541 research outputs found

    Spatial behaviour of wild boar

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    The spatial behaviour of an animal is influenced by decisions relating to foraging, movement, avoidance, resting, territorial activity, mating and rearing young. Many of these behaviours can be explained by the optimal foraging theory, exceptions being reproductive behaviours and predator avoidance. Predation risk and associated avoidance behaviors varies across the landscape, resulting in a divergence from patterns predicted by optimal foraging theory, instead optimizing fitness. Such risk effects can be large and affect both individuals and population demography. This thesis focus on external factors affecting movements and habitat selection of wild boar females (N=15-17 depending on the question) using data from GPS collared individuals (N>100.000 data points analyzed) over 4 years in the southern part of Sweden. My results show that habitat selection is affected by season and by risk effects, such as traffic and hunting. Intense traffic diverts wild boar from crossing roads, and reduce the number of traffic accidents when traffic intensity is high. Intense hunting results in fleeing while less intense hunting results in hiding. Hunts that results in flights affects habitat selection until wild boar returned to their homer range. Wild boar perceive crop fields as risky but rewarding habitats, and while using crop fields they prefer to be close to cover such as edges, hedges and ditches. Further, wild boar movement is affected by seasonal and temporal aspects and weather conditions. The most common reaction to stressful factors such as traffic, hunting and aversive weather was to reduce movement. The only exception was when wild boar were chased in drive hunts and fled. These results are important for understanding how weather conditions affect optimal foraging strategies and how the animals’ perception of risk affects movement patterns and habitat selection. From a management perspective, my results can be used to reduce crop damages and traffic accidents caused by wild boar. These findings are also useful in understanding how hunting as a management tool affects the space use of wild boar, and consequently can aid managers to select hunting methods that may reduce damages to crops

    WMU : World Maritime University, Malmoe Sweden

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    Practical application of indicators for genetic diversity in CBD post-2020 global biodiversity framework implementation

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    Genetic diversity is a key aspect of biological variation for the adaptability and survival of populations of species and must be monitored to assure maintenance. We used data from the Swedish Red List 2020 and from published reviews to apply three indicators for genetic diversity proposed for the post-2020 Global Biodiversity Framework of the Convention on Biological Diversity (CBD). We studied a wide range of taxonomic groups, and made more detailed indicator assessments for mammals and herptiles.For indicator 1, the proportion of populations with effective population size Ne > 500, 33% of 22,557 investigated species had a population size estimate that could be used as a proxy for Ne. For herptiles and mammals, 70% and 49% of populations of species, respectively, likely had Ne > 500.Data for evaluation of indicator 2, the proportion of remaining populations or historical range, was available for 20% of all species evaluated for the Red List. Meanwhile, 32% of the herptile and 84% of the mammal populations are maintaining their populations and range.For indicator 3, the number of species or populations in which genetic diversity is monitored using DNA-based methods, there are genetic studies on 3% of all species, and 0.3% are beeing monitored genetically. In contrast, 68% of mammals and 29% of herptiles are studied using DNA, and 8% of mammals and 24% of herptiles are genetically monitored.We conclude that the Red List provides data that are suitable for evaluating the genetic indicators, but the data quality can be improved. We also show that the genetic indicators capture conservation issues of genetic erosion that the Red List misses. There is a synergy in estimating the genetic indicators in parallel with the Red Listing process. We propose that indicator values could be included in national Red Listing as a new category "genetically threatened", based on the genetic indicators

    Trafikantinformation i stationsmiljöer

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    The aim of the thesis is to study and highlight the needs of passenger’s traffic information in the railway station environment, to identify and examine what its deficiencies depend on and come up with proposals on how they can be addressed. Thus, hopefully, improve the quality of information reaching the passengers in station environments. The method used included literature studies, among others, perception theory, which together with interviews, a focus group and field studies formed the basis for the analysis. The work has focused at the average traveller, therefore have groups with special needs such as disabled, visually impaired or children not been studied specifically

    Lessons from integrating behaviour and resource selection: activity-specific responses of African wild dogs to roads

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    Understanding how anthropogenic features affect species' abilities to move within landscapes is essential to conservation planning and requires accurate assessment of resource selection for movement by focal species. Yet, the extent to which an individual's behavioural state (e.g. foraging, resting, commuting) influences resource selection has largely been ignored. Recent advances in Global Positioning System (GPS) tracking technology can fill this gap by associating distinct behavioural states with location data. We investigated the role of behaviour in determining the responses of an endangered species of carnivore, the African wild dog Lycaon pictus, to one of the most widespread forms of landscape alteration globally: road systems. We collected high‐resolution GPS and activity data from 13 wild dogs in northern Botswana over a 2‐year period. We employed a step selection framework to measure resource selection across three behavioural states identified from activity data (high‐speed running, resting and travelling) and across a gradient of habitats and seasons, and compared these outputs to a full model that did not parse for behaviour. The response of wild dogs to roads varied markedly with both the behavioural and the landscape contexts in which roads were encountered. Specifically, wild dogs selected roads when travelling, ignored roads when high‐speed running and avoided roads when resting. This distinction was not evident when all movement data were considered together in the full model. When travelling, selection for roads increased in denser vegetative environments, suggesting that roads may enhance movement for this species. Our findings indicate that including behavioural information in resource selection models is critical to understanding wildlife responses to landscape features and suggest that successful application of resource selection analyses to conservation planning requires explicit examination of the behavioural contexts in which movement occurs. Thus, behaviour‐specific step selection functions offer a powerful tool for identifying resource selection patterns for animal behaviours of conservation significance

    Transmission routes of African swine fever virus to domestic pigs: current knowledge and future research directions

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    African swine fever (ASF) is a major threat to the pig industry in Europe. Since 2007, ASF outbreaks have been ongoing in the Caucasus, Eastern Europe and the Baltic countries, causing severe economic losses for many pig farmers and pork producers. In addition, the number of ASF cases in wild boar populations has dramatically increased over the past few years. Evidence supports direct contact with infectious domestic pigs and wild boars, and consumption of contaminated feed, as the main transmission routes of ASF virus (ASFV) to domestic pigs. However, significant knowledge gaps highlight the urgent need for research to investigate the dynamics of indirect transmission via the environment, the minimal infective doses for contaminated feed ingestion, the probability of effective contacts between infectious wild boars and domestic pigs, the potential for recovered animals to become carriers and a reservoir for transmission, the potential virus persistence within wild boar populations and the influence of human behaviour for the spread of ASFV. This will provide an improved scientific basis to optimise current interventions and develop new tools and strategies to reduce the risk of ASFV transmission to domestic pigs.ISSN:0042-490

    Computer-assisted mammographic imaging

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    Computer-assisted mammography imaging comprises computer-based analysis of digitized images resulting in prompts aiding mammographic interpretation and computerized stereotactic localization devices which improve location accuracy. The commercial prompting systems available are designed to draw attention to mammographic abnormalities detected by algorithms based on symptomatic practise in North America. High sensitivity rates are important commercially but result in increased false prompt rates, which are known to distract radiologists. A national shortage of breast radiologists in the UK necessitates evaluation of such systems in a population breast screening programme to determine effectiveness in increasing cancer detection and feasibility of implementation

    Partial differential equation techniques for analysing animal movement: a comparison of different methods

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    Recent advances in animal tracking have allowed us to uncover the drivers of movement in unprecedented detail. This has enabled modellers to construct ever more realistic models of animal movement, which aid in uncovering detailed patterns of space use in animal populations. Partial differential equations (PDEs) provide a popular tool for mathematically analysing such models. However, their construction often relies on simplifying assumptions which may greatly affect the model outcomes. Here, we analyse the effect of various PDE approximations on the analysis of some simple movement models, including a biased random walk, central-place foraging processes and movement in heterogeneous landscapes. Perhaps the most commonly-used PDE method dates back to a seminal paper of Patlak from 1953. However, our results show that this can be a very poor approximation in even quite simple models. On the other hand, more recent methods, based on transport equation formalisms, can provide more accurate results, as long as the kernel describing the animal's movement is sufficiently smooth. When the movement kernel is not smooth, we show that both the older and newer methods can lead to quantitatively misleading results. Our detailed analysis will aid future researchers in the appropriate choice of PDE approximation for analysing models of animal movement

    Computer aids and human second reading as interventions in screening mammography: Two systematic reviews to compare effects on cancer detection and recall rate

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    Background: There are two competing methods for improving the accuracy of a radiologist interpreting screening mammograms: computer aids (CAD) or independent second reading. Methods: Bibliographic databases were searched for clinical trials. Meta-analyses estimated impacts of CAD and double reading on odds ratios for cancer detection and recall rates. Sub-group analyses considered double reading with arbitration. Results: Ten studies compared single reading with CAD to single reading. Seventeen compared double to single reading. Double reading increases cancer detection and recall rates. Double reading with arbitration increases detection rate (CI: 1.02-1.15) and decreases recall rate (CI: 0.92-0.96). CAD does not have a significant effect on cancer detection rate (CI: 0.96-1.13) and increases recall rate (95% CI: 1.09-1.12). However, there is considerable heterogeneity in the impact on recall rate in both sets of studies. Conclusion: The evidence that double reading with arbitration enhances screening is stronger than that for single reading with CAD

    Monitoring status and trends in genetic diversity for the Convention on Biological Diversity: An ongoing assessment of genetic indicators in nine countries

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    Recent scientific evidence shows that genetic diversity must be maintained, managed, and monitored to protect biodiversity and nature's contributions to people. Three genetic diversity indicators, two of which do not require DNA-based assessment, have been proposed for reporting to the Convention on Biological Diversity and other conservation and policy initiatives. These indicators allow an approximation of the status and trends of genetic diversity to inform policy, using existing demographic and geographic information. Application of these indicators has been initiated and here we describe ongoing efforts in calculating these indicators with examples. We specifically describe a project underway to apply these indicators in nine countries, provide example calculations, address concerns of policy makers and implementation challenges, and describe a roadmap for further development and deployment, incorporating feedback from the broader community. We also present guidance documents and data collection tools for calculating indicators. We demonstrate that Parties can successfully and cost-effectively report these genetic diversity indicators with existing biodiversity observation data, and, in doing so, better conserve the Earth's biodiversity
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