Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis, particularly in domestic dogs Canis familiaris, has become the major impediment to global eradication of this human disease. 93% of all Guinea worms detected worldwide in 2020 were in dogs in Chad. Novel, non-classical pathways for transmission of Guinea worm in dogs, involving consumption of fish, have been hypothesized to support the maintenance of this animal reservoir. We quantified and analyzed variation in Guinea worm emergence in dogs in Chad, across three climatic seasons, in multiple villages and districts. We applied forensic stable isotope analyses to quantify dietary variation within and among dogs and GPS tracking to characterize their spatial ecology. At the end of the hot-dry season and beginning of the wet season, when fishing by people is most intensive, Guinea worm emergence rates in dogs were highest, dogs ate most fish, and fish consumption was most closely associated with disease. Consumption of fish by dogs enables a non-classical transmission pathway for Guinea worm in Chad. Seasonal fisheries and the facilitation of dogs eating fish are likely contributing to disease persistence and to this key impediment to human disease eradication. Interrelated natural resource use, climatic variation, companion animal ecology, and human health highlight the indispensability of One Health approaches to the challenges of eradicating Guinea worm and other zoonotic diseases.

The emergence and spread of infections can contribute to the decline and extinction of populations, particularly in conjunction with anthropogenic environmental change. The importance of heterogeneity in processes of transmission, resistance and tolerance is increasinglywell understood in theory, but empirical studies that consider both the demographic and behavioural implications of infection are scarce. Non-random mixing of host individuals can impact the demographic thresholds that determine the amplification or attenuation of disease prevalence. Risk assessment and management of disease in threatened wildlife populations must therefore consider not just host density, but also the social structure of host populations. Here we integrate the most recent developments in epidemiological research from a demographic and social network perspective, and synthesize the latest developments in social network modelling for wildlife disease, to explore their applications to disease management in populations in decline and at risk of extinction.We use simulated examples to support our key points and reveal howdisease-management strategies can and should exploit both behavioural and demographic information to prevent or control the spread of disease. Our synthesis highlights the importance of considering the combined impacts of demographic and behavioural processes in epidemics to successful disease management in a conservation context. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.

Eurasian otters are apex predators of freshwater ecosystems and a
recovering species across much of their European range; investigating
the dietary variation of this predator over time and space therefore
provides opportunities to identify changes in freshwater trophic
interactions and factors influencing the conservation of otter
populations. Here we sampled faeces from 300 dead otters across England
and Wales between 2007 and 2016, conducting both morphological analysis
of prey remains and dietary DNA metabarcoding. Comparison of these
methods showed that greater taxonomic resolution and breadth could be
achieved using DNA metabarcoding but combining data from both
methodologies gave the most comprehensive dietary description. All otter
demographics exploited a broad range of taxa and variation primarily
reflected changes in prey distributions and availability across the
landscape. This study provides novel insights into the trophic
generalism and adaptability of otters across Britain, which is likely to
have aided their recent population recovery, and may increase their
resilience to future environmental changes.

The Hazel Dormouse is predominantly an arboreal species that moves down to the ground to hibernate in the autumn in temperate parts of its distributional ranges at locations not yet well understood. In this study, we tested whether environmental characteristics surrounding Hazel Dormouse hibernacula can be identified using high-resolution remote sensing and data collected in situ. We modelled remotely sensed variables, including canopy height and cover, topographic slope, sky view, solar radiation and cold air drainage around 83 dormouse hibernacula in England (n=62) and the Netherlands (n=21), and identified environmental characteristics that may be favoured by pre-hibernating dormice. We also collected and analysed data on leaf litter depth, temperature, canopy cover and distance to the nearest tree collected in situ at hibernaculum locations in England. We found that remotely sensed data were effective in identifying attributes surrounding the locations of dormouse hibernacula and, when compared to in situ information, provided more conclusive results. Our study suggests that remotely sensed topographic slope, canopy height and sky view have an influence on animals choosing suitable locations to hibernate; whilst in situ data suggested that average daily mean temperature at the hibernaculum may also have an effect. Remote sensing proved capable of identifying localised environmental characteristics in the wider landscape that may be important for hibernating dormice. We also propose that this method can provide a novel progression from habitat modelling to conservation management for the Hazel Dormouse, as well as other species using habitats where topography and vegetation structure influence fine-resolution favourability.

The ultimate payoff of behaviours depends not only on their direct impact on an individual but also on the impact on their relatives. Local relatedness – the average relatedness of an individual to their social environment – therefore has profound impacts on social and life history evolution. Recent work has begun to show that local relatedness has the potential to change systematically over an individual’s lifetime, a process called kinship dynamics. However, it is unclear how general these kinship dynamics are, whether they are predictable in real systems and their impacts on behaviour and life history evolution. In this study, we combine modelling with data from real systems to explore the extent and impact of kinship dynamics. We use data from seven group-living mammals with diverse social and mating systems to demonstrate not only that kinship dynamics occur in animal systems, but also that the direction and magnitude of kinship dynamics can be accurately predicted using a simple model. We use a theoretical model to demonstrate that kinship dynamics can profoundly impact lifetime patterns of behaviour and can drive sex differences in helping and harming behaviour across the lifespan in social species. Taken together this work demonstrates that kinship dynamics are likely to be a fundamental dimension of social evolution, especially when considering age-linked changes and sex differences in behaviour and life history.

Illegal killing of wildlife is a major conservation issue that, to be addressed effectively, requires insight into the drivers of human behaviour. Here we adapt an established socio-psychological model, the theory of planned behaviour, to explore reasons for hunting the Endangered Bewick's swan Cygnus columbianus bewickii in the European Russian Arctic, using responses from hunters to a questionnaire survey. Wider ecological, legal, recreational and economic motivations were also explored. of 236 hunters who participated overall, 14% harboured intentions to hunt Bewick's swan. Behavioural intention was predicted by all components of the theory of planned behaviour, specifically: hunters' attitude towards the behaviour, perceived behavioural control (i.e. perceived capability of being able to perform the behaviour) and their subjective norms (perception of social expectations). The inclusion of attitude towards protective laws and descriptive norm (perception of whether other people perform the behaviour) increased the model's predictive power. Understanding attitudes towards protective laws can help guide the design of conservation measures that reduce non-compliance. We conclude that conservation interventions should target the socio-psychological conditions that influence hunters' attitudes, social norms and perceived behavioural control. These may include activities that build trust, encourage support for conservation, generate social pressure against poaching, use motivations to prompt change and strengthen peoples' confidence to act. This approach could be applied to inform the effective design, prioritization and targeting of interventions that improve compliance and reduce the illegal killing of wildlife.

Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis, particularly in domestic dogs Canis familiaris, has become the major impediment to global eradication of this human disease. 93% of all Guinea worms detected worldwide in 2020 were in dogs in Chad. Novel, non-classical pathways for transmission of Guinea worm in dogs, involving consumption of fish, have been hypothesized to support the maintenance of this animal reservoir. We quantified and analyzed variation in Guinea worm emergence in dogs in Chad, across three climatic seasons, in multiple villages and districts. We applied forensic stable isotope analyses to quantify dietary variation within and among dogs and GPS tracking to characterize their spatial ecology. At the end of the hot-dry season and beginning of the wet season, when fishing by people is most intensive, Guinea worm emergence rates in dogs were highest, dogs ate most fish, and fish consumption was most closely associated with disease. Consumption of fish by dogs enables a non-classical transmission pathway for Guinea worm in Chad. Seasonal fisheries and the facilitation of dogs eating fish are likely contributing to disease persistence and to this key impediment to human disease eradication. Interrelated natural resource use, climatic variation, companion animal ecology, and human health highlight the indispensability of One Health approaches to the challenges of eradicating Guinea worm and other zoonotic diseases.

In parts of the United Kingdom and Ireland, the European badger is a wildlife host for Mycobacterium bovis (the causative agent of bovine tuberculosis). Badger vaccination is one management option for reducing disease spread. Vaccination is currently achieved by parenteral vaccination of captured badgers, but an oral vaccine delivered in a bait may provide an additional approach in the future. We conducted two field experiments in wild badger populations to identify factors that influence uptake (% of individuals with evidence of bait consumption) of candidate oral vaccine baits. In both instances, baits containing the biomarker iophenoxic acid (as a proxy for the vaccine) were fed at burrows (setts) associated with badger social groups (study A = 48 groups, study B = 40 groups). Badgers were captured following a period of bait deployment to quantify uptake in relation to age, sex and social group. In addition, groups were allocated different treatments and the bait deployment protocol was varied to identify effects on uptake. Study a tested the effects of season, bait type, bait placement and packaging, while study B investigated the effects of bait quantity and badger activity levels. Overall bait uptake was low (Study A = 24 %, Study B = 37 %) but this varied among treatment groups (range 0-58 %). In both studies, bait uptake was significantly higher in cubs than in adults. Uptake was substantially higher where baits were placed directly into sett entrances (rather than under tiles near setts), and by badgers caught at main setts rather than at outlier setts. Season, bait type and packaging did not influence uptake, while increasing the quantity of bait available increased uptake by cubs but not by adults. Levels of badger activity at setts varied over time (suggesting potential disturbance), but were positively associated with levels of bait uptake.

BACKGROUND: Variation in host attributes that influence their contact rates and infectiousness can lead some individuals to make disproportionate contributions to the spread of infections. Understanding the roles of such 'superspreaders' can be crucial in deciding where to direct disease surveillance and controls to greatest effect. In the epidemiology of bovine tuberculosis (bTB) in Great Britain, it has been suggested that a minority of cattle farms or herds might make disproportionate contributions to the spread of Mycobacterium bovis, and hence might be considered 'superspreader farms'. OBJECTIVES AND METHODS: We review the literature to identify the characteristics of farms that have the potential to contribute to exceptional values in the three main components of the farm reproductive number - Rf : contact rate, infectiousness and duration of infectiousness, and therefore might characterize potential superspreader farms for bovine tuberculosis in Great Britain. RESULTS: Farms exhibit marked heterogeneity in contact rates arising from between-farm trading of cattle. A minority of farms act as trading hubs that greatly augment connections within cattle trading networks. Herd infectiousness might be increased by high within-herd transmission or the presence of supershedding individuals, or infectiousness might be prolonged due to undetected infections or by repeated local transmission, via wildlife or fomites. CONCLUSIONS: Targeting control methods on putative superspreader farms might yield disproportionate benefits in controlling endemic bovine tuberculosis in Great Britain. However, real-time identification of any such farms, and integration of controls with industry practices, present analytical, operational and policy challenges.

Species declines, which are both widespread and worsening, affect the ecological dynamics not only of declining populations, but also the species with which they interact. In the case of top carnivores, their marked declines are triggering trophic cascades whereby their structuring influence on communities is lost, resulting in release of prey species from predation pressure and sympatric carnivores from competitive pressure. Changes in competitive pressure both within and between sympatric species are predicted to result in changes in the ecological niches of individuals and populations, according to the niche variation hypothesis. Investigating the niche dynamics of communities experiencing top carnivore loss allows us to test theoretical predictions of how ecological niches respond to competition, as well as furthering our understanding of the role and function of top carnivores.
In this thesis, I have explored the effects of Tasmanian devil Sarcophilus harrisii decline, following the emergence of a transmissible cancer, devil facial tumour disease (DFTD). I used stable isotope analysis to characterise the trophic ecology of Tasmanian devils, a top marsupial carnivore, and to investigate the impact of disease and population decline on the trophic niches of devil individuals and populations, and of spotted-tailed quolls Dasyurus maculatus, a closely-related sympatric marsupial carnivore.
I first quantified patterns of isotopic variation within a Tasmanian devil population. Using δ13C and δ15N values from whisker tissue samples collected from Tasmanian devils at Wilmot, Tasmania, I demonstrated that both δ13C and δ15N, and group isotopic niche breadth decreased with increasing age in weaned Tasmanian devils. By characterising the isotopic niche breadth of a subset of individuals, I showed that individual niche breadth also decreased with increasing age, and revealed an isotopic signature of weaning in young Tasmanian devils.
Next, I explored the impact of DFTD on the trophic ecology of infected Tasmanian devils. I tested whether DFTD progression, measured as tumour volume, affected δ13C and δ15N values of whiskers of Tasmanian devils collected at six sites across Tasmania. I found isotope values did not change with increasing tumour volume, except at one site, Freycinet, which showed differences in the relative abundance of three common prey species compared to our other sites, based on species distribution models. I also showed that whisker isotope values of individual Tasmanian devils sampled before and after detection of clinical signs of disease do not differ, when compared to healthy control individuals. I conclude that, according to stable isotope analysis, devils do not generally change their diet in response to DFTD but that contextual ecological factors such as prey availability may elicit or allow a change in diet as the disease progresses.
I then used Bayesian stable isotope mixing models to estimate the proportional contribution of prey groups to the diet of Tasmanian devils. I examined variation in δ13C and δ15N values from Tasmanian devils and their putative prey species at six sites, and concluded only one site was suitable for mixing model analysis. The results suggested that the devil population at Woodbridge, Tasmania, consumed similar amounts of Tasmanian pademelon Thylogale billardierii and small mammals, and fewer Bennett’s wallabies Macropus rufogriseus. I highlight the importance of further research to quantify trophic discrimination factors in marsupial species, and the difficulty in sampling the prey base of opportunistic carnivores, with large ranges relative to their prey.
Considering the potential impact of Tasmanian devil decline on community niche dynamics, I examined the effect of devil decline upon the population and individual-level isotopic niche breadths of both Tasmanian devils and spotted-tailed quolls. The extent of devil decline, using time since disease arrival as a proxy, had no effect on population level isotopic niche breadths. However, niches of both species were significantly smaller in areas with high coverage of human-modified habitat. I did not find evidence of differences in individual specialisation between sites. I conclude that anthropogenic influences on resource availability have a larger impact on carnivore niches in this system than top carnivore decline.
Finally, I conclude by discussing the key findings of this thesis and placing them within the broader contexts of Tasmanian devil ecology, stable isotope analysis and ecological niche variation. This work demonstrates the robustness of Tasmanian devil isotopic niches to disease and decline, and shows that ecological context is a key driver of isotopic variation among Tasmanian devils. This research also reveals some of the challenges and opportunities afforded in applying stable isotope analysis to marsupials, particularly in Australia, which is thus far an under-utilised method in this taxon and in this region of the world. Ultimately, the work of this thesis contributes to our understanding of ecological niche dynamics, and highlights the need to consider both community-level and landscape-level perturbations when investigating ecological niches in changing communities.

1.The domestic cat shares a longstanding history with humans. Depending on the ecological and cultural contexts in which it lives, it can be classified as an invasive species, feral animal, pest-controller and companion animal. Cat behavioural plasticity and adaptability to all ecosystems is mainly related to the retention of hunting behaviour, the management of which is a source of social controversies. Pet owners are often opposed to common hunting management strategies, due to safety concerns or limits imposed upon what they perceive as natural feline behaviours. Conversely, wildlife conservationists often advocate cat confinement as cats pose a threat to wild animal populations. A better understanding of cat hunting behaviour and novel management strategies that recognise both views are required for ameliorating these conflicts.

2. The retention of hunting behaviour by cats is an underexplored issue. Through a literature review, I identified drivers and facilitators of hunting behaviour, and the available measures to reduce impact of cats on wild fauna through population-level and individual-level strategies. Hunting is driven by evolutionary constraints mainly related to an obligate carnivorous diet. Lethal approaches are considered indispensable for cat eradications from islands and large-scale population control. Enrichment has the potential to be a successful approach for reducing hunting in pet cats.

3. Confinement and collar-mounted devices reduce prey killed by domestic cats, but owner uptake of those is low. With a before-after-control-impact design trial, I found that, alongside conventional approaches, the novel enrichment measures of provision of high-meat content, grain-free food and introduction of daily object play reduced numbers of prey items brought home by 36%, and 25% respectively. Such approaches reduce hunting motivation, rather than impeding hunting, and are likely to find more support among cat owners concerned about welfare implications of other interventions.

4. The number of prey items brought home represents only a proportion of the total prey killed by cats, but other prey is eaten. I used Bayesian stable isotope mixing models (BSIMMs) to estimate contributions of wild and provisioned foods to diets of cats, analysing whiskers of cats that depredate wild animals. I also determined whether common deterrents and novel interventions affect the relative importance of wild prey in cats’ diet. Wild prey was discernible from provisioned pet foods, indicating that cat diets consisted primarily of provisioned foods and wild animals contribute a low proportion. Fitting cats with a BirdsBeSafe collar cover further reduces consumption of wild prey. I concluded that hunting wild prey is likely to address some micronutrients requirements, or behavioural motivations.

5. Cat owners express safety concerns regarding their cats’ roaming behaviour. Cats are also a threat to wild fauna when roaming outside. I investigated the spatial ecology of cats that were both free to roam and partially confined by owners, and whether intervention measures for reducing predation also affect cat spatial behaviour. Cat home range size and roaming behaviour are affected by outdoor access. Cats fitted with a bell, provided with high-meat content food and subjected to object play increased time cats were located at home (Bell +29%; Food +20%; Play +24%). The most effective approach for reducing roaming remains confinement, whether partial or permanent.

6. Cat personality has been hypothesised to affect between-individual variation in hunting behaviour. I tested whether variation in the ‘Feline Five’ personality factors (scored by owners) allowed discrimination between cats that bring home prey and those that do not, and whether variation in number of prey returned is related to personality scores. Cats returning home prey were perceived by owners to be high in ‘extraversion’ or low in ‘neuroticism’. Variation in number of prey returned was not affected by any of the personality factors. Assessing behavioural needs through characterisation of individual personality has the potential to enhance approaches for managing hunting by cats.

7. Domestic cats have retained hunting behaviour, which may satisfy behavioural motivational needs and/or nutritional requirements. The novel strategies proposed for reducing hunting in pet cats broaden the approaches owners can adopt while accommodating their diverse perspectives on cat husbandry. A better understanding of the analytical components making the food successful in reducing hunting motivation is advised, particularly for improving environmental sustainability of pet food. Hunting management can be enhanced by designing solutions that consider both the wild and the domestic sides of cats, leading to successful results for conservation.

The global programme for the eradication of Guinea worm disease, caused by the parasitic nematode Dracunculus medinensis, has been successful in driving down human cases, but infections in non-human animals, particularly domestic dogs (Canis familiaris), now present a major obstacle to further progress. Dog infections have mainly been found in Chad and, to a lesser extent, in Mali and Ethiopia. While humans classically acquire infection by drinking water containing infected copepods, it has been hypothesized that dogs might additionally or alternatively acquire infection via a novel pathway, such as consumption of fish or frogs as possible transport or paratenic hosts. We characterized the ecology of free-ranging dogs living in three villages in Gog woreda, Gambella region, Ethiopia, in April-May 2018. We analysed their exposure to potential sources of Guinea worm infection and investigated risk factors associated with infection histories. The home ranges of 125 dogs and their activity around water sources were described using GPS tracking, and the diets of 119 dogs were described using stable isotope analysis. Unlike in Chad, where Guinea worm infection is most frequent, we found no ecological or behavioural correlates of infection history in dogs in Ethiopia. Unlike in Chad, there was no effect of variation among dogs in their consumption of aquatic vertebrates (fish or frogs) on their infection history, and we found no evidence to support hypotheses for this novel transmission pathway in Ethiopia. Dog owners had apparently increased the frequency of clean water provision to dogs in response to previous infections. Variations in dog ranging behaviour, owner behaviour and the characteristics of natural water bodies all influenced the exposure of dogs to potential sources of infection. This initial study suggests that the classical transmission pathway should be a focus of attention for Guinea worm control in non-human animals in Ethiopia.

Devil facial tumor disease (DFTD) is a transmissible cancer affecting Tasmanian devils Sarcophilus harrisii. The disease has caused severe population declines and is associated with demographic and behavioral changes, including earlier breeding, younger age structures, and reduced dispersal and social interactions. Devils are generally solitary, but social encounters are commonplace when feeding upon large carcasses. DFTD tumors can disfigure the jaw and mouth and so diseased individuals might alter their diets to enable ingestion of alternative foods, to avoid conspecific interactions, or to reduce competition. Using stable isotope analysis (δ13C and δ15N) of whiskers, we tested whether DFTD progression, measured as tumor volume, affected the isotope ratios and isotopic niches of 94 infected Tasmanian devils from six sites in Tasmania, comprising four eucalypt plantations, an area of smallholdings and a national park. Then, using tissue from 10 devils sampled before and after detection of tumors and 8 devils where no tumors were detected, we examined whether mean and standard deviation of δ13C and δ15N of the same individuals changed between healthy and diseased states. δ13C and δ15N values were generally not related to tumor volume in infected devils, though at one site, Freycinet National Park, δ15N values increased significantly as tumor volume increased. Infection with DFTD was not associated with significant changes in the mean or standard deviation of δ13C and δ15N values in individual devils sampled before and after detection of tumors. Our analysis suggests that devils tend to maintain their isotopic niche in the face of DFTD infection and progression, except where ecological conditions facilitate a shift in diets and feeding behaviors, demonstrating that ecological context, alongside disease severity, can modulate the behavioral responses of Tasmanian devils to DFTD.

Behavioural differences between urban and rural wildlife have been widely reported, however, how these differences relate to individual differences in behaviour and the expression of personality variation remains less well understood. In a review of studies exploring personality variation in urban wildlife, this thesis finds that many of these studies appear to consider behavioural variation (repeatable among individual differences in behaviour) within the context of quite broad classifications of urban verses rural populations. Using these broad classifications may lead to difficulties in understanding and predicting how urban habitats might shape behavioural variation. Maintaining behavioural variation is likely to be an important factor in populations undergoing rapid human induced habitat change, thus being able to compare between studies in terms the relationships between behaviour and habitat features, could be important for making predictions about potential impacts.
Using grey squirrels as a model system, studies in this thesis attempt to address this issue by including habitat characteristics at the local habitat level into experimental field studies that investigate relationships between behavioural variation and habitat features associated with urbanisation. Firstly, it applies giving-up density (GUD) methodology to test for differences in risk perception and patch use in squirrels experiencing varying levels of urbanisation. This found that squirrels foraging near buildings and roads utilised ‘risky’ patches more readily than squirrels living further away from fixed features of potential disturbance risk. In addition, noise variability was found to be an important factor in squirrels perceived risk, with squirrels feeding under highly variable noise conditions leaving higher GUDs at ‘riskier’ feeding sites. To investigate the relationships between local habitat and personality variation, individual squirrels, at different sites, were measured on responses to handling and behaviours within an open-field test. This found that escape and exploration behaviours were repeatable for individuals, however, significant differences in personality variation between sites were not found. Local microhabitat features did not appear to significantly predict individual behaviours, although a trend for faster escape responses in individuals caught near roads was found at the urban site. Overall, differences in the mean levels of escape and exploration behaviours were found, with faster levels of escape responses and faster rates of exploration, although less total exploration, found in urban sites. These findings mirror those from other studies of personality variation in urban dwelling species, where levels of urbanisation experienced by populations were defined more broadly.
Like many successful urban species, urban grey squirrels live at higher population densities than their rural counterparts. The final study in this thesis uses auditory playbacks of conspecific calls to test if features of the urban built environment. influence behavioural responses during foraging under an auditory cue of potential competition risk. Results suggest that. squirrels foraging closer to roads and buildings appeared to be less attentive to conspecific playbacks. Further, local habitat quality level and noise were also found to impact time invested in social signalling behaviours, vigilance and feeding intake rate. Together these results show that foraging trade-offs under potential conspecific risk vary with local habitat features associated with proximity to human disturbance. Foragers under variable noise conditions and those feeding close to urban features appear to prioritise resource-acquisition over attending to conspecific risk.
Overall, the studies included in this thesis provide some insights into the behavioural differences between urban and rural grey squirrels in terms of resource-acquisition trade-offs, and the local habitat features affecting these. Integrating this approach into future studies of behavioural variation could aid in understanding of how urbanisation could impact behavioural variation in wildlife occupying these areas.

Pathogens which can infect wildlife, domestic species and humans can have serious health, welfare and economic implications around the world. Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a widespread disease that affects a wide variety of livestock, wild mammals and humans. In England bTB remains a substantial problem, despite long term management strategies. It is estimated to cost £120 million per year and in the year ending September 2020, 27,339 test-positive cattle were slaughtered. Mycobacterium bovis is proving difficult to manage, in part due to its generalist nature, infecting a broad variety of wild mammal species, and its ability to survive for extended periods of time in environmental substrates including water, soil and faeces. In this thesis, I explore two potential sources of M. bovis in the environment: water troughs, and the spreading of cattle manure and slurry onto the farming landscape. Using both camera traps and GPS collaring technology, I find that wild mammals do not regularly drink from water troughs, suggesting that the role of water troughs in interspecific transmission might be limited, although their potential role in intraspecific transmission warrants further investigation. By attaching GPS trackers to both muck spreaders and slurry tankers to monitor their movements, I find that slurry and manure spreading by farmers does not change in response to the detection of test-positive cattle on their farms, providing the opportunity for pathogen spread (both on and off the home farm). Whilst both water and cattle faeces management are covered in advisory guidance, their management to prevent infection risks is not enforceable. bTB provides an example of a disease with multiple possible routes of interspecific and intraspecific transmission, and for successful rapid disease control an understanding of all routes is necessary.

Reversing global declines in predator populations is a major conservation objective. Translocations are frequently used to address this but are associated with relatively low success rates. I used the opportunity of a pine marten Martes martes translocation to explore ecological and social aspects of the process. Translocations can be associated with adverse outcomes for animals, including long-distance dispersal, poor welfare, high mortality, and failure to establish populations. In chapter 2 I investigate the relationships between the behaviour of candidate animals in the wild at the source sites, their behaviour at the point of release, including stress levels in captivity, and their post release movement. I identified some simple assays employable at the source sites that indicate which individuals are most likely to exhibit greater levels of stress in captivity, and to disperse long distance from the release site. I suggest that these individuals require prioritized monitoring, reducing the potential for lost animals, improving the quality of monitoring and welfare of released individuals, satisfying responsibilities to stakeholders, and enabling proactive conflict mitigation by prioritizing monitoring of individuals that are most likely to come into contact with humans.
People frequently come into conflict over carnivore conservation.
In chapter 3 I use Q-methodology to investigate the perspectives of affected communities towards pine martens and the proposed translocation. I uncovered a spectrum of support characterised by three distinct perspectives, and one perspective in opposition to the proposed translocation. I elucidate in detail the factors contributing to these perspectives and discuss the implications for the proposition of pine marten reinforcement in Wales, presenting the outcomes in
3 a broader context of carnivore recovery and democratic process in conservation.
In chapter 4 I discuss and synthesize the findings of chapters 2 and 3, framing them within a context of coexistence between people and recovering carnivores.

Guinea worm Dracunculus medinensis causes debilitating disease in people and is subject to an ongoing global eradication programme. Research and controls are constrained by a lack of diagnostic tools. We developed a specific and sensitive LAMP method for detecting D. medinensis larval DNA in copepod vectors. We were able to detect a single larva in a background of field-collected copepods. This method could form the basis of a "pond-side test" for detecting potential sources of Guinea worm infection in the environment, in copepods, including in the guts of fish as potential transport hosts, enabling research, surveillance and targeting of control measures. The key constraint on the utility of this assay as a field diagnostic, is a lack of knowledge of variation in the temporal and spatial distribution of D. medinensis larvae in copepods in water bodies in the affected areas and how best to sample copepods to obtain a reliable diagnostic sample. These fundamental knowledge gaps could readily be addressed with field collections of samples across areas experiencing a range of worm infection frequencies, coupled with field and laboratory analyses using LAMP and PCR.

Following nineteenth-century declines, polecats Mustela putorius are recolonising Great Britain. Polecat diet relates to two potential risks to recovery. First, rabbits Oryctolagus cuniculus, which are important prey for polecats, have experienced extreme population fluctuations, with near extirpation due to myxomatosis in the 1950s, recovery in 1960s–1990s and declines in 1990s–2010s. Second, polecats are secondarily exposed to anticoagulant rodenticides by eating contaminated rodents, and the frequency of polecat exposure to rodenticides is increasing. We analysed stomach contents from 99 polecats collected in 2012–2016 and compared results with earlier studies. Lagomorphs were the most abundant prey (66% frequency of occurrence, 95% confidence interval 53–74%), followed by other mammals (12%, 4–18%), amphibians (10%, 3–16%) and birds (7%, 1–13%). Diet varied seasonally; lagomorph occurrence was highest in spring and summer and lowest in autumn. Dietary niche breadth was greater in the 1960s, when rabbits were scarce, than in other decades, but did not differ between the 1990s and 2010s, indicating that diets have not diversified with recent rabbit declines. This may be because rabbit abundance is not yet low enough to cause dietary diversification or because polecats were collected in areas where rabbits were still abundant. Rodents did not increase in diet between the 1990s and 2010s and still occur with < 10% frequency, indicating that rodents need not contribute much to diet to expose polecats to rodenticides. This potentially limits the effectiveness of management actions designed to minimise polecat exposure to contaminated rodent prey.

The scale at which variations in food availability affect the foraging habits of individual animals can determine how the distribution of food resources affects populations. For species of conservation concern, these factors can have important implications for the management of habitats, as spatial and temporal variations in resource availability influence the trophic ecology of both individuals and populations. The hazel dormouse Muscardinus avellanarius is a species with seasonal dietary shifts and limited ranging, and whose populations in Great Britain are exhibiting marked decline, despite conservation measures. We compared resource availability and variation in dormouse traits with their trophic characteristics, determined by stable isotope analysis of dormouse hair and of their putative food items. The trophic levels of individual dormice were associated with the abundance of invertebrates in the surrounding habitat and in the woodland as a whole. Assessment of dormouse dietary composition suggests that the proportions of invertebrates and of tree seeds and flowers in dormouse diets are affected by the abundance of food plants in the local habitat. This suggests that dormice can exploit both invertebrates and plants in proportion to their availability, and are variable in their predatory habits, in response to both the availability of invertebrates and plants. Dormouse populations exhibit a broader trophic niche in autumn than in spring, most likely a consequence of their consumption of foods derived from a wider variety of tree and shrub species. We found no relationship between isotope signatures or food availability and the body mass or torpor of individuals, or the status of populations. This may be because, on the sites we studied, dormice could adapt to different food availabilities without discernible individual and population effects. Dormice are opportunistic feeders, rather than specialists, making use of abundant food resources at a local scale. Habitat conservation for dormice, therefore, could benefit from establishing and maintaining habitats that increase the overall abundance and uniform distribution of both flower and fruit-bearing shrubs and trees and invertebrate populations, at a fine spatial scale.

Trading animals between farms and via markets can provide a conduit for spread of infections. By studying trading networks, we might better understand the dynamics of livestock diseases. We constructed ingoing contact chains of cattle farms in Great Britain that were linked by trading, to elucidate potential pathways for the transmission of infection and to evaluate their effect on the risk of a farm experiencing a bovine tuberculosis (bTB) incident. Our findings are consistent with variation in bTB risk associated with region, herd size, disease risk area and history of previous bTB incidents on the root farm and nearby farms. However, we also identified effects of both direct and indirect trading patterns, such that connections to more farms in the England High-Risk Area up to three movements away from the root farm increased the odds of a bTB incident, while connections with more farms in the England Low-Risk Area up to eight movements away decreased the odds. Relative to other risk factors for bTB, trading behaviours are arguably more amenable to change, and consideration of risks associated with indirect trading, as well direct trading, might therefore offer an additional approach to bTB control in Great Britain.

Vaccination is a useful approach for the control of disease in wildlife populations. However, its effectiveness is dependent in part on delivery to a sufficient proportion of the target population. Measuring the proportions of wild animal populations that have been vaccinated is challenging and so there is a need to develop robust approaches that can contribute to our understanding of the likely efficacy of wildlife vaccination campaigns. We used a modified capture mark recapture technique to estimate vaccine coverage in a wild population of European badgers (Meles meles) vaccinated by live-trapping and injecting with Bacillus Calmette-Guérin as part of a bovine tuberculosis control initiative in Wales, United Kingdom. Our approach used genetic matching of vaccinated animals to a sample of the wider population to estimate the percentage of badgers that had been vaccinated. Individual-specific genetic profiles were obtained using microsatellite genotyping of hair samples, which were collected directly from trapped and vaccinated badgers and non-invasively from the wider population using hair traps deployed at badger burrows (setts). With two nights of trapping at each sett in an annual campaign, an estimated 50 % (95 % confidence interval 40−60 %) of the badger population received at least one dose of vaccine in a single year. Using a simple population model this suggested that the proportion of the population that would have received at least one dose of vaccine over the course of the four year vaccination campaign was between 67 % and 83 %. This is the first attempt, outside of field trials, to quantify the level of vaccine coverage achieved by trapping and injecting badgers, which is currently the only option for delivering BCG vaccine to this species. The results therefore have specific application to bTB control policy and the novel approach may have wider value in wildlife management and research.

No other animal has a closer mutualistic relationship with humans than the dog (Canis familiaris). Domesticated from the Eurasian grey wolf (Canis lupus), dogs have evolved alongside humans over millennia in a relationship that has transformed dogs and the environments in which humans and dogs have co-inhabited. The story of the dog is the story of recent humanity, in all its biological and cultural complexity. By exploring human-dog-environment interactions throughout time and space, it is possible not only to understand vital elements of global history, but also to critically assess our present-day relationship with the natural world, and to begin to mitigate future global challenges. In this paper, co-authored by researchers from across the natural and social sciences, arts and humanities, we argue that a dog-centric approach provides a new model for future academic enquiry and engagement with both the public and the global environmental agenda.

Conflicts between people over protecting biodiversity are ubiquitous, damaging and among the most challenging problems facing wildlife conservation worldwide. Such conflicts typically emerge from ‘biodiversity impacts’ when there are disagreements about the management and allocation of natural resources. They are characterised by their inherent multi-layered complexity and their negative impacts on biodiversity, livelihoods and human wellbeing. A shift towards a greater understanding of the human causal drivers of complex conservation issues as well as their ecological impacts is urgently needed to prevent and de-escalate conflicts and halt potentially catastrophic biodiversity loss. I explore the ecological and socio-psychological contexts of two complex conservation issues – the illegal killing of Bewick’s swans Cygnus columbianus bewickii in the Russian Arctic (regarded as a biodiversity impact at risk of emerging as a conflict) and the poisoning of waterbirds from lead ammunition in the UK (currently in a ‘destructive’ phase of conflict) – using approaches and methodologies from the natural and social sciences and psychology. I also provide novel insights into their management and wildlife management more broadly.

I first examine the lesser known impacts of blood lead levels on the physiology of wild birds. I determine that sub-lethal impacts of lead on the body condition of Icelandic-breeding whooper swans Cygnus cygnus occur at the lower end of previously established clinical thresholds. Despite partial restrictions on the use of lead ammunition in the UK, I found a high prevalence of lead poisoning within this swan population. I recommend that previously suggested thresholds for adverse clinical effects should be revised downwards for free-living wildfowl. These findings reaffirm the importance of reducing contamination of the environment with lead shot and thus the availability and exposure of lead to waterbirds.

Next, using Q-methodology, I examined the perspectives of ammunition users around the use of lead ammunition and its potential impacts on wildlife and humans. Disagreements on the risks arising from the use of lead ammunition and appropriate mitigation measures continue to strain relationships between conservation and shooting stakeholder groups in the UK. I identified two statistically and qualitatively distinct perspectives (‘Open to change’ and ‘Status quo’) among ammunition users, and areas of consensus between these. I argue that the clarification of views held presents an opportunity for the shooting community and other stakeholders to take forward discussions and potentially forge new solutions for this long-running conflict.

To identify effective management approaches for reducing the illegal hunting of Bewick’s swans in the Russian Arctic, I examined the risk of accidental hunting and the drivers of deliberate hunting using responses to a questionnaire survey. I found an overall inability of hunters to visually distinguish between three swan species and conclude that the risk of Bewick’s swans being hunted arises in part when they are mistaken for the whooper and mute swan Cygnus olor, both of which are afforded weaker legal protections than the Bewick’s swan in certain areas. Additionally, a significant proportion of hunters were ignorant of the protective laws. I therefore recommend technical solutions that inform hunters about species identification and protective laws. The clarification and mitigation of this issue at the earliest opportunity will help prevent it from emerging as an intractable conservation conflict between conservationists and resource users.

Next, using the Theory of Planned Behaviour, I assessed the drivers for deliberate hunting. Hunters were more likely to harbour hunting intentions if they held negative attitudes towards protective laws and positive or neutral attitudes towards hunting Bewick’s swans, perceived few or no practical barriers to hunting them, and believed that the behaviour was socially acceptable. Wider ecological, recreation, legal and economic motivations were also identified. Future conservation interventions should therefore target social and psychological conditions that influence hunters’ attitudes, social norms and perceived behavioural control.

Finally, I collate the findings of this thesis and use an established conflict typology to partition the varying dimensions and thematic features of the lead shot conflict and identify characteristics of the illegal hunting issue that may facilitate its emergence as a conservation conflict. I suggest that conflict management approaches can be applied to complex biodiversity impacts to prevent their transition to conflict.

