Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
Context. Fertility control is being promoted as a non-lethal means of managing wildlife populations. We recently evaluated a single-dose injectable immunocontraceptive vaccine (GonaCon™) on captive female wild boar for effectiveness and potential side effects; reproductive output was inhibited for 4–6 years, with no obvious detrimental effects on physiology and behaviour.
Aims. We injected individual free-living wild boar individuals with the fertility-control vaccine GonaCon™ to examine its effectiveness (measured as raised levels of GnRH antibodies) and looked for potential changes in movement and activity patterns.
Methods. We trapped, fitted telemetry devices to, and released wild boar individuals living in woodland in the West Midlands region of England between 2006 and 2010. We compared data on movements and activity among 10 adult females treated with the vaccine and 11 controls treated with saline only. We measured anti-GnRH antibody titres in six recaptured boar individuals as an indicator of the effectiveness of the vaccine.
Key results. Post-treatment GnRH antibody titres varied among the boar individuals; four of five treated sows resampled between 9 and 30 weeks post-injection had antibody titres high enough to block reproduction (detectable at 1 : 32 000–1 : 64 000 dilution). At least three treated females were pregnant at the time of vaccination; there was no subsequent evidence that the vaccine interfered with pregnancy. According to the distances moved per hour over a 24-h cycle and the daily activity cycle in relation to season, there were no differences in the behaviour of treated and control females that were likely to be biologically significant. The behaviour of two treated females monitored soon after vaccination and again 12 months later also showed no major differences.
Conclusions. Free-living wild boar responded to treatment with a 1.0-mL (1000 µg) dose of an anti-GnRH vaccine and no major adverse effects on activity and movement were subsequently detected.
Implications. Our results indicated that the vaccine could be more widely evaluated in the field against overabundant or nuisance populations. Such populations are increasingly found in urban areas and parks, where culling may not be an option. We suggest that further refinement of this approach for managing wild boar populations, including development of an oral vaccine, are warranted.
Context. Poison-baiting programs coordinated among neighbouring landholders should provide the most effective and efficient tool for controlling fox (Vulpes vulpes) populations and impacts in mixed agricultural landscapes, but the effects of such programs on fox mortality and abundance have not been well described.
Aims. This study aimed to describe the effects of coordinated fox-control programs conducted by landholders on fox mortality and abundance, and to evaluate the likely impacts of reduced landholder participation rates on the proportion of the fox population exposed to baits.
Methods. The effects of two baiting programs on fox abundance were evaluated using camera-trap surveys and abundance-induced heterogeneity models. The proportion of foxes surviving baiting was estimated by tracking the fate of 19 GPS-collared individuals. The benefits of coordinated baiting were examined using simulated scenarios based on local fox movements and bait distribution patterns.
Key results. Examination of actual and simulated fox home ranges demonstrated that coordinated baiting increases exposure of the target population to baits. However, 69% of foxes captured on properties that later baited were estimated to have survived the baiting period. Camera-trap surveys across baited and unbaited properties showed no detectable decline in average fox abundance after baiting.
Conclusions. Coordinated baiting increases the proportion of the fox population encountering baited properties. However, high fox survival and the absence of detectable declines in abundance after baiting showed that even well coordinated baiting programs can produce suboptimal results if many of the foxes using baited properties fail to locate and ingest lethal baits.
Implications. Baiting programs aiming to reduce the density and impacts of foxes in agricultural landscapes should strive to maximise participation among neighbours. Programs may also benefit from taking steps to improve bait-encounter and consumption rates within properties, for example, by deploying baits at sufficient intensity to provide all foxes with access to at least one bait within their short-term home range. Future research should aim to identify optimal baiting intensities within properties and conditions to maximise bait uptake.
Context. The superb lyrebird Menura novaehollandiae is thought to be an important ecosystem engineer that, through its foraging, accelerates the decomposition of litter in Eucalyptus forests. Lyrebird foraging is therefore likely to affect forest fuel loads and hence fire behaviour in these fire-prone forests. In turn, fire is likely to reduce the abundance and influence the distribution of lyrebirds.
