Reports on badgers Meles meles in Dutch newspapers 1900–2013: same animals,different framings?

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狗獾夜间活动节律是受人类活动影响而形成的吗?基于青海湖地区的研究实例

青海湖地区是目前已知的狗獾分布海拔最高点。为了解狗獾在青藏高原严酷生态环境下的生活史特点, 并验证是否人类干扰造成了狗獾夜行性的假说, 我们利用红外相机技术, 结合无线电遥测和野外调查研究了青海湖湖东地区亚洲狗獾(Meles leucurus)的种群密度、洞穴口的行为及活动节律。结果表明: (1)研究地区狗獾的平均种群密度为1.2 ± 0.6只/km², 其分布受食物丰富度的影响; (2)狗獾基本在夜间活动, 出洞时间集中在20:00-23:00之间, 而回洞时间则集中在清晨4:00-7:00之间, 23:00-4:00之间是狗獾的活动高峰; (3)狗獾离洞前行为主要是警戒行为, 回洞穴时的行为主要是嬉戏行为, 其他行为较少见, 表达具有特定的时间性; (4)人类活动对于狗獾活动没有显著性影响(P < 0.05)。     

Blood biochemistry reflects seasonal nutritional and reproductive constraints in the eurasian badger (Meles meles)

Physiological responses to nutritional and reproductive constraints were explored in a wild population of Eurasian badgers (Meles meles) inhabiting Wytham Woods, Oxfordshire, United Kingdom. We compared seasonal blood levels of lipid and protein compounds to variables describing the sex, age, body condition, wounds, testes position, and flea abundance of the badgers. We found seasonal variations in albumin/globulins and urea/creatinine ratios matched by differences in body condition. High creatinine, urea, and triglycerides levels were obtained in animals in poor nutritional condition and with low levels of body fat. The maintenance of urea/creatinine ratios indicates that the badger does not demonstrate a stage of protein conservation in periods of food scarcity during the summer or periods of cold weather. Hypercholesterolaemia, especially in fat animals, was confirmed. We also offer baseline levels of metabolites commonly used in clinical biochemistry for their further use in the analysis of the status and the management of wild badger populations.     

Diagnostic Accuracy and Optimal Use of Three Tests for Tuberculosis in Live Badgers

Background

Accurate diagnosis of tuberculosis (TB) due to infection with Mycobacterium bovis is notoriously difficult in live animals, yet important if we are to understand the epidemiology of TB and devise effective strategies to limit its spread. Currently available tests for diagnosing TB in live Eurasian badgers (Meles meles) remain unvalidated against a reliable gold standard. The aim of the present study was to evaluate the diagnostic accuracy and optimal use of three tests for TB in badgers in the absence of a gold standard.

Methodology/Principal Findings

A Bayesian approach was used to evaluate the diagnostic accuracy and optimal use of mycobacterial culture, gamma-interferon assay and a commercially available serological test using multiple samples collected from 305 live wild badgers. Although no single test was judged to be sufficiently sensitive and specific to be used as a sole diagnostic method, selective combined use of the three tests allowed guidelines to be formulated that allow a diagnosis to be made for individual animals with an estimated overall accuracy of 93% (range: 75% to 97%). Employing this approach in the study population of badgers resulted in approximately 13 out of 14 animals having their true infection status correctly classified from samples collected on a single capture.

Conclusions/Significance

This method of interpretation represents a marked improvement on the current procedure for diagnosing M. bovis infection in live badgers. The results should be of use to inform future test and intervention strategies with the aim of reducing the incidence of TB in free-living wild badger populations.     

A Novel Use of Camera Traps to Study Demography and Life History in Wild Animals: A Case Study of Spider Monkeys (Ateles belzebuth)

Demographic and life history data from wild populations of long-lived primate species are difficult to acquire but are critical for evaluating population viability and the success of conservation efforts. Camera trapping provides an opportunity for researchers to monitor wild animal populations indirectly and could help provide demographic and life history data in a way that demands fewer person-hours in the field, is less disruptive to the study population because it requires less direct contact, and may be cost effective. Using data on group composition collected concurrently though both direct observation and camera trap monitoring, we evaluate whether camera traps can provide reliable information on population dynamics (births, disappearances, interbirth intervals, and other demographic variables) for a wild population of white-bellied spider monkeys (Ateles belzebuth), an Endangered species. We placed camera traps focused on the sole access point used by the monkeys to visit a geophagy site located roughly in the center of one group’s home range, and we reviewed all of the photos collected at that site over a roughly 3-yr period to identify the individual monkeys recorded in the pictures. Group composition based on 2947 photos containing 3977 individual monkey images matched perfectly data collected concurrently through direct observation. The camera traps also provided estimates of the dates when individuals disappeared from the study group, and of infant births during the study. We conclude that long-term camera trap monitoring of wild populations of white-bellied spider monkeys—and other animals that are individually recognizable and that regularly visit predictable resources—can be a useful tool for monitoring their population dynamics indirectly.     

Absence of antibodies against canine distemper virus in free-ranging populations of the Eurasian badger in Great Britain

Canine distemper virus (CDV) is a serious disease of wild carnivores throughout the world. In Europe, infection has been detected in several carnivores including the Eurasian badger (Meles meles). In the present study 182 badger blood samples were collected from an intensively studied population of wild badgers in southwestern England (January-July, 1997), and a further 286 from throughout southern Britain (June 1996-November 1998). A neutralizing peroxidase-linked antibody test was used for the detection of antibodies against CDV. All the samples were negative for CDV antibodies, suggesting that in contrast to mainland Europe, the disease may be either absent or maintained at low levels in British badgers.     

Phylogenetic relationships and genetic diversity of badgers from the Korean Peninsula: Implications for the taxonomic status of the Korean badger

Accurate taxonomic classification of wildlife species is crucial for guiding biological research and for developing effective management and conservation programs. The taxonomic status of Eurasian badgers from South Korea remains poorly resolved. Here we assessed the phylogenetic relationships and genetic variation of Eurasia badgers using partial mitochondrial fragments to elucidate the evolutionary history and taxonomic status of badgers from the Korean Peninsula. Forty-eight unique haplotypes from 125 individuals were observed. Phylogenetic reconstructions and reduced median networks indicate that Eurasian badgers consisted of four geographic clades (Japan, Eastern Eurasia, Western Eurasia, and Caucasus) with a relatively weak split observed within Eastern Eurasia. Estimated divergence time between the Japanese and Eastern Eurasian clades, including the Korean population, was 467,100 years (69,200–1,085,500 years). The results of this study support the hypothesis that the Japanese badger migrated from the Eurasian continent over the Korea-Japan land bridge and that the Korean Peninsula was an important refugia during the Pleistocene. Our study confirmed that the South Korean badger, Meles meles, belongs to the Eastern Eurasian clade. Based on these results and those of previous studies, we recommend that the scientific name of the Korean badger be changed from M. meles to Meles leucurus (Asian badger).     

Pathogen and rodenticide exposure in American badgers (Taxidea taxus) in California

Urban and agricultural land use may increase the risk of disease transmission among wildlife, domestic animals, and humans as we share ever-shrinking and fragmented habitat. American badgers (Taxidae taxus), a species of special concern in California, USA, live in proximity to urban development and often share habitat with livestock and small peridomestic mammals. As such, they may be susceptible to pathogens commonly transmitted at this interface and to anticoagulant rodenticides used to control nuisance wildlife on agricultural lands. We evaluated free-ranging badgers in California for exposure to pathogens and anticoagulant rodenticides that pose a risk to wildlife, domestic animals, or public health. We found serologic evidence of badger exposure to Francisella tularensis, Toxoplasma gondii, Anaplasma phagocytophilum, canine distemper virus, and three Bartonella species: B. henselae, B. clarridgeiae, and B. vinsonii subsp. berkhoffii. Badger tissues contained anticoagulant rodenticides brodifacoum and bromadiolone, commonly used to control periurban rodent pests. These data provide a preliminary investigation of pathogen and toxicant exposure in the wild badger population.     

Leucistic southern elephant seal at Marion Island

We observed a light coloured female southern elephant seal juvenile (Mirounga leonina) twice at Marion Island in August 2008 and confirmed that it was leucistic rather than albinistic. Though there have been a few previous reports of light-coloured southern elephant seals, this is the first confirmed case of leucism in this species. Judged to be 1-year old, perhaps 2-years old at the most, and because we have not observed any leucistic pups at Marion Island during the past 2 years despite an extensive monitoring and tagging program, we think that this animal was born at nearby Prince Edward Island or perhaps further afield at Îles Crozet.     

Effects of culling on badger abundance: implications for tuberculosis control

Culling is often considered as a tool for controlling wildlife diseases that can also infect people or livestock. Culling European badgers Meles meles can cause both positive and negative effects on the incidence of bovine tuberculosis (TB) in cattle. One factor likely to influence the outcome of different badger-culling strategies for cattle TB is the reduction in badger population density achieved. However, this reduction is difficult to measure because badgers, being nocturnal and fossorial, are difficult to count. Here, we use indices of badger abundance to measure the population impacts of two culling strategies tested in Britain. The densities of badger setts and latrines recorded before culling were correlated with the densities of badgers captured on initial culls, suggesting that both were indices of actual badger abundance. Widespread 'proactive' culling was associated with a 73% reduction in the density of badger latrines, a 69% reduction in the density of active burrows and a 73% reduction in the density of road-killed badgers. This population reduction was achieved by a coordinated effort entailing widespread and repeated trapping over several years. However, this strategy caused only modest reductions in cattle TB incidence in culled areas and elevated incidence in neighbouring unculled areas. Localized 'reactive' culling caused a 26% reduction in latrine density, a 32% reduction in active burrow density and a 10% reduction in the density of road-killed badgers, but apparently increased the incidence of cattle TB. These results indicate that the relationship between badger population reduction and TB transmission to cattle is strongly non-linear, probably because culling prompts changes in badger behaviour that influence transmission rates. These findings raise serious questions about the capacity of badger culling to contribute to the control of cattle TB in Britain.     

Impacts of Removing Badgers on Localised Counts of Hedgehogs

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.     

Genetic evidence that culling increases badger movement: implications for the spread of bovine tuberculosis

The Eurasian badger (Meles meles) has been implicated in the transmission of bovine tuberculosis (TB, caused by Mycobacterium bovis) to cattle. However, evidence suggests that attempts to reduce the spread of TB among cattle in Britain by culling badgers have mixed effects. A large-scale field experiment (the randomized badger culling trial, RBCT) showed that widespread proactive badger culling reduced the incidence of TB in cattle within culled areas but that TB incidence increased in adjoining areas. Additionally, localized reactive badger culling increased the incidence of TB in cattle. It has been suggested that culling-induced perturbation of badger social structure may increase individual movements and elevate the risk of disease transmission between badgers and cattle. Field studies support this hypothesis, by demonstrating increases in badger group ranges and the prevalence of TB infection in badgers following culling. However, more evidence on the effect of culling on badger movements is needed in order to predict the epidemiological consequences of this control strategy. Here, analysis of the genetic signatures of badger populations in the RBCT revealed increased dispersal following culling. While standard tests provided evidence for greater dispersal after culling, a novel method indicated that this was due to medium- and long-distance dispersal, in addition to previously reported increases in home-range size. Our results also indicated that, on average, badgers infected with M. bovis moved significantly farther than did uninfected badgers. A disease control strategy that included culling would need to take account of the potentially negative epidemiological consequences of increased badger dispersal.     

Weather influences trapping success for tuberculosis management in European badgers (<Emphasis Type="Italic">Meles meles</Emphasis>)

European badgers (Meles meles) in Ireland and the UK are a reservoir for Mycobacterium bovis, the causative agent of bovine tuberculosis (TB). A number of interventions have been evaluated in attempts to control bovine TB within badger populations, and many of which rely on the capture of badgers. One strategy being implemented within Ireland is intramuscular vaccination using Bacillus Calmette-Guérin (BCG), as an alternative to badger culling. The success of vaccination as a disease control strategy depends on the ability to capture badgers and administer vaccines; thus, trapping success is crucial to effectively vaccinate the population (maximize vaccine coverage). A field vaccine trial was conducted in County Kilkenny, Ireland, from 2010–2013. We used data from this trial to evaluate the association between weather (precipitation and temperature data), badger sett characteristics, and badger trapping success. Approximately 10% of capture efforts resulted in a badger capture. Our results indicate that badger captures were the highest in drizzle, rain, and heavy rain weather conditions, and when minimum temperatures ranged from 3–8 °C. Badger captures were the highest at main setts (large burrow systems), and when sett activity scores were high (qualitative classes 4 or 5). Using local precipitation and temperature data in conjunction with observed sett characteristics provides wildlife managers with guidelines to optimize trapping success. Implementing capture operations under optimal conditions should increase the trapping success of badgers and allow for increased delivery of vaccines to manage bovine TB.     

Burrow webs: Clawing the surface of interactions with burrows excavated by American badgers

Ecosystem engineers are organisms that influence their environment, which includes alterations leading to habitat provisioning for other species. Perhaps the most well‐examined guild of species provisioning habitat for other species is tree cavity excavators or woodpeckers (Picidae). Many studies have examined the suite of secondary cavity users that rely on woodpeckers, and how the ecological network of secondary users, collectively referred to as the nest web, changes across communities. Despite similar habitat provisioning processes, fewer studies have assessed the suite of species associated with burrowers providing access to subterranean habitat. Here, we begin to characterize the burrow web provisioned by American badgers (Taxidea taxus) and evaluate the diversity and frequency of species interactions we detected at abandoned badger burrows in Wyoming, USA. We deployed camera traps at 23 badger burrows and identified interactions with the burrow by birds, mammals, and reptiles. Overall, we discovered 31 other species utilizing badger burrows, consisting of 12 mammals, 18 birds, and 1 reptile. Mammals, other than American badgers themselves and other fossorial species such as ground squirrels (Urocitellus sp.), frequently using burrows included mice (Peromyscus sp.), long‐tailed weasel (Mustela frenata), pygmy rabbit (Brachylagus idahoensis), and desert cottontail (Sylvilagus audubonii). Of the 18 bird species detected, most accounted for <5% of overall detections, besides chipping sparrows (Spizella passerina) at 7.2%–11.5% of detections. The most common category of detection by bird species was foraging, contrary to mammals, which used the burrow frequently and were commonly observed entering and exiting the burrow. This work provides additional context on the ecological role of American badgers within their environment. More broadly, this work scratches the surface of many remaining questions to explore with the aim of advancing our understandings about burrow webs across the diversity of burrowing species and the communities in which they occur.     

Interspecific visitation of cattle and badgers to fomites: A transmission risk for bovine tuberculosis?

In Great Britain and Ireland, badgers (Meles meles) are a wildlife reservoir of Mycobacterium bovis and implicated in bovine tuberculosis transmission to domestic cattle. The route of disease transmission is unknown with direct, so‐called “nose‐to‐nose,” contact between hosts being extremely rare. Camera traps were deployed for 64,464 hr on 34 farms to quantify cattle and badger visitation rates in space and time at six farm locations. Badger presence never coincided with cattle presence at the same time, with badger and cattle detection at the same location but at different times being negatively correlated. Badgers were never recorded within farmyards during the present study. Badgers utilized cattle water troughs in fields, but detections were infrequent (equivalent to one badger observed drinking every 87 days). Cattle presence at badger‐associated locations, for example, setts and latrines, were three times more frequent than badger presence at cattle‐associated locations, for example, water troughs. Preventing cattle access to badger setts and latrines and restricting badger access to cattle water troughs may potentially reduce interspecific bTB transmission through reduced indirect contact.     

How many Eurasian badgers <Emphasis Type="Italic">Meles meles</Emphasis> L. are there in the Republic of Ireland?

In Ireland, the badger Meles meles L is a reservoir species for Mycobacterium bovis and, as such, contributes to the maintenance of bovine tuberculosis in cattle. A previous estimate of the badger population in the Republic was 200,000 badgers. In the current study, we obtained data on badger numbers from a large-scale badger removal project (the Four-Area project). The removal areas of the Four-Area Project were surrounded by barriers (either water or buffer areas where removals were also conducted) to prevent badger immigration. Within these areas, a grid of 0.25 km² was created within which we knew the badger numbers and habitat types (based on Corine data). Associations between badger numbers and habitat type were investigated using negative binomial modeling. Extrapolations from the model yielded an estimated badger population in the Republic of approximately 84,000 badgers. The implications of these findings are discussed.     

The badger (Meles meles) in Britain: present status and future population changes

Over the past 150 years the badger is believed to have undergone major changes in status, and possibly also in distribution. In the last century persecution by gamekeepers in particular had an impact on badger numbers, especially in East Anglia. More recent changes in badger numbers and the need for a quantified base line survey against which to monitor future population changes provided the stimulus for a quantified national badger survey. This was achieved in the mid-1980s by a stratified survey in which pre-selected one kilometre squares used in the Institute of Terrestrial Ecology land classification system were surveyed for badgers. A total of 2455 squares (1.05%) of the land area of Britain) was surveyed, and this provided a means to (a) assess the current distribution and status of the badger, (b) assess the current levels of persecution of badgers and (c) monitor future badger population changes. Currently there are approximately 43 000 badger social groups in Britain. Sett blocking and badger digging were found to he widespread, and their effects on the badger population are discussed, as are the effects of the current TB control operations in south-west Britain. Future patterns of land use, particularly in response to changes in farming practice, could have significant effects on badger numbers. These are discussed in relation to potential changes in the Common Agricultural Policy. The effects of an expansion of forestry and the spread of urban areas on badger numbers are also estimated.     

Optimising and Evaluating the Characteristics of a Multiple Antigen ELISA for Detection of Mycobacterium bovis Infection in a Badger Vaccine Field Trial

A long-term research programme has been underway in Ireland to evaluate the usefulness of badger vaccination as part of the national bTB (bovine tuberculosis) control strategy. This culminated in a field trial which commenced in county Kilkenny in 2009 to determine the effects of badger vaccination on Mycobacterium bovis transmission in badgers under field conditions. In the present study, we sought to optimise the characteristics of a multiplex chemiluminescent assay for detection of M. bovis infection in live badgers. Our goal was to maximise specificity, and therefore statistical power, during evaluation of the badger vaccine trial data. In addition, we also aimed to explore the effects of vaccination on test characteristics. For the test optimisation, we ran a stepwise logistic regression with analytical weights on the converted Relative Light Units (RLU) obtained from testing blood samples from 215 badgers captured as part of culling operations by the national Department of Agriculture, Food and the Marine (DAFM). The optimised test was applied to two other datasets obtained from two captive badger studies (Study 1 and Study 2), and the sensitivity and specificity of the test was attained separately for vaccinated and non-vaccinated badgers. During optimisation, test sensitivity was maximised (30.77%), while retaining specificity at 99.99%. When the optimised test was then applied to the captive badger studies data, we observed that test characteristics did not vary greatly between vaccinated and non-vaccinated badgers. However, a different time lag between infection and a positive test result was observed in vaccinated and non-vaccinated badgers. We propose that the optimized multiplex immunoassay be used to analyse the vaccine trial data. In relation to the difference in the time lag observed for vaccinated and non-vaccinated badgers, we also present a strategy to enable the test to be used during trial evaluation.     

In situ adaptive response to climate and habitat quality variation: spatial and temporal variation in European badger (Meles meles) body weight

Variation in climatic and habitat conditions can affect populations through a variety of mechanisms, and these relationships can act at different temporal and spatial scales. Using post‐mortem badger body weight records from 15 878 individuals captured across the Republic of Ireland (7224 setts across ca. 15 000 km²; 2009–2012), we employed a hierarchical multilevel mixed model to evaluate the effects of climate (rainfall and temperature) and habitat quality (landscape suitability), while controlling for local abundance (unique badgers caught/sett/year). Body weight was affected strongly by temperature across a number of temporal scales (preceding month or season), with badgers being heavier if preceding temperatures (particularly during winter/spring) were warmer than the long‐term seasonal mean. There was less support for rainfall across different temporal scales, although badgers did exhibit heavier weights when greater rainfall occurred one or 2 months prior to capture. Badgers were also heavier in areas with higher landscape habitat quality, modulated by the number of individuals captured per sett, consistent with density‐dependent effects reducing weights. Overall, the mean badger body weight of culled individuals rose during the study period (2009–2012), more so for males than for females. With predicted increases in temperature, and rainfall, augmented by ongoing agricultural land conversion in this region, we project heavier individual badger body weights in the future. Increased body weight has been associated with higher fecundity, recruitment and survival rates in badgers, due to improved food availability and energetic budgets. We thus predict that climate change could increase the badger population across the Republic of Ireland. Nevertheless, we emphasize that, locally, populations could still be vulnerable to extreme weather variability coupled with detrimental agricultural practice, including population management.     

Culling-induced changes in badger (Meles meles) behaviour, social organisation and the epidemiology of bovine tuberculosis

In the UK, attempts since the 1970s to control the incidence of bovine tuberculosis (bTB) in cattle by culling a wildlife host, the European badger (Meles meles), have produced equivocal results. Culling-induced social perturbation of badger populations may lead to unexpected outcomes. We test predictions from the 'perturbation hypothesis', determining the impact of culling operations on badger populations, movement of surviving individuals and the influence on the epidemiology of bTB in badgers using data dervied from two study areas within the UK Government's Randomised Badger Culling Trial (RBCT). Culling operations did not remove all individuals from setts, with between 34-43% of badgers removed from targeted social groups. After culling, bTB prevalence increased in badger social groups neighbouring removals, particularly amongst cubs. Seventy individual adult badgers were fitted with radio-collars, yielding 8,311 locational fixes from both sites between November 2001 and December 2003. Home range areas of animals surviving within removed groups increased by 43.5% in response to culling. Overlap between summer ranges of individuals from Neighbouring social groups in the treatment population increased by 73.3% in response to culling. The movement rate of individuals between social groups was low, but increased after culling, in Removed and Neighbouring social groups. Increased bTB prevalence in Neighbouring groups was associated with badger movements both into and out of these groups, although none of the moving individuals themselves tested positive for bTB. Significant increases in both the frequency of individual badger movements between groups and the emergence of bTB were observed in response to culling. However, no direct evidence was found to link the two phenomena. We hypothesise that the social disruption caused by culling may not only increase direct contact and thus disease transmission between surviving badgers, but may also increase social stress within the surviving population, causing immunosuppression and enhancing the expression of disease.