Infectious diseases of livestock can cause substantial production losses and have detrimental impacts upon human health, and animal health and welfare. To limit the impact of diseases, understanding more about the dynamics of transmission can assist in the control and prevention of infectious disease. In particular, understanding infection transmission on networks, ‘network epidemiology’, offers a flexible approach, incorporating between-host heterogeneity in potentially infectious contacts drawn from empirical study of interactions among individual animals, or among farms. Trading animals and optimising productivity are vital to the commercial viability of farms, however they necessarily involve compromises in biosecurity, animal health, and welfare. Better understanding of the relationships among these multiple factors might facilitate the development of sustainable livestock industries that are more resilient to disease outbreaks.
In this thesis I examine cattle interactions at two spatial scales, first at a national-level by studying the trading connections among farms, and then at a finer scale by analysing the social interactions among cattle. First, I introduce the concept of superspreaders, hosts that generate many more secondary infections than the rest of the population, and evaluate evidence for the notion that some farms might act as superspreaders of infection. I utilise the example of bovine tuberculosis (bTB) to illustrate this concept and find that farms might act as superspreaders in three main ways; first, via exceptional trading between farms, second, by factors that facilitate high within-herd transmission and trading of high-risk animals, and third, by harbouring undetected infection for long periods. I find mechanisms that align with all three processes in the cattle industry in Great Britain that might allow superspreader farms to contribute to the current bTB epidemic.
At a national level, I describe cattle movements among farms over time, finding that some farms consistently act as ‘hubs’ in trading networks, functioning in a similar way to markets, in that they are highly connected to other farms by many direct trades. Utilising the temporal network measure of ‘contact chains’, I quantify the farms that represent potential sources of infection (ingoing contact chains) and the potential farms that a farm might infect over 1 year periods. Farms divide into two groups: those with very few connections (less than 10 farms) that are relatively isolated from the network, and those with very many connections (more than 1000 farms) that are highly connected within the network. I find that a substantial number of farms have over 10,000 farms in both their ingoing and outgoing contact chains, such that, if infected, they might potentially act as superspreaders by being more at risk of both acquiring and spreading infection.
Building on my previous analysis, I then characterise the ‘source farms’ in the ingoing contact chains, in terms of their location and bTB history. I find that after controlling for previously-established risk factors for bTB, having more source farms in areas of higher bTB risk in the ingoing contact chain increases the odds of a bTB incident on the root farm, whilst having more source farms in lower risk areas is associated with lower odds of a bTB incident on the root farm.
At a finer scale of contacts among animals, I explore interactions among dairy cattle in multiple herds using automated proximity sensors and GPS devices. When aggregated over long periods, cattle interactions appear dense and unstructured, however finer time spatial and temporal perspectives revealed structure and variation in contacts. Herds in our study had variable grazing and housing access, allowing us to determine that cattle interact with more other cows, for longer time periods when they are in buildings compared to contacts at pasture. Cattle exhibited heterogeneity in their number and duration of contacts, and although the majority of cattle interacted more equally with other cows, a small proportion of cows in each group showed evidence of stronger social ties.
Next, I consider associations between social interactions, production, and health. I review the existing literature on social parameters such as dominance rank and re-grouping of cattle, and find inconclusive outcomes regarding their impact on milk yield and somatic cell count, an indicator of udder health. I perform my own analysis to examine the relationship between the time cows spend with other cows, milk yield and somatic cell count, and do not find a statistically significant relationship. In considering social preference, cows that had experienced the same number of lactations were more likely to interact, but cows spending more time with cows in the same lactation did not appreciably affect their milk yield or somatic cell count.
Finally, I draw together the findings of this thesis and reflect on how the identification of higher-risk farms might be useful in the control of livestock infections, and specifically bTB in Great Britain. I conclude that network analysis is a valuable tool to study the interactions of cattle and cattle farms, identifying unique opportunities for targeted approaches to disease control.

Controlling and preventing outbreaks of infectious diseases in human and non-human animals is a priority objective for public and animal health professionals, and failure to do so can result in a significant loss of life and have adverse effects on the economy and on the conservation of biodiversity.
Free-ranging domestic dogs are reservoirs for several zoonotic diseases, and are currently the focus of two major public health programmes; the ‘Zero by 30’ strategic plan to eliminate dog-mediated rabies and the Guinea worm eradication programme. The management of these and other dog-mediated diseases would benefit from insights into the social and spatial ecology of free-ranging domestic dogs, and their relationships to the dynamics of disease transmission.
In this thesis, I explore spatial and temporal dynamics in the contact rates and space use of free-ranging domestic dogs in rural Chad; a region where the risks to humans of infection with rabies and Guinea worm are high.
I first describe static contact networks for free-ranging dogs, using novel proximity sensors, and then simulate the transmission of a communicable disease similar to rabies through the networks. My results show that there is considerable variation in the number and duration of contacts between individuals, and that communities in the network were defined by household membership. Disease simulations showed that dogs with a higher ranked degree (more first order contacts) have a higher probability of starting an epidemic should they become infected, while those with a higher ranked eigenvector centrality (more second order contacts) tend to cause larger epidemics. Furthermore, in one settlement ranked eigenvector centrality was positively correlated with home range size. I demonstrate that dogs are not equal in the epidemiological risks that they present and that there may be traits (e.g. drivers behind space use) that could identify individuals that present a higher risk.
I then explore dog space use using GPS loggers and continuous time movement models to calculate the dogs’ home ranges and to investigate temporal patterns in their activity and space use. I find that dogs had larger ranges in the dry season, but that this was also when 70% of dogs can be more reliably found around their households. Owner activity explained some of the variation in dog space use, whereby dogs from households that went hunting had larger ranges in the dry season. These results demonstrate how dog spatial ecology can be used to inform disease management practices, such as vaccination campaigns, and highlight the potential to use targeted strategies at the household level.
Next, I use the detail of dyadic-level interactions to investigate the spatial-temporal variations in contact rates between dogs. I find that the probability that individuals were ever observed in contact and the hourly probability and duration of contacts should they have interacted, were all negatively correlated with the distance between the individual’s households. Contact rates were higher around the household and village where they peaked between 5am-9am and again between 6pm-8pm. However, the duration of contacts were highest when they occurred outside the village. Evidence for seasonal preferential mixing among the sexes was found, whereby male-male and male-female dyads had higher contact rates in the dry season.
Next, I quantify the exposure of free-ranging dogs to water sources in Chad; which are considered potential sources for Guinea worm infection. I use the activity of dogs (based on GPS data) as a proxy for variation in exposure. I find that 85% of dogs had visited at least one water source, but that dogs with larger ranges had higher activity levels around water sources. In all field sites and seasons, no more than 4 water sources accounted for 95% of dog visits, and these were all

Wildlife hosts are important reservoirs of a wide range of human and livestock infections worldwide, and in some instances, wildlife populations are threatened by disease. Yet wildlife diseases are difficult to monitor, and we often lack an understanding of basic epidemiological parameters that might inform disease management and the design of targeted interventions. The impacts of disease on host survival are generally associated with age, yet traditional epidemiological models tend to use simplistic categories of host age. Mortality trajectory analysis provides the opportunity to understand age-specific impacts of disease and uncover epidemiological patterns across complete life histories. Here, we use Bayesian survival trajectory analysis (BaSTA) software to analyse capture-mark-recapture data from a population of wild badgers Meles meles naturally infected with Mycobacterium bovis, the causative agent of tuberculosis in badgers and cattle. We reveal non-constant mortality trajectories, and show that infection exaggerates an age-dependent increase in late-life mortality. This study provides evidence for actuarial senescence in badgers, a species previously believed to display constant mortality throughout life. Our case study demonstrates the application of mortality trajectory analysis in wildlife disease research, but also highlights important limitations. We recommend BaSTA for mortality trajectory analysis in epidemiological research, but also suggest combining approaches that can include diagnostic uncertainty and the movement of hosts between disease states as they age. We recommend future combinations of multi-state and multi-event modelling frameworks for complex systems incorporating age-varying disease states.

The rate of biodiversity loss has been increasing since the beginning of the Anthropocene, driven by climate change, human population expansion and environmental degradation. Consequently, ecosystems have become simplified through the loss of important processes and species. Ecological restoration aims to reverse such changes through reinstating habitats, native species and their associated relationships, as well as removing invasive, non-native species. One strategy to restore ecological function is through the re-establishment of top-down processes driven by predators. The cascading effects of these predators, through direct predation and the fear they induce in prey can restore predator-prey dynamics in a disrupted food web.
In this thesis, I investigate the restoration of a native and recovering predator, the pine marten Martes martes, with particular focus on its ecology and behaviour after a translocation event from Scotland to Wales. Subsequently, I assess its impact on the behaviour of one of its prey species, the invasive, non-native grey squirrel Sciurus carolinensis to better understand the relationship between these two species.
I first introduce predator restoration using translocation in a project that aims to reintroduce and restore the native pine marten. I demonstrate that the phases of post-translocation movement comprise a period of ‘exploration’ followed by ‘settlement’ in all individuals, however the extent and duration of these movements differ between release groups. I show that conspecific presence is important in site fidelity and the resulting habitat in which martens establish themselves. I then investigate the diet of translocated martens at a population and individual level, before and after translocation. I reveal that pine martens consume a more diverse diet post-translocation, which incorporates grey squirrels, a prey item not found in their source sites in Scotland. Furthermore I document a degree of dietary specialisation within individuals, which is maintained relative to others after translocation. This suggests pine martens are facultative specialists with dietary preferences that they are able to supplement with readily available prey groups, enhancing their probability of survival after translocation.
Next, I address the impact of translocated pine martens on grey squirrel space use and survival. Grey squirrel range size and daily distance travelled was found to increase with increasing marten exposure. However, an impact on grey squirrel survival and range location was not found within the timeframe of this study. I then investigated the role that fear plays in the relationship between pine martens and grey squirrels. Using feeding experiments, I document a reduced volume of food consumed by squirrels in woodlands containing pine martens, suggesting that squirrels ‘give-up’ foraging earlier under such conditions. This suggests that squirrels display a fear-mediated response to pine marten risk, which in time may be detrimental to grey squirrel fitness. I consider the role of predation and fear in predator-prey dynamics and its importance in species management.
Finally I conclude the key findings of this thesis with regards to pine marten and grey squirrel management in the UK, as well as their contribution to carnivore restoration and species management strategies. This work identifies that social structure and dietary flexibility are key considerations for predator restoration projects. Furthermore, the cascading effects of predators can play a potential role in the management of invasive non-native species, which may be more economically and socially acceptable than current strategies. This work highlights the importance of studying ecological processes underlying landscape-scale patterns to better inform the management of native and non-native species alike.

Dominance hierarchies are widespread in animal societies and reduce the costs of within-group conflict over resources and reproduction. Variation in stability across a social hierarchy may result in asymmetries in the benefits obtained from hierarchy formation. However, variation in the stability and behavioural costs of dominance interactions with rank remain poorly understood. Previous theoretical models have predicted that the intensity of dominance interactions and aggression should increase with rank, but these models typically assume high reproductive skew, and so their generality remains untested. Here we show in a pack of free-living dogs with a sex - age-graded hierarchy that the central region of the hierarchy was dominated by more unstable social relationships and associated with elevated aggression. Our results reveal unavoidable costs of ascending a dominance hierarchy, run contrary to theoretical predictions for the relationship between aggression and social rank in high-skew societies, and widen our understanding of how heterogeneous benefits of hierarchy formation arise in animal societies.

Contact patterns strongly influence the dynamics of disease transmission in both human and non-human animal populations. Domestic dogs Canis familiaris are a social species and are a reservoir for several zoonotic infections, yet few studies have empirically determined contact patterns within dog populations. Using high-resolution proximity logging technology, we characterised the contact networks of free-ranging domestic dogs from two settlements (n = 108 dogs, covering >80% of the population in each settlement) in rural Chad. We used these data to simulate the transmission of an infection comparable to rabies and investigated the effects of including observed contact heterogeneities on epidemic outcomes. We found that dog contact networks displayed considerable heterogeneity, particularly in the duration of contacts and that the network had communities that were highly correlated with household membership. Simulations using observed contact networks had smaller epidemic sizes than those that assumed random mixing, demonstrating the unsuitability of homogenous mixing models in predicting epidemic outcomes. When contact heterogeneities were included in simulations, the network position of the individual initially infected had an important effect on epidemic outcomes. The risk of an epidemic occurring was best predicted by the initially infected individual’s ranked degree, while epidemic size was best predicted by the individual’s ranked eigenvector centrality. For dogs in one settlement, we found that ranked eigenvector centrality was correlated with range size. Our results demonstrate that observed heterogeneities in contacts are important for the prediction of epidemiological outcomes in free-ranging domestic dogs. We show that individuals presenting a higher risk for disease transmission can be identified by their network position and provide evidence that observable traits hold potential for informing targeted disease management strategies.

Movement of individuals, or their genes, can influence eco-evolutionary processes in structured populations. We have limited understanding of the extent to which spatial behavior varies among groups and individuals within populations. Here, we use genetic pedigree reconstruction in a long-term study of European badgers (Meles meles) to characterize the extent of extra-group paternity, occurring as a consequence of breeding excursions, and to test hypothesized drivers of variation at multiple levels. We jointly estimate parentage and paternity distance (PD; distance between a cub's natal and its father's social group), and test whether population density and sex ratio influence mean annual PD. We also model cub-level PD and extra-group paternity (EGP) to test for variation among social groups and parental individuals. Mean PD varied among years but was not explained by population density or sex ratio. However, cub-level analysis shows strong effects of social group, and parental identities, with some parental individuals being consistently more likely to produce cubs with extra-group partners. Group effects were partially explained by local sex ratio. There was also a strong negative correlation between maternal and paternal social group effects on cub paternity distance, indicating source-sink dynamics. Our analyses of paternity distance and EGP indicate variation in extra-group mating at multiple levels- a mong years, social groups and individuals. The latter in particular is a phenomenon seldom documented and suggests that gene flow among groups may be disproportionately mediated by a nonrandom subset of adults, emphasizing the importance of the individual in driving eco-evolutionary dynamics.

The emergence and spread of infections can contribute to the decline and extinction of populations, particularly in conjunction with anthropogenic environmental change. The importance of heterogeneity in processes of transmission, resistance and tolerance is increasinglywell understood in theory, but empirical studies that consider both the demographic and behavioural implications of infection are scarce. Non-random mixing of host individuals can impact the demographic thresholds that determine the amplification or attenuation of disease prevalence. Risk assessment and management of disease in threatened wildlife populations must therefore consider not just host density, but also the social structure of host populations. Here we integrate the most recent developments in epidemiological research from a demographic and social network perspective, and synthesize the latest developments in social network modelling for wildlife disease, to explore their applications to disease management in populations in decline and at risk of extinction.We use simulated examples to support our key points and reveal howdisease-management strategies can and should exploit both behavioural and demographic information to prevent or control the spread of disease. Our synthesis highlights the importance of considering the combined impacts of demographic and behavioural processes in epidemics to successful disease management in a conservation context. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.

The use of agricultural resources or environments by wildlife may result in opportunities for transmission of infections amongst wild animals, livestock and humans. Targeted use of biosecurity measures may therefore reduce disease risks, although this requires practical knowledge of where such measures would be most effective, and effective means of communicating risks so that stakeholders can make informed decisions about such investment. In parts of Europe, the European badger Meles meles may act as a wildlife reservoir for Mycobacterium bovis, the causative agent of bovine tuberculosis, and badger visits to farmyards may provide potential opportunities for transmission of M. bovis to cattle. Biosecurity measures are effective in reducing badger activity in farmyards, although it is unclear which farms should be targeted with such measures. We used cameras to monitor badger activity in 155 farmyards in south west England and Wales, and related variations in the presence and frequency of badger visits to farm characteristics. Badgers were recorded on camera in 40% of farmyards monitored. However, the frequency of visits was highly variable, with badgers recorded on >50% of nights in only 10% of farms. The presence of badgers in farmyards was positively associated with the density of badger setts, the number of feed stores and the number of cattle sheds, and negatively associated with the distance to the nearest active badger sett, the presence of a house/dwelling and the number of cattle housed on the farm. The frequency of visits was negatively associated with the distance to the nearest active badger sett and the number of cattle housed. Models predicted the presence/absence of badgers in farmyards with 73% accuracy (62% sensitivity, 81% specificity, using a cut off value of 0.265). Models could not distinguish between farms with low/high frequency of visits, although farms predicted as having badgers present typically had a higher frequency of visits than those that were not. We developed and present an interactive web based application: the Badger Farm Assessment Tool (BFAT), to allow users to enter the characteristics of a farm and generate a relative risk score describing the likelihood of badger visits.

After historical declines in population sizes and ranges, we compare and contrast the recent history and contemporary variation in the status of Great Britain's eight native mammalian carnivore species from the 1960s to 2017. Wildcat Felis silvestris conservation status is unfavourable and is masked by hybridisation with domestic cats Felis catus. Red foxes Vulpes vulpes remain widespread but are currently declining. European otter Lutra lutra, European pine marten Martes martes and European polecat Mustela putorius populations are characterised by rapid recovery. Otters have almost completely recolonised Great Britain, polecats have expanded their range throughout southern Britain from refugia in Wales and pine martens have expanded their range from the Scottish Highlands. European badgers Meles meles have generally increased in population density. Status assessments of stoats Mustela erminea and weasels Mustela nivalis are data-deficient but available evidence suggests that stoats may have increased while weasels may have declined. Anthropogenic processes influencing carnivore status include legal protections, habitat quality, reintroductions, predator control, pollutants, hybridisation and diseases and their associated control practices. Population effects of contaminants, such as anticoagulant rodenticides, remain poorly characterised. The widespread interface with domestic and feral cats makes the wildcat's situation precarious. Recent declines in rabbit Oryctolagus cuniculus populations are a concern, given that several carnivore species depend on them as food. We conclude that, with the exception of the wildcat, the status of Great Britain's mammalian carnivores has markedly improved since the 1960s. Better understanding of the social aspects of interactions between humans and expanding predator populations is needed if conflict is to be avoided and long-term co-existence with people is to be possible.

Stoats present a serious threat to the avian biodiversity of New Zealand. Control measures are needed to ensure the long-term survival of several bird species. Existing control technology is labour-intensive and expensive, and so new techniques and approaches are needed to provide long-lasting solutions to conservation challenges. We reviewed the literature on the demography, captive breeding, diseases, biological and non-lethal control, metabolism and toxicology of stoats and closely related mustelids. We conclude that a long-term solution to lethal stoat control may lie with specific disease agents, such as canine distemper, Aleutian disease virus and mink enteritis virus, and toxins, such as rodenticides and mycotoxins. The role of host-specific vectors in disease transmission may represent an existing method of accurately deploying non-lethal control agents. We urge caution in developing biotechnology without a parallel investigation of the effects of control on stoat populations and the survival of threatened birds. The establishment of captive breeding facilities for stoats deserves a high priority since these will be indispensable for technological development and validation. Throughout their native range, stoats are dependent on a range of prey species. In certain areas of New Zealand, they are dependent on very few prey species, and outbreaks of house mice lead to acute conservation problems at regular and predictable intervals. We therefore advocate a research effort directed towards the control of mouse outbreaks.

