Rabbit haemorrhagic disease virus (RHDV), introduced into in Australia and New Zealand as a biological-control agent for wild rabbits, is least efficacious in cool humid areas where a non-pathogenic calicivirus (RCV-A1) also circulates. Heavy rabbit mortality following release of RHDV on cold sub-Antarctic Macquarie Island, where RCV-A1 was apparently absent, not only complemented the planned rabbit eradication operations, especially by reducing secondary poisoning of sea-birds from aerial baiting, but also ruled out cool or humid climate as a major limiting factor of disease spread. In turn, this has advanced the idea that RCV-A1 antibodies inhibit RHDV spread as well as reducing disease severity and mortality.

Context . Helicopter shooting is an effective tool for reducing feral horse (Equus caballus) populations that are considered overabundant. However, this tool has been less commonly used in recent years because of concerns about animal-welfare outcomes, which have not previously been quantified.

Aims . The aims of the present study were to assess the helicopter shooting of feral horses to determine (1) the duration of stress, (2) the frequency of adverse animal-welfare events and (3) the influence of explanatory variables in determining welfare outcomes.

Methods . We quantified the welfare outcomes of three helicopter shooting programs in central Australia during 2013 and 2015. We conducted ante-mortem observations of 937 horses and post-mortem observations of 630 horses. We measured the following three parameters to estimate the duration of stress from pursuit and the mode of death: chase time (CT), time to death (TTD) and total time (TT; CT TTD). We quantified the frequency of adverse animal-welfare events, namely instantaneous death rate (IDR; percentage of animals for which TTD was zero), the apparent frequency of non-fatal wounding, and the frequency of bullet-wound tracts in different anatomical locations. We investigated the role of explanatory variables in determining whether or not a horse had an inferred instantaneous death.

Key results . For all horses, the median CT was 42 s, the median TTD was 0 s (median TTD for horses not killed instantaneously was 15 s), and median TT was 52 s. At least 1% of horses were non-fatally wounded, IDR was 63% (60–66%), and 3% (2–5%) of horses were not shot in the cranium, neck or thorax. Shooter skill was the most important determinant of whether or not a horse had an instantaneous death.

Conclusions . The animal-welfare outcomes of helicopter shooting appear to be similar for feral horses and feral camels (Camelus dromedarius), the only other species that has been studied using these methods, and could be refined by improving shooter skill.

Implications . Quantifying animal-welfare outcomes is particularly important for contentious wildlife management techniques. Wildlife managers should integrate the results of welfare studies into decision-making processes rather than excluding contentious techniques from consideration on the basis of perception.

Context. Intraspecific differences in behaviour can affect censuses and bias population estimates, suggesting that choice and implementation of census methods are fundamental, and need to be adapted to behavioural variations.

Aims. We investigated temporal variations in activity patterns during the rut among red deer (Cervus elaphus) categories and the implications for two different census methods.

Methods. We used a long-term dataset collected during 17 consecutive red deer rutting seasons in southernmost Sweden. The two census methods were: (1) a collection of observation ratios; and (2) a count of individuals including identification of males. Both methods are commonly used in ungulate management.

Key results. There was a difference in activity among age and sex categories, with a temporal variation in activity and/or presence at rutting grounds of adult (≥6 years) and subadult (2–5 years) males. Observation ratios of adult and subadult males increased from low at the start of the rut to a top level during peak rut, with subadults lagging behind adults. Before and during peak rut, the proportion of adult males was higher than that of subadults. After peak rut, the proportion of adult males decreased, whereas subadult males remained high, resulting in a higher number of subadults than of adults. The comparison of the two census methods revealed a strong correlation regarding the trends of population size and for the age and sex categories. There was also a strong consistency concerning the calf/female ratio. The male proportion was, however, consistently lower in the collected observations than in the counts.

Conclusions. The lower proportion of males in observations compared with counts may be explained by behavioural differences among male age classes, i.e. by temporal variations in presence and activity. That females, calves and yearling males are stationary during the rut, but adult and subadult males arrive and depart the rutting grounds at varying points of time, can lead to an underestimated male proportion in continuously collected observation data.

Implications. The results suggest that census should be conducted during peak rut, and that incorporating identification of individual males in the monitoring may be beneficiary.

Context. Since European settlement in 1788, much of the Australian terrestrial mammal fauna has declined or become extinct. The pattern of, and reason for, that decline was little documented, and is now difficult to decipher. Many mammal species are still declining, providing (an unfortunate) opportunity to better document the process, identify the causal factors and attempt to redress the problem.

Aim. We compare trends in mammal abundance reported in three recent longitudinal studies in conservation reserves in Australia. The studies were not established with the intention of documenting mammal decline, but marked simultaneous decline of co-existing species was the most striking feature of their results.

Methods. Long-term monitoring in Kakadu National Park, Northern Territory (2001–04 and 2007–09), the Upper Warren region of Western Australia (since 1974) and the Great Otway National Park, Victoria (since 1975) principally relied on trapping, but also some spotlighting and sand plots, to document changes and trends in abundance in their respective mammal assemblages.

Key results. Decline was reported in most mammal species, across taxonomic groups, diets and size classes, but mostly involved species <5500 g. The studies differed in their monitoring protocols and varied in the degree to which potential causal factors were monitored, thereby constraining interpretation of the drivers of declines. Inappropriate fire regimes and predation by feral cats are likely contributing factors in at least two study areas, and periods of markedly below-average rainfall are implicated in two areas.

Conclusions. We conclude the following: (1) conservation reserves in Australia may be failing to maintain at least some elements of the biodiversity that they were established to protect, and substantially enhanced management is required to redress this problem; (2) with current threats, mammal assemblages in Australia may be highly unstable; (3) substantial increase in effective long-term biodiversity monitoring programs in an adaptive management framework is needed; and (4) such monitoring programs will be more insightful if they also monitor factors driving population change.

Implications. Native mammal species declines and community disassembly may be occurring elsewhere. Long-term monitoring is critical for assessing trends in biodiversity and if done well, it can guide more effective and efficient management to deliver better conservation outcomes.

Context . Off-shore recruitment impairment of sea-turtle hatchlings because of light pollution is a growing concern to conservation of sea-turtle population throughout the world. Studies have focussed on sea-turtle hatchling sea-finding behaviour, and ignored the possible effect that on-shore lighting might have on hatchlings after they have entered the sea.

Aims . We experimentally evaluated the effect that on-shore light pollution has on the swimming behaviour of green turtle hatchlings once they have entered the sea and begun swimming off-shore. We also estimated the decrease in off-shore recruitment of hatchlings as a result of light pollution disruption of the off-shore swim.

Methods . Hatchling misorientation rates were quantified by releasing marked hatchlings to the sea from different land-based locations adjacent to light-polluted beach areas under a variety of environmental conditions. The beach in light-polluted regions was then searched for marked hatchlings returning to shore from the sea.

Key results . Misorientation rates were highest in trials conducted during moonless nights (66.7% of trials had some hatchlings return to shore) and lowest during trials conducted during moonlit nights (no trials had hatchlings return to shore). Green turtle hatchling off-shore recruitment for the entire 2014–15 nesting season at Heron Island was estimated to decrease 1.0 –2.4% as a result of on-shore lights disrupting hatchling off-shore swimming behaviour.

Conclusions . On moonless nights, sea-turtle hatchlings after having successfully completed their journey from nest to sea and entered the sea can be lured back to shore again by shore-based light pollution and, this will decrease their off-shore recruitment success.

Implications . To ensure maximum off-shore recruitment of sea-turtle hatchlings, on-shore light pollution adjacent to nesting beaches needs to be minimised so as to minimise misorientation and disorientation of hatchlings while on the beach and in near-shore waters.

Context Brazil has one of the richest biodiversity and one of the most extensive road networks in the world. Several negative impacts emerge from this interaction, including wildlife–vehicle collisions (WVC), which may represent a significant source of non-natural mortality in several species. The understanding of the main drivers of WVC is, therefore, crucial to improve the safe coexistence between human needs (transportation of goods and people) and animal populations.

Aims We aimed to (1) evaluate the relative influence of land-cover patterns on the distribution of WVC, (2) assess whether WVCs are clustered forming hotspots of mortality, and, if so, (3) evaluate the benefits of mitigating only hotspot sections.

