Sökning: "kräftor"

Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet kräftor.

  1. 1. The different roles of crayfish in benthic food webs

    Författare :Patrik Stenroth; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Marinbiologi; limnologi; aquatic ecology; marine biology; food chain length; stable isotopes; environmental gradients; diet; crayfish; akvatisk ekologi; limnology; Hydrobiology;

    Sammanfattning : I show that crayfish consume detritus, algae, macrophytes, and an array of invertebrates. Crayfish were found to reduce invertebrate densities. However, prey mobility seemed to be a key factor regulating the strength of interactions between crayfish and prey. LÄS MER

  3. 2. Dynamics of omnivorous crayfish in freshwater ecosystems

    Författare :Karin Olsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; crayfish; freshwater ecosystems; niche width; growth rate; stable isotope analysis; recruitment; RNA:DNA analysis; Ecology; food availability and quality; trophic position; population dynamics;

    Sammanfattning : In this thesis I examine the dynamics of crayfish in streams and lakes. I have studied the influence of abiotic and biotic factors on abundance, growth, trophic position, niche breadth, and recruitment of crayfish, by conducting field studies, an outdoor channel experiment and timeseries analysis. LÄS MER

  4. 3. Persistent organic pollutants in benthic foodwebs

    Författare :Niklas Holmqvist; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; limnologi; Marinbiologi; limnology; aquatic ecology; marine biology; Hydrobiology; Ekologi; Ecology; Intraspecific interactions; streams; nutrients; lakes; crayfish; eels; Persistent organic pollutants; Benthic foodwebs; akvatisk ekologi; Environmental chemistry; Miljökemi;

    Sammanfattning : Concentrations of persistent organic pollutants (POPs) in aquatic biota are dependent on several factors both on individual and on system level. Bioaccumulation of POPs in pelagic biota in lakes as well as fish in streams has been shown to be dependent on nutrient regime of the system. LÄS MER

  5. 4. Species interactions in streams - effects of predation, competition and ecosystem properties

    Författare :Erika Nilsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; behaviour; species abundance; stable isotopes; habitat complexity; niche width; niche overlap; competition; streams; predation;

    Sammanfattning : Stream ecosystems are dynamic and they have an inherent environmental variability. Organisms that live in streams are adapted to the continuously changing environment and the presence or absence of species are determined by their environmental requirements, while abundance is most often affected by interactions, such as competition and predation, with other species that are found in the same habitat. LÄS MER

  7. 5. Noble Crayfish (Astacus astacus) in a Changing World : Implications for Management

    Författare :Jenny K. M. Zimmerman; Thomas Palo; Nils Ekelund; Jostein Skurdal; Mittuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Noble crayfish Astacus astacus ; CPUE; climate change; water regulation; body growth; reintroduction; sustainable fishing; monitoring.;

    Sammanfattning : The noble crayfish (Astacus astacus) is critically endangered in Sweden. This is mainly due to the crayfish plague (Aphanomyces astaci), a lethal disease that, among other things, can be spread through the stocking of fish from contaminated water or contaminated fishing gear. LÄS MER