Context . Some ecologists argue that nesting success and abundance of wedge-tailed eagles (Aquila audax) are strongly linked to the abundance of introduced wild rabbits (Oryctolagus cuniculus). Consequently, concerns were expressed about eagle population viability when the biological control agent rabbit haemorrhagic disease virus (RHDV) heavily reduced rabbit numbers. However, observations following the spread of rabbit haemorrhagic disease (RHD) in Australia and Spain (where Aquila adalberti is an equivalent of A. audax) question this assertion. Eagle numbers did not fall even though rabbits declined regionally by up to 90% in both countries.

Aims . To reconsider the assumption of a strong link between rabbit abundance and wedge-tailed eagle breeding and population maintenance. Dispelling misconceptions, if any, about the eagles’ dependence on rabbits would benefit the future management of both eagles and rabbits.

Methods . We reviewed the literature associated with claims that eagles were heavily dependent on rabbits and asked whether these views could be substantiated given the lack of changes in eagle abundance following the spread of RHD. Data on eagle egg-clutch size and nesting success were also reviewed.

Conclusions . There is little evidence that eagles depend heavily on rabbits as prey. Instead, as rabbits decline, more kangaroos, reptiles and birds are eaten, partly because more native prey becomes available. Eagles have a high proportion of rabbits in their diets mainly where degradation of natural ecosystems, including that caused by rabbits, results in native prey being rare or unavailable. There has been minimal variation in average clutch size following major perturbations in rabbit population size.

Implications . Rather than perpetuating the idea that high populations of rabbits are needed for wedge-tailed eagle conservation, resources would be better re-directed into understanding continental-scale eagle population dynamics. This would provide a more rational framework to assist decisions on future biological control agents for rabbits.

Context . Community-based conservation managers and their funding providers must apportion limited resources to potential projects that provide varying biodiversity benefits. Funding applicants must demonstrate that proposed projects are likely to provide positive conservation returns on investments.

Aims . We investigated the practical usefulness of two bioeconomic frameworks, the Project Prioritisation Protocol and the Investment Framework for Environmental Resources (INFFER) in guiding community-based conservation funding decisions and the benefits and challenges to community groups in evaluating projects using the tools.

Methods . We evaluated four species-based community-led conservation projects in New Zealand using the tools, and assessed the quality, relevance and potential impact of the frameworks to community conservation, including users’ perceptions of their usefulness.

Key results . Benefit–cost metrics from both tools indicated that all four projects would provide a low return on investment. However, both tools were highly sensitive to key assumptions about the values of conservation assets (species) being managed and the values of predicted differences made by projects. Both tools scored well against criteria used to assess their technical ‘quality’. INFFER had greater flexibility for use in different situations, but its use by community groups may be constrained by the time demands of completing a full project evaluation. Both tools can help users define problems and formulate innovative solutions through assessment of success and risk factors and the identification of project efficiencies.

Conclusions . Although both tools provide quantitative, transparent processes for the relative evaluation and ranking of competing projects, their sensitivities to species and/or asset valuation and benefit estimates mean that users should not accept scores and project rankings uncritically. For community groups, evaluation frameworks are likely to be useful to document costs, conservation benefits and risk factors accurately and transparently, and can encourage applicants to develop more robust approaches to project management, including the development of specific and measurable management objectives.

Implications . Adoption of more transparent and standardised assessment of funding applications by agencies, despite some of the drawbacks of currently available tools, would facilitate more transparent prioritisation of competing funding bids and would encourage community groups to develop a more robust approach to project design and management.

Context . In Western Australia, baits containing 1080 poison are widely used to control the red fox (Vulpes vulpes) for fauna conservation. Despite long-term (15–17 years) baiting programs, bait uptake by target and non-target species is largely unknown, but affects baiting efficacy.

Aims . We examined bait uptake of 1080-poisoned fox baits laid according to current practice at seven riparian sites in the northern jarrah forest (of south-west Western Australia). There, intensive baiting regimes have been implemented for the protection of quokka (Setonix brachyurus) populations.

Methods . Over 9 months, 299 Probait^® baits were monitored regularly to determine their persistence, and, at 142 of these, Reconyx HC500 remote cameras were used to identify the species taking baits. To compare bait uptake with species presence at these sites, we calculated an activity index for each species from the number of passes of animals in front of the cameras.

Key results . The species taking baits was identified for 100 of the baits monitored with cameras, and, because of multiple species taking baits, 130 bait take incidents were recorded in total. The fate of 40 of the baits was not discernible and two baits were not removed. In all, 99% of baits monitored by cameras were taken by non-target species and quokkas took 48% of them. The majority of baits (62% of the total 299 monitored) were taken before or on the first night of deployment, and 95% of baits had been taken within 7 days. With the exception of feral pigs, which took more baits than predicted from their activity index at these sites, baits were taken in proportion to the activity index of species. Foxes were present at four of the seven sites, but only one fox was observed taking a bait.

Conclusions . The high level of uptake of baits by non-target animals reflects their diversity and abundance at these sites, but also significantly reduces the availability of baits to control foxes.

Implications . Strategies to reduce non-target bait uptake and increase bait availability for foxes are required.

Context . Helicopter shooting is a common and effective tool for reducing overabundant wildlife populations. However, there is little quantitative information on the humaneness of the method, leading to uncertainty in wildlife-management policy. There is, subsequently, a need for an improved understanding of the welfare implications of helicopter shooting.

Aim . A study was undertaken to infer the humaneness of helicopter shooting for a case study species, the feral dromedary camel (Camelus dromedarius).

Methods . Seven post-mortem studies (n = 715) and one ante-mortem study (n = 192) were undertaken during routine helicopter shooting programs of free-ranging camels. In these studies, we measured four animal-welfare parameters to allow inference on the humaneness of the technique. These parameters were time to death, instantaneous death rate (proportion of animals for which time to death = 0), wounding rate and location of bullet-wound tract. We also modelled these welfare variables against hypothesised explanatory variables to assist improvement of future programs.

Key results . The mean wounding rate was 0.4%, and the killing efficacy of the technique was 99.6%. Mean time to death was 4 s, and mean instantaneous death rate was 83%. Each animal displayed a mean 2.4 bullet-wound tracts, with 75%, 63% and 35% of animals shot at least once in the thorax, cranium and cervical spine, respectively. Regression analysis revealed that the identity of the shooter and the nature of the local vegetation were the most important factors associated with an animal experiencing an inferred instantaneous death or not.

Conclusions . Helicopter shooting of feral camels produces a very low wounding rate and rapid time to death. Shooter identity is the most important consideration for determining animal-welfare outcomes. Improvements to the humaneness of programs can be made by increasing the rigour of shooter selection and training.

Implications . Wildlife killing methods must be demonstrated to be humane to receive public support; however, few shooting methods are objectively examined. Helicopter shooting can be independently examined and operators assessed. Adoption of this examination template may allow continual improvement by industry as well as increasing societal acceptance of helicopter shooting.

Context . European rabbits (Oryctolagus cuniculus) are serious economic and environmental pests in Australia and New Zealand. Since the illegal introduction of rabbit haemorrhagic disease virus (RHDV) in New Zealand in 1997, the disease has persisted in most rabbit populations, with major epizootics occurring usually each autumn.

Aims . We evaluated the efficacy of the virus as a biological control agent in the southern South Island.

Methods . We used an index of rabbit abundance (kills per hunter) based on a region-wide annual rabbit-hunting competition to evaluate rabbit population trends 7 years before and 16 years after the first outbreak of RHD. We also evaluated the influence of rainfall and temperature in the preceding year on post-RHD trends in the index.

Key results . Kill rates declined by 60% following the initial epizootic. They remained low for the following 3 years and then increased steadily to intermediate levels punctuated by occasional declines. The instantaneous rate of increase in kill rates during the increase phase was low, but above zero (0.04 per year). No relationship between kill rates and rainfall was apparent, but there was a negative relationship between kill rates and winter temperature in the preceding season.

Conclusions . The kill-rate data obtained from this hunting competition suggest that RHD still appears to be killing rabbits. Every 2–3 years over the past decade, kill rates have been as low as they were when government rabbit-control programs were in place before RHD arrived, but the efficacy of RHD as a biological control agent is waning compared with the first outbreaks of the disease. This concurs with findings based on spotlight counts.

Implications . The data collected from this hunting competition are a good example of how ‘citizen science’ can be used to capture large volumes of pest-monitoring data from a wide geographic region for very little cost. The information is a valuable addition to understanding the effects of a major wildlife disease.

Context . Although the daily food intake of wild rabbits is broadly known, precise field estimates have not been made. Moreover, regressions based on metabolic body size and food intake of grazing herbivores in general are too imprecise to provide close predictions. Using such values could result in substantial errors when estimating grazing equivalents to sheep or cattle and resultant economic losses, or estimating the numbers of rabbits per hectare based on rates of deposition of faeces.

Aim . To re-analyse previously collected data on estimated food digestibility and food intake of rabbits, and provide a framework for better estimating economic and conservation losses attributable to wild rabbits.

Methods . Food intake of wild free-ranging rabbits was calculated from past measurements of water turnover obtained from dilution of injected tritiated water and estimates of the water content and digestibility of the food eaten.

Key results . During spring, male rabbits were estimated to eat 65.7 ± 12.5 g dry matter per corrected bodyweight (W^–0.75) per day and lactating females ate 97.0 ± 19.4 g dry matter W^–0.75 day^–1. Similar results were obtained on repetition of trials at a second field site and from wild rabbits held in captivity.

Conclusions . The estimates of food digestibility and intake obtained, although not precise, are an improvement on theoretical expectations alone and help put previously published data in better perspective.

Implications . Improved estimates of food consumption provide more confidence in estimates of rabbit grazing pressure. Even moderate densities of rabbits (5 rabbits per ha) could remove about half the pasture produced in an average year in Australia’s arid-zone.

Context . Frog species are now targets for delivery of high-value managed environmental flows on floodplains. Information on the drivers of frog presence and abundance is required to support adaptive management, including analysis of the roles of flood frequency, flood timing and habitat type.

Aims . This paper describes frog species richness and abundance responses to flooding and habitat type in the Barmah Forest, part of the largest river red gum forest in the world.

Methods . Surveys were conducted at 22 sites over 6 years, to determine species presence, relative abundance, and evidence of breeding. Data were then used to examine temporal patterns within and between wet and dry years and spatial relationships with site geomorphology, vegetation form and wetting frequency.

Key results . Six species were common and widespread, and three were rare. The seasonal timing of peak numbers of calling males differed among species. The seasonal pattern of calling for each species did not differ between wet and dry years; however, significantly lower numbers of frogs were recorded calling in dry years. The number of frogs calling was significantly higher in well vegetated grassy wetlands. Evidence of a positive relationship between wetting frequency and numbers of calling males was found for Limnodynastes fletcheri, Crinia signifera and Limnodynastes dumerilii. The abundance of tadpoles was significantly higher in wet years.

Conclusions . The seasonal timing of flooding in Barmah Forest will influence the breeding success of individual species with different preferences. Flooding from September to December is required to cover most preferred breeding seasons, but longer durations may be required to maximise recruitment. This, together with regular flooding of well vegetated grassy wetland habitat, will increase the likelihood of species persistence and maximise diversity. Insufficient flooding frequency will result in reduced frog species richness and abundance.

Implications . Managed flooding is important for frog abundance and species richness. This study emphasises the value of key habitats such as well vegetated grassy wetlands and reinforces the need to make their preservation a priority for management. It has identified knowledge gaps to drive future data collection for improved modelling, including a need for further research on flow-regime change and frog communities.

Context . Species vary broadly in their ability to adapt to urbanisation. Freshwater turtles are vulnerable to the loss and degradation of terrestrial and aquatic habitat in urban environments. There have been few publications investigating impacts of urbanisation on freshwater turtles in Australia.

Aims . We investigated the effects of urbanisation on the distribution and abundance of the eastern long-necked turtle (Chelodina longicollis) in greater Melbourne.

Methods . We examined occurrence and relative abundance of C. longicollis at 55 wetlands across an urban–rural gradient in relation to site- and landscape-level factors. Occupancy was modelled using the program PRESENCE, and incorporated landscape and habitat covariates. A negative binomial regression model was used to examine the influence of landscape and habitat factors on relative abundance by using WinBUGS.

Key results . C. longicollis occupied 85% of the 55 wetlands we surveyed, and we found no evidence that wetland occupancy was influenced by the variables we measured. However, relative abundance was highest at wetlands with low water conductivity and heavy metal pollution, and in wetlands furthest from rivers.

Conclusions . C. longicollis appears to be resilient to urbanisation and is likely to persist in urban landscapes, possibly because of the creation of new wetlands in Australian cities. However, long-term studies focussed on demographic parameters, or survivorship, may elucidate as yet undetected effects of urbanisation. Although no specific management recommendations may be necessary for C. longicollis in urban areas at this time, this species may be in decline in non-urban areas as a result of climatic changes and wetland drying.

Implications . Our findings suggest that caution is required before drawing generalised conclusions on the impacts of urbanisation on turtles, as the effects are likely to be species-specific, dependent on specific ecology and life-history requirements. Further studies are required to ascertain these relationships for a wider array of species and over longer time spans.

Context . Life-history theory attempts to explain the way in which an organism is adapted to its environment as well as explaining the differences in life-history strategies among and within species.

Aims . The aim of this paper was to compare life-history traits of the Norway rat and the house mouse living in different habitats and geographic regions so as to find patterns related to environmental characteristics on the basis of published ecological studies conducted before 2011.

Methods . The environments where rodent populations lived were characterised according to climate type, occurrence of freezing temperatures and frost, degree of anthropisation and trapping location. Four demographic characteristics were analysed. A canonical correspondence analysis was performed to explain the effects of environmental variables on the demographic characteristics of rodents. Information was gathered from 35 articles published between 1945 and 2010.

Key results . Most populations of both species showed differences in abundance throughout the year, but no defined pattern was common among populations. The pregnancy rate of Norway rat was highest during spring and autumn in urban environments, during spring and winter in rural environments and during summer in sylvan habitats. House mouse populations were most frequently reported to experience high pregnancy rates during summer. Contrary to urban and rural populations, in sylvan environments the occurrence of a reproductive break was the most commonly reported pattern for both species. Litter size of Norway rat depended on the degree of anthropisation and the occurrence of freezing temperatures and frost. Litter size was greater in rural environments and in areas without freezing temperatures and frost. House mouse did not show differences in litter size resulting from any of the environmental characteristics analysed.

Conclusions . Both species are able to modify their reproductive strategies according to environmental characteristics, especially according to the degree of anthropisation of the environment. In sylvan areas, where animals are more exposed to seasonal changes in weather conditions, changes in reproductive investment are more evident.

Implications . Regarding the implications for rodent control, the best time to apply control measures could be winter in sylvan and urban environments. In rural environments, the best time for conducting control efforts is less clear, although cold seasons seem also to be the best.