Context. In New Zealand, the Australian brushtail possum is a pest, because this species preys on native birds and transmits bovine tuberculosis (bTB) to livestock. Previous studies on possums have shown that home-range characteristics differ depending on habitat and/or population density. However, direct comparisons between studies are limited because of the use of differing monitoring techniques, some of which are now out-dated and imprecise. Understanding how possum ranging behaviour varies in response to habitat and density may allow the development of more effective and site-specific control operations. For example, variations in home-range characteristics (e.g. home-range overlap with conspecifics) among populations may mean that bTB transmission risk is not uniform among populations, resulting in the need for some sites to be prioritised for control over others.

Aims. To investigate whether home-range characteristics varied among three sites of differing habitat and population density, and investigate whether possum home-range characteristics varied between males and females.

Methods. Global Positioning System (GPS)- and VHF-tracking were used to compare possum home-range characteristics among three sites. Two sites were within pine (Pinus radiata) habitat and had low-density possum populations, and one site was within oak (Quercus robur) and sycamore (Acer pseudoplatanus) habitat, and had a higher-density possum population.

Key results. Possum home-range characteristics did not vary between the two low-density sites. However, these populations exhibited considerably larger home-range sizes and home-range overlap between pairs of collared possums than did the high-density population. In addition, the low-density populations used more dens and changed these more often. Across all sites, there were generally no intersexual differences in home-range characteristics.

Key conclusions. The present research highlights that the home-range characteristics of possums can vary among populations, depending on habitat and/or population density.

Implications. Further research into the drivers of possum home-range characteristics would be beneficial to allow identification of how spatial behaviour is likely to vary depending on habitat and density. This would allow the design of more targeted and therefore effective control strategies that account for these variations in behaviour, such as using a larger spatial scale of control devices where possums are known to range further.

Context. Criticisms of wildlife restocking operations typically focus on concerns that translocations can lead to the introduction of pathogens, and risk the integrity of locally adapted genetic diversity. Restocking programs aiming to stabilise population declines of European brown hares using captive-bred individuals have been carried out in several European countries, including Greece.

Aims. To assess the potential for imported hares to introduce novel strains of European brown hare syndrome virus (EBHSV) during restocking operations, by (1) inferring the origin of wild Greek hares on the basis of their mitochondrial DNA (mtDNA) haplotype, (2) screening the hares to detect and characterise EBHSV, and (3) determining whether certain hare origin–EBHSV combinations occur in the wild.

Methods. RNA extraction, polymerase chain reaction (PCR) amplification, and sequence and phylogenetic analyses of EBHSV were performed on 53 hares. Diagnostic RFLP markers of the mtDNA were used to infer the origins of sampled hares.

Key results. Thirty-three hares had ‘typical’ native Greek haplotypes and 20 had mtDNA haplotypes matching those found in imported and released hares. Twelve of the latter and none of the former were positive for EBHSV. Phylogenetic analysis showed that nine virus isolates formed a single genetic lineage distinct from northern–central European ones. Three virus sequences from three imported reared-and-released hares, from Chalkidiki, were closely related to the northern–central European EBHS viruses.

Conclusions. Alien strains of EBHSV are co-introduced with released captive-bred animals, possibly resulting in negative impacts on populations of Greek hares that have not evolved resistance to these novel virus strains.

Implications. The identification of these allopatric EBHSV strains has led the authorities to ban captures and transportations of local brown hares for any restocking operation. We consider it imperative to reinforce microbiological and genetic controls before further releases of captive-bred game species in the wild in Greece.

Context. In most natural populations, exhaustive counts are not possible and estimates need to be derived from partial sampling by using analytical methods that account for biological processes, sampling errors and detection probability. The methods available have contrasting pitfalls and payoffs in relation to the assumptions made but are seldom contrasted on the same population.

Aims. We compared density estimates derived by different sampling methods. Despite the real density being unknown, the ‘soft’ validation of density estimates might help to better understand the possible pitfalls and payoffs of each method. This was done in three closed populations and with three different habitat typologies to disentangle the effects of different capture-detection processes to those introduced by the method itself.

Methods. We considered the problem of estimating population density of the endemic Balearic lizard, Podarcis lilfordi, in three island populations. We compared estimates derived by distance sampling (LT) in three types of habitat with those calculated from a simultaneous 3-day capture–mark–recapture study. Capture histories of marked individuals were used to estimate density using spatially explicit capture–recapture models (SECR) and a capture–mark–recapture model without spatial data (CMR). Moreover, we empirically assessed the influence of survey duration by extending the survey in the largest island to five occasions. The real population density was unknown and absolute accuracy of each method cannot be assessed; nevertheless, relative estimates might be informative.

Key results. LT estimates had the greatest coefficient of variation in vegetated habitats, corresponding to possible departures from model assumptions. SECR estimates differed among islands and were from 12% to 37% lower than those derived by LT but only in the largest islands with high and dense vegetation. CMR estimates depended on the number of occasions whereas SECR did not and showed lower variance. LT and SECR estimates showed differences across islets.

Conclusions. Line-transect and capture–recapture methods gave comparable results but the interaction between recapture processes and habitat types should be considered when inferring density to the whole area. We found density estimates between 1500 and 2500 individuals ha^–1, being a higher value than those found for lizards in continental regions.

Implications. Pitfalls and payoffs of each method are discussed to optimise experimental design in estimating population density.

Context. Efforts to protect or restore degraded plant communities by population control of invasive herbivores frequently fail to achieve their goals.

Aims. We seek to quantify changes in diet of an introduced herbivore, the brushtail possum (Trichosurus vulpecula), following population control, and determine how these may contribute to variable responses in plant condition.

Methods. Stomach contents of possums from five areas of indigenous forest in northern New Zealand were analysed to measure diet before and after the application of possum control.

Key results. The contribution of fruit, and foliage of some early successional forest species, to total possum diet increased up to 27-fold following possum population control. This was accompanied by declines in consumption of the main pre-control possum foods (foliage from common canopy trees). Dietary changes were a combination of an immediate response to control (1 year) and a strengthening of these initial changes with increasing time since control.

Conclusions. Possums in the study areas changed diet following population control, from a diet dominated by foliage of common canopy tree species to one dominated by fruits, and foliage of uncommon early successional plants. Pest control instantaneously increased the per capita availability of all foods, and probably permitted absolute increases in some foods through plant recovery, enabling possums to substitute scarce, high-preference foods for abundant but less preferred canopy foliage.

Implications. Following control of a pest herbivore, dietary changes reduce benefits for the most vulnerable preferred plant foods, but enhance benefits for less favoured plants. Intense pest control can permit some recovery of highly preferred foods, despite increased per capita consumption of these foods by survivors of control.

Context. The role of wildlife in faecal pollution of water bodies (deposition of Escherichia coli (E. coli)) is not well understood. Current water-quality and land-use planning research largely relies on unreliable wildlife data (e.g. poor sourcing of abundance estimates, population density estimates applied to multiple fundamentally different areas, suspect or insufficiently described data collection techniques)

Aims. Our goal for the present research was to investigate deposition of E. coli into a floodplain by free-ranging mammals. Objectives of the research were to determine the density of important free-ranging meso- and large mammals in the study area, determine faecal E. coli loads for each species, and evaluate spatial data on species-specific faecal deposition.

Methods. We conducted our research in south-eastern Texas, USA, on two cattle ranches bisected by Cedar Creek (44-km long). Cedar Creek has elevated E. coli concentrations. We conducted mark–recapture and mark–resight population density estimates (2008/09) for meso- and large mammals in the study areas. We collected faecal samples from all captured wildlife. We also conducted transects through the study area to determine faecal-deposition patterns.

Key results. We found that raccoons (Procyon lotor), wild pigs (Sus scrofa), Virginia opossums (Didelphis virginiana) and white-tailed deer (Odocoileus virginianus) all had substantial faecal E. coli loads and population densities, thus implying an important role in E. coli deposition into the study floodplain. All species were widely distributed through the floodplain.

Conclusions. Free-ranging mammals contribute E. coli to floodplains and potentially affect water quality. We determined that four species commonly found in floodplains throughout North America all contributed E. coli to the study floodplain, thus implying mammal E. coli contributions in many locations and this is potentially important for E. coli management.

Implications. Improved locally specific mammal population estimates and estimates of locally derived E. coli concentration will improve floodplain and water-quality models that often depend on data of various quality. Additionally, our analyses demonstrated the need for continued research into the role of wildlife in E. coli deposition.

Context . In New Zealand, the introduced brushtail possum, Trichosurus vulpecula, is a reservoir of bovine tuberculosis and as such poses a major threat to the livestock industry. Aerial 1080 poisoning is an important tool for possum control but is expensive, creating an ongoing need for ever more cost-effective ways of using this technique.

Aims . To develop geographic information system (GIS) models to better predict spatial variation in the distribution of unmanaged possum populations, to facilitate better targeting of control activities.

Methods . Relative abundance of possums and their distribution among habitat types were surveyed in a dry high-country area of the northern South Island. Two GIS-based models were developed to predict the relative abundance of possums on trap lines. The first model used remotely sensed (digital) environmental data; the second complemented the remotely sensed data with fine-scale habitat and topographic data collected on the ground.

Key results . Digital environmental factors and habitat features proved to be key predictors of relative possum abundance. In both GIS models, height above valley floor, presence of forest cover and mean annual temperature were the strongest predictors.

Conclusions . Predictive maps (projections) of relative possum abundance produced from these models can provide useful decision-support tools for pest-control managers, by enabling possum control to be targeted spatially.

Implications . Spatially targeted pest control could allow effective control activities for invasive species or disease vectors to be applied at a lower cost for the same benefit.

Context. Long-term studies of large, vertebrate mammals using capture–recapture data are scarce, even though long-term ecological studies are requisite to understanding quantitative genetics and evolutionary processes that can be applied as part of management programs.

Aims. Objectives were to (1) partition components of variation in body mass to understand the differential effects of environmental variation on the sexes during ontogeny, to better prescribe habitat-improvement projects, and (2) estimate repeatability to assess potential for selection on body mass.

Methods. We used a 23-year dataset (1983–2005) of capture–recapture records of wild white-tailed deer (Odocoileus virginianus) to estimate components of variance and repeatability of body mass. We used an animal-model approach that employed the use of general linear mixed models and restricted maximum likelihood to adjust for the effects of age (i.e. fixed effect), and to partition the total phenotypic variance into among-individual (i.e. the deer), permanent environmental (i.e. year of birth) and temporary environmental (i.e. year of measurement and residual) effects (all modelled as random effects).

Key results. We found that body mass increased with age in both sexes, repeatability of body mass was 0.595 for females and 0.716 for males, and among-individual variation was more influential on body mass than were permanent and temporary environmental effects combined. Year of birth was more important in males than females, but changed during the course of ontogeny for both sexes. Year of measurement did not influence post-rut body mass in males, but did contribute to variation in body mass of females.

Conclusions. These long-term data offer insights into the sources of variation that influence body mass of deer, which can be used to understand how environmental sources of variation influence phenotypic traits, and for developing management plans and making selection decisions.

Implications. Knowledge of repeatability (as an upper limit to heritability) can be used to make management decisions related to selection, culling and breeding, whereas understanding environmental effects can lead to better management recommendations (e.g. habitat-improvement projects).

Context . A population of yellow-bellied glider on the Bago Plateau, near Tumbarumba, was listed as an Endangered Population in 2008 under the New South Wales (NSW) Threatened Species Conservation Act 1995. The listing was based on limited data that suggested that the population is geographically and genetically distinct and its habitat in decline.

Aims . To review the validity of the endangered-population listing following the collection of new data on its distribution, habitat preferences and responses to logging.

Methods . Surveys for the yellow-bellied glider were conducted at a subset of sites established in 1995 on the Bago Plateau as well as across parts of the neighbouring Kosciuszko National Park, which had not been surveyed previously. The distribution of suitable habitat throughout these areas was evaluated.

Key results . The yellow-bellied glider was recorded at 29% of 48 sites resurveyed in 2010, 54% of which were previously occupied in 1995. Most changes in glider occupancy occurred at sites that had not been logged during the intervening period. The gliders preferred forest types dominated by montane gums (Eucalyptus dalrympleana, E. viminalis, E. camphora, E. pauciflora and E. stellulata) and used forest types of montane gums mixed with E. robertsonii or E. delegatensis in proportion to their availability across the landscape. The gliders were not observed to use monospecific stands of E. delegatensis. The yellow-bellied glider was also recorded frequently in Kosciuszko National Park. E. dalrympleana was consistently represented in the distribution of this species across the NSW Snowy Mountains.

Conclusions . Yellow-bellied glider site occupancy was not related to timber harvesting. Its habitat was not restricted by elevation or confined within Bago and Maragle State Forests by the Tumut River Gorge, Blowering and Talbingo Dams, as previously thought. We estimated that there is a large population of the gliders occupying up to 440 000 ha of contiguous habitat across the broader Snowy Mountains region of NSW, extending also into ACT and Victoria.

Implications . The listing of the Bago Plateau portion of this population as an endangered population appears inconsistent with relevant listing criteria and requires review.

Context. Optimal management of invasive species should determine the interval between lethal-control operations that will sustain a desired population suppression at minimum cost. This requires an understanding of the species’ rate of recruitment following control. These data are difficult to acquire for vertebrate carnivores such as the red fox (Vulpes vulpes), which are not readily trapped or observed.

Aims. To provide a long-term evaluation of the effects of 1080 poison baiting on the abundance and extent of movement of red foxes in a semiarid environment.

Methods. We used non‐invasive DNA sampling of fox hairs in semi-arid Western Australia where the population was subject to two episodes of aerially delivered sodium fluoroacetate (1080) poison baits within 12 months. Sampling took place at ∼45-day intervals and individual foxes were identified by genotyping eight microsatellite DNA markers and a gender-specific marker. Open-population and spatially explicit mark–recapture models were used to estimate the density, apparent survival and movements of foxes before and following baiting.

Key results. Following a severe reduction in density after baiting, fox density during the ensuing 12 months increased slowly (0.01 foxes km^–2 month^–1), such that density had only reached 22% of pre-baiting levels ∼10 months after the initial baiting. Moreover, recovery was non‐linear as population growth was negligible for 6 months, then exhibited a nine-fold increase 7–9 months after control, coincident with the dispersal of juveniles in autumn. Fox movements between recaptures were on average 470% greater after baiting than before, in line with expectations for low-density populations, suggesting that the probability of encountering baits during this period would be higher than before baiting.

Conclusions. Baiting with 1080 poison significantly reduced the density of foxes, and the low density was sustained for more than 6 months. Foxes moved significantly further between recaptures after baiting when at low densities.

Implications. Control programs in this region may be carried out at low frequency to suppress fox density to a fraction of unbaited levels. The intensity of follow-up baiting may also be adjusted downwards, to take account of an increased probability of bait encounter in more mobile foxes.

Context. Oil spills cause significant detrimental impacts on many shoreline species. There is limited information in the scientific literature about the management and response of shorebirds to oil spills. Northern New Zealand dotterels (Charadrius obscurus aquilonius) were pre-emptively captured as part of the oiled wildlife response to the container vessel Rena oil spill, to ensure the survival of a regional population should there be a catastrophic release of oil. Previous attempts to hold dotterels in captivity have resulted in high mortality.

Aims. To describe the captive husbandry and veterinary management of wild-caught adult dotterels, to outline the common problems encountered, and make recommendations for future captive management.

Methods. The dotterels were caught by noose mat on beaches at risk of further contamination by oil. Initially, dotterels were kept individually indoors and force-fed until they converted to self-feeding on a diet of an artificial insect analogue, ox heart and mealworms. Once self-feeding, the birds were shifted to individual outdoor aviaries.

Key results. Sixty dotterels were caught. About half of birds had oil contamination of the legs, nine birds had light oil staining of feathers and only three of these birds required washing. The degree of oiling and washing did not affect survival. Dotterels took a median of 5 days (range 1–15 days) to convert to the captive diet. Common problems encountered in captivity included carpal and beak abrasions (61.7%) and pododermatitis (75%); however, these did not affect survival. Seven birds (11.7%) developed respiratory disease and six of these died from aspergillosis. The incidence of aspergillosis increased with length of time in captivity and was largely refractory to treatment. The 54 surviving birds were released at their capture sites after a median time of 49 days in captivity (with a range of 39–61 days).

Conclusions. The captive management of the dotterels achieved a 90% survival rate over a period of about 2 months. Deaths were solely due to respiratory aspergillosis, but intensive captive husbandry was required to convert the birds to a captive diet, to minimise traumatic injuries and to manage pododermatitis.

Implications. Although the captive management of shorebird species as a pre-emptive strategy to minimise the effects of oil spills carries significant costs and risks to the birds, it should be considered in the emergency management of high-priority species.