33 research outputs found

    The diet of red-throated divers (Gavia stellata) overwintering in the German Bight (North Sea) analysed using molecular diagnostics

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    In Europe, the German Bight is one of the most important non-breeding areas for protected red-throated divers (Gavia stellata). It is unclear what attracts the birds to this area, especially as the food composition of seabirds outside the breeding season is notoriously difficult to study. To obtain information on prey species composition of red-throated divers in this area, faecal samples from 34 birds caught alive were analysed using DNA metabarcoding. Prey DNA was detected in 85% of the samples with a mean number of 4.2 ± 0.7 taxa per sample (n = 29). Altogether, we found a broad prey spectrum with 19 fish taxa from 13 families dominated by five groups: clupeids, mackerel, gadoids, flatfish and sand lances with clupeids being the most frequently detected prey. Our results indicate that red-throated divers are generalist opportunistic feeders in the German Bight, but pelagic schooling fish that aggregate at frontal zones and have a high energetic value might be favoured. Atlantic mackerel appears to be a more important prey for red-throated divers in this area than previously thought. The precision achievable using metabarcoding has revealed a number of prey species that are consumed by red-throated divers in the German Bight, which helps to explain the selection of this area by divers in winter and spring

    Co‐developing guidance for conservation: An example for seabirds in the North‐East Atlantic in the face of climate change impacts

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    Conservation guidance—an authoritative source of information and recommendations explicitly supporting decision-making and action regarding nature conservation—represents an important tool to communicate evidence-based advice to conservation actors. Given the rapidly increasing pressure that climate change poses to biodiversity, producing accessible, well-informed guidance on how to best manage the impacts and risks of changing climatic conditions is particularly urgent. Guidance documents should ideally be produced with multistage input from stakeholders who are likely to use and implement such advice; however, this step can be complicated and costly, and remains largely unformalized. Moreover, there is currently little direct evidence synthesized for actions that specifically target climate change and guidance remains largely absent. Here, we introduce a process for co-developing guidance for species conservation in the face of climate change, using seabirds in the North-East Atlantic as a case study. Specifically, we collated evidence on climate change vulnerability and possible conservation actions using literature synthesis, stakeholder surveys, and ecological modeling. This evidence base was then discussed, refined, and expanded using structured stakeholder workshops. We summarize the knowledge gained through stakeholder engagement and provide recommendations for future international efforts to co-produce conservation guidance for managing wildlife, in the context of a rapidly changing climate.info:eu-repo/semantics/publishedVersio

    A time-resolved proteomic and prognostic map of COVID-19

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    COVID-19 is highly variable in its clinical presentation, ranging from asymptomatic infection to severe organ damage and death. We characterized the time-dependent progression of the disease in 139 COVID-19 inpatients by measuring 86 accredited diagnostic parameters, such as blood cell counts and enzyme activities, as well as untargeted plasma proteomes at 687 sampling points. We report an initial spike in a systemic inflammatory response, which is gradually alleviated and followed by a protein signature indicative of tissue repair, metabolic reconstitution, and immunomodulation. We identify prognostic marker signatures for devising risk-adapted treatment strategies and use machine learning to classify therapeutic needs. We show that the machine learning models based on the proteome are transferable to an independent cohort. Our study presents a map linking routinely used clinical diagnostic parameters to plasma proteomes and their dynamics in an infectious disease

    Co-developing guidance for conservation: an example for seabirds in the North-East Atlantic in the face of climate change impacts

    Get PDF
    Conservation guidance—an authoritative source of information and recommendations explicitly supporting decision-making and action regarding nature conservation—represents an important tool to communicate evidence-based advice to conservation actors. Given the rapidly increasing pressure that climate change poses to biodiversity, producing accessible, well-informed guidance on how to best manage the impacts and risks of changing climatic conditions is particularly urgent. Guidance documents should ideally be produced with multistage input from stakeholders who are likely to use and implement such advice; however, this step can be complicated and costly, and remains largely unformalized. Moreover, there is currently little direct evidence synthesized for actions that specifically target climate change and guidance remains largely absent. Here, we introduce a process for co-developing guidance for species conservation in the face of climate change, using seabirds in the North-East Atlantic as a case study. Specifically, we collated evidence on climate change vulnerability and possible conservation actions using literature synthesis, stakeholder surveys, and ecological modeling. This evidence base was then discussed, refined, and expanded using structured stakeholder workshops. We summarize the knowledge gained through stakeholder engagement and provide recommendations for future international efforts to co-produce conservation guidance for managing wildlife, in the context of a rapidly changing climate

    Anthropogenic pressure in a marine world: Distribution, movement, diet and parasite infestation of red-throated divers Gavia stellata in the context of habitat change

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    Information on the behaviour and ecology of seabirds provides an important basis for better understanding the effects of changes in their habitats and developing conservation strategies accordingly. The red-throated diver Gavia stellata breeds in Arctic regions and is found in coastal marine offshore areas outside the breeding season. German waters contain some important non-breeding areas for this species, with internationally relevant populations such as in the German Bight. Nevertheless, these areas are also characterized by high anthropogenic use, leading to strong responses in this species with avoidance distances of over 10 km and significant changes in distribution patterns. If these responses have long-term effects at the population level is still unclear due to the lack of basic studies on behavioural-ecological aspects. Therefore, this dissertation, aimed at filling the knowledge gapes related to dietary, migratory, and disease ecology. The cumulative dissertation presented here is structured into three chapters, each of which addresses a behavioural-ecological topic presented in chapters 1, 2, and 3, respectively. Specifically, the diet of red-throated divers in the German Bight was analysed using DNA-metabarcoding on sample sets from two consecutive years (Chapter 1). The results showed an opportunistic piscivorous prey spectrum which, however, included a high proportion of energetic rich species in both years, with clupeids as the most frequented prey items. These findings confirm other studies from e.g. the Baltic Sea. The continuous presence of high-energy prey fish in the diet helps to explain the importance of the German Bight due to the high availability of those fish species. Migratory behaviour and site use throughout the year, was studied using satellite telemetry and analysis of isotopic values from feather samples (Chapter 2). Breeding, moulting, and wintering sites were successfully determined of individuals inhabiting the German Bight. Migratory behaviour was characterized by regular staging stops, probably to refuel energy reserves. Individuals breeding in northern Russia showed low migratory connectivity, indicated by variable site use among individuals. However, between two consecutive years, individual movement patterns showed high repeatability. Furthermore, a correlation between migratory phenology and the location of the breeding area was revealed. A potential stressor, which has not yet been investigated in red-throated divers, could be the infestation of blood parasites or haemosporidia (Plasmodium, Haemoproteus, Leucocytozoon), which can have a negative impact on health (chapter 3). Haemosporidia were detected in red-throated divers using molecular tools, with low prevalence and identification of one new lineage each of Leucocytozoon and Plasmodium. The low prevalence indicates a rather insignificant impairment. In summary, the results of the behavioural ecological aspects reported in this dissertation fill previously existing knowledge gaps about a seabird species sensitive to disturbance. The integrative approach of dietary, migratory and disease ecology illustrates that for migratory species, impairments that occur during the annual cycle should be considered cumulatively rather than in isolation. Along their migration route red-throated divers, as well as other migratory species use various staging and stop-over sites and thus are vulnerable to experience a number of impacts, such as gill net fisheries, pollution or ship traffic, that individually, may still be compensable, but collectively might lead to population-level impacts

    Adopting Bacteria in Order to Adapt to Water—How Reed Beetles Colonized the Wetlands (Coleoptera, Chrysomelidae, Donaciinae)

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    The present paper reviews the biology of reed beetles (Donaciinae), presents experimental data on the role of specific symbiotic bacteria, and describes a molecular method for the detection of those bacteria. Reed beetles are herbivores living on wetland plants, each species being mono- or oligo-phagous. They lay their eggs on the host plant and the larvae live underwater in the sediment attached to its roots. The larvae pupate there in a water-tight cocoon, which they build using a secretion that is produced by symbiotic bacteria. The bacteria are located in four blind sacs at the foregut of the larvae; in (female) adults they colonize two out of the six Malpighian tubules. Tetracycline treatment of larvae reduced their pupation rate, although the bacteria could not be fully eliminated. When the small amount of bacterial mass attached to eggs was experimentally removed before hatching, symbiont free larvae resulted, showing the external transmission of the bacteria to the offspring. Specific primers were designed to detect the bacteria, and to confirm their absence in manipulated larvae. The pupation underwater enabled the reed beetles to permanently colonize the wetlands and to diversify in this habitat underexploited by herbivorous insects (adaptive radiation)

    Prevalence of Haemosporidian Parasites in an Arctic Breeding Seabird Species—The Red-Throated Diver (Gavia stellata)

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    Haemosporida, vector-transmitted blood parasites, can have various effects and may also exert selection pressures on their hosts. In this study we analyse the presence of Haemosporida in a previously unstudied migratory seabird species, the red-throated diver Gavia stellata. Red-throated divers were sampled during winter and spring in the eastern German Bight (North Sea). We used molecular methods and data from a related tracking study to reveal (i) if red-throated divers are infected with Haemosporida of the genera Leucocytozoon, Plasmodium and Haemoproteus, and (ii) how infection and prevalence are linked with the breeding regions of infected individuals. Divers in this study were assigned to western Palearctic breeding grounds, namely Greenland, Svalbard, Norway and Arctic Russia. We found a prevalence of Leucocytozoon of 11.0% in all birds sampled (n = 45), of 33.0% in birds breeding in Norway (n = 3) and of 8.3% in birds breeding in Arctic Russia (n = 25). For two birds that were infected no breeding regions could be assigned. We identified two previously unknown lineages, one each of Plasmodium and Leucocytozoon. Haemosporida have not been detected in birds from Greenland (n = 2) and Svalbard (n = 2). In summary, this study presents the first record of Haemosporida in red-throated divers and reports a new lineage of each, Plasmodium and Leucocytozoon GAVSTE01 and GAVSTE02, respectively
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