Context. Detection probability is a key attribute influencing population-level wildlife estimates necessary for conservation inference. Increasingly, camera traps are used to monitor threatened reptile populations and communities. Komodo dragon (Varanus komodoensis) populations have been previously monitored using camera traps; however, considerations for improving detection probability estimates for very low-density populations have not been well investigated.

Aims. Here we compare the effects of baited versus non-baited camera monitoring protocols to influence Komodo dragon detection and occupancy estimates alongside monitoring survey design and cost considerations for ongoing population monitoring within the Wae Wuul Nature Reserve on Flores Island, Indonesia.

Methods. Twenty-six camera monitoring stations (CMS) were deployed throughout the study area with a minimum of 400 m among CMS to achieve independent sampling units. Each CMS was randomly assigned as a baited or non-baited camera monitoring station and deployed for 6 or 30 daily sampling events.

Key results. Baited camera monitoring produced higher site occupancy estimates with reduced variance. Komodo dragon detection probability estimates were 0.15 ± 0.092–0.22 (95% CI), 0.01 ± 0.001–0.03, and 0.03 ± 0.01–0.04 for baited (6 daily survey sampling events), unbaited (6 daily survey sampling events) and long-unbaited (30 daily survey sampling events) sampling durations respectively. Additionally, the provision of baited lures at cameras had additional benefits for Komodo detection, survey design and sampling effort costs.

Conclusions. Our study indicated that baited cameras provide the most effective monitoring method to survey low-density Komodo dragon populations in protected areas on Flores.

Implications. We believe our monitoring approach now lends itself to evaluating population responses to ecological and anthropogenic factors, hence informing conservation efforts in this nature reserve.

Context. Human activities in general, and hunting in particular, often have significant impacts on the behaviour of wildlife through the anti-predator behaviours they evoke. Wild boar populations are rapidly expanding worldwide and their population densities are increasing.

Aims. To examine hunting effects in combination with different land-use factors on the behaviour and social structure of wild boars (Sus scrofa) in Israel. Specifically, to examine differences in vigilant behaviour and social structure in agricultural areas (hunting permitted) and nature reserves (hunting prohibited).

Methods. Motion-triggered cameras were installed to record wild boars’ social structure and vigilance behaviour along movement trails. Age and sex of individual wild boars were identified, as were the size and structure of their social groups, and hunting in each of the studied areas was quantified.

Key results. Results indicated significant differences in the vigilance behaviour of wild boars between agricultural areas and nature reserves. In agricultural areas, adult females were significantly more vigilant (P < 0.001) compared with adult males (P = 0.150). Additionally, in these areas there were significantly more adult males and fewer females leading family groups (P < 0.001). Furthermore, male yearlings were significantly more vigilant in agricultural areas (P < 0.001) compared with female yearlings (P = 0.164). Male yearlings tended to roam significantly more with family groups in agricultural areas compared with nature reserves, where they tended to roam alone or in groups (P = 0.029, P = 0.035).

Conclusions. These results indicate social and behavioural differences in wild boars between agricultural areas and nature reserves, suggesting that hunting may have a substantial impact on their social structure and behaviour.

Implications. Overall, the findings support the behavioural and social consequences of human hunting. Long-term implications of altered behavioural and social responses should be considered in management and conservations strategies. For instance, the high proportion of male yearlings in family groups in agricultural areas in autumn (October–December, mating season) may offer young males early access to reproductive females, even within the same social group. This may eventually lead to an increase in the reproductive potential of female wild boars.

Context. Monitoring schemes provide vital data on the distribution and population dynamics of species. This information can be used to inform conservation management and, especially for legally protected species, ensure legislative compliance in development contexts. For bats, acoustic activity surveys are widely used and often involve (1) deployment of automated fixed-point detectors or (2) using bat detectors on walked or driven transects. Transect surveys are typically performed for 2 h, commencing approximately at sunset; automated fixed-point surveys record continually between sunset and sunrise, often over multiple consecutive nights.

Aims. Despite both walked transects and fixed-point surveys being common methods used to survey bat activity in many parts of the world, often just one technique is used per site. We test the similarity of these two survey methods by comparing acoustic data encompassing 12 species of European bat to determine whether data from different surveys are directly comparable.

Methods. In this study, we use acoustic data covering 2349 survey hours over a 3-year period to investigate the relative effectiveness of walked activity transects and automated fixed-point methods for 12 species of European bats.

Key results. A greater number of bat species were recorded via the fixed-point method. Three species, namely, greater horseshoe (Rhinolophus ferrumequinum), lesser horseshoe (Rhinolophus hipposideros) and Daubenton’s (Myotis daubentonii), were recorded only by using automated detectors, possibly because the survey window encompassed the entire night rather than the period immediately after sunset. However, activity transects recorded a significantly higher mean species richness per hour than fixed-point surveys. When both methods were used at the same sites on the same nights, providing paired data for direct comparison, detection of brown long-eared (Plecotus auratus) and soprano pipistrelle (Pipistrellus pygmaeus) bat activity was significantly higher for transect surveys.

Conclusions and implications. This study demonstrated important differences in the data resulting from different bat survey methods and highlighted the potential for combining acoustic survey types to obtain rigorous and reliable monitoring data for bat populations.

Context. Providing wildlife with supplementary water is a conservation technique that offers an immediate positive impact to animals. However, the potential negative impacts should be assessed.

Aims. We aimed to assess the potential negative effects of water stations on visiting wildlife due to the risk of predation and disease transmission.

Methods. We assessed potential benefits and costs of water supplementation in rural Australia by investigating the behavioural response of animals, at koala (Phascolarctos cinereus) water stations, to weather and to previous visitor species. To determine the risk of disease transmission, water and swab samples were taken from the water stations. Faecal contamination was quantified, and real-time PCR was used to identify various pathogens, including Chlamydia.

Key results. We found that koalas, brushtail possums (Trichosurus vulpecula) and foxes (Vulpes vulpes) responded to hot, dry weather with longer visits to water stations, indicating a benefit of water supplementation to native wildlife, but also to invasive species. Native animals did not alter their behaviour when their visits were preceded by another species, even when this was a potential predator. The presence of pathogens (i.e. Chlamydia and C. perfringens) at the stations did not depend on the number of species that visited but was higher in summer (December to February), representing a potential risk of disease transmission.

Conclusions. Water stations are an effective conservation tool because they can benefit threatened species during hot, dry weather, but there are risks associated with using supplemental water.

Implications. Although potential risks are low, they should still be considered. Efforts should be taken to exclude invasive species and water stations should be cleaned regularly while appropriate personal protective equipment is worn.

Context. Small and medium-sized native mammals have declined precipitously across northern Australia. Feral cats have been implicated in causing declines and ongoing suppression of populations.

Aims. The aim of the present study was to evaluate the response of small and medium-sized native mammal populations when cat predation was removed.

Methods. A field experiment was conducted in a tropical savanna environment of northern Australia. Three experimental treatments were applied to six plots to compare and contrast responses of native mammals to predator exclusion and the additive effects of frequent fire. Plots were monitored regularly between 2013 and 2017.

Key results. After 4 years of monitoring, no significant difference in capture rates of native mammals was detected between cat-accessible plots and those where they were excluded.

Conclusions. There was no evidence of population recovery of native mammals in response to predator exclusion. There was some evidence that frequent burning, independent of cat exclusion, adversely affects native mammal diversity.

Implications. Although predation by feral cats is a major threat to small and medium-sized native mammals, disturbance from fire, and grazing by introduced herbivores, have been shown to significantly impede native mammal population recovery in tropical savanna ecosystems. Management programs that solely focus on suppressing feral cat populations may be inadequate in ameliorating ongoing mammal declines in landscapes with other significant disturbance regimes.

Context. Wild house mice cause substantial economic damage to grain crops in Australia, particularly during mouse plagues. Populations were monitored to detect changes in abundance, with data from surveys used in models to forecast likely mouse outbreaks. However, it is not always feasible to use live-trapping (the ‘gold standard’) for assessing mouse abundance at a large number of monitoring sites spread across south-eastern Australia. A range of alternative methods was tried to assist the grains industry with strategic decisions to reduce crop damage.

Aims. The aim of this work was to determine which survey methods could provide useful and effective indexes of mouse abundance across a large area.

Methods. Monitoring of mouse populations was conducted at representative grain farms by using (1) live-trapping at long-term ‘benchmark’ sites (n = 2), and (2) mouse chew cards and active burrow counts at ‘rapid-assessment’ sites (n = 44 farms across 5 regions). Monitoring was conducted for 22 monitoring sessions over 7.5 years through low, medium and high mouse abundance conditions.

Key results. Live-trapping provided the most useful, but most resource-intensive, information. There were strong relationships between the index of mouse abundance from live-trapping with mouse chew cards and active burrow counts at a local (explaining 63% and 71% of variation respectively) and regional (explaining 71% and 81% of variation respectively) scales. The same quantitative relationship held between the mouse chew cards and trapping regardless of season and year. However, the relationship between active burrow counts and trapping was best in winter and autumn seasons. There was a strong relationship between mouse abundance from live-trapping and active burrows across 1 ha grids (R² = 0.88). We determined there were 1.3 ± 0.2 (mean ± s.e.) mice per active burrow.

Conclusions. Live-trapping supplemented with data from chew cards and active burrows remains sufficient to monitor a wide range of sites to show regional trends.

Implications. It is likely that live-trapping will need to be used for the foreseeable future to provide useful parameters such as breeding condition and population abundance that are required for the forecast models. Supplementary monitoring at rapid-assessment sites (using chew cards in all seasons and active burrow counts particularly in autumn and winter), that can be collected easily without the need for animal handling, will provide additional indications of region-specific changes in mouse abundance and activity.

Context. Knowledge on the drivers of breeding behaviour is vital to understand amphibian ecology and conservation. Proposed drivers of amphibian reproductive behaviour include selection of optimum water quality, and avoidance of tadpole predators and competition. These hypotheses are underpinned by the logic that amphibians will choose breeding habitat that will result in enhanced metamorph output.

Aims. We aimed to infer key drivers that influence metamorph output in the threatened green and golden bell frog (Litoria aurea). We hypothesised that (1) metamorph output would be higher in recently refilled wetlands than in wetlands with a longer hydroperiod, (2) metamorph output would be negatively correlated with tadpole predator abundance, and (3) waterbodies with long hydroperiods would have higher abundances of aquatic predators and lower abundances of L. aurea tadpoles.

Methods. We tested these hypotheses by monitoring breeding, tadpole and predator abundances in a wild population of L. aurea. We coupled this with metamorph counts that were adjusted to represent per capita numbers via genetic means. We also ruled out the influence of detection probability in explaining the results with a manipulative experiment.

Key results. We found support for all three hypotheses and hence provide evidence that the adaptive behaviour of L. aurea to preference recently refilled wetlands is governed by the abundance of tadpole predators. We found metamorph counts per clutch to be 8.2-fold greater in short-hydroperiod wetlands (26 ± 15–44 95% CI) than in long-hydroperiod wetlands (3 ± 2–5 95% CI). Four predator taxa were associated with low metamorph output and two of these occurred in higher abundances in longer-hydroperiod wetlands.

Conclusions and implications. These results have provided evidence that the behavioural adaptation of L. aurea to select recently refilled wetlands has evolved in response to tadpole predation pressure. We recommend practitioners to conduct tadpole releases in newly refilled wetlands to enhance survival to metamorphosis in future reintroductions.

Context. Synchronised acoustic recorders can be used as a non-invasive tool to detect and localise sounds of interest, including vocal wildlife and anthropogenic sounds. Due to the high cost of commercial synchronised recorders, acoustic localisation has typically been restricted to small or well funded surveys. Recently, low-cost acoustic recorders have been developed, but until now their efficacy has not been compared with higher specification recorders.

Aims. The present study aimed to compare the efficacy of a newly developed low-cost recorder, the Conservation at Range through Audio Classification and Localisation (CARACAL), with an established, high-end recorder, the Wildlife Acoustics Song Meter (SM).

Methods. Four recorders of each type were deployed in a paired set-up across five nights in Wisconsin, USA. The recordings allowed for manual identification of domestic dog (Canis familiaris), grey wolf (Canis lupus), coyote (Canis latrans) and barred owl (Strix varia) calls, and then the ability of each recorder type to detect and localise the vocalising animals was compared.

Key results. The CARACALs were less sensitive, detecting only 47.5% of wolf, 55% of coyote, 65% of barred owl and 82.5% of dog vocalisations detected by the paired SMs. However, when the same vocalisations were detected on both recorders, localisation was comparable, with no significant difference in the precision or maximum detection ranges.

Conclusions. Low-cost recording equipment can be used effectively for acoustic localisation of both wild and domestic animals. However, the lower sensitivity of the CARACALs means that a denser network of these recorders would be needed to achieve the same efficacy as the SMs. Deploying a greater number of cheaper recorders increases the labour time in the field and the quantity of data to process and store. Thus, there is a trade-off between cost and time to be considered.

Implications. The ability to use low-cost recorders for acoustic localisation provides new avenues for tracking, managing and researching a wide range of wildlife species. Presently, CARACALs are more suited to monitoring species that have small home ranges and high amplitude vocalisations, and for when a large time investment for in situ equipment checks and data processing is feasible.

Context. Feral cats (Felis catus), wild dogs/dingoes (Canis familiaris) and foxes (Vulpes vulpes) are predators of the endangered bridled nail-tailed wallaby (BNTW; Onychogalea frenata). Predator-proof fencing is advocated as a solution to ensure their conservation in the wild.

Aims. The aims of this study were to determine whether predator control translated into a reduction in their activity, find evidence of cats preying on BNTWs and understand factors that influence changes in the BNTW population size living in an unfenced reserve, particularly focusing on the influence of cat and dog control and rainfall.

Methods. An activity index, calculated using spoor on sand pads and images on remote cameras, was undertaken to monitor predator activity. The stomach contents of cats caught were examined to determine how commonly BNTWs feature as a prey item. The size of the BNTW population and annual survival of individuals was assessed through annual capture–mark–recapture (CMR) surveys and vehicle spotlight counts. Rainfall was measured at the study site and using data from the Bureau of Meteorology.

Key results. The core BNTW population estimated by CMR data increased by 214% over 4 years (2013–2017), to 400 individuals in 2017, whereas spotlight data indicated that the population had increased by 262% over 8 years (2012–2020), to 1265 individuals in 2020. The percentage of small (≤3.5 kg) BNTWs caught increased substantially over the study period. There was no detectable difference in cat or dog activity following control and no correlation was found among predator activity, rainfall and BNTW survival. The remains of BNTWs were found in 20% of cats removed from the core BNTW area.

Conclusions. The study confirmed that cats frequently ate BNTWs, and a combination of control methods is required to manage the threat, but there was no statistical support for a relationship between predator activity and BNTW survival.

Implications. The study found that native species conservation in fox-free environments is possible without the need for predator-proof fences and the ongoing maintenance costs.