aims of this study were to develop, assess and refine a helicopter darting technique for wild chital deer in northern Australia by quantifying: (1) reliable pharmacological doses for immobilisation; (2) the efficacy of the technique (including the duration of procedures); and (3) the frequency of adverse animal welfare events. Methods The study was conducted in three stages: an initial protocol (n = 25 deer captured) in July−August 2018; a refined second protocol implemented in June 2019 (n = 12 deer captured); and a further refined third protocol implemented in June 2019 (n = 12 deer captured). Parameters to estimate the duration of procedures were measured and the frequency of several adverse animal welfare events during capture were quantified: mortality (at the time of capture and within 14 days of capture), hyperthermia, hypoxaemia, dart inaccuracy and manual restraint. Finally, GPS location collars with a mortality-sensing function were used to monitor post-release mortality. Results Mortality within 14 days of capture was 40% for the first stage, 25% for the second stage and 17% for the third stage. Considerable refinement of procedures occurred between stages in consultation with an Animal Ethics Committee. One-third of all 15 mortalities occurred at the time of capture and were attributed to ballistic trauma from dart impact and acute capture myopathy. The majority (n = 10) of mortalities, however, occurred post-release and were only detected by mortality-sensing GPS location collars. These post-release mortalities were attributed to capture myopathy. Conclusions Helicopter darting of wild chital deer poses animal welfare risks, but these can be minimised through the selection of the most appropriate pharmacological agents and attempts at preventing factors such as hyperthermia and hypoxaemia that contribute to the development of capture myopathy. Further research into capture protocols is needed for helicopter-based immobilisation of chital deer. Fitting animals with GPS location collars enabled post-release mortality, which was significant, to be evaluated.

Lowland tapir exposure to pesticides and metals in the Brazilian Cerrado

Abstract: Context The Cerrado is a Global Biodiversity Hotspot as well as Brazil’s main frontier for large-scale agriculture and livestock production, making it one of the most threatened biomes in the country. Brazil is one of the biggest consumers of pesticides in the world and allows the use of chemicals that are banned in many other countries due to their adverse health effects in a wide range of species, including humans. Aims This study aimed to assess pesticide and metal exposure of the lowland tapir – a threatened, large herbivorous mammal – to support future studies of the role of these chemicals in tapir health, survivorship, and population viability. Methods Foot pad, proboscis, stomach contents, liver, bone, and nail samples were obtained from tapir carcasses found along highways (n = 87). (i) Atomic absorption spectrophotometry (AAS) was used to detect metals in bone, nail and liver tissue; (ii) gas chromatography – nitrogen phosphorous detector (GC-NPD) to detect organophosphates in liver and skin; and (iii) high performance liquid chromatography – ultraviolet (HPLC-UV) to detect pyrethroids and carbamates in stomach contents. Key results Two carbamates (aldicarb and carbaryl), three organophosphates (diazinon, malathion, and mevinphos), two pyrethroids (deltamethrin and permethrin), and two toxic metals (cadmium and lead) were detected in different tapir tissue samples, some at concentrations high enough to cause adverse health effects. In 90% of roadkill tapirs that were subjected to a full post-mortem examination (n = 25), macroscopic alterations of liver and/or kidney tissue were observed. Conclusions This study provides the first report to date of the detection of pesticides and metals in lowland tapirs. Implications Some of the reported pesticide concentrations exceed environmental safety thresholds. Consequently, results from this study raise concerns over potential adverse health effects in tapirs that could lead to population level impacts, thus requiring further investigation.

Experimentally testing the response of feral cats and their prey to poison baiting

Abstract: Context Feral cats, Felis catus, have caused the decline and extinction of many species worldwide, particularly on islands and in Australia where native species are generally naive to the threat of this introduced predator. Effectively reducing cat populations to protect wildlife is challenging because cats have a cryptic nature, high reproductive rate and strong reinvasion ability. Aims We experimentally tested the response of feral cats and their native prey to an Eradicat® poison baiting program at a conservation reserve. Methods Baits were distributed by hand along roads and tracks every 50 m (~10 baits km−2). We used camera traps to monitor the response of cats to baiting using a repeated before–after, control–impact design over 6 years. We also measured introduced rabbit, Oryctolagus cuniculus, activity by using sand pads and small mammal and reptile captures by using pitfall trapping. Key results Dynamic occupancy modelling showed only modest effects of baiting on cats in 2 of 6 years, with occupancy in the baited area decreasing from 54% to 19% in 2014 (–35%) and from 89% to 63% in 2017 (–26%). Baiting effectiveness was not related to antecedent rainfall or prey availability. Bait availability was reduced by non-target interference; 73% of 41 monitored baits were removed by non-target species. We found no evidence for persistent changes in small mammal or reptile capture rates in the baited area relative to the unbaited area over the life of the project. Conclusions Relatively low baiting density and non-target interference with baits are likely to have reduced baiting efficacy. Further testing and refinement of ground baiting is needed, including trialling higher baiting densities and/or frequencies. Implications We highlight key areas for future research that should benefit feral cat management not only in Australia, but also on the many islands worldwide where cats threaten native wildlife.

Animal welfare testing for shooting and darting free-ranging wildlife: a review and recommendations

Abstract: Several important techniques for managing wildlife rely on ballistics (the behaviour of projectiles), including killing techniques (shooting) as well as capture and marking methods (darting). Because all ballistic techniques have the capacity to harm animals, animal welfare is an important consideration. Standardised testing approaches that have allowed refinement for other physical killing and capture methods (e.g. traps for mammals) have not been applied broadly to ballistic methods. At the same time, new technology is becoming available for shooting (e.g. subsonic and lead-free ammunition) and darting (e.g. dye-marker darts). We present several case studies demonstrating (a) how basic ballistic testing can be performed for novel firearms and/or projectiles, (b) the benefits of identifying methods producing undesirable results before operational use, and (c) the welfare risks associated with bypassing testing of a technique before broad-scale application. Following the approach that has been used internationally to test kill-traps, we suggest the following four-step testing process: (1) range and field testing to confirm accuracy and precision, the delivery of appropriate kinetic energy levels and projectile behaviour, (2) post-mortem assessment of ballistic injury in cadavers, (3) small-scale live animal pilot studies with predetermined threshold pass/fail levels, and (4) broad-scale use with reporting of the frequency of adverse animal welfare outcomes. We present this as a practical approach for maintaining and improving animal welfare standards when considering the use of ballistic technology for wildlife management.

Small mammal diversity is higher in infrequently compared with frequently burnt rainforest–savanna mosaics in the north Kimberley, Australia

Abstract: Context Populations of native mammals are declining at an alarming rate in many parts of tropical northern Australia. Fire regimes are considered a contributing factor, but this hypothesis is difficult to test because of the ubiquity of fire. Aims This preliminary study investigated relative abundance and richness of small mammals on a gradient of fire regimes in the Uunguu Indigenous Protected Area (north Kimberley, Australia). Methods Species were sampled using 40 unbaited camera traps, positioned for a year on 20 transects crossing the rainforest–savanna boundary at locations with comparable environment and geology but varying fire history. The relative importance of the factors ‘fire frequency’, ‘late dry season fire frequency’, ‘time since burnt’ and ‘vegetation type’ as predictors of the number of small mammal species and detections was tested using Spatial Generalised Linear Mixed Models to account for spatial autocorrelation. Key results Nine species of small mammals were observed. Mammals were more abundant and diverse in locations with low overall fire frequency, which was a better predictor than late dry season fire frequency or time since burnt. The model including fire frequency and vegetation explained the highest proportion of total variation in mammal diversity (R2 = 42.0%), with most of this variation explained by fire frequency alone (R2 = 40.5%). The best model for number of detections (R2 = 20.9%) included both factors. Conclusions In the north Kimberley, small mammals are likely to be more abundant and diverse in areas with low fire frequency. Implications This natural experiment supports the theory that frequent fires are contributing to the decline of small mammals observed across northern Australia.

Cats are a key threatening factor to the survival of local populations of native small mammals in Australia’s tropical savannas: evidence from translocation trials with Rattus tunneyi

Abstract: Context Invasive predators are a key threat to biodiversity worldwide. In Australia, feral cats are likely to be responsible for many extinctions of native mammal species in the south and centre of the continent. Aims Here we examine the effect of feral cats on native rodent populations in the second of two translocation experiments. Methods In a wild-to-wild translocation, we introduced pale field rats, Rattus tunneyi, whose populations are declining in the wild, into two pairs of enclosures where accessibility by feral cats was manipulated. Key results Individual rats translocated into enclosures accessible to cats were rapidly extirpated after cats were first detected visiting the enclosures. Rats in the enclosure not exposed to cats were 6.2 times more likely to survive than those exposed to cats. Two individual cats were responsible for the deaths of all but 1 of 18 cat-accessible rats. Rats in the site with denser ground cover persisted better than in the site with more open cover. Conclusions These results are consistent with our previous study of a different native rat species in the same experimental setup, and provide further evidence that, even at low densities, feral cats can drive local populations of small mammals to extinction. Implications Effective feral cat control may be necessary to enable recovery of small mammals.

Evaluation of the use of drones to monitor a diverse crocodylian assemblage in West Africa

Abstract: Context West African crocodylian populations are declining and in need of conservation action. Surveys and other monitoring methods are critical components of crocodile conservation programs; however, surveys are often hindered by logistical, financial and detectability constraints. Increasingly used in wildlife monitoring programs, drones can enhance monitoring and conservation efficacy. Aims This study aimed to determine a standard drone crocodylian survey protocol and evaluate the drones as a tool to survey the diverse crocodylian assemblage of West Africa. Methods We surveyed crocodile populations in Benin, Cote d’Ivoire, and Niger in 2017 and 2018, by using the DJI Phantom 4 Pro drone and via traditional diurnal and nocturnal spotlight surveys. We used a series of test flights to first evaluate the impact of drones on crocodylian behaviour and determine standard flight parameters that optimise detectability. We then, consecutively, implemented the three survey methods at 23 sites to compare the efficacy of drones against traditional crocodylian survey methods. Key results Crocodylus suchus can be closely approached (>10 m altitude) and consumer-grade drones do not elicit flight responses in West African large mammals and birds at altitudes of >40–60 m. Altitude and other flight parameters did not affect detectability, because high-resolution photos allowed accurate counting. Observer experience, field conditions (e.g. wind, sun reflection), and site characteristics (e.g. vegetation, homogeneity) all significantly affected detectability. Drone-based crocodylian surveys should be implemented from 40 m altitude in the first third of the day. Comparing survey methods, drones performed better than did traditional diurnal surveys but worse than standard nocturnal spotlight counts. The latter not only detected more individuals, but also a greater size-class diversity. However, drone surveys provide advantages over traditional methods, including precise size estimation, less disturbance, and the ability to cover greater and more remote areas. Drone survey photos allow for repeatable and quantifiable habitat assessments, detection of encroachment and other illegal activities, and leave a permanent record. Conclusions Overall, drones offer a valuable and cost-effective alternative for surveying crocodylian populations with compelling secondary benefits, although they may not be suitable in all cases and for all species. Implications We propose a standardised and optimised protocol for drone-based crocodylian surveys that could be used for sustainable conservation programs of crocodylians in West Africa and globally.

Sign surveys can be more efficient and cost effective than driven transects and camera trapping: A comparison of detection methods for a small elusive mammal, the numbat (Myrmecobius fasciatus)

Abstract: Context Determining the most efficient detection method for a target species is key for successful wildlife monitoring and management. Driven transects and sign surveys are commonly used to monitor populations of the endangered numbat (Myrmecobius fasciatus). Camera trapping is being explored as a new method. These methods were unevaluated for efficacy and cost for numbat detection. Aims To compare efficacy and costing of driven transects, sign surveys and camera trapping for detecting numbats in the Upper Warren region, Western Australia. Methods Seven repeat sign surveys and driven transects, as well as 4 months of camera trapping, were conducted concurrently at 50 sites along three transects. Numbat detection rates and costing of the three techniques were compared, and detection probabilities were compared between sign surveys and camera trapping. Key results Numbat signs were detected during 88 surveys at 39 sites, exceeding camera trapping (26 detections at 13 sites) and driven transects (seven detections near five sites). The estimated probability for detecting a numbat or a sign thereof (at a site where numbats were present) ranged from 0.21 to 0.35 for a sign survey, and 0.02 to 0.06 for 7 days of camera trapping. Total survey costs were lowest for driven transects, followed by camera trapping and sign surveys. When expressed as cost per numbat detection, sign surveys were cheapest. Conclusions Comparative studies of survey methods are essential for optimal, cost-effective wildlife monitoring. Sign surveys were more successful and cost effective than camera trapping or driven transects for detecting numbats in the Upper Warren region. Together with occupancy modelling, sign surveys are appropriate to investigate changes in occupancy rates over time, which could serve as a metric for long-term numbat monitoring. Implications There is no ‘best’ method for wildlife surveys. Case-specific comparison of animal detection methods is recommended to ensure optimal methods. For the numbat population in the Upper Warren region, further studies are needed to improve numbat detection rates from camera trapping, and to test sign surveys in autumn (March to May), when surviving juvenile numbats have established their own territory and assumptions regarding population closure are less likely to be violated.

Post release immune responses of Tasmanian devils vaccinated with an experimental devil facial tumour disease vaccine

Abstract: Context: Disease is increasingly becoming a driver of wildlife population declines and extinction risk. Vaccines are one of the most successful health interventions in human history, but few have been tested for mitigating wildlife disease. The transmissible cancer, devil facial tumour disease (DFTD), triggered the Tasmanian devil’s (Sarcophilus harrisii) inclusion on the international endangered species list. In 2016, 33 devils from a DFTD-free insurance population were given an experimental DFTD vaccination prior to their wild release on the Tasmanian north coast. Aim: To determine the efficacy of the vaccination protocol and the longevity of the induced responses. Method: Six trapping trips took place over the 2.5 years following release, and both vaccinated and incumbent devils had blood samples and tumour biopsies collected. Key results: Eight of the 33 vaccinated devils were re-trapped, and six of those developed DFTD within the monitoring period. Despite the lack of protection provided by the vaccine, we observed signs of immune activation not usually found in unvaccinated devils. Firstly, sera collected from the eight devils showed that anti-DFTD antibodies persisted for up to two years post vaccination. Secondly, tumour infiltrating lymphocytes were found in three out of four biopsies collected from vaccinated devils which contrasts with the ‘immune deserts’ typical of DFT’s; only one of the twenty incumbent devils with DFTD had a tumour biopsy exhibiting immune cell infiltrate. Thirdly, immunohistochemical analysis of the vaccinated devils’ tumour biopsies identified the functional immune molecules associated with antigen presenting cells (MHC-II) and T cells (CD3), and the immune checkpoint molecule PD-1, all associated with anti-tumour immunity in other species. Conclusions: These results correlate with our previous study on captive devils in which a prophylactic vaccine primed the devil immune system and, following DFTD challenge and tumour growth, immunotherapy induced complete tumour regressions. The field trial results presented here provide further evidence that the devil immune system can be primed to recognise DFTD cells, but additional immune manipulation could be needed for complete protection or induction of tumour regressions. Implications: A protective DFTD vaccine would provide a valuable management approach for conservation of the Tasmanian devil.

Developing a correction factor to apply to animal–vehicle collision data for improved road mitigation measures

Abstract: Context Road mitigation to reduce animal–vehicle collisions (AVCs) is usually based on analysis of road survey animal carcass data. This is used to identify road sections with high AVC clusters. Large mammals that are struck and die away from a road are not recorded nor considered in these analyses, reducing our understanding of the number of AVCs and the cost–benefit of road mitigation measures. Aims Our aim was to develop a method to calculate a correction factor for large mammal carcass data reported through road survey. This will improve our understanding of the magnitude and cost of AVCs. Method Citizen scientists reported animal carcasses on walking surveys along transects parallel to the highway and reported observations using a smartphone application at three sites over a 5-year period. These data were compared with traditional road survey data. Key result We found that many large mammals involved in AVCs die away from the road and are, therefore, not reported in traditional road surveys. A correction factor of 2.8 for our region can be applied to road survey data to account for injury bias error in road survey carcass data. Conclusions For large mammals, AVCs based on road survey carcass data are underestimates. To improve information about AVCs where little is known, we recommend conducting similar research to identify a correction factor to conventionally collected road survey carcass data. Implications Identifying road mitigation sites by transportation agencies tends to focus on road sections with above-threshold AVC numbers and where cost–benefit analyses deem mitigation necessary. A correction factor improves AVC estimate accuracy, improving the identification of sites appropriate for mitigation, and, ultimately, benefitting people and wildlife by reducing risks of AVCs.

