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Abstract ContextTo predict the success of an invasive species, it is important to understand the habitat factors that influence its distribution and abundance. In northern Queensland, chital deer (Axis axis) is an introduced ungulate that occupies specific areas over periods of several decades. AimsThe aim was to compare mineral concentrations in the soil and food plants of areas that chital occupy in high and low densities, and to assess mineral levels in blood sera. MethodsFaecal counts were used to identify areas of high and low chital density. Samples of soil and food plants were analysed from high- and low-density areas to determine the concentrations of 10 minerals from 32 collection sites. Laboratory examination was conducted on serum collected from 46 culled chital to evaluate mineral concentrations. Key resultsChital density varied markedly, with higher mineral concentrations found in soil and food plants in areas of high chital density compared with low-density locations. Average-ranked analyses indicated soil phosphorus levels were significantly (1.5×) higher in areas of high chital density, together with levels of Na (3.4×), Mg (2.3×), Mn (2.1×) and Fe (1.3×) in grasses that comprise more than 90% of the wet season (November to March) diet. Based on minimum requirements for ruminants, the concentrations of Na and Zn in grasses were suboptimal for chital. Serum Zn concentrations suggest a marginal deficiency in most of the animals sampled. ConclusionsMineral requirements of ungulates are such that deficiencies in availability of key nutrients may be sufficient to influence density and distribution. If there are deficiencies, the principal determinants of habitat selection are likely to be P in soil, and Na and Zn in food plants. Deficiencies of both Na and Zn in the diet may limit growth and reproductive output. Implications Mineral adequacy in the diet of chital may be a determinant of their current distribution and a predictor of the habitats they may successfully colonise in the future. Recognition of mineral nutrition as a habitat predictor may aid in the management of chital as a keystone species where it is native on the Indian subcontinent, and as an invasive species where it has become naturalised.

Abstract Context Wildlife detection dogs have been used globally in environmental monitoring. However, their effectiveness in the Australian context has been only minimally researched. Increased understanding of detection dog accuracy and efficacy is required for their inclusion in survey guidelines used by proponents of referred actions potentially impacting Australia's threatened mammals. Evaluation of new methods is also important for advancing population monitoring, particularly for threatened species. Aims To determine the efficacy of wildlife detection dogs as a survey tool for low-density, cryptic species, using northern (Dasyurus hallucatus) and spotted-tailed (D. maculatus) quolls as subjects. We compared detection dogs, human search effort and camera trapping results, in simulated accuracy and efficacy trials, and field surveys. Methods Two wildlife detection dogs' scores for sensitivity (ability to identify a target species scat) and specificity (ability to distinguish target from non-target species scats) were calculated during accuracy trials. The dogs were tested using 288 samples, of which 32 were targets, where northern and spotted-tailed quoll scat were the targets in separate trials. Survey efficacy was determined following completing 12 simulated surveys (6 per target species) involving a single, randomly placed scat sample in a 1–1.5 ha search area. During the northern quoll simulated surveys the dogs' survey efficacy was compared with that of a human surveyor. The dogs also undertook field surveys for both northern and spotted-tailed quolls, in conjunction with camera trapping for comparison. Key results During accuracy trials the dogs had an average sensitivity and specificity respectively of 100% and 98.4% for northern quoll, and 100% and 98% for spotted-tailed quoll. Their average search time in efficacy trials for northern quoll was 11.07 min (significantly faster than the human surveyor), and 2.98 min for spotted-tailed quoll in the 1–1.5 ha search areas. During field surveys, northern quoll scats were detected at sites where camera trapping failed to determine their presence. No spotted-tailed quoll scat was detected by the dogs during field surveys. Conclusions Trained and experienced detection dogs can work very accurately and efficiently, which is vital to their field success. Detection dogs are therefore capable of detecting evidence of species presence where alternative methods may be unsuccessful. Implications Our study supports the future use of highly trained detection dogs for wildlife surveys and monitoring in Australia. Our results demonstrate that detection dogs can be highly accurate and are a beneficial stand-alone or complimentary method.

Context
Understanding the environmental factors influencing the occurrence of wildlife has become increasingly important, contributing to better conservation actions for threatened species.

Aims
We aimed to understand the factors that influence the occurrence probability of the Southwest China serow (Capricornis milneedwardsii), a threatened species, thereby developing conservation interventions to save the species from local extirpation on the Cat Ba Archipelago, Vietnam.

Methods
An integrated approach, including literature reviews, interviews, field surveys, logistic generalised linear models and Bayesian networks, was applied to identify environmental variables and species occurrence, and model the occurrence probability of the species. Sensitivity analysis and scenarios were also performed to identify the influence of environmental variables on the probability of the species occurrence.

Key results
Distance to ranger station was found to be the most influential factor on serow occurrence, followed by total forest, distance to village, steepness and elevation. Hunting pressure has probably forced serows to inhabit the areas where they are well protected, and this need probably over-rides the effect of ecological variables.

Conclusion
Through combing knowledge of forest rangers and members of forest-protection groups, field surveys and logistic generalised linear models, a Bayesian network was developed to predict the occurrence probability of the threatened Southwest China serow on the Cat Ba Archipelago for conservation actions. The modelling results and findings from the present study provided further understanding of the relationships between environmental factors and the probability of the species occurrence, which have been rarely studied throughout the range of this species.

Implications
The modelling predictions give managers basic information for conservation and recovery planning in situations where integrated conservation interventions should be urgently conducted to save the threatened species from local extirpation.

The use of Judas goats to locate remnant animals is a potentially powerful tool for enhancing goat-eradication efforts, which are especially important to island conservation. However, current Judas goat methodology falls short of its potential efficacy. Female Judas goats are often pregnant at the time of deployment or become impregnated in the field; pregnant females leave associated goats to give birth, causing downtime of Judas goat operations. Further, male Judas goats may inseminate remnant females. Sterilising Judas goats prior to deployment removes these inefficiencies. Here, we describe two methods (epididymectomy for males and tubal occlusion for females) that sterilise Judas goats while still maintaining sexual motivation and other behaviours associated with intact animals. These surgeries are straightforward, time efficient, and may be conducted in the field by staff with minimal training. Given the widespread and deleterious impacts of non-native herbivores to ecosystems and the importance of Judas operations in detecting animals at low densities, sterilisation and termination of pregnancy should be applied routinely in Judas goat (and possibly other species) programs to increase the efficacy of low-density control operations and eradication campaigns.