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Showing result 1 - 5 of 13 swedish dissertations matching the above criteria.

  2. 1. The effects of crayfish on interactions in freshwater benthic communities

    Author : Per Nyström; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; exotic species; trophic cascades; omnivory; crayfish; Trophic interactions; freshwater; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Abstract : This thesis examines how freshwater crayfish affect community interactions in benthic food webs. I have mainly studied the influence of the introduced signal crayfish (Pacifastacus leniusculus) on littoral communities, but also the influence of the native noble crayfish (Astacus astacus). READ MORE

  4. 2. Marine seaweed invasions : Impacts and biotic resistance in native ecosystems

    Author : Josefin Sagerman; Sofia Wikström; Fransisco Arenas; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Plant invasion; exotic species; generalist herbivores; plant-herbivore interactions; enemy-release hypothesis; ecosystem function; marin ekotoxikologi; Marine Ecotoxicology;

    Abstract : Marine seaweeds constitute one of the most productive plant systems known on Earth and a rich fauna including juvenile fish and crustaceans is dependent on the habitats they form. Human influence on marine costal ecosystems has resulted in large scale changes to the abundance and distribution of species, where species introductions constitute an obvious part. READ MORE

  5. 3. Global Changes and European Terrestrial Ecosystems

    Author : Emmanuel Gritti; Institutionen för naturgeografi och ekosystemvetenskap; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; European species; Climatic risk; pedology; cartography; climatology; Fysisk geografi; geomorphology; Physical geography; Vegetation modelling; Pollen analysis; Plant invasion; geomorfologi; marklära; kartografi; klimatologi; Global Changes;

    Abstract : Global environmental changes are topics of important societal concern and current scientific interest. These changes are driven by many different forcing and feedbacks occurring at various time and geographic scales and are largely influencing the various Earth systems. READ MORE

  6. 4. Extinctions in Ecological Communities : direct and indirect effects of perturbation on biodiversity

    Author : Alva Curtsdotter; Bo Ebenman; Peter Münger; Elisa Thébault; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In the dawning of what may become Earth’s 6th mass extinction the topic of this thesis, understanding extinction processes and what determines the magnitude of species loss, has become only too relevant. The number of known extinctions (~850) during the last centuries translates to extinction rates elevated above the background rate, matching those of previous mass extinction events. READ MORE

  7. 5. Collision Induced Fragmentation of Molecules and Molecular Clusters : Knockout Driven Reactions in Fullerenes and PAHs

    Author : Michael Gatchell; Henning Zettergren; Henrik Cederquist; Henning Schmidt; Ulf Saalmann; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; fysik;

    Abstract : This licentiate thesis covers experimental and theoretical studies of the fragmentation and sub- sequent reactions of fullerenes or Polycyclic Aromatic Hydrocarbons (PAHs). I present results from experiments where atoms or ions collide with fullerenes, PAHs, or clusters of these mole- cules at energies from 100 eV up to tens of keV. READ MORE