Sökning: "Large herbivores"

Visar resultat 16 - 20 av 46 avhandlingar innehållade orden Large herbivores.

  1. 16. 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

  3. 17. Marine Seaweed Invasions : the Ecology of Introduced Fucus evanescens

    Författare :Sofia A. Wikström; Lena Kautsky; Ove Eriksson; Paul Lavery; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; biological invasions; marine; seaweed; algae; herbivory; enemy release hypothesis; phlorotannins; anti-fouling; Fucus evanescens; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Biological invasions are an important issue of global change and an increased understanding of invasion processes is of crucial importance for both conservation managers and international trade. In this thesis, I have studied the invasion of the brown seaweed Fucus evanescens, to investigate the fate and effect of a perennial, habitat-forming seaweed introduced to a coastal ecosystem. LÄS MER

  4. 18. Influence of herbivore-induced changes in host plants on reproductive behaviours in Spodoptera littoralis : herbivore-plant interactions

    Författare :Ali Zakir; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Insect herbivores orient towards host plants using sensory cues and olfaction plays a major role, especially in nocturnal herbivores, during selection of host plants suitable for feeding, mating and oviposition. Plants defend themselves from herbivore feeding by producing volatiles as well as non-volatiles chemical compounds. LÄS MER

  5. 19. Seaweed Invasions and Novel Chemical Defences

    Författare :Swantje Enge; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Biological invasions; enemy release; increased competitive ability; novel weapon; chemical defence; plant-herbivore interactions; competition; seaweeds; Bonnemaisonia hamifera;

    Sammanfattning : Biological invasions pose a risk to the biodiversity and the functioning of ecosystems in invaded areas. The reasons why some introduced species become dominant and widespread in their new environments is still largely an unsettled question. LÄS MER

  7. 20. Indirect effects of moose on the birds and the bees

    Författare :Karen Marie Mathisen; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Large herbivores are important drivers of ecosystem processes, affecting plant species richness and composition, primary productivity, habitat structure as well as nutrient cycling. Large herbivore activities may therefore have important indirect effects on other plants and animals in the same ecosystem. LÄS MER