Many carnivore species are experiencing declines due to anthropogenic factors such as direct killing, habitat loss, secondary exposure to chemical control agents, and depletion of prey resources. Due to their top-down effects on the structure and function of ecosystems, carnivores are, however, increasingly the focus of efforts towards ecological restoration. To enable such restoration to take place, wildlife managers need to understand both the ecological processes and the social-ecological factors that may affect carnivore recovery and establishment.
In this thesis, I use the European polecat Mustela putorius, which is currently recolonising Great Britain following near extirpation in the nineteenth century, as a case study through which to explore the processes of carnivore recovery. I investigate social and ecological risks to the polecat’s continuing range and population expansion, which may also be pertinent to the wider challenges of carnivore conservation.
In my introduction, I outline the importance of carnivores to ecosystem function and review the wide-ranging and cascading effects their reinstatement can have. I provide an overview of human-carnivore interactions and the anthropogenic processes that directly or indirectly lead to carnivore declines. I give a historical context to human-carnivore relations in Great Britain, introduce polecats, their biology and changing status and provide an overview of my research objectives and thesis structure.
I then carry out a detailed literature review of the changing status of the eight terrestrial mammalian carnivores native to Great Britain. I summarise the anthropogenic processes that have influenced their status. I find that polecats have recolonised Great Britain less quickly than otters Lutra lutra but more quickly than pine martens Martes martes. Badgers Meles meles have increased in abundance. Foxes Vulpes vulpes are experiencing a decline and wildcat are imperilled by hybridisation with domestic cats. Stoats Mustela erminea and weasels Mustela nivalis are data deficient, but evidence suggests that stoats may be increasing in number relative to weasels.
Next, I explore polecat resource use during a period of ecological change by analysing the stable isotopes of carbon and nitrogen from a museum collection of polecat whiskers. I find that variation in isotope ratios and isotopic niches indicate differences in resource use between polecats collected from the leading edge of the range compared to the established parts of the range and that this effect was greatest in the 1960s when rabbits Oryctolagus cuniculus—an important prey for polecats—were in low abundance. I also find that female polecats show greater variation in resource use than males, indicating that they may have different needs as part of conservation efforts.
Next, I carry out a study of polecat diets to assess responses to fluctuating abundance of rabbits. I analyse the stomach contents from polecat carcasses collected between 2013 and 2016. I compare my results with those from earlier polecat dietary studies and find that the proportion of lagomorphs increased in polecat diet between the 1960s and 1990s. Although rabbit populations have been declining since the 1990s, I find no difference in the proportion of lagomorphs in polecat diet between the 1990s and 2010s.
Secondary exposure to second generation anticoagulant rodenticides is a contemporary risk to polecat recovery that is also related to their diet, as polecats are likely exposed to rodenticides by eating contaminated rodents. In Chapter 5, I analyse the livers from polecat carcasses collected between 2013 and 2016 to measure current levels of secondary exposure and explore factors that may affect exposure. I find that the frequency of exposure to rodenticides was 79% in polecats and that this represents a 1.7 fold increase in exposure frequency over 25 years. I find that the probability of exposure increases with age and with increasing values of ẟ15N, suggesting that resource use influences polecat exposure to rodenticides.
I then explore the principles underpinning modern gamekeeping practices, by carrying out interviews with gamekeepers to find out what they do and why. In this qualitative study, I analyse gamekeepers’ conception of the Balance, which is an overarching narrative that they have adopted to explain their approach to wildlife management. Although the Balance includes echoes of the heuristic of the ‘balance-of-nature’, it is most often employed in the context of maximising shootable game surpluses while providing opportunities to other wildlife that do not conflict with this objective. I find that keeping the Balance requires a ritualised, highly interventionist approach to producing game that presents both risks and rewards to predators. The multiplicity of the Balance—in which gamekeepers are stewards of both game and the countryside—creates an ambiguity that, when associated with the regular culling of predators and negative perceptions of sport shooting, may cause misunderstandings between gamekeepers and other publics.
In conclusion, I find that polecats have been able to recolonise most of southern Britain despite the risks of fluctuating rabbit populations, increasing exposure to rodenticides and predator controls. Polecat recovery has occurred with minimal direct conservation effort. It has also taken a long time: one hundred years after their population nadir, polecats are yet to fully recolonise their former range. More broadly, a low-intervention approach is unlikely to succeed, or be desirable, for all carnivores. In particular, those that are slower to mature, have lower reproductive rates, more specialised resource requirements and greater impact on anthropogenic practices, or where the potential ecological benefits that may be derived from a species’ restoration necessitate an expedited recovery.

Parasites are ubiquitous in wild animal populations and have wide ranging effects on the health, fitness and eco-evolutionary dynamics of their host populations. To counter parasites, hosts have evolved a myriad of defence strategies, but individuals vary considerably in the efficacy of these strategies, and so, in their susceptibility to infection. While variation can generally be viewed as stemming from genetic and environmental effects, we currently have little knowledge of their relative importance in wild and unmanaged host populations. In this thesis, I use long-term mark-recapture data on a population of European badgers (Meles meles) to examine the genetic basis of variation in bovine tuberculosis infection and its progression. I first estimate a genetic pedigree and characterise variation in extra-group paternity in the population (Chapter 2). Then, adopting a pedigree-based quantitative genetic approach, I investigate the relative importance of genetic and social environmental sources of variation in bTB infection status (Chapter 3). Thirdly, I characterise associations between body weight and bTB infection and test for variation in host tolerance (Chapter 4). and finally, I examine the genetic basis of (co)variation in and among four diagnostic test responses, representing different aspects of host immune function (Chapter 5). Taken together, this work provides novel insight into the genetic architecture of bovine tuberculosis infection in a wild host species, and the evolutionary potential of immune traits in the wild.

The surveillance and control of introduced and invasive species has become an increasingly important component of environmental management. However, initiatives targeting ‘charismatic’ wildlife can be controversial. Opposition to management, and the subsequent emergence of social conflict, present significant challenges for would-be managers. Understanding the substance and development of these disputes is therefore vital for improving the legitimacy and effectiveness of wildlife management. It also provides important insights into human-wildlife relations and the 'social dimensions’ of wildlife management. Here, we examine how the attempted eradication of small populations of introduced monk parakeets (Myiopsitta monachus) from England has been challenged and delayed by opposition from interested and affected communities. We consider how and why the UK Government's eradication initiative was opposed, focusing on three key themes: disagreements about justifying management, the development of affective attachments between people and parakeets, and the influence of distrustful and antagonistic relationships between proponents and opponents of management. We draw connections between our UK case and previous management disputes, primarily in the USA, and suggest that the resistance encountered in the UK might readily have been foreseen. We conclude by considering how management of this and other introduced species could be made less conflict-prone, and potentially more effective, by reconfiguring management approaches to be more anticipatory, flexible, sensitive, and inclusive.

The deployment of baits containing vaccines or toxins has been used successfully in the management of wildlife populations, including for disease control. Optimisation of deployment strategies seeks to maximise uptake by the targeted population whilst ensuring cost-effectiveness. Tuberculosis (TB) caused by infection with Mycobacterium bovis affects a broad range of mammalian hosts across the globe, including cattle, wildlife and humans. The control of TB in cattle in the UK and Republic of Ireland is hampered by persistent infection in European badgers (Meles meles). The present study aimed to determine the best strategy for maximising uptake of an oral vaccine by wild badgers, using a surrogate novel bait deployed at 40 badger social groups. Baits contained a blood-borne biomarker (Iophenoxic Acid, IPA) in order to measure consumption in badgers subsequently cage trapped at targeted setts. Evidence for the consumption of bait was found in 83% (199/240) of captured badgers. The probability that badgers had consumed at least one bait (IPA >10 μg ml-1) was significantly higher following deployment in spring than in summer. Lower uptake amongst social groups where more badgers were captured, suggested competition for baits. The probability of bait consumption was significantly higher at groups where main and outlier setts were provided with baits than at those where outliers were present but not baited. Badgers captured 10-14 days post bait feeding had significantly higher levels of bait uptake compared to those caught 24-28 days later. Uptake rates did not vary significantly in relation to badger age and whether bait was placed above ground or down setts. This study suggests that high levels of bait uptake can be achieved in wild badger populations and identifies factors influencing the potential success of different deployment strategies. The implications for the development of an oral badger vaccine are discussed.

Cultural inheritance, the transmission of socially learned information across generations, is a non-genetic, “second inheritance system” capable of shaping phenotypic variation in humans and many non-human animals [1–3]. Studies of wild animals show that conformity [4, 5] and biases toward copying particular individuals [6, 7] can result in the rapid spread of culturally transmitted behavioral traits and a consequent increase in behavioral homogeneity within groups and populations [8, 9]. These findings support classic models of cultural evolution [10, 11], which predict that many-to-one or one-to-many transmission erodes within-group variance in culturally inherited traits. However, classic theory [10, 11] also predicts that within-group heterogeneity is preserved when offspring each learn from an exclusive role model. We tested this prediction in a wild mammal, the banded mongoose (Mungos mungo), in which offspring are reared by specific adult carers that are not their parents, providing an opportunity to disentangle genetic and cultural inheritance of behavior. We show using stable isotope analysis that young mongooses inherit their adult foraging niche from cultural role models, not from their genetic parents. As predicted by theory, one-to-one cultural transmission prevented blending inheritance and allowed the stable coexistence of distinct behavioral traditions within the same social groups. Our results confirm that cultural inheritance via role models can promote rather than erode behavioral heterogeneity in natural populations. Sheppard, Marshall, et al. demonstrate cultural inheritance of adult foraging niche in wild banded mongooses. As theory predicts, one-to-one cultural inheritance in this system maintains behavioral diversity within groups.

Modern management of multifunctional woodlands must address many and various demands, including for recreation, timber production and the conservation of biodiversity. The responses of individuals and populations of protected species to woodland management and habitat change are often not well understood. Using radio-tracking and LiDAR, we investigated the short-term habitat preferences of hazel dormice Muscardinus avellanarius, and their ranging and resting behaviours before and after small-scale tree felling, following a before-after control-impact design. Mean dormouse home range size was 0.51 Ha (±0.07 SE, n = 16) and did not vary between sexes or among sites, though heavier animals had smaller ranges. Dormice preferred mid-height woodland habitat (5–10 m tall), with low proportions of high forest (over 10 m tall), for both ranging and resting sites. Ranging habitats were often located on woodland edges and relatively dense vegetation. Dormice preferentially used yew, rowan and hazel during ranging. There was no difference in the distances travelled by dormice before and after felling, but dormice in areas where trees had been felled showed less evidence of a shift in ranging area than those in unfelled areas. Although the limited response of dormice to tree felling activities has the potential to be associated with increased mortality and/or limited dispersal of individual dormice, the requirements of dormice for mid-successional and edge habitats that arise after tree removal means that a dynamic optimum of felling and regeneration is essential for conservation of dormouse populations.

The mutation accumulation theory of senescence predicts that age-related deterioration of fitness can be exaggerated when inbreeding causes homozygosity for deleterious alleles. A vital component of fitness, in natural populations, is the incidence and progression of disease. Evidence is growing for natural links between inbreeding and ageing; between inbreeding and disease; between sex and ageing; and between sex and disease. However, there is scant evidence, to date, for links among age, disease, inbreeding and sex in a single natural population. Using ecological and epidemiological data from a long-term longitudinal field study, we show that in wild European badgers (Meles meles) exposed naturally to bovine tuberculosis (bTB), inbreeding (measured as multilocus homozygosity) intensifies a positive correlation between age and evidence of progressed infection (measured as an antibody response to bTB), but only among females. Male badgers suffer a steeper relationship between age and progressed infection than females, with no influence of inbred status. We found no link between inbreeding and the incidence of progressed infection during early life in either sex. Our findings highlight an age-related increase in the impact of inbreeding on a fitness-relevant trait (disease state) among females. This relationship is consistent with the predictions of the mutation accumulation theory of senescence, but other mechanisms could also play a role. For example, late-life declines in condition, arising through mechanisms other than mutation accumulation might have increased the magnitude of inbreeding depression in late life. Whichever mechanism causes the observed patterns, we have shown that inbreeding can influence age-dependent patterns of disease and, by extension, is likely to affect the magnitude and timing of the late-life declines in components of fitness that characterise senescence. Better understanding of sex-specific links between inbreeding, disease and ageing provides insights into population-level pathogen dynamics and could influence management strategies for wildlife reservoirs of zoonotic disease.

Individual foraging specialisation has important ecological implications, but its causes in group-living species are unclear. One of the major consequences of group living is increased intragroup competition for resources. Foraging theory predicts that with increased competition, individuals should add new prey items to their diet, widening their foraging niche (‘optimal foraging hypothesis’). However, classic competition theory suggests the opposite: that increased competition leads to niche partitioning and greater individual foraging specialisation (‘niche partitioning hypothesis’). We tested these opposing predictions in wild, group-living banded mongooses (Mungos mungo), using stable isotope analysis of banded mongoose whiskers to quantify individual and group foraging niche. Individual foraging niche size declined with increasing group size, despite all groups having a similar overall niche size. Our findings support the prediction that competition promotes niche partitioning within social groups and suggest that individual foraging specialisation may play an important role in the formation of stable social groupings.

As a result of legal protection and population recovery, European polecats (Mustela putorius) in Great Britain are expanding into areas associated with greater usage of second-generation anticoagulant rodenticides (SGARs). We analysed polecat livers collected from road casualties from 2013 to 2016 for residues of five SGARs. We related variation in residues to polecat traits and potential exposure pathways, by analysing stable isotopes of carbon (δ13C) and nitrogen (δ15N) in their whiskers. 54 of 68 (79%) polecats had detectable residues of at least one SGAR. Bromadiolone (71%) was the most frequently detected compound, followed by difenacoum (53%) and brodifacoum (35%). Applying historical limits of detection to allow comparison between these new data and previous assessments, we show that in the 25 years from 1992 to 2016 inclusive, the rate of detection of SGARs in polecats in Britain has increased by a factor of 1.7. The probability of SGAR detection was positively related to increasing values of δ15N, suggesting that polecats feeding at a higher trophic level were more likely to be exposed. Total concentrations of SGARs in polecats with detectable residues were higher in polecats collected in arable compared to pastoral habitats, and in the west compared to the east of Britain. The number of compounds detected and total concentrations of SGARs increased with polecat age. There was no evidence of regional or seasonal variation in the probability of detecting SGARs, suggesting that the current risk of exposure to SGARs does not vary seasonally and has increased (from that in the 1990s) throughout the polecat's range. We recommend quantification of current practices in rodenticide usage, particularly in the light of recent regulatory changes, to enable assessment and mitigation of the risks of secondary exposure to rodenticides in non-target wildlife. 79% of polecats in Great Britain were found to have been exposed to rodenticides from 2013 to 2016 and exposure has increased by a factor of 1.7 since the 1990s.

Detecting opportunities for between-species transmission of pathogens can be challenging, particularly if rare behaviours or environmental transmission are involved. We present a multilayer network framework to quantify transmission potential in multi-host systems, incorporating environmental transmission, by using empirical data on direct and indirect contacts between European badgers Meles meles and domestic cattle. We identify that indirect contacts via the environment at badger latrines on pasture are likely to be important for transmission within badger populations and between badgers and cattle. We also find a positive correlation between the role of individual badgers within the badger social network, and their role in the overall badger-cattle-environment network, suggesting that the same behavioural traits contribute to the role of individual badgers in within- and between-species transmission. These findings have implications for disease management interventions in this system, and our novel network approach can provide general insights into transmission in other multi-host disease systems.

Population structure is critical to infectious disease transmission. As a result, theoretical and empirical contact network models of infectious disease spread are increasingly providing valuable insights into wildlife epidemiology. Analyzing an exceptionally detailed dataset on contact structure within a high-density population of European badgers Meles meles, we show that a modular contact network produced by spatially structured stable social groups, lead to smaller epidemics, particularly for infections with intermediate transmissibility. The key advance is that we identify considerable variation among individuals in their role in disease spread, with these new insights made possible by the detail in the badger dataset. Furthermore, the important impacts on epidemiology are found even though the modularity of the Badger network is much lower than the threshold that previous work suggested was necessary. These findings reveal the importance of stable social group structure for disease dynamics with important management implications for socially structured populations.

Biodiversity, ecosystems, industry and human health are threatened by invasive plant species. The costs of mitigating damages run into billions of pounds per annum. Fundamental to the control of invasive plant species is an ability to predict which species will become invasive. Yet identification of predictive differences between invasive and non-invasive species has proven difficult to pinpoint. In this thesis I identify several weaknesses within published literature, and using field experiments and meta-analyses we address these to find consistent predictors of invasiveness amongst plants. Specifically, I recognize that predictors of invasiveness can be identified by studying plant species in the native range because species may undergo phenotypic and demographic changes following naturalization (Chapters 2 – 5). I also recognize the importance of comparing globally invasive and non-invasive species, and the importance of accounting for phylogenetic relationships so as not to inflate or conceal differences (Chapters 2 – 4). Finally, I investigate whether particular analyses are more appropriate for investigating life history and demographic differences (Chapter 5).

This thesis comprises an introductory chapter (Chapter 1), four data chapters (Chapters 2 - 5) and a general discussion (Chapter 6). Chapters 2 and 3 compare life history traits of plant species known to be invasive elsewhere, with their exported but non-invasive sympatric relatives in the native range. Chapter 4 utilizes Population Projection Matrices held within the COMPADRE Plant Matrix Database, to compare demographic projections of stable and transient dynamics of invasive and non-invasive plants; and Chapter 5 compares ten metrics, derived from Population Projection Matrices, of seven invasive species between the native and invaded range to determine if there are demographic or life history differences that facilitate invasion, and to identify those analyses that are most likely to reveal such differences.

I find reproductive capacity to be a predictor of invasiveness, and that analyses of transient dynamics are more likely than analyses of projected stable dynamics to reveal demographic or life history differences between invasive and non-invasive species or populations of plants. I discuss these findings in the context of invasive risk assessment protocols and highlight future research opportunities.

The European badger (Meles meles) is of considerable interest in the UK as it is both a protected species and the main wildlife reservoir for bovine tuberculosis infection in cattle. While there have been three national badger surveys in the 1980s, 1990s and 2011–13, using the number of badger main setts as a proxy for the abundance of badger social groups, none has combined contemporary data on social group size at landscape and national scales. We estimated social group size by genotyping hair samples collected at 120 main setts across England and Wales and employing a capture-mark-recapture method based on genotypes. The estimated mean social group size in England and Wales was 6.74 (±0.63) badgers. There was considerable variation in badger social group size among Land Class Groups (LCGs), with a low of 2.67 in LCG3 and a high of 7.92 in LCG4. Combining these results with the recent Badger Sett Survey of England and Wales, we estimate there are approximately 485,000 badgers (95% confidence intervals 391,000–581,000) in England and Wales. Although direct comparison with previous estimates is not ideal owing to methodological differences, our results are consistent with a marked increase in the badger population of England and Wales since the 1980s.

Savanna ecosystems are an integral part of the African landscape and sustain the livelihoods of millions of people. Woody encroachment in savannas is a widespread phenomenon but its causes are widely debated. We review the extensive literature on woody encroachment to help improve understanding of the possible causes and to highlight where and how future scientific efforts to fully understand these causes should be focused. Rainfall is the most important determinant of maximum woody cover across Africa, but fire and herbivory interact to reduce woody cover below the maximum at many locations. We postulate that woody encroachment is most likely driven by CO2 enrichment and propose a two-system conceptual framework, whereby mechanisms of woody encroachment differ depending on whether the savanna is a wet or dry system. In dry savannas, the increased water-use efficiency in plants relaxes precipitation-driven constraints and increases woody growth. In wet savannas, the increase of carbon allocation to tree roots results in faster recovery rates after disturbance and a greater likelihood of reaching sexual maturity. Our proposed framework can be tested using a mixture of experimental and earth observational techniques. At a local level, changes in precipitation, burning regimes or herbivory could be driving woody encroachment, but are unlikely to be the explanation of this continent-wide phenomenon.

As a result of ecological and social drivers, the management of problems caused by wildlife is becoming more selective, often targeting specific animals. Narrowing the sights of management relies upon the ecology of certain ‘problem individuals’ and their disproportionate contribution to impacts upon human interests. We assess the ecological evidence for problem individuals and confirm that some individuals or classes can be both disproportionately responsible and more likely to reoffend. The benefits of management can sometimes be short-lived, and selective management can affect tolerance of wildlife for better or worse, but, when effectively targeted, selective management can bring benefits by mitigating impact and conflict, often in a more socially acceptable way.

The control of tuberculosis (TB) in cattle in the UK and Ireland is compromised by transmission of Mycobacterium bovis to cattle from the European badger (Meles meles), which acts as a wildlife reservoir. Vaccination of badgers could potentially contribute to TB control but the only licensed vaccine is injectable BadgerBCG which requires the live-capture of badgers. Current research is aimed at developing an oral TB vaccine (where vaccine is contained within bait) that is intended to be more cost-effective to deploy over large areas. In order to identify a lead product, candidate baits identified from captive badger studies were evaluated in three successive bait screening studies with wild badgers. A fourth field study, using the lead candidate bait and biomarkers, investigated the effectiveness of different carriers for their potential to deliver liquid payloads (vaccine surrogate). In each field study, bait disappearance was monitored daily for ten days and remote video surveillance was used to determine preference (i.e. the order in which baits were taken). In the carrier study, biomarkers were used to determine what proportion of subsequently trapped badgers had ingested the bait and the vaccine-carrier biomarker payload. Across all four studies, 79% (3397/4330) of baits were taken by badgers although the number varied significantly by badger social group and bait type. In all studies, bait disappearance increased over time, with 75–100% of baits being taken by day ten. In the carrier study, 75% (9/12) of trapped badgers tested positive for at least one of the biomarkers and the type of carrier did not influence bait attractiveness. Together with data from complementary laboratory and captive animal studies, this study identified a highly attractive and palatable bait (peanut-based paste bait; PT) and vaccine-carrier (hydrogenated peanut oil; HPO) combination with the potential to deliver a liquid vaccine to wild badgers.

Environmental conflicts are often framed by an assumption that there are clear divisions between interested parties. As a result, there is a tendency to polarise debates, simplify arguments and miss opportunities for constructive engagement. While these conflicts are rarely amenable to resolution through direct dialogue, diplomacy may offer a means to generate possible political settlements. In this paper, we seek to identify the scope for such diplomacy in the seemingly entrenched conflict that surrounds the case of bovine tuberculosis and badger culling in England. First, we use Q methodological techniques to map prevailing views among concerned publics about this highly contentious and apparently intractable issue. Second, we combine this method with diplomatic theory in order to identify areas in which diplomatic modes of engagement may be constructive. Our results show that there are predictable conflictual elements within two positions organised around opposition to, and support for, the culling of badgers. These positions, which we label ‘ethical empiricist’ and ‘nostalgic autonomist’, respectively, are not always straightforwardly oppositional. Their points of contact, as well as intersections with a third, alternative, subject position, which we label ‘liberal pragmatist’, suggest starting-points for diplomacy.

Knowledge of badger distribution is important for the management of bovine tuberculosis. At the farm level, typically the only information on badger activity available is from the farmers themselves. This study compares how well farmer perceptions of badger activity match data obtained from ecological surveys. Farmer estimates of numbers of badger setts (burrows) surrounding their farms were generally correlated with field survey results, but tended to be underestimates. Farmers correctly recorded 50 per cent of setts recorded in surveys, with larger setts and active setts more likely to be correctly recorded. Badger visits to farm buildings and yards were also monitored using surveillance cameras. The majority of farmers were aware of badger visits to their farm buildings, but in 22 per cent of cases farmers were not aware of badger visits. At the farm level, knowledge of badger activity will be useful in informing vets and animal health professionals of the potential risks of disease transmission, and hence directing management interventions. However, the tendency to underestimate activity, combined with a lack of detailed knowledge of sett locations, means that farmer estimates of badger activity should be interpreted with caution and in isolation may not be sufficient to inform management interventions.

Wildlife reintroductions can unsettle social and ecological norms, and are often controversial. In this paper, we examine the recent (re)introduction of Eurasian beavers to England, to analyse responses to an unauthorised release of a formerly resident species. Although the statutory response to the introduction was to attempt to reassert ecological and political order by recapturing the beavers, this action was strongly opposed by a diverse collective, united and made powerful by a common goal: to protect England’s ‘new’ nonhuman residents. We show how this clash of state resolve and public dissent produced an uneasy compromise in the form of a formal, licensed ‘beaver reintroduction trial’, in which the new beaver residents have been allowed to remain, but under surveillance. We propose that although the trial is unorthodox and risky, there is an opportunity for it to be treated as a ‘wild experiment’ through which a more open-ended, experimental approach to co-inhabiting with wildlife might be attempted.

Social interactions among hosts influence the persistence and spread of infectious pathogens. Daily and seasonal variation in the frequency and type of social interactions will play an important role in disease epidemiology and, alongside other factors, may have an influence on wider disease dynamics by causing seasonal forcing of infection, especially if the seasonal variation experienced by a population is considerable. We explored temporal variation in within-group contacts in a high-density population of European badgers Meles meles naturally infected with Mycobacterium bovis (the causative agent of bovine tuberculosis). Summer contacts were more likely and of longer duration during the daytime, while the frequency and duration of winter contacts did not differ between day and night. In spring and autumn, within-group contacts peaked at dawn and dusk, corresponding with when they were of shortest duration with reduced potential for aerosol transmission of pathogens. Summer and winter could be critical for transmission of M. bovis in badgers, due to the high frequency and duration of contacts during resting periods, and we discuss the links between this result and empirical disease data. This study reveals clear seasonality in daily patterns of contact frequency and duration in species living in stable social groups, suggesting that changes in social contacts could drive seasonal forcing of infection in wildlife populations even when the number of individuals interacting remains similar.

© 2017 British Ecological Society.Host social structure is fundamental to how infections spread and persist, and so the statistical modelling of static and dynamic social networks provides an invaluable tool to parameterise realistic epidemiological models. We present a practical guide to the application of network modelling frameworks for hypothesis testing related to social interactions and epidemiology, illustrating some approaches with worked examples using data from a population of wild European badgers Meles meles naturally infected with bovine tuberculosis. Different empirical network datasets generate particular statistical issues related to non-independence and sampling constraints. We therefore discuss the strengths and weaknesses of modelling approaches for different types of network data and for answering different questions relating to disease transmission. We argue that statistical modelling frameworks designed specifically for network analysis offer great potential in directly relating network structure to infection. They have the potential to be powerful tools in analysing empirical contact data used in epidemiological studies, but remain untested for use in networks of spatio-temporal associations. As a result, we argue that developments in the statistical analysis of empirical contact data are critical given the ready availability of dynamic network data from bio-logging studies. Furthermore, we encourage improved integration of statistical network approaches into epidemiological research to facilitate the generation of novel modelling frameworks and help extend our understanding of disease transmission in natural populations.

Contact networks, behavioral interactions, and shared use of space can all have important implications for the spread of disease in animals. Social networks enable the quantification of complex patterns of interactions; therefore, network analysis is becoming increasingly widespread in the study of infectious disease in animals, including wildlife. We present an introductory guide to using social-network-Analytical approaches in wildlife disease ecology, epidemiology, and management. We focus on providing detailed practical guidance for the use of basic descriptive network measures by suggesting the research questions to which each technique is best suited and detailing the software available for each. We also discuss how using network approaches can be used beyond the study of social contacts and across a range of spatial and temporal scales. Finally, we integrate these approaches to examine how network analysis can be used to inform the implementation and monitoring of effective disease management strategies.

Antimicrobial resistance (AMR) represents a serious threat to human health worldwide. We have tested the use of free-living small mammals (mice, voles and shrews) as sentinels of variation in the distribution of AMR in the environment and the potential for transmission from the natural environment to animal hosts. Escherichia coli isolated from the faeces of small mammals trapped at paired coastal and inland sites were tested for resistance to four antibiotics: trimethoprim, ampicillin, ciprofloxacin and cefotaxime. Coastal individuals were over twice as likely to carry AMR E. coli than inland individuals (79% and 35% respectively), and both between-site and between-species variation was observed. Animals from coastal populations also excreted increased numbers of AMR E. coli and a greater diversity of E. coli phylotypes, including human-associated pathogenic strains. Small mammals appear to be useful bioindicators of fine-scale spatial variation in the distribution of AMR and, potentially, of the risks of AMR transmission to mammalian hosts, including humans.

In the UK and the Republic of Ireland, the European badger (Meles meles) is a maintenance host for Mycobacterium bovis, and may transmit the infection to cattle causing bovine tuberculosis (TB). Vaccination of badgers using an injectable Bacillus Calmette-Guerin (BCG) vaccine is undertaken in some areas of the UK with the intention of interrupting this transmission, and vaccination research is underway in Ireland. An oral badger TB vaccine is also under development. We investigated the behaviour of badgers and non-target wildlife species towards three candidate baits being considered for delivering BCG to badgers orally. Bait preference was investigated by recording removal rates of baits and through the use of video surveillance at 16 badger setts. We found high variation in rates of bait removal by badgers among setts but no significant differences in removal rates among bait types or in preference behaviour from video footage. Variation in bait removal among setts correlated with the number of nights on which badgers were seen at the sett, with most baits being removed where badgers were seen on >50% of nights during the ten-day study period. Relatively few baits were removed at setts with low levels of recorded badger activity. Monitoring badger activity prior to bait deployment may therefore be useful in increasing bait uptake and vaccine coverage. Bait removal by badgers increased over the ten-day study period, suggesting initial neophobic behaviour at some setts and that a period of ‘pre-feeding’ may be required prior to vaccine deployment. Our results indicate that all three candidate baits are attractive to badgers. Removal of baits by non-target wildlife species was generally low, but varied among bait types, with smaller baits in packaging less likely to be removed. Enclosing baits in packaging is likely to deter non-target species, although in some cases non-target species did remove up to 13% of packaged baits.

The importance of social- and kin-structuring of populations for the transmission of wildlife disease is widely assumed but poorly described. Social structure can help dilute risks of transmission for group members, and is relatively easy to measure, but kin-association represents a further level of population sub-structure that is harder to measure, particularly when association behaviours happen underground. Here, using epidemiological and molecular genetic data from a wild, high-density population of the European badger (Meles meles), we quantify the risks of infection withMycobacterium bovis(the causative agent of tuberculosis) in cubs. The risk declines with increasing size of its social group, but this net dilution effect conceals divergent patterns of infection risk. Cubs only enjoy reduced risk when social groups have a higher proportion of test-negative individuals. Cubs suffer higher infection risk in social groups containing resident infectious adults, and these risks are exaggerated when cubs and infectious adults are closely related. We further identify key differences in infection risk associated with resident infectious males and females. We link our results to parent–offspring interactions and other kin-biased association, but also consider the possibility that susceptibility to infection is heritable. These patterns of infection risk help to explain the observation of a herd immunity effect in badgers following low-intensity vaccination campaigns. They also reveal kinship and kin-association to be important, and often hidden, drivers of disease transmission in social mammals.

Demographic buffering allows populations to persist by compensating for fluctuations in vital rates, including disease-induced mortality. Using long-term data on a badger (Meles meles Linnaeus, 1758) population naturally infected with Mycobacterium bovis, we built an integrated population model to quantify impacts of disease, density and environmental drivers on survival and recruitment. Badgers exhibit a slow life-history strategy, having high rates of adult survival with low variance, and low but variable rates of recruitment. Recruitment exhibited strong negative density-dependence, but was not influenced by disease, while adult survival was density independent but declined with increasing prevalence of diseased individuals. Given that reproductive success is not depressed by disease prevalence, density-dependent recruitment of cubs is likely to compensate for disease-induced mortality. This combination of slow life history and compensatory recruitment promotes the persistence of a naturally infected badger population and helps to explain the badger's role as a persistent reservoir of M. bovis.

Bovine tuberculosis (bTB) causes substantial economic losses to cattle farmers and taxpayers in the British Isles. Disease management in cattle is complicated by the role of the European badger (Meles meles) as a host of the infection. Proactive, non-selective culling of badgers can reduce the incidence of disease in cattle but may also have negative effects in the area surrounding culls that have been associated with social perturbation of badger populations. The selective removal of infected badgers would, in principle, reduce the number culled, but the effects of selective culling on social perturbation and disease outcomes are unclear. We used an established model to simulate non-selective badger culling, non-selective badger vaccination and a selective trap and vaccinate or remove (TVR) approach to badger management in two distinct areas: South West England and Northern Ireland. TVR was simulated with and without social perturbation in effect. The lower badger density in Northern Ireland caused no qualitative change in the effect of management strategies on badgers, although the absolute number of infected badgers was lower in all cases. However, probably due to differing herd density in Northern Ireland, the simulated badger management strategies caused greater variation in subsequent cattle bTB incidence. Selective culling in the model reduced the number of badgers killed by about 83% but this only led to an overall benefit for cattle TB incidence if there was no social perturbation of badgers. We conclude that the likely benefit of selective culling will be dependent on the social responses of badgers to intervention but that other population factors including badger and cattle density had little effect on the relative benefits of selective culling compared to other methods, and that this may also be the case for disease management in other wild host populations.

Lead poisoning, through the ingestion of spent lead gunshot, is an established cause of morbidity and mortality in waterbirds globally, but the thresholds at which blood levels begin to affect the physiology of birds in the wild are less well known. Here we determine the prevalence of lead exposure in whooper swans and, for the first time, identify the level of blood lead associated with initial reductions in body condition. Blood lead elevated above background levels (i.e. >20 μg dL(-1)) was found in 41.7% (125/300) of swans tested. Blood lead was significantly negatively associated with winter body condition when levels were ≥44 μg dL(-1) (27/260 = 10%). Our findings indicating that sub-lethal impacts of lead on body condition occur at the lower end of previously established clinical thresholds and that a relatively high proportion of individuals in this population may be affected, reaffirm the importance of reducing contamination of the environment with lead shot.

Invasive, non-native species are one of the major causes of global biodiversity loss. Although they are, by definition, successful in their non-native range, their populations generally show major reductions in their genetic diversity during the demographic bottleneck they experience during colonization. By investigating the mitochondrial genetic diversity of an invasive non-native species, the stoat Mustela erminea, in New Zealand and comparing it to diversity in the species' native range in Great Britain, we reveal the opposite effect. We demonstrate that the New Zealand stoat population contains four mitochondrial haplotypes that have not been found in the native range. Stoats in Britain rely heavily on introduced rabbits Oryctolagus cuniculus as their primary prey and were introduced to New Zealand in a misguided attempt at biological control of rabbits, which had also been introduced there. While invasive stoats have since decimated the New Zealand avifauna, native stoat populations were themselves decimated by the introduction to Britain of Myxoma virus as a control measure for rabbits. We highlight the irony that while introduced species (rabbits) and subsequent biocontrol (myxomatosis) have caused population crashes of native stoats, invasive stoats in New Zealand, which were also introduced for biological control, now contain more genetic haplotypes than their most likely native source.

Bovine tuberculosis is one of the biggest challenges facing cattle farming in Great Britain. European badgers (Meles meles) are a reservoir host for the causal agent, Mycobacterium bovis. There have been significant recent advances in diagnostic testing for tuberculosis in humans, cattle and badgers, with the development of species-specific assays for interferon-γ (IFN-γ), an important cytokine in tuberculous infections. Using data collected from longitudinal studies of naturally infected wild badgers, we report that the magnitude of the IFN-γ response to M. bovis antigens at the disclosing test event was positively correlated with subsequent progression of disease to a seropositive or excreting state. In addition, we show that the magnitude of the IFN-γ response, despite fluctuation, declined with time after the disclosing event for all badgers, but remained significantly higher in those animals with evidence of disease progression. We discuss how our findings may be related to the immunopathogenesis of natural M. bovis infection in badgers.

An important goal for invasive species research is to find key traits of species that predispose them to being invasive outside their native range. Comparative studies have revealed phenotypic and demographic traits that correlate with invasiveness among plants. However, all but a few previous studies have been performed in the invaded range, an approach which potentially conflates predictors of invasiveness with changes that happen during the invasion process itself. Here, we focus on wild plants in their native range to compare life-history traits of species known to be invasive elsewhere, with their exported but noninvasive relatives. Specifically, we test four hypotheses: that invasive plant species (1) are larger; (2) are more fecund; (3) exhibit higher fecundity for a given size; and (4) attempt to make seed more frequently, than their noninvasive relatives in the native range. We control for the effects of environment and phylogeny using sympatric congeneric or confamilial pairs in the native range. We find that invasive species are larger than noninvasive relatives. Greater size yields greater fecundity, but we also find that invasives are more fecund per-unit-size. Synthesis: We provide the first multispecies, taxonomically controlled comparison of size, and fecundity of invasive versus noninvasive plants in their native range. We find that invasive species are bigger, and produce more seeds, even when we account for their differences in size. Our findings demonstrate that invasive plant species are likely to be invasive as a result of both greater size and constitutively higher fecundity. This suggests that size and fecundity, relative to related species, could be used to predict which plants should be quarantined. We provide the first multi-species comparison of size and fecundity of invasive versus non-invasive plants in their native range. We find that invasive species are larger. Greater size yields greater fecundity, but we also find that invasives are more fecund per-unit-size.

Although intra-population variation in niches is a widespread phenomenon with important implications for ecology, evolution and management of a range of animal species, the causes and consequences of this variation remain poorly understood. We used stable isotope analysis to characterise foraging niches and to investigate the causes and consequences of individual niche variation in the European badger, a mustelid mammal that lives in territorial social groups, but forages alone. We found that the degree of individual niche variation within social groups was negatively related to the availability of farmland habitats, which represent an important foraging habitat for badgers; and was positively related to territory size, supporting the idea that resource limitation and ecological opportunity lead to increased individual specialisation. We also found that the degree of individual specialisation related to an individual's body condition and that this effect varied with ecological context; such that specialisation had a stronger positive relationship with body condition in social groups with reduced availability of key farmland habitats. Body condition was also related to the utilisation of specific resources (woodland invertebrates), but again this relationship varied with the availability of farmland foraging habitats. This study supports the idea that resource availability plays an important role in determining patterns of individual niche variation, and identifies the potential adaptive consequences of specialised foraging strategies.

Increasingly, stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR) using δ(15)N, and carbon range (CR) using δ(13)C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ(15)N or δ(13)C from source to consumer) between trophic levels and among food chains. δ(15)N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰), and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ(13)C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ(13)C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority of ecological systems.

Throughout the European Union, the EC Habitats Directive requires that member states undertake national surveillance of designated species. Despite biological connections between-populations across-borders, national assessments need not be co-ordinated in any way. We conducted a trans-boundary assessment of the status of Eurasian otters (Lutra lutra) aimed at providing consistency across a single biogeographical unit, i.e. the island of Ireland, comprising two states, i.e. the Republic of Ireland and the United Kingdom (Northern Ireland). Our aim was to ensure consistency with previous assessments conducted separately in each state, and permit each Government to fulfil their separate statutory reporting commitments. The species range increased by 23% from 1996-2006 and 2007-11. The population estimate of 9400 [95%CI 8700-12,200] breeding females during 2010/11 was not significantly different from 8300 [95%CI 7600-9800] breeding females established as a baseline during 1981-82. Modelling of species-habitat associations suggested that available habitat was not limiting and no putative pressures recorded at sites surveyed negatively affected species occurrence. Thus, under the statutory parameters for assessing a species' conservation status, i.e. range, population, habitat and future prospects, the otter was judged to be in 'Favourable' status throughout Ireland and in both discrete political jurisdictions. Thus, we provide a trans-boundary test case for EU member states that share habitats and species across ecoregions, ensuring conservation assessment data are standardised, synchronised, spatially consistent and, therefore, biologically relevant without compromising legal and administrative autonomy within separate jurisdictions. © 2014 Elsevier Ltd. All rights reserved.