Methods We collected WVC data involving medium–large mammals (4–260 kg) along three road transects (920 km), fortnightly over 1 year (n = 1006 records). We used boosted regression trees to relate the WVC locations with a set of environmental variables including a roadkill index, reflecting overall habitat suitability and landscape connectivity, while accounting for spatial autocorrelation effects. We identified hotspots of mortality using Ripley’s K statistic and testing whether data follow a random Poisson distribution correcting for Type I error.

Key results We found a strong association between WVC probability and roadkill index for all focal species. Distance to riparian areas, tree cover, terrain ruggedness and distance to urban areas were also important predictors, although to a lesser extent. We detected 21 hotspots of mortality, yet with little spatial overlapping as only four road sections (2%) were classified as hotspot for more than one species.

Conclusions Our results supported that WVC mainly occur in road sections traversing areas with more abundant and diverse mammal communities. Hotspots of mortality may provide important information to prioritise road sections for mitigation, but this should be used in complement with roadkill indexes accounting for overall mortality.

Implications The results support focusing on hotspots and habitat quality and landscape connectivity for a better assessment of road mortality. At the local scale, a larger number and improved road passages with exclusionary fencing of appropriate mesh size in riparian areas may provide safe crossings for many species and constitute a promising mitigation measure.

Context. When understanding species occupancy, estimation of detection probability for the target species is often required, provided by repeated surveys. However, if the actual detection probability of the species is determined experimentally, such estimates are not required, and the reliability of the occupancy data obtained by a particular survey effort can be determined.

Aims. The aim of this study was to determine the detection rate of tadpoles using visual field surveys, as well as to explore the effects of survey time, species and tadpole density on the tadpole-detection rate. The suitability of visual surveys for detecting tadpole occupancy was also assessed.

Methods. Batch-identified tadpoles were released into several pools and repeatedly counted over successive days to calculate detection rates using visual observation. In Experiment 1, the effects of tag colour, survey time (morning vs night) and species on the detection rates of two species of tadpoles (Babina subaspera and Odorrana splendida) were examined. In Experiment 2, the effects of tadpole density on O. splendida were examined.

Key results . Detection rates varied by survey time, species and tadpole density; mean rates ranged from 0.2 to 0.6 for B. subaspera and 0.4 to 0.8 for O. splendida, with higher rates at night. There was a negative relationship between detection rate and tadpole density. Based on these detection rates, it was calculated that single visual surveys of O. splendida tadpoles can achieve detection probabilities near 1.0 when more than four individuals occur in a patch.

Conclusions . Variations in detection probability should be considered in field surveys. If the factors that cause variations in detection rates are controlled, visual surveys of tadpoles should, at least in some species, provide detection probabilities near 1.0.

Implications. When repeated surveys to estimate species occupancy are not practicable, determination of the actual detection probability of the target species using real detection rates provides a robust alternative approach.

Context. Habitat loss and degradation has contributed significantly to the decline of many species worldwide. To address this loss, we first require a comprehensive understanding of habitat requirements and resource-use patterns of the species under threat.

Aims. The study aimed to quantify variation in the habitat of a species threatened by habitat loss and degradation, the brush-tailed phascogale (Phascogale tapoatafa tapoatafa), by measuring several physical characteristics of trees and ground cover, as well as to determine potential foraging resource preferences using abundance data from a long-term monitoring study.

Methods. Phascogale monitoring surveys were conducted over a 13-year period from 2000 to 2012. Habitat variables characterising tree communities, ground cover and coarse woody debris were used to develop explanatory models of phascogale abundance at the site scale. Tree species preference by foraging phascogales was evaluated by comparing usage (trees on which they were captured) and availability.

Key results. The highest overall animal abundance was at sites characterised by associations of red stringybark, red box, grey box and broad-leaved and narrow-leaved peppermints. At these sites, red stringybark and grey box trees were of small diameter and tended to have small hollows. These sites also had low average tree height, low grass and/or herb and shrub cover and low volumes of coarse woody debris. From a resource-use perspective, phascogales foraged preferentially on certain species of Eucalyptus.

Conclusions. Our study suggests that phascogale abundance is highly spatially and temporally variable, most likely as a response to heterogeneity in habitat and foraging resources operating at a range of spatial scales.

Implications. This study has provided new information concerning spatial patterns of phascogale abundance and resource use within a forested area in central Victoria that has been subjected to multiple disturbances. Currently, the composition and age structure of tree communities and ground habitats are a response to severe disturbance due to past mining and harvesting activities. Successful conservation of this threatened species could be enhanced through active management of this forest to maintain the ongoing supply of nesting hollows and foraging resources.

Context. Wild pigs are an invasive species linked to numerous negative impacts on natural and anthropogenic ecosystems in many regions of the world. Robust estimates of juvenile wild pig survival are needed to improve population dynamics models to facilitate management of this economically and ecologically important invasive species. Despite this critical knowledge gap, to date no successful known-fate study of wild piglet survival (<5 months of age) has been conducted, due to a lack of appropriate method for this species.

Aims. To aid in locating and tagging neonates, we piloted the use of vaginal implant transmitters (VITs) in adult wild pigs and evaluated average retention times of stud ear-tag transmitters, clip ear-tag transmitters, sutured and epoxied transmitters, harness transmitters, and surgically implanted transmitters to monitor known-fate survival of piglets.

Methods. We captured pregnant female pigs and implanted them with VITs. We tagged subsequently located neonates and piglets captured in traps with the aforementioned transmitters and monitored them to determine retention times and feasibility of each method.

Key results. VITs were effectively used to determine the location and time of wild pig parturition, allowing counting and tagging of neonate wild pigs. Stud ear-tag and abdominal implant transmitters were well retained by piglets weighing ≥3 kg, in contrast to the other tested transmitters.

Conclusions. Stud ear-tag and abdominal implant transmitters allowed known-fate monitoring of juvenile wild pigs, although, of these, stud ear-tag transmitters may be more practical as they do not require field surgery on piglets. Due to their relatively large size, the stud ear tag transmitters were infeasible for monitoring of true neonates (∼1 kg); however, this application method may be suitable for neonates upon development of lighter-weight transmitters. The other transmitter attachment methods we tested were ineffective for monitoring of piglet survival, due to poor retention of transmitters.

Implications. The techniques piloted in this study will facilitate research into the reproductive ecology of wild pigs and known-fate studies of piglet mortality to aid in population modelling and evaluation of cause-specific mortality and factors affecting survival of these often-invasive animals.

Context. At some sites, wild horse populations have been effectively and non-invasively regulated using remote darting with porcine zona pellucida (PZP) immunocontraceptive vaccines. However, this model has not been widely applied to wild horse herds in western USA, many of which are difficult to access because they roam large areas and are wary of people. Single-treatment, multi-year contraceptive vaccines would significantly broaden the scope for successful contraceptive management.

Aims. The aims of the present field studies were to (1) test the contraceptive effectiveness and longevity of primers incorporating PZP–adjuvant emulsions plus PZP and adjuvant in controlled-release pellets (‘PZP-22’); and (2) compare the contraceptive effectiveness and duration of PZP–adjuvant emulsion-only boosters with those of PZP-22 boosters when administered by hand or remote darting to PZP-22-primed mares.

Methods. Wild horses in herd management areas in Colorado and Utah, USA, were rounded up in 2008 and in Utah again in 2012. Previously untreated females received a single hand-injection of PZP–emulsion plus controlled-release PZP pellets (‘PZP-22’ vaccine) and were then released. In Autumn 2010, 50 Colorado females treated in 2008 were booster-darted with either the PZP-22 vaccine or the PZP emulsion alone. In Utah, 57 previously treated females rounded up in 2012 received hand-injections of either the PZP emulsion–pellet vaccine or the PZP emulsion alone. Maternity was established through field observation of nursing and other close associations.

Key results. Effectiveness of initial controlled-release PZP treatments over 2 years was low relative to previous trials. However, boosters delivered by dart or by hand to PZP-22-primed mares yielded high levels of contraceptive effectiveness for 3 years, with no consistent difference between simple PZP-emulsion boosters and boosters incorporating controlled-release pellets.

Conclusions. Priming mares with PZP-22 extends the efficacy of a subsequent PZP booster to at least 3 consecutive years.

Implications. Regulation of wild horse populations may be achieved with existing contraceptive agents by developing models and management plans that account for the increased longevity of repeated contraceptive treatments.