Scars of human–elephant conflict: patterns inferred from field observations of Asian elephants in Sri Lanka

Abstract: Context Human–elephant conflict (HEC) is a major threat to Asian elephants as humans and elephants are forced to share common resources. In Sri Lanka, human-dominated landscapes adjacent to protected areas promote high rates of HEC, especially in the form of crop-foraging by elephants. Crop-foraging can be dangerous to both elephants and humans involved in the conflict. Gunfire is a common way for human communities to deter crop-foraging elephants, and gunshot wounds are commonly described in this elephant population on necropsy. Aims We sought to quantify and describe unique scar patterns among Asian elephants in a protected area, Wasgamuwa National Park, attributed to HEC. Methods We identified 38 adult female and 64 adult male elephants and recorded the age class and body condition of each with established standards. Using photographs, we counted the number, position, and relative size of all scars on each animal. Key results Male elephants had significantly more scars than did females, and for males, the number of scars increased progressively with age. Additionally, male elephants with higher body conditions had more scars. Finally, males tended to have more scars towards the head, especially at older ages. Conclusions Differences in total scar counts between the sexes in this population imply that male elephants in this area more frequently engage in HEC than do females, following observations previously described in the literature. Furthermore, the fact that male elephants acquired progressively more scars as they aged, and that fatter elephants had more scars, indicates that previous exposure to HEC may not have been a deterrent for future events among these males, and potentially, crops served as valuable food sources for these animals. Finally, the changing body locations of these scars with age in males possibly shows plastic behavioural responses during crop-foraging or lower tolerance by farmers towards habitual crop foragers. Implications These results emphasise the need for animal-based approaches to HEC mitigation. Similarly, conservation managers in Sri Lanka and other elephant range countries should investigate similar methods that estimate patterns of HEC to develop effective management strategies directly targeting animals most likely to engage in conflict.

The assemblage of birds struck by aircraft differs among nearby airports in the same bioregion

Abstract: Context Bird–aircraft collisions impose an economic cost and safety risk, yet ecological studies that inform bird hazard management are few, and to date no study has formally compared species’ strike profiles across airports. In response to strike risks, airports have implemented customised management on an airport-by-airport basis, based on the assumption that strike risk stems from prevailing local circumstances. We tested this assumption by comparing a decade of wildlife–aircraft strikes at three airports situated in the same bioregion (likely to have similar fauna) of Victoria, Australia. Aim To compare the assemblage of wildlife struck by aircraft at three major airports in the same bioregion. Method Standardised wildlife strike data were analysed from three airports (Avalon, Melbourne and Essendon Airports), in the Victorian Volcanic Plains bioregion, central Victoria, Australia. Ten discrete 1-year sampling periods from each airport were compared, spanning the period 2009–19. Bird data were comparable, and data on mammals were considered less reliable, so emphasis was placed on birds in the present study. Results In total, 580 bird strikes were analysed, with the most commonly struck species being Australian magpie (Cracticus tibicen; 16.7%), Eurasian skylark (Alauda arvensis; 12.2%), Australian pipit (Anthus australis; 12.1%), masked lapwing (Vanellus miles; 5.9%), nankeen kestrel (Falco cenchroides; 5.0%), house sparrow (Passer domesticus; 4.8%), welcome swallow (Hirundo neoxena; 4.3%) and tree martin (Petrochelidon nigricans; 4.0%). The assemblage of birds struck by aircraft over the decade of study differed between airports. The most commonly struck species drove the assemblage differences between airports. Conclusions and implications In the present study system, airports experienced discrete strike risk profiles, even though they are in the same bioregion. The airports examined differed in terms of air traffic movement rates, aircraft types, landscape context and bird hazard management effort. Given that strike risks profiles differ among airports, customised management at each airport, as is currently the case, is supported.

Cost-effectiveness of thermal imaging for monitoring a cryptic arboreal mammal

Abstract: Context The development of reliable and cost-efficient survey techniques is key to the monitoring of all wildlife. One group of species that presents particular challenges for monitoring is the arboreal mammals. Traditional techniques for detecting these species often yield low detection probabilities (detectability) and are time-consuming, suggesting the potential for novel methods to enhance our understanding of their distribution, abundance and population trajectories. One technique that has been shown to increase detectability in a range of terrestrial species is thermal imaging, although it has rarely been applied to arboreal species. The true conservation status of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) is uncertain because of low detectability under typical survey techniques, and a more suitable method is required to enable effective monitoring of the species, making it an ideal candidate for the present study. Aims We aimed to compare the success and cost-effectiveness of surveys utilising thermal imaging with two traditional methods, namely, spotlighting and daytime surveys, so as to optimise monitoring of D. lumholtzi. Methods We conducted surveys at 10 sites in Queensland (Australia) where D. lumholtzi was known to occur, by using each method, and modelled both the detectability of D. lumholtzi and the cost-effectiveness of each technique. Key results Detectability of D. lumholtzi was significantly higher with the use of thermal imaging than it was with the other survey methods, and thermal detection is more cost-effective. In average survey conditions with a trained observer, the single-visit estimated detectability of D. lumholtzi was 0.28 [0.04, 0.79] in a transect through rainforest, by using thermal imaging. Using only spotlights, the detection probability was 0.03 [0, 0.28] under the same conditions. Conclusions These results show that incorporating thermal technology into monitoring surveys will greatly increase detection probability for D. lumholtzi, a cryptic arboreal mammal. Implications Our study highlighted the potential utility of thermal detection in monitoring difficult-to-detect species in complex habitats, including species that exist mainly in dense forest canopy.

Koala tree selection in a mixed-tenure landscape and post-fire implications

Abstract: Context The more frequent and intense bushfires predicted under climate change are likely to heavily impact koalas living inside protected areas and intact forests, which makes koala habitat in asset protection zones more important. Understanding how koalas use different habitats in a mixed-tenure landscape can inform effective conservation management. Aims The aims of this study were to determine (1) the species and size of trees used by koalas, (2) whether choice of daytime trees was affected by available proportions of tree species and sizes in koala home ranges, and (3) whether developed land was used as frequently as native forest. Methods Tree use by koalas was determined by radio-tracking 10 koalas for an average of 12 months and recording the species and diameter of trees they occupied. To compare the proportions of tree species used by koalas with those available, tree availability was measured using random quadrats in the home ranges of five koalas that used forested areas extensively. The habitats used by 10 koalas were classified as native forest or developed land to investigate the importance of human-modified areas. Key results Eucalyptus punctata was a preferred tree species, but each individual used four to nine species. Tree species were not chosen solely on the basis of available proportions; some species were selected preferentially. Half of the koalas used more developed land than native forest. Koalas preferentially used trees with larger diameters than the mean of available trees, and selected larger trees in developed areas than in native forest and when re-using trees. Conclusions Despite the higher availability of trees in protected native forest at the site, 70% of the koalas used developed land in and around asset protection zones. Koalas whose home ranges were geographically close, but had different soil types and vegetation communities, were able to utilise different tree species. Implications Koalas would benefit from protection of remnant native forests containing preferred trees on shale cap soil and conservation of native vegetation corridors along fence lines and in paddocks in developed areas because they are valuable resources and connect patchy landscapes. Protecting koalas on developed land improves their likelihood of surviving bushfires, allowing recolonisation of surrounding protected areas.

Lost at sea: determining geographic origins of illegally traded green sea turtles (Chelonia mydas) rescued on Hainan Island, China

Abstract: Context Green sea turtles are threatened by exploitation for food and medicine markets, with Asian populations facing the heaviest pressures. Sea turtle confiscations that happen out at sea can give a general area that poachers are targeting, but it can be difficult to determine the impact on specific nesting rookeries. Previous studies circumvented this difficulty by using genetic markers to identify nesting rookery origins of confiscated green turtles. Aims To determine the impact on nesting rookeries from the illegal harvesting of green sea turtles by Hainan fishermen and describe the genetic diversity of the Paracel Islands’ green sea turtle population. Methods In the present study, we sequenced 384 bp of mitochondrial DNA control region from 85 illegally traded green sea turtles rescued on Hainan Island, China, to investigate their population of origin. For reference-source data, we used previously published mtDNA haplotype data from rookeries from Australasian waters and mtDNA haplotype data from 16 newly collected samples from the Paracel Islands in the South China Sea, a previously unsampled area. Key results Ten and four mtDNA haplotypes, all being reported before, were detected from the Hainan confiscation and Paracel Islands rookery respectively. However, CmP19, an infrequent haplotype that has been found only in 10 green sea turtles previously, made up ~45% of our rescued samples and ~62% of the Paracel Islands sample, suggesting a potential association between CmP19 and the Paracel Island rookery. Haplotype diversity of the rescued green sea turtles was relatively high (h = 0.7143 ± 0.04), whereas nucleotide diversity was relatively low (π = 0.0031 ± 0.00), compared with other rookeries. Mixed-stock analysis suggested that the rookeries in the Paracel Islands (~57%) and the Sulu Sea (~29%) are experiencing the greatest impact from illegal harvesting by fishermen from Hainan and neighbouring countries. Conclusions The Paracel Islands population contains a unique genetic makeup compared with other studied rookeries, particularly the high frequency of the previously rare CmP19 haplotype. The current harvesting of green sea turtles by Hainan fishermen affects not only protected local populations (Paracel Islands), but also distant populations (Sulu Sea) in protected international waters. Implications Establishment of a large-scale Sea Turtle Nature Reserve in the South China Sea, including a special law enforcement team to monitor this National Marine Park, needs to be top priority to help curb illegal harvesting. The Paracel Islands represents a newly defined population, and conservation measures need to be taken immediately to preserve this distinct population.

Density and activity patterns of Pallas’s cats, Otocolobus manul, in central Mongolia

Abstract: Context The ranges of many small, at-risk felid species occur almost entirely in unprotected areas, where research efforts are minimal; hence data on their density and activity patterns are scare Aims We estimated density and activity patterns of Pallas’s cats on unprotected lands in central Mongolia during two periods (May–August and September–November) in 2019 Methods We used spatially explicit capture–recapture models to estimate population density at 152 ± 48 individuals per 100 km2 Key results We obtained 484 Pallas’s cat images from 153 detections during 4266 camera-days We identified Pallas’s cats using pelage markings and identified 16 individuals from 64 detections Pallas’s cat activity was consistent between the two survey periods (~050), with cats mainly active during crepuscular hours in the first period and strictly diurnal in the second Conclusions We provide the first estimation of a Pallas’s cat population density using camera-trapping Compared with other methods used, densities were high in our study area, which was likely to be due to a combination of highly suitable habitat and abundant prey Seasonal shifts in the activity patterns of Pallas’s cats indicated a likely adaptive response to reduced risk of depredation by raptors Implications We recommend August to November as the best time for camera-trapping surveys for Pallas’s cats, given their high daily activity and the easiest interpretation of images used for individual identification collected during this time We also suggest that future camera-trapping surveys of Pallas’s cat be mindful of potential camera-trap avoidance through time

Underlying beliefs linked to public opinion about gene drive and pest-specific toxin for pest control

Abstract: Context Developing a new tool for wide-scale rat eradication is necessary for significant biodiversity gains. Underlying beliefs linked to public opinion can help guide policy makers to understand public concern and inform an effective discourse. Aims We investigated underlying beliefs linked to levels of support for a potentially disruptive tool, gene drive, compared with a traditional stepwise tool, aerial distribution of a new pest-specific toxin. Methods Using the theory of planned behaviour, we surveyed (n = 1200) a representative sample of New Zealanders to assess the level of support for the tool related to attitude, normative and control beliefs. Key results Attitude (e.g. gene drive is good/bad and gene drive is risky/safe) and two norms (e.g. people like me and people in my household) were key contributors to level of support for gene drive. Behavioural beliefs (if scientific evidence can prove it works, concern there are unknown consequences, a humane way to rid New Zealand of rats, and gene drive goes against natural way of life) were also significant. For aerial distribution of a new pest-specific toxin, the same attitudes and normative beliefs identified for gene drive also contributed significantly to the model. Four behavioural beliefs, namely, aerial delivery could affect areas outside the target zones, if there is scientific evidence, and it is impossible to make a pest-specific toxin that would not harm our native wildlife were also significant. The impact either tool may have on biodiversity was not significant in either model. Conclusions Decision making about both gene drive (a disruptive technology) and aerial distribution of a pest-specific toxin (a stepwise technology) is primarily influenced by attitudes, with a few beliefs also influencing decision making. Novelty of the tool does not affect the underlying beliefs that are influencing levels of support. Implications Public engagement that acknowledges and responds to these underlying beliefs, rather than a traditional campaign based on biodiversity and environmental gains, may be more effective at creating a constructive dialogue about if and how these tools should be used, and to avoid replicating the polarised debate about 1080.

Adaptive monitoring: using citizen scientists to track wolf populations when winter-track counts become unreliable

Abstract: Context In many countries, annual wolf surveys based on snow-track counts have become unreliable because of inconsistent snow coverage. We considered incidental observations by volunteers throughout the year as an alternative monitoring protocol. Aims We recruited interested citizens throughout Lithuania, including hunters, foresters and farmers, to estimate wolf distribution, abundance, pack numbers and group size from 2015 to 2018. Methods Observation-based records of wolves were collected using simple questionnaires that included time, location and method of observation (e.g. track, scat, vocalisation or prey-kill remains). We summarised 979 reports of 1938 observed wolves. Key results Volunteer reports suggested an increase in wolf distribution and abundance from 2015 to 2018. The observed number of wolf packs was estimated to be at least 100 by 2018, pack size increased to 3.6, and the share of single wolves decreased from 56% in 2015 to 40% in 2018. Conclusions We found that volunteer observations can provide useful information on wolf distribution, pack size and pack numbers. Our results support previous reports of expanding wolf populations in the Baltic region. Implications Results of our citizen-science effort by Nature Research Centre and Lithuanian Hunters and Fishers Association have been accepted by the Ministry of Environment as a complement to other surveys in Lithuania and should aid in developing an informed wolf-management policy.

When do predator exclusion fences work best? A spatially explicit modelling approach

Abstract: Context Exclusion fences are increasingly used to prevent interactions between predators (introduced and native) and assets such as endangered species or livestock. However, challenges remain in identifying when exclusion fences are an optimal investment and the intended outcome is likely to be achieved. The level of association with complementary methods of control that is needed is also unclear. Aims We aimed to quantify the interactions among factors that affect fencing efficiency, including the size of the fenced area, the fence permeability, the initial density of the predator population, and its survival of complementary control methods. Methods Using a spatially explicit, individual-based model, we simulated wild dog (dingo) populations as a proxy for describing predator dynamics inside a fenced area under different management practices and fence designs. We then fit a generalised linear model to the model outcomes to assess the effects of the four factors mentioned above. Key results Lethal control had a strong effect on wild dog density when the survival of control was lower than 0.5. Fences generally had an effect on wild dog density only when their permeability was lower than ~1% and their effect was most noticeable when the initial density was very low (<2 dogs per 100 km2), or when survival of control was very low (<0.5). Conversely, when the initial density was very high (~12 dogs per 100 km2), a fence with a low permeability (<1.5%) caused the paradoxical effect that wild dog density could be higher than that obtained with a more permeable fence. Wild dog eradication was possible only when survival of control was 0.25 or lower, except when either initial density or fence permeability were extremely low (<2 dogs per 100 km2 and <0.1% respectively). Conclusions Our results demonstrated that large exclusion fences can be an effective aid in managing predator populations. We recommend that this tool should be used as a preventive measure before predators establish a population inside the area targeted for exclusion, in tandem with lethal control, or when an initial marked reduction of predator density can be achieved. We also demonstrated that eradication can be achieved only when a narrow combination of parameters is met. Implications Land managers should carefully evaluate when and at what scale control tools should be deployed to control wild dog populations. Landscape application of exclusion fences faces the challenge of high maintenance to ensure low permeability, coupled with very high sustained suppression of wild dog density, which are unlikely to be feasible options in the long term. Conversely, the same control techniques could provide efficient asset protection at a smaller scale where fence maintenance and sufficient control effort can be sustained.