In the United Kingdom, European badgers Meles meles are a protected species and an important wildlife reservoir of bovine tuberculosis. We conducted a survey of badger dens (main setts) in 1614 1�
km squares across England and Wales, between November 2011 and March 2013. Using main setts as a proxy for badger social groups, the estimated mean density of badger social groups in England and Wales was 0.485�
km(-2) (95% confidence interval 0.449-0.521) and the estimated abundance of social groups was 71,600 (66,400-76,900). In the 25 years since the first survey in 1985-88, the annual rate of increase in the estimated number of badger social groups was 2.6% (2.2-2.9%), equating to an 88% (70-105%) increase across England and Wales. In England, we estimate there has been an increase of 103% (83-123%) in badger social groups, while in Wales there has been little change (-25 to +49%).

Experimental evidence of the interactions among mammalian predators that eat or compete with one another is rare, due to the ethical and logistical challenges of managing wild populations in a controlled and replicated way. Here, we report on the opportunistic use of a replicated and controlled culling experiment (the Randomised Badger Culling Trial) to investigate the relationship between two sympatric predators: European badgers Meles meles and western European hedgehogs Erinaceus europaeus. In areas of preferred habitat (amenity grassland), counts of hedgehogs more than doubled over a 5-year period from the start of badger culling (from 0.9 ha-1 pre-cull to 2.4 ha-1 post-cull), whereas hedgehog counts did not change where there was no badger culling (0.3-0.3 hedgehogs ha-1). This trial provides experimental evidence for mesopredator release as an outcome of management of a top predator.

Individual specialisation has been identified in an increasing number of animal species and populations. However, in some groups, such as terrestrial mammals, it is difficult to disentangle individual niche variation from spatial variation in resource availability. In the present study, we investigate individual variation in the foraging niche of the European badger (Meles meles), a social carnivore that lives in a shared group territory, but forages predominantly alone. Using stable isotope analysis, we distinguish the extent to which foraging variation in badgers is determined by social and spatial constraints and by individual differences within groups. We found a tendency for individual badgers within groups to differ markedly and consistently in their isotope values, suggesting that individuals living with access to the same resources occupied distinctive foraging niches. Although sex had a significant effect on isotope values, substantial variation within groups occurred independently of age and sex. Individual differences were consistent over a period of several months and in some instances were highly consistent across the two years of the study, suggesting long-term individual foraging specialisations. Individual specialisation in foraging may, therefore, persist in populations of territorial species not solely as a result of spatial variation in resources, but also arising from individuals selecting differently from the same available resources. Although the exact cause of this behaviour is unknown, we suggest that specialisation may occur due to learning trade-offs which may limit individual niche widths. However, ecological factors at the group level, such as competition, may also influence the degree of specialisation.

In animal populations, males are commonly more susceptible to disease-induced mortality than females. However, three competing mechanisms can cause this sex bias: weak males may simultaneously be more prone to exposure to infection and mortality; being 'male' may be an imperfect proxy for the underlying driver of disease-induced mortality; or males may experience increased severity of disease-induced effects compared with females. Here, we infer the drivers of sex-specific epidemiology by decomposing fixed mortality rates into mortality trajectories and comparing their parameters. We applied Bayesian survival trajectory analysis to a 22-year longitudinal study of a population of badgers (Meles meles) naturally infected with bovine tuberculosis (bTB). At the point of infection, infected male and female badgers had equal mortality risk, refuting the hypothesis that acquisition of infection occurs in males with coincidentally high mortality. Males and females exhibited similar levels of heterogeneity in mortality risk, refuting the hypothesis that maleness is only a proxy for disease susceptibility. Instead, sex differences were caused by a more rapid increase in male mortality rates following infection. Males are indeed more susceptible to bTB, probably due to immunological differences between the sexes. We recommend this mortality trajectory approach for the study of infection in animal populations.

Bovine tuberculosis (bTB) is a very important disease of cattle in Great Britain, where it has been increasing in incidence and geographical distribution. In addition to cattle, it infects other species of domestic and wild animals, in particular the European badger (Meles meles). Policy to control bTB is vigorously debated and contentious because of its implications for the livestock industry and because some policy options involve culling badgers, the most important wildlife reservoir. This paper describes a project to provide a succinct summary of the natural science evidence base relevant to the control of bTB, couched in terms that are as policy-neutral as possible. Each evidence statement is placed into one of four categories describing the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material.

Although disease hosts are classically assumed to interact randomly, infection is likely to spread across structured and dynamic contact networks. We used social network analyses to investigate contact patterns of group-living European badgers Meles meles, which are an important wildlife reservoir of bovine tuberculosis (TB). We found that TB test-positive badgers were socially isolated from their own groups but were more important for flow, potentially of infection, between social groups. The distinctive social position of infected badgers may help explain how social stability mitigates, and social perturbation increases, the spread of infection in badgers.

Heterogeneities in behaviours of individuals may underpin important processes in evolutionary biology and ecology, including the spread of disease. Modelling approaches can sometimes fail to predict disease spread, which may partly be due to the number of unknown sources of variation in host behaviour. The European badger is a wildlife reservoir for bovine tuberculosis (bTB) in Britain and Ireland, and individual behaviour has been demonstrated to be an important factor in the spread of bTB among badgers and to cattle. Radio-telemetry devices were deployed on 40 badgers from eight groups to investigate patterns of den (sett) use in a high-density population, where each group had one or two main and three to eight outlier setts in their territory. Badgers were located at their setts for 28 days per season for one year to investigate how patterns differed between individuals. Denning behaviour may have a strong influence on contact patterns and the transmission of disease. We found significant heterogeneity, influenced by season, sex and age. Also, when controlling for these, bTB infection status interacting with season was highly correlated with sett use. Test-positive badgers spent more time away from their main sett than those that tested negative. We speculate that wider-ranging behaviour of test-positive animals may result in them contacting sources of infection more frequently and/or that their behaviour may be influenced by their disease status. Measures to control infectious diseases might be improved by targeting functional groups, specific areas, or times of year that may contribute disproportionately to disease spread.

The behaviour of certain infected individuals within socially structured populations can have a disproportionately large effect on the spatio-temporal distribution of infection. Endemic infection with Mycobacterium bovis in European badgers (Meles meles) in Great Britain and Ireland is an important source of bovine tuberculosis in cattle. Here we quantify the risk of infection in badger cubs in a high-density wild badger population, in relation to the infection status of resident adults. Over a 24-year period, we observed variation in the risk of cub infection, with those born into groups with resident infectious breeding females being over four times as likely to be detected excreting M. bovis than cubs from groups where there was no evidence of infection in adults. We discuss how our findings relate to the persistence of infection at both social group and population level, and the potential implications for disease control strategies.

Summary: the nitrogen (δ15N) and carbon (δ13C) isotope ratios of animal tissues can help identify the composition of diets and open up a myriad of ecological applications. However, consumers do not ingest or assimilate all components of food items, and it is not well understood how sampling different tissues of sources and consumers may affect isotopic values ascribed, and thereby how such variation affects derived ecological measures. Utilizing a simple prey-predator feeding relationship in insects, we examined isotopic differences in soft, exoskeleton and whole tissues using samples with and without lipid extraction. As a derived ecological measure, we calculated trophic discrimination factors, changes in δ15N or δ13C between source and consumer, for the different prey-predator tissue combinations. Lipid extraction did not affect δ15N values, and we found significant tissue differences in δ15N that varied between prey and predator. Lipid extraction enriched δ13C values in most instances, and it was only after extraction of lipids that we observed consistent depletion of δ13C in exoskeleton relative to soft tissues in prey and predator. Isotopic differences between tissue types propagated marked variation in derived ecological parameters. Common sampling practice using whole tissue for prey and predator (whole/whole) resulted in a trophic discrimination factor of 0·48‰ for δ15N, compared with correct factors of 0·97‰ (soft/whole) and 2·18‰ (soft/soft) using prey soft tissue actually ingested by the predator. For δ13C, variation across discrimination factors was less, with whole/whole tissue of -0·14‰, whilst correct factors were -0·55‰ (soft/whole) and -0·04‰ (soft/soft). Our results indicate that tissue selection and preparation are important considerations for isotopic studies using arthropods. Lipid extraction is necessary to derive accurate δ13C values based on proteins, whilst consequences of tissue selection are likely context-dependent: in poorly defined systems where sources are isotopically similar or have larger variance, our results indicate that tissue selection within sources is important to avoid significant error, whether estimating trophic positions or dietary proportions using mixing models. In such cases, we strongly recommend exclusion of source materials not assimilated in consumers. © 2013 British Ecological Society.

Tuberculosis (TB) due to infection with Mycobacterium bovis is transmitted between cattle and badgers (Meles meles) in the UK and Ireland but it is unclear where or when transmission occurs. We investigated direct and indirect interactions between badgers and cattle using automated proximity loggers on animals and at badger latrines located on pasture, in an area of south-west England with a high-density badger population. Direct contacts (interactions within 1·4 m) between badgers and cattle at pasture were very rare (four out of >500 000 recorded animal-to-animal contacts) despite ample opportunity for interactions to occur. Indirect interactions (visits to badger latrines by badgers and cattle) were two orders of magnitude more frequent than direct contacts: 400 visits by badgers and 1700 visits by cattle were recorded. This suggests that indirect contacts might be more important than direct contacts in terms of disease transmission at pasture. The TB infection status of individual badgers (ascribed with 93% accuracy using three diagnostic tests) did not affect the frequency or duration of their visits to latrines located on pasture grazed by cattle. Nevertheless, there was wide variation in contact behaviour between individuals, which highlights the importance of understanding heterogeneity in contact patterns when developing strategies to control disease spread in wildlife and livestock. Copyright © Cambridge University Press 2013.

Heterogeneity in the progression of disease amongst individual wild animals may impact on both pathogen and host dynamics at the population level, through differential effects on transmission, mortality and reproductive output. The role of the European badger (Meles meles) as a reservoir host for Mycobacterium bovis infection in the UK and Ireland has been the focus of intense research for many years. Here, we investigate life-history correlates of infection in a high-density undisturbed badger population naturally infected with M. bovis. We found no evidence of a significant impact of M. bovis infection on female reproductive activity or success, with evidence of reproduction continuing successfully for several years in the face of M. bovis excretion. We also found evidence to support the hypothesis that female badgers are more resilient to established M. bovis infection than male badgers, with longer survival times following the detection of bacterial excretion. We discuss the importance of infectious breeding females in the persistence of M. bovis in badger populations, and how our findings in male badgers are consistent with testosterone-induced immunosuppression. In addition, we found significant weight loss in badgers with evidence of disseminated infection, based on the culture of M. bovis from body systems other than the respiratory tract. For females, there was a gradual loss of weight as infection progressed, whereas males only experienced substantial weight loss when infection had progressed to the point of dissemination. We discuss how these differences may be explained in terms of resource allocation and physiological trade-offs.

Knowledge about the diet of fish-eating predators is critical when evaluating conflicts with the fishing industry. Numerous primary studies have examined the diet of grey seals Halichoerus grypus and common seals Phoca vitulina in a bid to understand the ecology of these predators. However, studies of large-scale spatial and temporal variation in seal diet are limited. Therefore this review combines the results of seal diet studies published between 1980 and 2000 to examine how seal diet varies at a range of spatial and temporal scales. Our results revealed extensive spatial variation in gadiform, perciform and flatfish consumption, likely reflecting variation in prey availability. Flatfish and gadiform consumption varied between years, reflecting changes in fish assemblages as a consequence of factors such as varying fishing pressures, climate change and natural fluctuations in populations. Perciform and gadiform consumption varied seasonally: in addition there was a significant interaction between season and seal species, indicating that grey and common seals exhibited different patterns of seasonal variation in their consumption of Perciformes and Gadiformes. Multivariate analysis of grey seal diet revealed spatial variation at a much smaller scale, with different species dominating the diet in different areas. The existence of spatial and temporal variation in seal diet emphasizes that future assessments of the impact of seal populations should not be based on past or localized estimates of diet and highlights the need for up-to-date, site specific estimates of diet composition in the context of understanding and resolving seal/fisheries conflict. © 2012 Marine Biological Association of the United Kingdom.

Wildlife is a global source of endemic and emerging infectious diseases. The control of tuberculosis (TB) in cattle in Britain and Ireland is hindered by persistent infection in wild badgers (Meles meles). Vaccination with Bacillus Calmette-Guérin (BCG) has been shown to reduce the severity and progression of experimentally induced TB in captive badgers. Analysis of data from a four-year clinical field study, conducted at the social group level, suggested a similar, direct protective effect of BCG in a wild badger population. Here we present new evidence from the same study identifying both a direct beneficial effect of vaccination in individual badgers and an indirect protective effect in unvaccinated cubs. We show that intramuscular injection of BCG reduced by 76% (Odds ratio = 0.24, 95% confidence interval (CI) 0.11-0.52) the risk of free-living vaccinated individuals testing positive to a diagnostic test combination to detect progressive infection. A more sensitive panel of tests for the detection of infection per se identified a reduction of 54% (Odds ratio = 0.46, 95% CI 0.26-0.88) in the risk of a positive result following vaccination. In addition, we show the risk of unvaccinated badger cubs, but not adults, testing positive to an even more sensitive panel of diagnostic tests decreased significantly as the proportion of vaccinated individuals in their social group increased (Odds ratio = 0.08, 95% CI 0.01-0.76; P = 0.03). When more than a third of their social group had been vaccinated, the risk to unvaccinated cubs was reduced by 79% (Odds ratio = 0.21, 95% CI 0.05-0.81; P = 0.02).

Animal populations generally increase after release from hunting pressure and/or cessation of illegal persecution. Implementation of full legislative protection of the Eurasian badger Meles meles in Great Britain is thought to have led to increases in badger abundance due to reduced levels of persecution. Conversely, prevalence of badger persecution in Northern Ireland was historically much higher than in Great Britain, and badger abundance remained stable over time despite similar legislative protection. We examined temporal changes in the prevalence of badger sett disturbance in Northern Ireland from 1990/1993 to 2007/2008 in relation to population status. A total of 56 (12.6%) of 445 setts surveyed during 1990/1993 had been disturbed compared to 29 (4.4%) of 653 setts during 2007/2008. This was a significant decline (-65%) in the incidence of sett disturbance over the 14-18-year period. Most notably, the incidence of digging at badger setts, indicative of local badger baiting activity, declined from 50% to 3.5% of disturbed setts. Signs of recent disturbance were significantly more frequent at disused setts suggesting that once disturbed, badgers may vacate a sett. The number of badger social groups in Northern Ireland did not differ between the two study periods, suggesting that previously high levels of badger persecution did not limit the number of badger social groups. The stability of the badger population in Northern Ireland compared to the growing population in Great Britain cannot be attributed to changes in the prevalence of persecution. Differences in the trajectories of both populations could be due to a range of factors including climate, habitat composition and structure, farming practices or food availability. More work is needed to determine how such factors influence badger population dynamics. © 2011 Springer-Verlag.

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, continues to be a serious economic problem for the British cattle industry. The Eurasian badger (Meles meles) is partly responsible for maintenance of the disease and its transmission to cattle. Previous attempts to manage the disease by culling badgers have been hampered by social perturbation, which in some situations is associated with increases in the cattle herd incidence of bTB. Following the licensing of an injectable vaccine, we consider the relative merits of management strategies to reduce bTB in badgers, and thereby reduce cattle herd incidence. We used an established simulation model of the badger-cattle-TB system and investigated four proposed strategies: business as usual with no badger management, large-scale proactive badger culling, badger vaccination, and culling with a ring of vaccination around it. For ease of comparison with empirical data, model treatments were applied over 150 km2 and were evaluated over the whole of a 300 km2 area, comprising the core treatment area and a ring of approximately 2 km. The effects of treatment were evaluated over a 10-year period comprising treatment for five years and the subsequent five year period without treatment. Against a background of existing disease control measures, where 144 cattle herd incidents might be expected over 10 years, badger culling prevented 26 cattle herd incidents while vaccination prevented 16. Culling in the core 150 km2 plus vaccination in a ring around it prevented about 40 cattle herd breakdowns by partly mitigating the negative effects of culling, although this approach clearly required greater effort. While model outcomes were robust to uncertainty in parameter estimates, the outcomes of culling were sensitive to low rates of land access for culling, low culling efficacy, and the early cessation of a culling strategy, all of which were likely to lead to an overall increase in cattle disease. © 2012 Smith et al.

We analysed the incidence of cattle herd breakdowns due to bovine tuberculosis (Mycobacterium bovis) in relation to experimental badger culling, badger populations and farm characteristics during the Randomized Badger Culling Trial (RBCT). Mixed modelling and event history analysis were used to examine the individual risk factors. The interdependencies of covariates were examined using structural equation modelling. There were consistent findings among the different analyses demonstrating that during a badger culling programme farms experiencing: reactive culling, larger herd sizes, larger holdings and holdings with multiple parcels of land were all at greater risk of a herd breakdown. Proactive culling reduced risks within the culling area, but we did not assess any potential effects in the periphery of the treatment area. Badger-related variables measured prior to the start of culling (number of social groups and length of badger territorial boundaries) did not consistently point to an increase in risk, when set against a background of ongoing badger culling. This could be because (1) the collected variables were not important to risk in cattle, or (2) there were insufficient data to demonstrate their importance. Our findings highlight the difficulty in identifying simple predictors of spatial variation in transmission risks from badger populations and the consequent challenge of tailoring management actions to any such field data. © 2011 Cambridge University Press.

The estimation of animal abundance has a central role in wildlife management and research, including the role of badgers Meles meles in bovine tuberculosis transmission to cattle. This is the first study to examine temporal change in the badger population of Northern Ireland over a medium-to long-term time frame of 14-18 years by repeating a national survey first conducted during 1990-1993. A total of 212 1-km 2 squares were surveyed during 2007-2008 and the number, type and activity of setts therein recorded. Badgers were widespread with 75% of squares containing at least one sett. The mean density of active main setts, which was equivalent to badger social group density, was 0.56 (95% CI: 0.46-0.67) active main setts per km 2 during 2007-2008. Social group density varied significantly among landclass groups and counties. The total number of social groups was estimated at 7,600 (95% CI: 6,200-9,000) and, not withstanding probable sources of error in estimating social group size, the total abundance of badgers was estimated to be 34,100 (95% CI: 26,200-42,000). There was no significant change in the badger population from that recorded during 1990-1993. A resource selection model provided a relative probability of sett construction at a spatial scale of 25 m. Sett locations were negatively associated with elevation and positively associated with slope, aspect, soil sand content, the presence of cover, and the area of improved grassland and arable agriculture within 300 m. © 2012 Wildlife Biology, NKV.

Knowledge of the way in which animals interact through social networks can help to address questions surrounding the ecological and evolutionary consequences of social organisation, and to understand and manage the spread of infectious diseases. Automated proximity loggers are increasingly being used to record interactions between animals, but the accuracy and reliability of the collected data remain largely un-assessed. Here we use laboratory and observational field data to assess the performance of these devices fitted to a herd of 32 beef cattle (Bos taurus) and nine groups of badgers (Meles meles, n = 77) living in the surrounding woods. The distances at which loggers detected each other were found to decrease over time, potentially related to diminishing battery power that may be a function of temperature. Loggers were highly accurate in recording the identification of contacted conspecifics, but less reliable at determining contact duration. There was a tendency for extended interactions to be recorded as a series of shorter contacts. We show how data can be manipulated to correct this discrepancy and accurately reflect observed interaction patterns by combining records between any two loggers that occur within a 1 to 2 minute amalgamation window, and then removing any remaining 1 second records. We make universally applicable recommendations for the effective use of proximity loggers, to improve the validity of data arising from future studies.

We compared capture rates and exposure to SGARs of wood mice (Apodemus sylvaticus) and house mice (Mus domesticus) in autumn/winter on farms that currently used, had previously used, and never used SGARs. 6-10 weeks after baiting programmes began, 15 % of 55 wood mice and 33 % of 12 house mice had detectable liver SGAR residues. Wood mice with residues occurred on farms not using rodenticides, reflecting the high mobility of these animals, and four had multiple liver residues, possibly due to cross-contamination of baits. The winter decline in wood mouse numbers was similar on farms that did and did not use SGARs, suggesting little long-term impact of SGARs on populations on farms. Our results indicate residual levels of rodenticides will be ever present in small mammal prey across the agricultural landscape unless all farms in a locality cease application. The implications for secondary exposure and poisoning of predators are discussed.

Tuberculosis (TB) is a chronic disease caused by Mycobacterium bovis and related members of the Mycobacterium tuberculosis complex. Infection affects not only cattle but also other livestock species, companion animals and wild mammals. Humans are also susceptible; hence, zoonotic infection is a driver for disease control in animal hosts. As bovine TB prevalence has been reduced in livestock, the relative epidemiological and socio-economic importance of wildlife reservoirs has increased, and there is a need for disease management strategies. We review the current status of TB in European wild mammals, identifying epidemiological trends and areas for future research and management. TB has a complex epidemiology, which may involve multiple hosts, and is influenced by climate and habitat. Consequently, the role of wild and domestic hosts in the epidemiology of TB varies among regions. In Europe, there are three regional examples of M.bovis maintenance hosts: the Eurasian badger Meles meles in Great Britain and Ireland, the Eurasian wild boar Sus scrofa in the Iberian Peninsula and deer belonging to the subfamily Cervinae in several European regions. In other parts of Europe, these species are currently regarded as spillover hosts, although in time their status may change depending on local or regional risk factors. Nevertheless, in most situations, the relative contribution of wild mammals to M.bovis infection in cattle is still a matter of debate. Also, the outcome of management interventions to control disease in wildlife populations may be complex and counter-intuitive. As our knowledge of disease dynamics in wild mammals improves, options for disease control in wildlife reservoirs, such as vaccination, improved biosecurity and population management, are likely to broaden. In order to evaluate our existing control options, we must monitor the effects of interventions on TB occurrence in the affected regions of Europe and share our collective experiences. © 2011 the Authors. Mammal Review © 2011 Mammal Society/Blackwell Publishing.

Ireland has a restricted small mammal prey guild but still includes species most likely to consume anticoagulant rodenticide (AR) baits. This may enhance secondary exposure of predators to ARs. We compared liver AR residues in foxes (Vulpes vulpes) in Northern Ireland (NI) with those in foxes from Great Britain which has a more diverse prey guild but similar agricultural use of ARs. Liver ARs were detected in 84% of NI foxes, more than in a comparable sample of foxes from Scotland and similar to that of suspected AR poisoned animals from England and Wales. High exposure in NI foxes is probably due to greater predation of commensal rodents and non-target species most likely to take AR baits, and may also partly reflect greater exposure to highly persistent brodifacoum and flocoumafen. High exposure is likely to enhance risk and Ireland may be a sentinel for potential effects on predator populations.

BACKGROUND: Bovine tuberculosis caused by Mycobacterium bovis is a serious and economically important disease of cattle. Badgers have been implicated in the transmission and maintenance of the disease in the UK since the 1970s. Recent studies have provided substantial evidence of widespread and frequent visits by badgers to farm buildings during which there is the potential for close direct contact with cattle and contamination of cattle feed. METHODOLOGY: Here we evaluated the effectiveness of simple exclusion measures in improving farm biosecurity and preventing badger visits to farm buildings. In the first phase of the study, 32 farms were surveyed using motion-triggered infrared cameras on potential entrances to farm buildings to determine the background level of badger visits experienced by each farm. In the second phase, they were divided into four treatment groups; "Control", "Feed Storage", "Cattle Housing" and "Both", whereby no exclusion measures were installed, exclusion measures were installed on feed storage areas only, cattle housing only or both feed storage and cattle housing, respectively. Badger exclusion measures included sheet metal gates, adjustable metal panels for gates, sheet metal fencing, feed bins and electric fencing. Cameras were deployed for at least 365 nights in each phase on each farm. RESULTS: Badger visits to farm buildings occurred on 19 of the 32 farms in phase one. In phase two, the simple exclusion measures were 100% effective in preventing badger entry into farm buildings, as long as they were appropriately deployed. Furthermore, the installation of exclusion measures also reduced the level of badger visits to the rest of the farmyard. The findings of the present study clearly demonstrate how relatively simple practical measures can substantially reduce the likelihood of badger visits to buildings and reduce some of the potential for contact and disease transmission between badgers and cattle.

Introduced mammalian predators have had significant impacts on many native prey species. Although control of such predators for conservation management is becoming increasingly commonplace, it is often undertaken at a relatively small scale in relation to the overall predator population. Processes such as immigration mean that it remains difficult to determine the effectiveness of control measures. We investigated the impacts of feral ferret Mustela furo removal on the entire feral ferret population on Rathlin Island, UK. Removal of ferrets prior to breeding led to a substantial increase in the post-dispersal population through the enhanced survival of juveniles. Despite increased numbers, overwinter survival remained high, potentially aided by the reduced territoriality shown by this feral species compared to wild carnivores. The response of this ferret population to control is a further illustration of the complex ecological processes and outcomes arising from the disruption of wildlife populations. It highlights how partial or localised management may prove ineffective, and at worst might exacerbate the problems that management was designed to avert.

Introduced carnivores have had a significant impact on the fauna of a number of countries, particularly on islands. In the British Isles, several offshore islands holding internationally important aggregations of seabirds and shorebirds support self-sustaining feral ferret Mustela furo populations, often as the top terrestrial predator. However, little is known about the interactions between ferrets and both native and nonnative prey in these locations. We examined the diet of feral ferrets on Rathlin Island, Northern Ireland. We determined the frequency of occurrence of prey items and constructed energetic models to determine their potential impact on both native and introduced prey. Rabbits Oryctolagus cuniculus occurred in 75% of scats, while birds, carrion, and brown rats Rattus norvegicus were important secondary items. There was little difference between the diets of males and females. Estimates of the energy requirements of the population at current, and with hypothetically reduced, rabbit availability revealed the potential for carrion to maintain the ferret population over winter. Management options could thus focus on reducing anthropogenic food sources as an immediate way of mitigating the threat to ground-nesting birds, while other strategies, including eradication, are considered.

Usage of anticoagulant rodenticides (ARs) is an integral component of modern agriculture and is essential for the control of commensal rodent populations. However, the extensive deployment of ARs has led to widespread exposure of a range of non-target predatory birds and mammals to some compounds, in particular the second-generation anticoagulant rodenticides (SGARs). As a result, there has been considerable effort placed into devising voluntary best practice guidelines that increase the efficacy of rodent control and reduce the risk of non-target exposure. Currently, there is limited published information on actual practice amongst users or implementation of best practice. We assessed the behaviour of a typical group of users using an on-farm questionnaire survey. Most baited for rodents every year using SGARs. Most respondents were apparently aware of the risks of non-target exposure and adhered to some of the best practice recommendations but total compliance was rare. Our questionnaire revealed that users of first generation anticoagulant rodenticides rarely protected or checked bait stations, and so took little effort to prevent primary exposure of non-targets. Users almost never searched for and removed poisoned carcasses and many baited for prolonged periods or permanently. These factors are all likely to enhance the likelihood of primary and secondary exposure of non-target species.

The amount of supplementary food humans provide to wild animals is increasing yet the full effects of this provisioning remain unclear. For these effects to be assessed at the levels of both the population and the individual, the degree to which individuals are using this resource must be quantified. Traditional approaches rely on observations of feeding animals and analysis of gut contents and feces, but these have several limitations. Stable-isotope analysis can overcome some of these. If supplementary food items are isotopically distinct from natural ones, the relative contribution of supplementary food to the diet may be quantified accurately. We demonstrate how the isotopic signature of supplementary foods can be manipulated to increase their discrimination from natural food sources and provide an example of the utility of this approach in a supplementary feeding study. We rovided supplementary food over a winter, then sampled birds during the following breeding season and analyzed their claws for their isotopic signature to estimate diet choices. The results highlight considerable variation in individuals' use of supplementary food, both within a study site and between different sites. Often the results from supplementation experiments are inconclusive. Even within the same species there can be an effect in one year or location but not in others, so a method for quantifying variation in food uptake could help in interpretation of the results. Stable-isotope analysis allows the effects of experimentally increased food supplies on ecology and behavior to be assessed accurately. © the Cooper Ornithological Society 2011.

1. The detrimental impacts of invasive, non-native species on islands are widely acknowledged and it is often best to act rapidly against such species, even where uncertainty exists over the best way to proceed. If management actions are evaluated and refined, using information learnt from the biology of culled animals, this uncertainty can be gradually reduced, increasing the likelihood of a successful outcome.
2. American mink Neovison vison carcasses were collected as part of an eradication campaign on several islands of the Outer Hebrides, Scotland, and stable isotope analysis was used to describe ecological variation in this invasive non-native predator.
3. Isotope profiles from individual mink whiskers demonstrated how behaviour at a population level changed markedly over time. As the eradication campaign progressed, mink increased their reliance on marine food sources and focused their activity on the coastline. Stable isotope analyses also demonstrated sex-related changes in foraging and ranging behaviour in relation to food resource availability on the two main island complexes.
4. Synthesis and applications. Our findings contribute to the refinement of a campaign to extend the successful eradication of mink from Uist and Harris, to the whole of the Outer Hebrides archipelago, UK. They also highlight the potential for stable isotope approaches to provide more detailed postmortem information that can inform adaptive management of wildlife populations for conservation objectives.

Summary

1. Managing populations of predators and their prey to achieve conservation or resource management goals is usually technically challenging and frequently socially controversial. This is true even in the simplest ecosystems but can be made much worse when predator-prey relationships are influenced by complex interactions, such as biological invasions, population trends or animal movements.
2. Lough Neagh in Northern Ireland is a European stronghold for pollan Coregonus autumnalis, a coregonine fish, and for river lamprey Lampetra fluviatilis, which feeds parasitically as an adult. Both species are of high conservation importance. Lampreys are known to consume pollan but detailed knowledge of their interactions is scant. While pollan is well known to be a landlocked species in Ireland, the life cycle of normally anadromous river lamprey in Lough Neagh has been unclear. The Lough is also a highly perturbed ecosystem, supporting several invasive, non-native fish species that have the potential to influence lamprey-pollan interactions.
3. We applied stable isotope techniques to resolve both the movement patterns of lamprey and trophic interactions in this complex community. Recognising that stable isotope studies are often hampered by high-levels of variability and uncertainty in the systems of interest, we employed novel Bayesian mixing models, which incorporate variability and uncertainty.
4. Stable isotope analyses identified trout Salmo trutta and non-native bream Abramis brama as the main items in lamprey diet. Pollan only represented a major food source for lamprey between May and July.
5. Stable isotope ratios of carbon in tissues from 71 adult lamprey showed no evidence of marine carbon sources, strongly suggesting that Lough Neagh is host to a highly unusual, non-anadromous freshwater population. This finding marks out the Lough’s lamprey population as of particular scientific interest and enhances the conservation significance of this feature of the Lough.
6. Synthesis and applications. Our Bayesian isotopic mixing models illustrate an unusual pattern of animal movement, enhancing conservation interest in an already threatened population. We have also revealed a complex relationship between lamprey and their food species that is suggestive of hyperpredation, whereby non-native species may sustain high lamprey populations that may in turn be detrimental to native pollan. Long-term conservation of lamprey and pollan in this system is likely to require management intervention, but in light of this exceptional complexity, no simple management options are currently supported. Conservation plans will require better characterisation of population-level interactions and simulation modelling of interventions. More generally our study demonstrates the importance of considering a full range of possible trophic interactions, particularly in complex ecosystems, and highlights Bayesian isotopic mixing models as powerful tools in resolving trophic relationships.

We investigated the concentrations of 22 essential and non-essential elements among a community of Procellariiformes (and their prey) to identify the extent to which trophic position and foraging range governed element accumulation. Stable isotope analysis (SIA) was used to characterise trophic (delta(15)N) and spatial patterns (delta(13)C) among species. Few consistent patterns were observed in element distributions among species and diet appeared to be highly influential in some instances. Arsenic levels in seabird red blood cells correlated with delta(15)N and delta(13)C, demonstrating the importance of trophic position and foraging range for arsenic distribution. Arsenic concentrations in prey varied significantly across taxa, and in the strength of association with delta(15)N values (trophic level). In most instances, element patterns in Procellariiformes showed the clearest separation among species, indicating that a combination of prey selection and other complex species-specific characteristics (e.g. moult patterns) were generally more important determining factors than trophic level per se.

In common with other farmland species, hares (Lepus spp.) are in widespread decline in agricultural landscapes due to agricultural intensification and habitat loss. We examined the importance of habitat heterogeneity to the Irish hare (Lepus timidus hibernicus) in a pastoral landscape. We used radio-tracking during nocturnal active and diurnal inactive periods throughout one year. In autumn, winter and spring, hares occupied a heterogeneous combination of improved grassland, providing food, and Juncus-dominated rough pasture, providing refuge. In summer, hares significantly increased their use of improved grassland. This homogeneous habitat can fulfil the discrete and varied resource requirements of hares for feeding and shelter at certain times of year. However, improved grassland may be a risky habitat for hares as silage harvesting occurs during their peak birthing period of late spring and early summer. We therefore posit the existence of a putative ecological trap inherent to a homogeneous habitat of perceived high value that satisfies the hares' habitat requirements but which presents risks at a critical time of year. To test this hypothesis in relation to hare populations, work is required to provide data on differential leveret mortality between habitat types. © 2010.

The diet of brown skuas (Catharacta antarctica lonnbergi) on Bird Island, South Georgia was assessed using a combination of stable isotope analysis (SIA) and mixing model techniques. We found evidence that individual specialisation in diet of adult brown skuas was related to timing of breeding, which may reflect differences in intrinsic quality. Adults with more enriched 13C values hatched chicks earlier than those with depleted 13C values. Individuals with enriched 13C fed predominantly on Antarctic fur seal (Arctocephalus gazella) carrion and placenta while those with lower ratios appeared to rely more on burrowing petrels (e.g. Antarctic prions Pachyptila desolata). Individual foraging differences clearly influenced timing of breeding and potentially the reproductive output of breeding pairs. We confirmed that the main components of the diet of brown skuas during incubation are, in decreasing order of importance, Antarctic fur seal placenta, burrowing petrels and fur seal muscle. In addition, we identified fur seal faeces in the diet during this stage, which had not been detected previously by traditional sampling methods. Finally we identified a correlation in δ13C values between pair members, attributable to the influence of courtship feeding of females by males, or assortative mating according to foraging preference or intrinsic quality. © 2008 Springer-Verlag.

Seabirds are often advocated as biomonitors for marine contaminants such as mercury (Hg). However, contaminant levels can vary widely depending on among-individual and among-species variation in foraging preferences and physiology, and on tissue types used for analyses. Using stable isotope analysis (SIA), we investigated the effects of trophic position, season, and tissue type on Hg burdens in a group of 10 closely related seabirds (Procellariiformes) from a single colony in the South Atlantic. Analysis of blood (reflecting breeding season diet) showed that among-species Hg concentrations varied as a function of trophic position (δ15N) and were also influenced to a lesser degree by foraging range (δ13C). This pattern did not hold for feathers, which reflect the non-breeding period. Mercury levels in feathers formed during the non-breeding season appear to be more strongly governed by species effects (such as moult schedule), demonstrating the need to carefully consider tissue type when formulating predictions regarding Hg burdens and dynamics. Assessment at a community rather than the species level, and across a number of tissue types, provided a more complete picture of the complex interactions between Hg and foraging ecology in seabirds. © Inter-Research 2009.

Although predator control programmes rarely consider complex competitive interactions among predators, it is becoming clear that removal of larger 'superior' competitors often releases the 'inferior' ones and can precipitate trophic cascades. In contrast, our study indicates that culling hooded crows Corvus cornix appears to release a larger competitor, the common raven Corvus corax. Ravens ranged more widely, and the predation of artificial nests was significantly faster (although total predation was similar), after the removal of crows. Our study provides evidence of a novel reversal of competitive release where a larger species was freed from constraints imposed on its distribution and behaviour by a smaller species, and emphasizes the importance of considering community and ecosystem effects of predator manipulations when undertaken for conservation or game management.

1. Stable isotope analysis (SIA) has the potential to become a widespread tool in mammalian ecology, because of its power in resolving the ecological and behavioural characteristics of animals. Although applications of the technique have enhanced our understanding of mammalian biology, it remains underused. Here we provide a review of previous applications to the study of extant mammals, drawing when appropriate on examples from the wider ecological literature, to identify the potential for future development of the approach. 2. Stable isotope analysis has been applied successfully to understanding the basic foraging decisions of mammals. However, SIA generates quantitative data on a continuous scale meaning that the approach can be particularly powerful in the characterization of community metrics, such as dimensions of resource partitioning within species assemblages or nutrient dynamics in food chains. Resolving spatial and temporal patterns of individual, intraspecific and interspecific resource use is of fundamental importance in animal ecology and evolutionary biology and SIA will emerge as a critical tool in these fields. 3. Geographical differences in naturally occurring stable isotopes have allowed ecologists to describe large-scale mammal migrations. Several isotopic gradients exist at smaller spatial scales, which can provide finer resolution of spatial ecology. 4. A combination of foraging and movement decisions is of prime importance in the study of ecotoxicology, since this discipline requires quantitative understanding of exposure risk. © Journal compilation © 2008 Mammal Society.

Changes in the relative abundance of sympatric carnivores can have far-reaching ecological consequences, including the precipitation of trophic cascades and species declines. While such observations are compelling, experimental evaluations of interactions among carnivores remain scarce and are both logistically and ethically challenging. Carnivores are nonetheless a particular focus of management practices owing to their roles as predators of livestock and as vectors and reservoirs of zoonotic diseases. Here, we provide evidence from a replicated and controlled experiment that culling Eurasian badgers Meles meles for disease control was associated with increases in red fox Vulpes vulpes densities of 1.6-2.3 foxes km-2. This unique experiment demonstrates the importance of intraguild relations in determining species abundance and of assessing the wider consequences of intervention in predator populations.

Invasive, non-native species are a major threat to global biodiversity. Stoats were introduced from Britain to New Zealand in the 1880s and have since caused grave conservation problems. A histopathological and serological survey of disease and infection in stoats from New Zealand was undertaken to identify agents that might be used or modified to control this population. of 60 stoats examined, 63% exhibited inflammation of the lung, mostly occurring as local or diffuse interstitial pneumonia, 30% showed signs of inflammatory liver disease and 14% were positive for antibodies reactive with feline calicivirus. In Britain only 11% of 44 stoats exhibited symptoms of pulmonary inflammatory disease, suggesting higher rates of infection or compromise of the pulmonary immune system among invasive stoats, possibly related to genetic founder effects or environmental variation. These findings could be exploited in biological control programmes.

Britain's Randomised Badger Culling Trial provides robust evidence of the role badgers have in transmission of Mycobacterium bovis to cattle. Culling badgers perturbed their social structure, and brought positive and negative effects for bovine tuberculosis incidence in cattle, leading to the conclusion that culling could not make a meaningful contribution to disease control. The RBCT highlights the complexities of disease transmission in social animals and the importance of host ecology for controlling wildlife diseases.

Fragmentation of natural populations can have negative effects at the genetic level, thus threatening their evolutionary potential. Many of the negative genetic impacts of population fragmentation can be ameliorated by gene flow and it has been suggested that in wind-pollinated tree species, high or even increased levels of gene flow are a feature of fragmented populations, although several studies have disputed this. We have used a combination of nuclear microsatellites and allele-specific PCR (AS-PCR) analysis of chloroplast single nucleotide polymorphisms (SNPs) to examine the levels and patterns of genetic diversity and population differentiation in fragmented populations of juniper (Juniperus communis) in Ireland and inform conservation programs for the species. Significant population differentiation was found for both chloroplast and nuclear markers, indicating restricted gene flow, particularly over larger geographic scales. For conservation purposes, the existence of genetically distinct clusters and geographically localised chloroplast haplotypes suggests that the concept of provenance should be taken into account when formulating augmentation or reintroduction strategies. Furthermore, the potential lack of seed dispersal and seedling establishment means that ex-situ approaches to seed and seedling management may have to be considered. © 2007 Springer Science+Business Media B.V.

Invasive species often cause the decline of native prey or competitors. We highlight a contrasting example of the large-scale recovery of a native species and the concurrent decline and likely displacement of an established invasive competitor. Invasive American mink Mustela vison became widespread in the British Isles at the same time as native Eurasian otters Lutra lutra were declining as a result of water pollution. In common with other invasive predators, mink cause conservation problems for a range of native prey species, most notably water voles Arvicola terrestris. Recent trends in the distribution of native otters and invasive mink in north-east England were examined using a novel regression modelling approach to analyse presence/absence data from field surveys, corroborated by contemporary predator culling records. Between 1991 and 2002, the percentage of sites where mink signs were found decreased from 80% to 20%, while otter signs increased from 18% to 80%. Annual indices of mink captures on shooting estates increased between 1980 and 1996, but were followed by a decline thereafter. Indices of the incidence of native otters were significantly related to those indicating the decline or displacement of invasive mink. This large-scale field study is supportive of localized experimental evidence for the return of dominant, native otters being concurrent with the decline of the invasive alien mink. The recovery of a dominant native species may represent a reversal of the mesopredator release that allowed invasive mink to establish and may eventually serve to mitigate their impact on native prey species. © 2007 the Authors.

Hare coursing is a widespread but controversial activity. In an attempt to reduce hare mortality and mitigate the activity's impact on hare welfare, the Irish Coursing Club introduced measures including the compulsory muzzling of dogs in 1993. However, the efficacy of these measures remained the subject of heated debate. Official records, corroborated by independent video evidence, were used to assess the fate of individual Irish hares (Lepus timidus hibernicus) during coursing events from 1988-2004. Muzzling dogs significantly reduced levels of hare mortality. In courses using unmuzzled dogs from 1988/89-1992/93 mean hare mortality was 15.8%, compared to 4.1% in courses using muzzled dogs from 1993/94-2003/04. Further reductions in mortality could not be accounted for by muzzling dogs, supporting the efficacy of other factors such as improved hare husbandry. The duration of the head start given to the hare prior to the release of the dogs significantly affected the outcome of the course. Hares that were killed had head starts of greater duration than those that were chased but survived, suggesting the former may have been slower. The selection of hares by assessment of their running ability may provide means to reduce hare mortality during courses further. Our findings support the efficacy of measures taken to mitigate the impact of coursing on individual hares. However, it is necessary to evaluate the impact of removing hares from the source population and of returning coursed hares to the wild before the wider impact of coursing on wild hare populations can be determined. © 2007 Universities Federation for Animal Welfare.

1. Agri-environment schemes (AESs) are designed to create landscape-scale improvements in biodiversity. While the specific aims of AESs do not always include the enhancement of species of conservation concern, associated conservation strategies, such as the UK Biodiversity Action Plan, often rest on the assumption that AESs enhance environmental conditions and thereby improve the conservation status of target species. However, there is little evidence for the general efficacy of AESs in this respect. 2. To evaluate the effects of the Environmentally Sensitive Area (ESA) scheme, a widespread AES in Northern Ireland, a spotlight survey of the relative abundance of three mammal species, Irish hare Lepus timidus hibernicus, European rabbit Oryctolagus cuniculus and red fox Vulpes vulpes, was conducted. of these, the Irish hare is a priority species for conservation action and the focus of a species action plan, while rabbit and fox are commonly considered agricultural pests. The effects of ESA designation and habitat on each species were assessed at 150 ESA and 50 non-ESA sites, matched for landscape characteristics. 3. The ESA scheme had no demonstrable effect on the abundance of Irish hares, and this agri-environment scheme did not target the landscape and habitat variables associated with hares. 4. In contrast, the abundance of rabbits and foxes was significantly greater within ESAs than the wider countryside. Agricultural factors such as reduced livestock stocking density, reduced overgrazing and field boundary enhancements may create more favourable conditions for both species. Aside from the implications for farm economics, the proliferation of rabbit populations within conservation areas may raise issues concerning the grazing of important plant communities, while increases in fox populations may adversely affect ground-nesting birds and other animal species of conservation concern. 5. Synthesis and applications. The abundance of rabbits and foxes corroborates recent work that suggests AESs may benefit common species but can not be relied upon to encourage rarer species. The Irish hare species action plan relies on agri-environment schemes to enhance the species' status and realize the target of increasing the hare population by 2010 by promoting suitable habitat. However, the ESA scheme is unlikely to help in achieving these objectives. Targeted and evidence-based agri-environment prescriptions are clearly required in order to ensure the realization of species-specific conservation targets. © 2007 the Authors.

The current Irish biota has controversial origins. Ireland was largely covered by ice at the Last Glacial Maximum (LGM) and may not have had land connections to continental Europe and Britain thereafter. Given the potential difficulty for terrestrial species to colonize Ireland except by human introduction, we investigated the stoat (Mustela erminea) as a possible cold-tolerant model species for natural colonization of Ireland at the LGM itself. The stoat currently lives in Ireland and Britain and across much of the Holarctic region including the high Arctic. We studied mitochondrial DNA variation (1771 bp) over the whole geographical range of the stoat (186 individuals and 142 localities), but with particular emphasis on the British Isles and continental Europe. Irish stoats showed considerably greater nucleotide and haplotype diversity than those in Britain. Bayesian dating is consistent with an LGM colonization of Ireland and suggests that Britain was colonized later. This later colonization probably reflects a replacement event, which can explain why Irish and British stoats belong to different mitochondrial lineages as well as different morphologically defined subspecies. The molecular data strongly indicate that stoats colonized Ireland naturally and that their genetic variability reflects accumulation of mutations during a population expansion on the island. © 2007 the Royal Society.

Assessing the effects of invading species on native community structure is often confounded by environmental factors and weakened by lack of replicated, long-term pre- and post-invasion monitoring. Here, we uncouple the community effects of a freshwater amphipod invader from environmental differences. In Irish rivers, the introduced Gammarus pulex replaces the native Gammarus duebeni celticus. However, the River Lissan in Northern Ireland is dissected by a weir that has slowed the upstream invasion by G. pulex. This allowed us in 2000 to sample three contiguous 150-m reaches that were (1) G. pulex dominated; (2) mixed Gammarus spp.; and (3) G. duebeni celticus only. In 2003, we resampled these reaches and one additional of mixed Gammarus species and one with only G. duebeni celticus further upstream. In temperature, conductivity, and pH, there were statistically significant but no biologically relevant differences among the five reaches of 2003, and between the three reaches surveyed in both years. Although there was evidence of recovery in macroinvertebrate diversity and richness in invaded reaches between years, continued upstream invasion was associated with sustained reductions in these community metrics as compared to un-invaded sites. Community ordination indicated (1) different associations of community composition attributed to the distribution, abundance, and biomass of the invader; and (2) increasing similarity of invaded communities over time. The impact mechanisms of G. pulex on macroinvertebrate community composition may include predation and competition. The consequences of the observed community changes for ecosystem functioning require further investigation. © 2006 the Authors.

We assess the status and diet of otters in Northern Ireland in 2002. Signs of otter presence were noted at 65% of 441 sites surveyed. This figure suggests a decline in signs of otters since the 1980s. Highest occurrence of signs of otters was around lakes, with coastal sites having the lowest occurrence. Percentage occurrence of signs of otter varied considerably with respect to catchment. The highest levels were in Lough Melvin, County Fermanagh, and around the Foyle catchment, County Londonderry; fewest signs occurred along the Antrim coast. Signs of otter occurrence were higher in larger rivers and at unpolluted sites (68%) as compared to polluted sites (57%). Over 50% of otter spraints were composed of stickleback (Gasterosteus aculeatus), salmonids and cyprinids, with stickleback constituting the most frequently occurring prey category. The frequency of occurrence of eels (Anguilla anguilla) in otter diet was found to be consistently higher in spraints collected from smaller streams across all land class groups. The frequency of occurrence of most prey items differed significantly with catchment with the exception of salmonids, which occurred consistently in spraints collected throughout all catchments in Northern Ireland. The current investigation confirms that otters remain widespread in Northern Ireland. However, otters may be feeding on less profitable prey items. Further investigations into the relationship between water quality, prey availability and prey selection are required to fully understand the factors affecting otter diet in Northern Ireland. © Royal Irish Academy.

The management of invasive non-native species is a frequent cause of conflict in the field of biodiversity conservation because perceptions of their costs and benefits differ among stakeholder groups. A lack of cohesion between scientific researchers, the commercial sector and policy makers lies at the root of a widespread failure to develop and implement sustainable management practices for invasive species. The crisis of this situation is intensified by drivers stemming from international conventions and directives to address invasive species issues. There are further direct conflicts between legislative instruments promoting biodiversity conservation on the one hand while liberalizing trade at the national, European and global level on the other. The island of Ireland provides graphic illustration of the importance of cross-jurisdictional approaches to biological invasions. Using primarily Irish examples in this review, we emphasize the importance of approaching risk assessment, risk reduction and control or eradication policies from a cost-efficient, highly flexible perspective, incorporating linkages between environmental, economic and social objectives. The need for consolidated policies between Northern Ireland and the Republic of Ireland is particularly acute, though few model cross-border mechanisms for such consolidation are available. The importance of engaging affected stakeholders through positive interactions is discussed with regard to reducing the currently fragmented nature of invasive species management between the two jurisdictions. © 2006 Springer.

1. A questionnaire survey of the numbers of animals brought home by domestic cats Felis catus was conducted between 1 April and 31 August 1997. A total of 14 370 prey items were brought home by 986 cats living in 618 households. Mammals made up 69% of the items, birds 24%, amphibians 4%, reptiles 1%, fish

1. British gamekeepers commonly trap and shoot stoats and weasels in order to increase the abundance of game. We provide details of the population biology of 822 stoats and 458 weasels collected on 25 game estates and use simple population models to assess the effects of culling. 2. Seventy-one per cent of stoats and 94% of weasels were trapped, while 26% of stoats and 5% of weasels were shot. While trapped samples exhibited typically male-biased sex ratios, the sex ratio of shot stoats was even. Eight of 305 female stoats and six of 77 female weasels were visibly pregnant, with mean litters of 9·0 and 6·2 embryos, respectively. Median ages at death were 11·6 and 8·0 months for male and female stoats, respectively, and 9·3 and 9·2 months for male and female weasels. Male and female stoats, but not male and female weasels, had significantly different rates of survival. 3. Model weasel populations continued to increase (λ = 1·35) despite culling as a result of high productivity when sufficient food was available. Model stoat populations declined slightly (λ = 0·95), probably as a result of concerted culling effort when young stoats were dependent on maternal survival. This suggests that persistence of culled stoat populations may depend on immigration. 4. To reduce stoat populations without affecting the survival of dependent juveniles, culling effort could be focused on trapping females in late winter and shooting females in early spring, where landscape and climate permit. For control of weasel populations, trapping effort should be, and in practice often is, focused on late spring, following a period of high natural mortality. 5. High rates of immigration mean that culling by gamekeepers will not ordinarily lead to any long-term decline in actual stoat and weasel populations. We suggest that measures taken to enhance immigration will improve the long-term status of stoats and weasels in regions where their conservation is desirable, and whilst this persists the impact of culling will be short-lived and local.

Forty-four free-living stoats were collected from five game estates in England and examined for evidence of disease. All the macroscopic lesions were attributable to the trauma associated with being trapped or shot. There were no significant microscopic lesions in 27 (61 per cent) of the stoats. There was evidence of nematode parasitism in the intestines of six stoats (14 per cent), and in the lungs of five stoats (11 per cent), and of pulmonary granulomatous inflammation or microgranulomas in five stoats. In two of the stoats, blood-filled cavities in the liver were suggestive of peliosis hepatis, possibly associated with infection by Bartonella species or with sublethal exposure to anticoagulant rodenticides.

Stoats present a serious threat to the avian biodiversity of New Zealand. Control measures are needed to ensure the long-term survival of several bird species. Existing control technology is labour-intensive and expensive, and so new techniques and approaches are needed to provide long-lasting solutions to conservation challenges. We reviewed the literature on the demography, captive breeding, diseases, biological and non-lethal control, metabolism and toxicology of stoats and closely related mustelids. We conclude that a long-term solution to lethal stoat control may lie with specific disease agents, such as canine distemper, Aleutian disease virus and mink enteritis virus, and toxins, such as rodenticides and mycotoxins. The role of host-specific vectors in disease transmission may represent an existing method of accurately deploying non-lethal control agents. We urge caution in developing biotechnology without a parallel investigation of the effects of control on stoat populations and the survival of threatened birds. The establishment of captive breeding facilities for stoats deserves a high priority since these will be indispensable for technological development and validation. Throughout their native range, stoats are dependent on a range of prey species. In certain areas of New Zealand, they are dependent on very few prey species, and outbreaks of house mice lead to acute conservation problems at regular and predictable intervals. We therefore advocate a research effort directed towards the control of mouse outbreaks.

Rarely seen but endowed with a larger-than-life reputation, stoats and weasels are among our most common and yet most enigmatic predators. They are the world's smallest carnivores and they spend much of their short lives in a frenetic search for prey. Their quicksilver behaviour and 'burn-out not fade-away' lifestyle provide many puzzles for biologists and conservationists alike.

The diet of 789 stoats Mustela erminea and 458 weasels M. nivalis collected in Great Britain between 1995 and 1997 is described from analyses of their gut contents. As a percentage frequency of occurrence, stoat diet consisted of 65% lagomorphs, 16% small rodents and 17% birds and birds' eggs. Weasel diet consisted of 25% lagomorphs, 68% small rodents, mainly Microtus agrestis, and 5% birds and birds' eggs. Male stoats ate a greater proportion of lagomorphs than females, which ate more small rodents. No differences in diet between the sexes of the weasels were detected. The proportion of lagomorphs in the diet of both species was greatest in the spring. Both species ate more lagomorphs in the 1990s than in the 1960s as a result of increasing rabbit populations following recovery from myxomatosis. The importance of small rodents had decreased for stoats and increased for weasels. Both species had a dietary niche that was more specialized than in the 1960s. The implications of these findings for stoat and weasel conservation are discussed.

Several studies have highlighted the potential risk to nontarget wildlife associated with accidental exposure to vertebrate control agents. In order to provide information that may assist in the mitigation of this problem, we questioned 215 gamekeepers in Great Britain about the use of vertebrate control agents on the land for which they were responsible. Fumigants were used to control Rabbits Oryctolagus cuniculus by 59% of gamekeepers. Use of fumigants was more common than on farms in general. 91% of gamekeepers reported the use of rodenticides, 95% of which were anticoagulants. Patterns of rodenticide use were similar to those on arable farms, though chlorophacinone and warfarin were used more commonly on game estates. Future studies of the exposure of nontarget wildlife to anticoagulants should be expanded to include these compounds. Rodenticides were apparently used in accordance with label recommendations in most cases. However, better information and guidelines for users may improve standards of agent application and reduce potential risks to nontarget wildlife.

1. Trapping and hunting records are frequently used as an index of animal abundance. This study demonstrates that these records can be misleading if sampling effort is not controlled for. 2. Mean numbers of stoats Mustela erminea and weasels M. nivalis trapped by British gamekeepers have been decreasing since 1975 and 1961 respectively, giving rise to concern that populations of both species may be declining. However, trapping effort has not been quantified over this period. 3. A total of 203 gamekeepers in England were questioned about the trapping effort they expended and the number of stoats and weasels they trapped in 1997. The most significant factor affecting the number of stoats and weasels trapped was trapping effort. 4. Gamekeepers that relied on hand-rearing game birds for shooting regarded stoats and weasels as a less serious problem, and made substantially less trapping effort, than gamekeepers that relied on wild game birds. 5. The national decline in the numbers of stoats and weasels trapped may be the result of a decline in stoat and weasel populations. However, the decline is equally consistent with a reduction in trapping effort, corresponding to a national increase in reliance on hand-rearing game birds for shooting. 6. When the effect of trapping effort was controlled for, the number of weasels trapped by gamekeepers in 1997 was significantly lower in the south-west than in other regions of England and was unusually low in some local areas. 7. Trapping records can be used effectively to monitor populations of stoats and weasels, as long as gamekeepers record the number of traps set in each month and monthly totals of animals killed. Ideally, the sex of each animal and whether it was trapped or shot should also be recorded. Similar modifications should also be made to other wildlife monitoring schemes based on trapping and hunting records.

Concentrations of six anticoagulant rodenticides were examined in the livers of stoats Mustela erminea L. and weasels Mustela nivalis L. trapped or shot by gamekeepers between August 1996 and March 1997. Residues of rodenticides were detected in nine out of 40 stoats (23%) and three out of ten weasels (30%) from five out of eight estates in central and eastern England. Bromadiolone (0.04-0.38 mg kg-1 wet wt) was detected in three stoats and one weasel, coumatetralyl (0.0085-0.06 mg kg-1) in six stoats and three weasels and brodifacoum (0.12 mg kg-1) in one stoat. One stoat and one weasel contained combinations of two rodenticides. Exposure to rodenticides was more prevalent in female stoats than in males. Rodenticides were widely used away from buildings on the sampled estates and so mustelids need not forage around buildings to be exposed. We conclude that stoats and weasels are secondarily exposed to rodenticides mainly by eating non-target species. Copyright (C) 1998 Elsevier Science Ltd.

Ship rats Rattus rattus are amongst the rarest mammals in Britain and yet they are officially classified as pests. They exist independently of contemporary human settlement at only two sites both of which are important seabird breeding colonies. There may be a conflict between conserving this rare species while ensuring the welfare of seabirds. We present a case study of the potential conservation dilemma of ship rat management on the Shiant Islands. Using capture-mark-recapture the pre-breeding rat population in May 1996 was estimated to be between 230 and 400. Evidence of rat predation on eggs and chicks was scarce at the time of our survey. The small number of rats was not thought to have a substantial effect on the nesting success of the comparatively large seabird populations. We suggest that the scientific interest of the rat population may outweigh the conservation needs of the seabirds and that formal control measures are currently unwarranted.