Sökning: "Vertebrate"

Visar resultat 21 - 25 av 199 avhandlingar innehållade ordet Vertebrate.

  1. 21. Herbivory and plant community structure in a subarctic altitudinal gradient

    Författare :Jon Moen; Nancy Huntly; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; arctic and alpine vegetation; competition; exclosures; lemmings; plant defences; plant-plant interactions; Ranunculus glacialis; snow-bed; structuring factors; tall herb meadow; vertebrate grazing; voles;

    Sammanfattning : The object of this thesis was to study plant community structure, especially in relation to vertebrate herbivory, in an altitudinal gradient in the Fennoscandian mountain chain.A sowing experiment in a high alpine Ranunculus glacialis population showed that seeds germinated better in cleared microsites than under established individuals. LÄS MER

  3. 22. Top-down and bottom-up effects in a Fennoscandian tundra community

    Författare :Doris Grellmann; Lars Ericson; Lauri Oksanen; Richard Inouye; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; consumer-resource interactions; exclosures; food web dynamics; grey-sided voles; lemmings; NPK-fertilization; plant defences; reindeer; soil microbes; vertebrate grazing;

    Sammanfattning : The objective of this thesis was to investigate the effects of mammalian grazers, such as microtine rodents and reindeer, (top-down effects) and nutrient availability (bottom- up effects) on the plant community of a tundra heath.I conducted a large-scale fertilization experiment and studied the impact of grazers using exclosures. LÄS MER

  4. 23. Costs in the ecology and evolution of the vertebrate immune system

    Författare :Lars Råberg; MEMEG; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cost of resistance; ecological immunology; immunocompetence; Parus caeruleus; transgenic mice; Animal ecology; Djurekologi; blue tit; basal metabolic rate;

    Sammanfattning : A central assumption of theories of the ecology and evolution of immunological defence is that defence has not only benefits (in the form of resistance against parasites), but also costs. The aim of my studies was to investigate the nature and magnitude of costs of the vertebrate immune system, and to examine some of the consequences of these costs. LÄS MER

  5. 24. Vertebrate remains from the Upper Silurian-Lower Devonian of North Greenland

    Författare :Henning Blom; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Utvecklingsbiologi;

    Sammanfattning : .... LÄS MER

  7. 25. Two conformationally distinct regions in the large subunits of vertebrate ribosomes

    Författare :Arne Sjöqvist; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER