Sökning: "trophic cascades"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden trophic cascades.

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

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

    Sammanfattning : 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). LÄS MER

  3. 2. The spatial and temporal dynamics of plant-animal interactions in the forest herb Actaea spicata

    Författare :Hugo von Zeipel; Johan Ehrlén; Ove Eriksson; Saskya van Nouhuys; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Eupithecia immundata; parasitoid; rodent; seed predation; dispersal; recruitment; multitrophic; metapopulation; trophic cascades; community complexity; Biology; Biologi; Plant Ecology; växtekologi;

    Sammanfattning : Landscape effects on species performance currently receives much attention. Habitat loss and fragmentation are considered major threats to species diversity. Deciduous forests in southern Sweden are previous wooded pastures that have become species-rich communities appearing as islands in agricultural landscapes, varying in species composition. LÄS MER

  4. 3. Effects of warming on the ecology of algal-dominated phytobenthic communities in the Baltic Sea

    Författare :Filip Svensson; Pauline Snoeijs; Johan Eklöf; Hans Kautsky; Nils Ekelund; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; climate change; warming; photosynthesis; trophic cascades; pigments; community traits; temperature gradient; invasive mussel; marin ekologi; Marine Ecology;

    Sammanfattning : Through climate change, the global average air and surface water temperature has risen 0.85°C during the last 100 years. The Baltic Sea experienced one of the most rapid increase in temperature recorded of marine ecosystems. LÄS MER

  5. 4. Predator-prey interactions in freshwater systems: The importance of chemical communication

    Författare :Kajsa Åbjörnsson; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi; Hydrobiology; trophic cascades; non-lethal effects; benefits; costs; heredity; predator experience; alarmsubstances; dietary cues; amphibian larvae; invertebrates; visibility; fish; behaviour; Predator-prey; chemical cues;

    Sammanfattning : Predator released chemical cues provide a valuable source of information to prey organisms that can be used to alter their behaviour in order to reduce predation risk. In this thesis, I have examined under what circumstances chemical cues may be used by prey, and if prey discriminate between different cues. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER