Search for dissertations about: "invertebrate grazing"

Showing result 1 - 5 of 6 swedish dissertations containing the words invertebrate grazing.

  2. 1. Population biology of the clonal plant Ranunculus lingua

    Author : Mats E. Johansson; Christer Nilsson; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clonal fragmentation; emergent macrophytes; fungal pathogens; hydrochoiy; invertebrate grazing; marginal population; Peronospora gigantea Prasocuris phellandrt regional abundance; rhizome production; size-number trade-off; vegetative reproduction; water-level fluctuation;

    Abstract : The scope of this thesis was to identify, describe and quantify important life-history traits for the pseudoannual aquatic plant Ranunculus lingua in different ecological settings, by comparing populations from geographically marginal vs. central habitats. READ MORE

  4. 2. Top-down and bottom-up effects in a Fennoscandian tundra community

    Author : Doris Grellmann; Lars Ericson; Lauri Oksanen; Richard Inouye; Umeå universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 3. Nutrient Stoichiometry in Benthic Food Webs – Interactions Between Algae, Herbivores and Fish

    Author : Antonia Liess; Peter Eklöv; Dag Hessen; Uppsala universitet; []
    Keywords : Ecology; ecologial stoichiometry; periphyton; grazer; benthos; trophic interactions; nutrient; algae; Ekologi;

    Abstract : The aim of this thesis was to identify general structuring mechanisms in benthic food webs within the framework of ecological stoichiometry theory. Ecological stoichiometry is defined as the balance of multiple chemical substances in ecological interactions and explicitly considers the combined dynamics of key elements such as carbon (C), nitrogen (N) and phosphorus (P). READ MORE

  6. 4. Interactions between gray-sided voles (Clethrionomys rufocanus) and vegetation in the Fennoscandian tundra

    Author : Jonas Dahlgren; Lauri Oksanen; Johan Olofsson; John Terborgh; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; gray-sided voles; tundra vegetation; trophic cascades; plant-herbivore interactions; bilberry; plant communities; herbivory; plant resistance; Terrestrial ecology; Terrestisk ekologi;

    Abstract : I have, in this thesis, studied the interactions between gray-sided voles (Clethrionomys rufocanus) and tundra vegetation, on islands in, and mainland sites close to the lake Iešjávri, in northern Norway. As isolated islands are virtually free of predation, I have been able to compare plant-herbivore interactions in the presence and absence of predators. READ MORE

  7. 5. Drivers and food web effects of Gonyostomum semen blooms

    Author : Karin Johansson; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : The flagellate Gonyostomum semen forms dense late-summer blooms in humic lakes and is a nuisance to swimmers because it forms a slimy coat on the skin, causing irritation in sensitive individuals. Increasing occurrence and bloom incidence of G. READ MORE