Aims. Our goal was to determine the impacts of a major bushfire on the habitat and food sources for the superb lyrebird and the effects of foraging activities of lyrebirds on litter fuel and potential fire behaviour in gullies of herb-rich foothill forests.
Methods. The effect of fire on lyrebirds and their habitat in the post-fire environment was examined at the landscape-scale, 2 years after fire; and at the patch-scale, 3 years after fire. Paired exclusion and control plots were also used over a 9-month period to assess the effects of foraging by the lyrebird on litter accumulation and fuel connectivity. Fire-behaviour models were used to determine the potential influence of lyrebird scratchings on fire behaviour.
Key results. At the landscape scale, lyrebirds were present in both unburnt and ground-burnt sites, but not in canopy-burnt sites. Within patchily burnt sites, lyrebirds favoured foraging in unburnt patches. On average, lyrebird foraging reduced litter fuel loads by 25% (1.66 t ha–1) in plots in which they were free to forage, compared with plots from which they were excluded, over a 9-month period. Fire-behaviour modelling showed that lyrebird foraging led to a lower likelihood of fire occurring and less intense fire.
Conclusions. Distinctly different vegetation structure and composition between burnt and unburnt patches appears to influence both the foraging patterns and distribution of lyrebirds. Additionally, foraging by lyrebirds reduces surface fuel loads and fuel connectivity such that fire spread is likely to be inhibited.
Implications. We propose that alternative stable states may emerge in Eucalyptus forests as a result of feedback mechanisms among lyrebirds, vegetation and fuel accumulation. Therefore, the ecological role of lyrebirds is an important consideration in forest fuel management and conservation in these extensive, fire-prone forests in south-eastern Australia.
Context. Southern red-backed voles (Myodes gapperi) disappear from clearcuts within the first year or two after harvest, at least in studies in coniferous and mixed forests of western North America. Post-harvest woody debris arranged in large piles and windrows supports populations of M. gapperi on clearcuts and may extend their persistence there.
Aims. To test the hypotheses (H) that for M. gapperi, (H1) population parameters of abundance, reproduction, and survival would be higher in windrow–forest than isolated windrow sites, and higher or similar to those in interior old forest sites; (H2) connectivity provided by windrow-forest structures will mitigate potential negative effects of clearcuts and abundance of M. gapperi will remain similar at the abrupt edge between forest and new clearcuts; and (H3) connectivity provided by windrow–forest structures will allow increased movements between both habitats.
Methods. Study areas were located in three forest ecological zones in southern British Columbia, Canada. Populations of M. gapperi were sampled from 2010 to 2012 in three types of habitats on new clearcuts: isolated windrows of woody debris, windrows attached to uncut old forest, and in uncut old forest.
Key results. Higher mean values of abundance and number of juvenile recruits of M. gapperi in the isolated windrow and windrow–forest sites than forest sites was contrary to our prediction for H1. In support of H2, we could not detect any differences in the mean number of captures among forest, edge and windrow sections of the windrow–forest sites, nor in the mean range length among the three habitat types. For H3, connectivity provided by windrow–forest structures may mitigate potential negative effects on abundance for M. gapperi at the abrupt edge between forest and new clearcuts.
Conclusions and Implications. Voles did not commonly move between the forest and windrow habitats, but did move readily within forest and within windrows. Substantial movement by M. gapperi within windrows suggested that this microtine will move along windrows and potentially use these paths of connectivity to cross clearcuts. If the prey base is present, windrow connectivity may enhance these open areas for small mustelids and other carnivores and help maintain abundance and diversity of some forest mammals on clearcuts.
Context. Predator-control aims to reduce an impact on prey species, but efficacy of long-term control is rarely assessed and the reductions achieved are rarely quantified.
Aims. We evaluated the changing efficacy of a 58-year-long campaign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian mainland via a bridge. The campaign aimed to eliminate the impact of foxes on ground-nesting birds, particularly little penguins (Eudyptula minor).
Methods. We monitored the success rate of each fox-control technique employed, the level of effort invested if available, demographics of killed foxes, the numbers of penguins killed by foxes and penguin population size.
Key results. The campaign began as a bounty system that ran for 30 years and was ineffective. It transitioned into a coordinated, although localised, control program from 1980 to 2005 that invested considerable effort, but relied on subjective assessments of success. Early during the control period, baiting was abandoned for less effective methods that were thought to pose fewer risks, were more enjoyable and produced carcasses, a tangible result. Control was aided by a high level of public awareness, by restricted fox immigration, and by a clear, achievable and measurable target, namely, to prevent little penguin predation by foxes. Carcasses did prove valuable for research, revealing the genetic structure and shifts in fox demographics. The failure of the program was evident after scientific evaluation of fox population size and ongoing fox impacts. In 2006, the campaign evolved into an eradication attempt, adopting regular island-wide baiting, and since then, has achieved effective knock-down of foxes and negligible predation on penguins.
Conclusions. Effective predator control was achieved only after employing a dedicated team and implementing broad-scale baiting. Abandoning widespread baiting potentially delayed effective control for 25 years. Furthermore, both predator and prey populations should be monitored concurrently because the relationship between predator abundance and impact on prey species is not necessarily density dependent.
Implications. Critical to adopting the best management strategy is evaluating the efficacy of different methods independently of personal and public biases and having personnel dedicated solely to the task.
Context.The conversion of tropical rainforest to grazing pasture results in a drastic change in small-mammal community composition. Restoring the landscape through ecological revegetation is thus an increasingly important management technique to conserve rainforest mammals.
Aims.This study aimed to determine the habitat ages at which species of small mammals recolonised revegetated habitats on the southern Atherton Tablelands, north-eastern Queensland, Australia. We focussed on changes in rainforest mammal abundance and diversity with increasing habitat age.
Methods.Small-mammal trapping and mark–recapture techniques investigated mammal diversity, abundance and community composition within remnant rainforest, three age classes of ecological revegetation and abandoned grazing pasture.
Key results.Small-mammal community composition differed between remnant rainforest and abandoned grazing pasture. The pasture and 3-year old revegetated sites were similar in composition, both lacking rainforest small mammals. Six- and 7-year old revegetation plantings provided suboptimal habitat for both rainforest and grassland mammals, whereas 16- and 22-year old revegetated habitats were dominated by rainforest species, with some individuals being frequently recaptured.
Conclusions.As revegetated habitats aged, the small-mammal community composition transitioned from a grassland-like composition to a community dominated by rainforest species.
Implications.Although rainforest small mammals were very occasionally captured within the 6- and 7-year old habitats, revegetated plantings were not dominated by rainforest species until the habitat was 16 years old. This highlights the importance of commencing revegetation as early as possible to minimise future population declines and maximise the conservation of rainforest mammals.
Context. Both manual call surveys (MCS) and visual encounter surveys (VES) are popular methods used to monitor anuran populations. Recent statistical developments, specifically the development of occupancy models that permit the use of data from various survey methods to assess method-specific detection probabilities, provide a rigorous framework for evaluating the effectiveness of field methods.
Aim. To compare species-specific detection probabilities generated by MCS and VES and to evaluate the effectiveness of these methods throughout the activity season of several riparian-zone anuran species.
Methods. During 2010 and 2011, we sampled 21 sites along the Broad and Pacolet Rivers, in South Carolina, USA, using MCS and VES. Anuran species were surveyed across three seasons (fall, spring and summer) each year.
Key results. For six species, MCS resulted in a higher mean probability of detection, whereas VES resulted in a higher mean probability of detection for four species. In addition, survey date was an important influence on detection probability of most anurans when using MCS, but largely unimportant when employing VES.
Conclusions. Our findings indicated that VES are as effective as MCS for detecting some species of anurans, and for others, VES represent a more effective method. Furthermore, when using VES outside the breeding window, some anurans can be reliably detected, and in some cases, detected more easily than by using MCS.
Implications. We suggest that VES is a complimentary technique to MCS and a potentially important tool for population monitoring of anurans. VES can provide more flexibility for anuran researchers, as robust estimates of detection and occupancy can be obtained outside a narrow breeding window.
Context. Wild deer are increasing worldwide and, in Australia, prompting land managers to review management strategies. Management activities may be ineffective without a sound understanding of the ecology of the species. No peer-reviewed research has been published for wild red deer in Australia, where they have been introduced.
Aims. To help land managers gain an understanding of some movement parameters of introduced wild red deer out of their natural range.
Methods. GPS collars were used to obtain movement rates (m h–1), annual home range using three estimators and seasonal home range using the Local Convex Hull estimator.
Key findings. Deer at our study site displayed typical crepuscular movements. However, the lack of elevated activity for stags in summer varies greatly to reports from overseas. The annual home range of hinds was much smaller than that of stags. Large differences for seasonal home ranges from the same deer for two winters suggest that seasonal conditions may exert a large influence on the size of home ranges. The home ranges of deer at our study site were comparable with the largest reported in European studies, but the relationship between deer density and home-range area was markedly different.
Conclusions. It appears that Australian wild red deer behave differently from their European conspecifics for several important movement parameters. Wild stags did not display the high levels of movement activity in summer, like those in Europe, and the home-range areas of our deer were very large for the high densities we encountered compared with overseas reports.
Implications. Targeted management of hinds may prove beneficial as hinds had a much smaller and continuous home range than stags. If managers want to target stags, there is only a short rut period when they continually associate with hinds and that may be the most efficacious time for control. Additionally, future research may need to explore the link between home range and deer density, and the effect of variation in rainfall on home range and movement of wild red deer which may influence management activities more than do the regular seasonal patterns found in Europe.
Context.The study of threatened species is often challenged by their rarity and secretive life-history traits. Species adapted to extreme environments prone to stochastic conditions present further challenges because of fluctuating populations and patchy distributions. We employed a variety of methods to gather records and habitat information on the bronzeback legless lizard (Ophidiocephalus taeniatus), an endemic, nationally vulnerable monotypic pygopod reptile that is poorly understood because of fossorial, cryptic behaviour and remote distribution in the stony deserts of inland Australia.
Aims.Our aim was to determine foundational information on the distribution and landscape parameters relevant to this species and its disturbance-prone habitat and to formulate conceptual models to guide understanding, future research and management of threats.
Methods.We used multiple data sources, including targeted field surveys with Antakarintja traditional land owners across ∼5000 km2 of previously unsurveyed habitat, sampled the catch of uncapped mine shafts with community volunteers, trialled artificial refuge substrates and elicited public opportunistic sightings.
Key results.We gathered 30 new records of the species from leaf litter mats of six shrub species, across four land systems. Examination of these records in the context of land system boundaries demonstrated a continuous distributional link between previously known areas of habitat and suggested large tracts of potential habitat that remain unsurveyed for the species. This information in combination with other published data was used to create conceptual models of habitat preference, population and disturbance, in which we suggest that O. taeniatus favours microhabitats that are prone to severe and long-lasting disturbance in some parts of the landscape, exacerbated by human land use practices.
Conclusions.Our study suggests that O. taeniatus distribution is unlikely to be severely fragmented, as had previously been suggested. Its total extent of occurrence may be greater than previously thought, despite a very low area of occupancy within this.
Implications.This study emphasises the value of using multiple, innovative data sources when studying rare and cryptic species. Further distributional surveys in identified areas of potential habitat in combination with testing and refinement of our conceptual model of habitat and population drivers are needed to fully assess the distribution, conservation status and ecological drivers of O. taeniatus.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere